Pneumococcal vaccines formulated with interleukin-12

Abstract

This invention pertains to vaccine compositions comprising a mixture of antigen, such as a pneumococcal or meningococcal antigen, and interleukin IL-12, which may be adsorbed onto a mineral in suspension. The pneumococcal or meningococcal antigen may be conjugated to a carrier molecule. These vaccine compositions modulate the protective immune response to the antigen.

Description

BACKGROUND OF THE INVENTION

The immune system uses many mechanisms for attacking pathogens; however, not all of these mechanisms are necessarily activated after immunization. Protective immunity induced by vaccination is dependent on the capacity of the vaccine to elicit the appropriate immune response to resist or eliminate the pathogen. Depending on the pathogen, this may require a cell-mediated and/or humoral immune response.

The current paradigm for the role of helper T cells in the immune response is that they can be separated into subsets on the basis of the cytokines they produce, and that the distinct cytokine profile observed in these cells determines their function. This T cell model includes two major subsets: TH-1 cells that produce IL-2 and interferon γ(IFN-γ) which augment both cellular and humoral immune responses, and TH-2 cells that produce IL-4, IL-5 and IL-10 which augment humoral immune responses (Mosmann et al., J. Immunol . 126:2348 (1986)). It is often desirable to enhance the immunogenic potency of an antigen in order to obtain a stronger immune response in the organism being immunized and co strengthen host resistance to the antigen-bearing agent. A substance that enhances the immunogenicity of an antigen with which it is administered is known as an adjuvant. For example, certain lymphokines have been shown to have adjuvant activity, thereby enhancing the immune response to an antigen (Nencioni et al., J. Immunol . 139:800-804 (1987); EP285441 to Howard et al.).

SUMMARY OF THE INVENTION

This invention pertains to vaccine compositions comprising a mixture of one or more pneumococcal or meningococcal antigens, the interleukin IL-12 and a mineral in suspension. The IL-12 can be either adsorbed onto the mineral suspension or simply mixed therewith. In a particular embodiment of the invention, the IL-12 is adsorbed onto a mineral suspension such as alum (e.g., aluminum hydroxide or aluminum phosphate). These vaccine compositions modulate the protective immune response to the antigen; that is, the vaccine composition is capable of quantitatively and qualitatively improving the vaccinated host's antibody response, and quantitatively increasing cell-mediated immunity for a protective response to a pathogen. In a particular embodiment of the invention, the antigen is a pneumococcal or meningococcal antigen; the antigens are optionally conjugated to a carrier molecule, such as in a pneumococcal or meningococcal glycoconjugate.

Studies described herein show that IL-12 can modify the humoral response of mice immunized with pneumococcal and meningococcal glycoconjugate vaccines formulated with aluminum phosphate (AlPO 4 ) The particular pneumococcal polysaccharide serotypes exemplified herein are serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F, and 23F, (Pn1, Pn4, Pn5, Pn6B, Pn9V, Pn14, Pn18C, Pn19F, Pn23F), and the meningococcal polysaccharide is type C (Men C). These serotypes, however, are not to be construed to limit the scope of the invention, as other pneumococcal and meningococcal serotypes are also suitable for use herein. Moreover, it will be apparent to the skilled artisan that conjugation to a carrier molecule, such as the CRM 197 protein exemplified herein, is optional, depending upon the immunogenicity of the selected pneumococcal or meningococcal antigen.

Doses of IL-12 ranging from about 8 ng to about 1,000 ng increased the IgG1, IgG2a, IgG2b and IgG3 response to alum-adsorbed Pn14 or Pn6B. In addition they increased the IgG2a response to Pn4 and Pn9V. Doses of IL-12 of about 5,000 ng markedly reduced the overall IgG titers to Pn14, and especially the IgG1 and IgG2b titers.

The invention also pertains to methods for preparing an immunogenic composition or a vaccine composition comprising a mixture of antigen and IL-12 with a mineral in suspension. In particular, the IL-12 is adsorbed onto the mineral suspension. The invention also pertains to methods for eliciting or increasing a vaccinee's IFN-γ-producing T cells and complement-fixing IgG antibodies for a protective immune response, comprising administering to a mammalian, e.g., human or primate, host an effective amount of a vaccine composition comprising a mixture of antigen, IL-12 and a mineral in suspension in a physiologically acceptable solution. In particular, the IL-12 is adsorbed onto the mineral suspension.

DETAILED DESCRIPTION OF THE INVENTION

Work described herein reveals the ability of IL-12 to increase the immune response to alum-based pneumococcal vaccines, particularly serotype 14 and serotype 6B pneumococcal glycoconjugate vaccines, and meningococcal vaccines, particularly type C, to increase the proportion of complement-fixing IgG2a and IgG2b antibodies. As described herein, PnPs-14-CRM 197 vaccine comprises a serotype 14 pneumococcal polysaccharide conjugated to a non-toxic mutant of diphtheria toxoid (cross-reacting material) designated CRM 197 , and PnPs6B-CRM 197 vaccine comprises a serotype 6B pneumococcal polysaccharide conjugated to CRM 197 . IL-12 was compared to MPL® (3-O-deacylated monophosphoryl lipid A; RIBI ImmunoChem Research, Inc., Hamitton, Mont.), which in mice is a potent adjuvant for pneumococcal vaccines. In a separate experiment conducted in Balb/c mice, the effect of IL-12 on the cytokine profile of the CRM-specific T cells induced by the exemplary conjugate vaccines on alum was examined.

IL-12 is produced by a variety of antigen-presenting cells, principally macrophaqes and monocytes. It is a critical element in the induction of TH-1 cells from naive T cells. Production of IL-12 or the ability to respond to it has been shown to be critical in the development of protective TH-1-like responses, for example, during parasitic infections, most notably Leishmaniasis (Scott et al., U.S. Pat. No. 5,571,55). The effects of IL-12 are mediated by IFN-γ produced by NK cells and T helper cells. Interleukin-12 (IL-12), originally called natural killer cell stimulatory factor, is a heterodimeric cytokine (Kobayashi et al., J. Exp. Med . 170:827 (1989)). The expression and isolation of IL-12 protein in recombinant host cells is described in International Patent Application WO 90/05147, published May 17, 1990.

The studies described herein reveal the utility of IL-12 as an adjuvant in a pneumococcal or meningococcal vaccine, and particularly a pneumococcal or meningococcal glycoconjugate vaccine. Accordingly, this invention pertains to vaccine compositions comprising a mixture of such an antigen, IL-12 and a mineral in suspension. In a particular embodiment of the invention, the IL-12 is adsorbed onto a mineral suspension such as alum (e.g., aluminum hydroxide or aluminum phosphate). These vaccine compositions modulate the protective immune response to the antigen; that is, the vaccine composition is capable of eliciting the vaccinated host's complement-fixing antibodies for a protective response to the pathogen. In a particular embodiment of the invention, the antigen is a pneumococcal antigen, particularly a pneumococcal polysaccharide; the pneumococcal antigen is optionally conjugated to a carrier molecule, such as in a pneumococcal glycoconjugate. The particular pneumococcal polysaccharide serotypes exemplified herein are serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F, and 23F; however, these serotypes are not to be construed to limit the scope of the invention, as other serotypes are also suitable for use herein.

In another embodiment of the invention, the antigen is a meningococcal antigen, particularly a meningococcal polysaccharide; the meningococcal antigen is optionally conjugated to a carrier molecule, such as in a meningococcal glycoconjugate. Type C Neisseria meningitidis is exemplified herein; however, this type is not to be construed to limit the scope of the invention, as other types are also suitable for use herein.

IL-12 can be obtained from several suitable sources. It can be produced by recombinant DNA methodology; for example, the gene encoding human IL-12 has been cloned and expressed in host systems, permitting the production of large quantities of pure human IL-12. Also useful in the present invention are biologically active subunits or fragments of IL-12. Commercial sources of recombinant human and murine IL-12 include Genetics Institute, Inc. (Cambridge, Mass.).

The antigen of this invention, e.g., a pneumococcal or meningococcal antigen or a pneumococcal or meningococcal glycoconjugate, can be used to elicit an immune response to an antigen in a mammalian host. For example, the antigen can be a serotype 14 or 6B pneumococcal polysaccharide or a portion thereof which retains the ability to stimulate an immune response. Additional suitable antigens include polysaccharides from other encapsulated bacteria and conjugates thereof, secreted toxins and outer membrane proteins.

The method comprises administering to the mammal, e.g., human or primate, an immunologically effective dose of a vaccine composition comprising a mixture of an antigen, such as a pneumococcal antigen or a pneumococcal conjugate, and an adjuvant amount of IL-12 adsorbed onto a mineral in suspension.

As used herein, an “immunologically effective” dose of the vaccine composition is a dose which is suitable to elicit an immune response. The particular dosage of IL-12 and the antigen will depend upon the age, weight and medical condition of the mammal to be treated, as well as on the method of administration. Suitable doses will be readily determined by the skilled artisan. The vaccine composition can be optionally administered in a pharmaceutically or physiologically acceptable vehicle, such as physiological saline or ethanol polyols such as glycerol or propylene glycol.

The vaccine composition may optionally comprise additional adjuvants such as vegetable oils or emulsions thereof, surface active substances, e.g., hexadecylamin, octadecyl amino acid esters, octadecylamine, lysolecithin, dimethyl-dioctadecylammonium bromide, N,N-dicoctadecyl-N′-N′bis (2-hydroxyethyl-propane diamine), methoxyhexadecylglycerol, and pluronic polyols; polyamines, e.g., pyran, dextransulfate, poly IC, carbopol; peptides, e.g., muramyl dipeptide, dimethylglycine, tuftsin; immune stimulating complexes; oil emulsions; liposaccharides such as MPL® and mineral gels. The antigens of this invention can also be incorporated into liposomes, cochleates, biodegradable polymers such as poly-lactide, poly-glycolide and poly-lactide-co-glycolides, or ISCOMS (immunostimulating complexes), and supplementary active ingredients may also be employed. The antigens of the present invention can also be administered in combination with bacterial toxins and their attenuated derivatives. The antigens of the present invention can also be administered in combination with other lymphokines, including, but not limited to, IL-2, IL-3, IL-15, IFN-γ and GM-CSF.

The vaccines can be administered to a human or animal by a variety of routes, including but not limited to parenteral, intradermal, transdermal (such as by the use of slow release polymers), intramuscular, intraperitoneal, intravenous, subcutaneous, oral and intranasal routes of administration. The amount of antigen employed in such vaccines will vary depending upon the identity of the antigen. Adjustment and manipulation of established dosage ranges used with traditional carrier antigens for adaptation to the present vaccine is well within the ability of those skilled in the art. The vaccines of the present invention are intended for use in the treatment of both immature and adult warm-blooded animals, and, in particular, humans. Typically, the IL-12 and the antigen will be co-administered; however, in some instances the skilled artisan will appreciate that the IL-12 can be administered close in time cut prior to or after vaccination with the antigen.

The pneumococcal and meningococcal antigens of the present invention can be coupled to a carrier molecule in order to modulate or enhance the immune response. Suitable carrier proteins include bacterial toxins rendered safe by chemical or generic means for administration to mammals and immunologically effective as carriers. Examples include pertussis, diphtheria, and tetanus toxoids and non-toxic mutant proteins (cross-reacting materials (CRM)), such as the non-toxic variant of diphtheria toxoid, CRM 197 . Fragments of the native toxins or toxoids, which contain at least one T-cell epitope, are also useful as carriers for antigens, as are outer membrane protein complexes. Methods for preparing conjugates of pneumococcal antigens and carrier molecules are well known in the art and can be found, for example, in Dick and Burret, Contrib Microbiol Immunol . 10:48-114 (Cruse J M, Lewis R E Jr, eds; Basel, Krager (1989)) and U.S. Pat. No. 5,360,897 (Anderson et al.).

The adjuvant action of IL-12 has a number of important implications. The adjuvanticity of IL-12 can increase the concentration of protective functional antibodies produced against the antigen in the vaccinated organism. The use of IL-12 as an adjuvant can enhance the ability of antigens which are weakly antigenic or poorly immunogenic to elicit an immune response. It may also provide for safer vaccination when the antigen is toxic at the concentration normally required for effective immunization. By reducing the amount of antigen, the risk of toxic reaction is reduced.

Typically, vaccination regimens call for the administration of antigen over a period of weeks or months in order to stimulate a “protective” immune response. A protective immune response is an immune response sufficient to protect the immunized organism from productive infection by a particular pathogen or pathogens to which the vaccine is directed.

As shown in the Examples, in an alum-formulated vaccine, comprising IL-12 adsorbed onto AlPO 4 and a serotype 14 or serotype 6B pneumococcal polysaccharide conjugated to CRM 197 , which normally induces a response dominated by IgG1, 0.2 μg of IL-12 substantially increased the IgG2a and IgG3 subclasses in both Balb/c and Swiss Webster mice, but had little or no effect on IgG1. Enhancement of IgG2b to Pn14 was seen with Swiss Webster mice; 0.2 μg of IL-12 had the same effect as 25 μg of MPL® on the IgG subclass response to Pn14, suggesting that IL-12 is at least 100-fold more biologically active than MPL® in this regard. As expected from the IgG subclass distribution, especially the enhanced IgG2a response, the opsonophagocytic activity of the antisera for Pn14 pneumococci from mice receiving 0.2 μg IL-12 was higher than that of controls and was equivalent to that of mice immunized with vaccine formulated with a much larger amount of MPL®.

Briefly, IgG2a and IgG2b antibodies are very efficient at activating the complement system, whereas IgG1 antibodies are not. The complement system consists of a series of plasma proteins which come together around IgG2a or IgG2b bound to antigen (e.g., bacteria) to form a large molecular complex. Deposition of this complex on the surface of bacteria results in the killing of the bacteria by perforating the cell membrane (bactericidal activity) or by facilitating the recognition of the bacteria by phagocytic cells (such as polymorphonuclear cells (PMN) used in this study), which take up the bacteria and kill them (opsonophagocytosis).

Increasing the dose of IL-12 profoundly reduced the IgG1 and IgG2b responses. The reduction in these immunoglobulin subclasses was not simply due to a change in the kinetics of the antibody response, as has been observed in the hen egg lysozyme (HEL) system (Buchanan, Van Cleave and Metzger, Abstract #1945; 9 th International Congress of Immunology (1995)), as these subclasses were reduced at all time points tested. The effect on IgG1 was expected given that switching of B cells to this subclass requires IL-4, a TH-2 cytokine whose production is inhibited by IL-12. The reduction in IgG2b, however, was not expected since in previous studies increased levels of IgG2b have correlated with the presence of TH-1-like T cells. It is likely that cytokines other than, or in addition to, IFN-γ are involved in regulation of IgG2b. For example, Germann et al. ( Eur J. Immunol 25:823-829 (1995)) found that treating mice with anti-IFN-γ inhibited the ability of IL-12 to promote IgG2a responses, but not IgG2b. Other studies have implicated TGF-β as an important factor in the induction of IgG2b (reviewed by J. Stavnezer, J. Immunol . 55:1547-1651 (1995)). Without wishing to be bound by theory, it is possible that high doses of IL-12 may affect TGF-β production or responsiveness to it.

IFN-γ is critical for the induction of IgG2a antibodies to T-dependent protein antigens (Finkelman and Holmes, Annu. Rev. Immunol . 8:303-33 (1990)) and IgG3 responses to T-independent antigens (Snapper et al., J. Exp. Med . 175:1367-1371 (1992)). Increased IFN-γ response was consistently found after a single vaccination with vaccine (PnPs-14-CRM 197 ) containing IL-12 and AlPO 4 and after boosting. The effect of IL-12 on the TH-2 cytokines IL-5 and IL-10 appears to depend on when the lymphoid cells are harvested after vaccination, and possibly on the particular cytokine. Exogenous IL-12 completely abolished antigen-specific IL-5 and IL-10 production by lymph node cells (LNC) harvested 1 week after primary vaccination. After secondary vaccination, differences were seen between these two cytokines; IL-5 production by either LNC or splenocytes was completely abolished by 1 μg IL-12 in the vaccine, but IL-10 production was largely unaffected after boosting. It is unclear whether these differences are due to setting up the cultures at different times or reflect the expansion of a TH-2-like population upon subsequent revaccination. The latter possibility is consistent with data from Wolf and colleagues (Bliss et al., J. Immunol 156:887-894 (1996)), indicating that IL-4-producing T cells can be recovered from Balb/c mice previously immunized with vaccine containing IL-12 and boosted with soluble antigen. In their studies, IL-4 was detected even if IL-12 was included in the secondary vaccine. The presence of TH-2 cytokines after boosting may explain why, in Balb/c mice, even high levels of IL-12 could not reduce the secondary IgG1 response to below control levels (conjugate vaccine on alum). Unlike the Balb/c mice, high doses of IL-12 severely inhibited the IgG1 response of Swiss Webster mice. Whether this is associated with decreased production of TH-2 cytokines after the second vaccination is unclear.

In the present studies, IL-12 exhibited either only immunomodulatory activity or behaved both as a “classical” adjuvant, and a immunomodulator, depending on the vaccine. In the study with PnPs14-CRM 197 the IgG response (especially the primary response) to the vaccine was not substantially elevated by the presence of the cytokine but certain subclasses, i.e. IgG2a and IgG3, were elevated whereas the others were unchanged or diminished. Thus, IL-12 is useful for altering the humoral response to an already immunogenic vaccine. It is possible that in these studies the adjuvant activity of IL-12 was masked by the presence of alum, which is an adequate adjuvant on its own for the highly immunogenic PnPs-14 conjugate. The adjuvanticity of IL-12 may be better demonstrated in the absence of alum, by reducing the dose of conjugate or by using a poorly immunogenic conjugate. Thus, further evaluations were carried out using IL-12 in the presence and absence of alum with PnPs6B conjugate vaccines, which are less immunogenic in Swiss Webster mice than PnPs-14 conjugate vaccines.

An additional study was designed to address the issue of IL-12 adjuvant activity for a poorly immunogenic pneumococcal conjugate. The Pn18C conjugate was chosen, as it is poorly immunogenic when formulated with AlPO 4 , i.e., it induces low IgG Liters and not all mice respond to it. When formulated with MPL or QS-21, higher IgG fibers and a greater frequency of responders can be achieved.

One hundred μg MPL® plus AlPO 4 or 20 μg QS-21™ were the best adjuvants in this study for a Pn18C response as they induced the highest frequency of responders to this serotype. Nonetheless, IL-12 had marked effects on the IgG response to the carrier protein, CRM 197 , in mice immunized with this conjugate. Moreover, the effects of the cytokine were modified by the presence of AlPO 4 in the vaccine. IL-12 clearly acted as an adjuvant for vaccines formulated without AlPO 4 , causing a dose-dependent increase in IgG titers after primary and secondary vaccination. IL-12 enhanced the IgG2a response to CRM 197 , which is consistent with its ability to favor the induction of TH-1-like helper cells (IFN-γ producers). However, IL-12 also enhanced the IgG1 response to CRM 197 after primary and secondary vaccination. IgG1 antibodies are normally associated with TH-2-like helper cells whit. produce IL-4.

Inclusion of 0.1 μg IL-12 into an AlPO 4 -based Pn18C conjugate vaccine (which on its own induced a 10-fold higher CRM 197 response) had no effect on IgG1 but substantially increased the IgG2a titer. The IgG2a titer achieved with 0.1 μg IL-12 was at least as high as that obtained with 5 μg IL-12 the absence of AlPO 4 . It should be noted, however, that the presence of AlPO 4 does not preclude the enhancement of IgG1 responses by IL-12. In mice immunized with the Pn14 conjugate on AlPO 4 , a 0.2 μg dose of IL-12 enhanced the IgG1, IgG2a and IgG2b titers to CRM 197 . The differences in the effect on IgG1 may reflect differences in the immunogenicity of the two conjugates for CRM 197 IgG responses; the Pn14 conjugate on AlPO 4 induced 10-fold lower CRM 197 IgG titers so that there was room for IL-12 to enhance an IgG1 response, but not when mice were immunized with Pn18C conjugate on AlPO 4 . The fact that MPL® and QS-21™ markedly increased the IgG1 titers in mice immunized with Pn18C conjugate on AlPO 4 indicates that the IgG1 response had not been maximally stimulated. Alternatively, the nature of the saccharides on the conjugates may be a factor. In both experiments, higher doses of IL-12 resulted in a marked diminution of the IgG1, IgG2a and IgG2b tiers to CRM 197 , an effect that was not seen in the absence of AlPO 4 .

IL-12 probably exerts its adjuvant effect differently than MPL® or QS-21™. IL-12 markedly enhanced the CRM 197 , 9 , IgG2a titers in mice immunized with Pn18C conjugate but had minimal effects on IgG2b. In contrast, MPL® and QS-21™ enhanced the titers of both IgG subclasses. The dissociation of these two subclasses suggests that IgG2b is induced by cytokines other than, or in addition to, the IFN-γ that drives switching to IgG2a and is known to mediate the immunomodulatory effects of IL-12. One candidate for driving IgG2b production is TGFb. The nature of the antigen cannot be excluded, however, since in mice immunized with Pn14 conjugate, 0.2 μg IL-12 caused IgG2a and IgG2b to be elevated to similar levels which were equivalent to the titers promoted by 25 μg MPL®.

Studies utilizing a bivalent vaccine consisting of a PnPs14-CRM 197 conjugate mixed with a conjugate of capsular polysaccharide from serotype 6B pneumococci covalently linked to CRM 197 (PnPs6B-CRM 197 ) confirmed and extended the above-described findings. IL-12 not only modified the IgG response to the Pn6B conjugate, but also enhanced the overall IgG titer to the conjugate. Moreover, this work further demonstrates that the adjuvant activity of relatively low doses of IL-12 is enhanced by formulating it with AlPO 4 . Unlike the above-described studies with PnPs-14-CRM 197 glycoconjugate, IL-12/AlPO 4 enhanced both the IgG1 and IgG2a subclasses to Pn6B, indicating that the apparent lack of enhancement of the Pn14 IgG1 response by IL-12 is probably not a generalizable phenomenon. This work further supports the idea that the mechanisms of adjuvant activity by IL-12 and MPL® are not equivalent. Both adjuvants enhanced the Pn6B IgG1 and IgG2a titers to similar levels, but MPL® was more effective at promoting IgG2b and IgG3 antibodies.

IL-12/AlPO 4 did nor act as an adjuvant for the Pn14 IgG response. The reason for this is not clear; however, without wishing to be bound by theory, this most likely reflects the fact that in previous studies mice were immunized with a 1 μg dose of PnPs-14-CRM 197 glycoconjugate, i.e., 10-fold higher than in the Pn6B studies. The applicability of IL-12 to more complex pneumococcal vaccines was demonstrated using a nonavalent vaccine containing glycoconjugates from serotype 1, 4, 5, 6B, 9V, 14, 18C, 19F and 23F pneumococci. The combination of IL-12 with AlPO 4 enhanced the IgG2a antibodies to PnPs4 and PnPs9V, in addition to PnPs6B and PnPs14, and increased the ability of mice to respond to glycoconjugate prepared with serotype 18C pneumococcal saccharide (PnPs-18C-CRM 197 ) which is poorly immunogenic in mice.

In further examples, IL-12 was tested with a glycoconjugate vaccine against type C Neiserria meningitidis (MenC) and a glycoconjugate vaccine against type B Hemophilus influenzae (HbOC). Formulating that vaccine with 50 ng IL-12 and AlPO 4 enhanced the IgG2a titers to MenC capsular polysaccharide although not to HbOC.

The data presented herein indicate that AlPO 4 can greatly enhance the potency of IL-12 so that substantially lower doses of the cytokine can be used. One possible mechanism is that IL-12 binds to AlPO 4 , thereby enhancing its persistence in the animal; additional studies indicate that IL-12 rapidly binds to alum (data not shown). Alternatively, the local inflammatory effect of AlPO 4 may induce cytokines that potentiate the biological activity of IL-12.

In addition to understanding the physical interaction of IL-12 with AlPO 4 , several other issues arise from the present work with pneumococcal vaccines formulated with IL-12. Given that AlPO 4 enhances the activity of IL-12, it would be useful to know the minimal dose of cytokine needed to adjuvant the IgG response to pneumococcal glycoconjugates, as well as whether IL-5-producing T cells are activated by IL-12-containing glycoconjugate vaccines. These two questions were addressed in the studies in Balb/c mice described in Example 4.

The following Examples are offered for the purpose of illustrating the present invention and are not to be construed to limit the scope of this invention. The teachings of all references cited herein are hereby incorporated herein by reference.

EXAMPLES

Example 1

Effect of IL-12 on the IgG Response of Swiss Webster Mice to Serotype 14 Pneumococcal Capsular Polysaccharide Conjugated to CRM 197 on Aluminum Phosphate (PnPs-14-CRM 197 /AlPO 4 )

STUDY DESIGN

Swiss Webster mice (10 per group) were immunized twice (at weeks 0 and 3) with 1 μg PnPs-14-CRM 197 formulated with 100 μg AlPO 4 and either no IL-12, 0.2 μg, 1 μg or 5 μg IL-12. All vaccines included 0.25% normal mouse serum for the purpose of stabilizing the IL-12 when used at low concentrations. PnPs14-CRM 197 is a conjugate of capsular polysaccharide from serotype 14 pneumococci covalently linked to the generically detoxified diphtheria toxin, CRM 197 , by reductive amination. Another group received 25 μg MPL® (3-O-deacylated monophosphoryl lipid A, RIBI Immunochem Research, Inc., Hamilton Montana) instead of IL-12. The vaccinations were given subcutaneously three weeks apart. Sera were collected at week 3 (primary response) and weeks 5 and 7 (secondary responses 2 and 4 weeks after boosting). The sera were analyzed for IgG antibodies to PnPs-14.

The sera were also analyzed for the ability to promote opsonophagocytic killing of type-14 pneumococci by human polymorphonuclear cells (PMN). Type 14 pneumococci were opsonized with dilutions o: antisera and C8-depleted serum as a source of complement. They were then incubated with human polymorphonuclear cells (PMN), and the percent of bacteria surviving was determined by colony counts.

RESULTS

Table 1 shows that 1 μg and 5 μg IL-12 substantially reduced the anti-PnPs-14 IgG response in mice immunized with conjugate formulated with AlPO 4 . The lowest dose (0.2 μg) of cytokine had no effect on the total IgG response but caused major chances in the levels of the individual immunoglobulin subclasses. At weeks 5 and 7 (2 and 4 weeks after boosting, respectively), 0.2 μg IL-12 induced substantially higher IgG2a, IgG2b and IgG3 titers but left the IgG1 levels essentially unaltered. The IgG subclass profile induced by 0.2 μg IL-12 was indistinguishable from that obtained with 25 μg MPL®, and sera from mice receiving these adjuvants had higher opsonophagocytic activity than those from mice immunized with a vaccine containing only AlPO (Table 2).

The higher doses of IL-12 markedly reduced the IgG1 antibodies; at 5 μg cytokine, IgG1 titers were an least 10-fold lower than in mice immunized without IL-12. This effect was apparent both during the primary response and after boosting. Increasing the IL-12 dose did not cause further increases in IgG2a, IgG2b and IgG3, and, like IgG1, they also declined, although to varying degrees. IgG2b showed the greatest reduction such that vaccines containing 1 μg or 5 μg IL-12 induced the same IgG2b titer as those without adjuvant. IgG2a and IgG3 were less sensitive to the effects of high IL-12 dose; even with 5 μg IL-12, after the second vaccination these subclasses were higher than in the controls.

These studies showed that IL-12 could modulate the IgG subclass response to a PnPs14-CRM 197 conjugate vaccine formulated with AlPO 4 . A 0.2 μg dose of IL-12 increased the IgG2a, IgG2b and IgG3 response to Pn14 without affecting the IgG1 response. Higher doses of IL-12 resulted in a marked reduction in the IgG1 and IgG2b titers. IgG2a and IgG3 titers also appeared to decline at these doses, but they were still higher than in mice immunized in the absence of IL-12. Example 2 demonstrates that the IgG subclass changes were associated with enhanced induction of IFN-γ -producing, CRM 197 -specific T cells and a marked reduction in antigen-specific IL-5 production, suggesting a change In the helper cell phenotype from TH-2-like to TH-1-like.

TABLE 1
Effect of IL-12 on the immunogenicity of PnPs-14-
CRM 197 /alum vaccine
	Ad-	Dose	PnPs14 IgG Response
Time	juvant	(μg)	IgG	IgG1	IgG2a	IgG2b	IgG3
week 3	None		56,035	8,394	481	298	1,312
	IL-12	5	13,137	480	2,417	388	2,398
	IL-12	1	26,131	1,521	3,249	736	3,858
	IL-12	0.2	90,220	13,779	4,731	1,454	7,944
	MPL ®	25	46,451	14,303	1,506	8,506	18,203
week 5	None		531,270	189,571	5,507	14,463	18,158
	IL-2	5	231,015	16,900	28,719	6,002	56,982
	IL-12	1	198,044	36,327	27,420	11,841	30,740
	IL-12	0.2	722,360	305,623	60,701	89,397	99,794
	MPL ®	25	751,066	221,324	44,957	91,265	77,989
week 7	None		694,471	244,212	1,801	6,849	9,245
	IL-12	5	177,438	17,232	20,276	3,494	26,859
	IL-12	1	183,571	44,213	21,246	5,063	13,447
	IL-12	0.2	852,292	251,157	37,104	37,717	88,933
	MPL ®	25	783,622	187,055	30,694	89,153	59,297

TABLE 2
Opsonophagocytic activity of sera of mice immunized
with PnPs-14-CRM 197 /AlPO 4 formulated with IL-12 or MPL ®
Initial	% Bacteria Surviving
Serum	Week 5 Sera	Week 7 Sera
Dilution	No.	0.2 μg	1 μg	5 μg	25 μg	No.	0.2 μg	1 μg	5 μg	25 μg
Tested	IL-12	IL-12	IL-12	IL-12	MPL ®	IL-12	IL-12	IL-12	IL-12	MPL ®
2	6	10	6	6	9	6	6	7	7	5
8	12	7	9	9	7	21	4	10	9	6
16	32	4	24	25	3	47	8	17	26	8
32	71	12	61	94	23	68	6	85	90	21
64	64	46	90	89	51	116	34	79	99	76

Example 2

Nature of T Helper Cells Induced by Pneumococcal Conjugate Vaccine (PnPs-14-CRM 197 /AlPO 4 ) Formulated With IL-12

STUDY DESIGN

Groups of eight (8) Balb/c mice were immunized subcutaneously at the base of the tail with 1 μg PnPs-14-CRM 197 conjugate formulated with 100 μg AlPO 4 and different doses of IL-12. Normal mouse serum (0.25%) was included as a carrier protein. One week later, draining lymph node cell suspensions were prepared from half the mice in each group and cultured with CRM 197 , lysozyme, ConA or in medium alone for 6 days. Culture supernatants from parallel cultures were harvested at day 3 and day 6 and assayed for IFN-γ, IL-5 and IL-10 by ELISA.

At three weeks, the remaining mice were bled and reimmunized with the same vaccine formulation used in the first immunization. Fourteen days after the second immunization (week 5), the mice were bled once more. Four days later their draining lymph node cells and splenocytes were harvested and cultured or six days with CRM 197 , lysozyme, ConA or in medium alone. Culture supernatants from parallel cultures were harvested at day 3 and day 6 and assayed for IFN-γ, IL-5 and IL-10 by ELISA.

RESULTS

Formulating PnPs-4-CRM 197 /AlPO 4 vaccine with the lower doses of IL-12 (0.2 μg and 1.0 μg) greatly enhanced the IgG2a and IgG3 responses to Pn14 at week 5, but not IgG1 (see Table 3) Several differences were seen between the results obtained with Balb/c mice and Swiss Webster mice in the previous experiment; in this experiment IL-12 did not dramatically increase the IgG2b antibodies to Pn14, nor did the 5 μg IL-12 dose cause the dramatic (>10-fold) reduction in IgG1 titers relative to the control group without cytokine.

One week after immunization, lymph node cells from mice immunized without IL-12 produced IFN-γ, IL-5 and IL-10 when stimulated with CRM 197 in vitro (Table 4) Adding IL-12 to the vaccine dramatically increased the antigen-specific production of IFN-γ and abolished the ability of the lymdhoid cells to produce IL-5 and IL-10. Maximal IFN-γ production was obtained with the lowest dose of IL-12 (0.2 μg); higher doses, particularly 5 μg, appeared to reduce the levels of this cytokine. This was most clearly seen in cultures simulated with 1 μg/mL CRM 197 . The reduction in IFN-γ with higher doses of IL-12 may not reflect a generalized suppressive phenomenon since IFN-γ production in response to ConA was the same regardless of the dose of IL-12 in the vaccine.

Two weeks after the second immunization, lymph node cells and splenocytes from mice immunized with vaccine containing IL-12 continued to produce elevated levels of IFN-γ in response to stimulation with CRM 197 compared to mice immunized without IL-12 (Table 5). As observed 7 days after primary vaccination, 0.2 μg to 1.0 μg IL-12 were optimal doses of IL-12 for augmentation of an IFN-γ response. In contrast, however, IL-5 and IL-10 production were differentially affected. The 1.0 and 5.0 μg doses of IL-12 essentially eliminated the IL-5 response but, by comparison, had only a minor effect on IL-10 production. IL-12 (5.0 μg) abolished the ability of splenocytes but not lymph node cells to produce IL-10 (Tables 5 and 6).

TABLE 3
Effect of IL-12 on immune response to an alum-based
PnPs14 glycoconjugate vaccine in Balb/c Mice
Week	IL-12 Dose	IgG	IgG1	IgG2a	IgG2b	IgG3
3	none	41,480	7,347	1,387	895	2,333
	0.2	26,253	1,521	1,118	171	5,911
	1	26,124	966	2,155	248	5,991
	5	10,753	541	671	183	3,242
5	none	234,220	33,284	2,896	3,105	2,487
	0.2	674,996	71,808	18,245	6,789	107,470
	1	622,714	32,022	22,749	7,853	44,350
	5	224,832	19,495	10,083	1,287	25,212

TABLE 4
Cytokines produced by lymph node cells taken 7 days after
single immunization with PnPs-14 conjugate
formulated with AlPO and IL-12
	Day 6 Cultures
	Antigen		No	0.2 μg	1.0 μg	5.0 μg
Cytokine	in vitro	ug/ml	IL-12	IL-12	IL-12	IL-12
IFN-γ	CRM	30	23.2	102.7	60.5	32.2
(U/mL)	CRM	1	<0.75	65.2	28.6	8.7
	Lysozyme	30	<0.75	2.9	6.6	4.5
	Con A	1	43.8	97.1	107.1	105.4
	Medium	—	<0.75	3.6	10.6	5.2
IL-5	CRM	30	7.2	<0.22	<0.22	<0.22
(ng/mL)	CRM	1	2.2	<0.22	<0.22	<0.22
	Lysozyme	30	<0.22	<0.22	<0.22	<0.22
	Con A	1	<0.22	<0.22	<0.22	<0.22
	Medium	—	<0.22	<0.22	<0.22	<0.22
IL-10	CRM	30	10.4	0.8	0.21	0.21
(ng/mL)	CRM	1	2.6	0.21	0.21	0.21
	Lysozyme	30	<0.14	0.21	0.21	0.21
	Con A	1	<0.14	0.21	0.21	0.21
	Medium	—	<0.14	0.21	0.21	0.21

TABLE 5
Cytokine production by splenocytes two weeks after
secondary vaccination with PnPs-14 conjugate
formulated with AlPO and IL-12
	Day 6 Cultures
	Antigen		No	0.2 μg	1.0 μg	5.0 μg
Cytokine	in vitro	ug/ml	IL-12	IL-12	IL-12	IL-12
IFN-γ	CRM	30	7.0	98.4	83.2	50.9
(U/mL)	CRM	1	1.0	89.2	76.8	16.4
	Lysozyme	30	<0.4	<0.4	<0.3	<0.3
	Con A	1	42.7	48.7	50.6	49.5
IL-5	CRM	30	13.2	3.1	0.6	<0.2
(ng/mL)	CRM	1	4.5	4.4	0.8	<0.2
	Lysozyme	30	<0.3	<0.3	<0.2	<0.2
	Con A	1	<0.3	<0.3	<0.2	<0.2
IL-10	CRM	30	8.6	4	7.1	0.6
(ng/mL)	CRM	1	1.1	2.5	1.7	<0.2
	Lysozyme	30	<0.2	<0.2	<0.3	<0.2
	Con A	1	0.5	0.4	<0.3	<0.2

TABLE 6
Cytokine production by lymph node cells two weeks
after secondary vaccination with PnPs-14 conjugate
formulated with AlPO and IL-12
	Day 6 Cultures
	Antigen		No	0.2 μg	1.0 μg	5.0 μg
Cytokine	in vitro	ug/ml	IL-12	IL-12	IL-12	IL-12
IFN-γ	CRM	30	9.8	86.9	58.7	62.0
(U/mL)	CRM	1	0.6	78.6	62.9	36.8
	Lysozyme	30	<0.4	<0.4	<0.3	<0.3
	Con A	1	17.7	57.6	45.7	69.0
IL-5	CRM	30	12.5	1.4	<0.2	0.5
(ng/mL)	CRM	1	4.8	2.2	<0.2	<0.2
	Lysozyme	30	<0.3	<0.3	<0.2	<0.2
	Con A	1	1.1	<0.3	<0.2	<0.2
IL-10	CRM	30	11.3	9.9	7.2	3.6
(ng/mL)	CRM	1	4.4	5.5	3.3	1
	Lysozyme	30	<0.2	<0.2	<0.2	<0.2
	Con A	1	<0.2	<0.2	<0.2	<0.2

Example 3

IL-12 Adjuvant Activity With Poorly Immunogenic Pneumococcal Conjugate

Study Design

Swiss-Webster mice (10 per group) were immunized with 1 μg Pn18C conjugate formulated with or without 100 μg AlPO 4 . The vaccines were supplemented with either IL-12 (0.2, 1 or 5 μg), 100 μg MPL® or 20 μg QS-21™. Normal mouse serum 0.5% final) was used to stabilize the diluted IL-12 and was added to all vaccines, regardless of composition. Three weeks later, the mice were bled and boosted with the same vaccine formulation used at the primary immunization. Bleeds were also taken at weeks 5 and 7 of the study (2 and 4 weeks after boosting, respectively). Pooled sera were tested at week 5 for Pn18C and CRM 197 total IgG and IgG subclasses. To determine the frequency of responders to Pn18C, the sera for individual mice were diluted 1/500 and tested by ELISA for IgG antibodies to Pn18C. Results are reported as optical density.

Results

The Pn18C IgG responses are presented in Table 7. The addition if IL-12 to alum-formulated conjugate vaccine had no consistent effect on the IgG response to Pn18C. A dose of 5 μg of IL-12 caused a 3-fold rise in the IgG titer of pooled week 5 sera, whereas vaccine formulated with 1 μg of IL-12 appeared to induce no Pn18C response. The lowest dose of IL-12 (0.1 μg) induced the same response as the AlPO 4 -formulated vaccine not containing IL-12. The vaccine formulated with MPL®/AlPO 4 induced the highest frequency of responses; 7/10 mice gave OD>0.2, in contrast to QS-21™/AlPO 4 and AlPO 4 alone, each of which induced 4/10 responders. Mice immunized with vaccine containing IL-12 plus AlPO 4 induced 2/10, 0/10 and 1/10 responders at IL-12 doses of 0.1 μg, 1.0 μg, and 5 μg, respectively.

In this experiment MPL® and QS-21™ caused at most a 3- to 4-fold increase in the Pn18C IgG response. In the absence of AlPO 4 , IL-12 did not have a profound adjuvant effect on the Pn18C IgG response. The vaccine containing a 1 μg dose of IL-12 induced the same Pn18C response as vaccine without IL-12. Vaccines containing the lower and higher doses of IL-12 appeared to induce lower responses than the control vaccine. Neither MPL® nor QS-21™ appeared to enhance the Pn18C IgG response. Among the vaccines formulated without AlPO 4 , QS-21™ induced the highest frequency of responders (7/10 with OD>0.2), whereas all other formulations induced 4/10 responders, at most.

To confirm that the IL-12 in the vaccine was indeed active, the CRM 197 IgG response in these mice was evaluated. Tables 8 and 9 show that after primary (week 3) and secondary (week 5) vaccination, IL-12 causes a dose-dependent increase in CRM 197 IgG response in mice immunized with vaccine formulated without AlPO 4 . Moreover, there was an IL-12 dose-dependent increase in both IgG1 and IgG2a titers at weeks 3 and 5, as well as an increase in IgG2b at week 5. The IgG1 and IgG2a titers at week 5 were similar to those induced by vaccine formulated with 100 μg MPL®. In contrast, the IgG2b titers promoted by IL-12 were 20-fold lower than those induced by MPL® . These data suggest that IgG2a and IgG2b are controlled by different mechanisms, IgG2a being dependent on a mechanism activated by IL-12 and IgG2b being controlled by an IL-12-independent mechanism. These data clearly indicate that IL-12 can act as adjuvant for IgG responses to a protein antigen. Moreover the increase in both IgG1 and IgG2a titers suggest that, within this model at least, IL-12 enhances priming of both TH-1-like and TH-2-like helper cells by PnOs18C-CRM 197 conjugate in the absence of AlPO 4 .

When added to the Pn18C conjugate vaccine formulated with AlPO 4 , the 0.1 μg dose of IL-12 caused little if any increase in the week 3 total IgG response to CRM 197 but a 3-fold increase at week 5. However, this dose of IL-12 increased the IgG2a titer at week 5, promoting titers similar to that induced by vaccine containing MPL or QS-21. IL-12 did not markedly increase the IgG2b titers. As seen in previous experiments, higher doses of IL-12 resulted in a sharp decline in IgG titers with all subclasses being affected.

TABLE 7
Effect of IL-12 on IgG response to PnOs18C conjugate
	IgG titer	IgG subclasses at Week 5
Adjuvant (μg/dose)	wk 3	wk 5	IqG1	IgG2a	IgG2b	IgG3
AlPO	<100	4,608	4,591	116	<100	<100
0.1 μg IL-12 +	<100	3,681	1,472	265	259	450
AlPO 4
1.0 μg IL-12 +	<100	138	<100	<100	<100	<100
AlPO 4
5.0 μg IL-12 +	260	13,545	7,820	1,426	<100	1,481
AlPO 4
100 μg MPL/AlPO 4	233	9,027	1,522	935	877	<100
QS-21 + AlPO 4	<100	7,989	879	1,395	1,062	1,004
none	1.07	10,768	5,238	345	<100	144
0.1 μg IL-12	<100	1,808	336	105	<100	<100
1.0 μg IL-12	<100	22,257	12,443	671	172	773
5.0 μg IL-12	<100	460	203	<100	<100	480
100 μg MPL	112	1,729	524	363	189	126
QS-21	<100	3,573	2,483	101	<100	113

TABLE 8
Effect of IL-12 on CRM 10 IgG response three weeks after
vaccination with PnOs18C conjugate
	Adjuvant (μg/dose)	IgG	IgG1	IgG2a
	AlPO 1	70,964	8,706	3,516
	0.1 μg IL-12 + AlPO 4	103,589	4,754	13,025
	1.0 μg IL-12 + AlPO 4	26,927	506	2,926
	5.0 μg IL-12 + AlPO 4	19,579	241	2,665
	100 μg MPL ®/AlPO 4	651,315	92,245	79,508
	QS-21 ™/ALPO 4	572,255	116,583	38,419
	None	7,630	452	1,023
	0.1 μg IL-12	32,403	3,475	3,713
	1.0 μg IL-12	60,987	4,615	5,951
	5.0 μg IL-12	128,697	10,498	10,686
	100 μg MPL ®/TEM	462,289	40,010	24,979
	QS-21 ™	556,440	111,533	53,799

TABLE 9
Effect of IL-12 on CRM197 IgG response five weeks after
vaccination with PnOs18C conjugate (two weeks after boosting)
Adjuvant (μg/dose)	TgG	IgG1	IgG2a	IgG2b
AlPO 4	634,631	102,974	45,955	8,812
0.1 μl IL-12 + AlPO 4	2,225,000	88,204	317,083	16,869
1.0 μg IL-12 + AlPO 4	105,765	8,018	12,598	1,096
5.0 μg IL-12 + AlPO 4	71,618	1,582	13,806	744
100 μg MPL ®/AlPO 4	4,384,000	637,655	371,652	111,646
QS-21 ™/ALPO 4	>5,000,000	>1,000,000	873,674	144,132
None	62,341	12,783	3,655	1,679
0.1 μg IL-12	296,791	52,288	23,741	7,069
1.0 μg IL-12	1,026,060	101,381	96,024	11,862
5.0 μg IL-12	1,367,771	74,494	108,815	14,258
100 μg MPL ®/TEM	4,173,765	264,691	266,160	303,662
QS-21 ™	>5,000,000	1,303,508	445,712	131,991

Example 4

Effect of IL-12 on the IgG Response of Swiss Webster Mice to Bivalent Vaccine Containing PnPs53-CRM 197 and PnPs-14-CRM 197

STUDY DESIGN

Swiss Webster mice were immunized subcutaneously at weeks 0 and 3 with a vaccine comprising 0.1 μg per dose of PnPs6B-CRM 197 glycoconjugate (a conjugate of capsular polysaccharide from serotype 6B pneumococci covalently linked to CRM 197 ) plus 0.1 μg per dose of PnPs14-CRM 197 glycoconjugate. The vaccines were administered with 0, 8, 40, or 200 ng IL-12, either alone or in combination with 100 μg alum (AlPO 4 ). Normal mouse serum (0.25%) was included as a carrier protein to stabilize the IL-12 at low concentrations. A control group of mice was immunized with the vaccine formulated with 100 μg monophosphoryl lipid A (MPL®). The mice were bled at week 3 (primary response) and week 5 (secondary response). Sera were tested for IgG antibodies to Pn6B and Pn14 capsular polysaccharide by ELISA.

RESULTS

Response to PnPs6B Conjugate

Table 10 illustrates the pooled serum IgG response to the Pn6B component of the bivalent vaccine. Little or no response to Pn53 was detected at week 3 if the vaccine contained no adjuvant or was formulated with only AlPO 4 . The highest titers after a single vaccination appeared to be induced by vaccine containing either MPL® or 8-40 ng of IL-12 co-formulated with alum These titers however were low, i.e., less than 3,000. The week 5 responses show that after boosting, vaccines formulated with 40 ng IL-12 plus AlPO 4 or with MPL® induced the highest IgG titers to Pn6B. In the absence of alum, IL-12 in the 8 to 200 ng dose range did not enhance the IgG titers to Pn6B.

The IgG subclass response to Pn6B at week 5 is shown in Table 10. The titers of individual IgG subclasses were similar in mice immunized with vaccine containing no adjuvant or vaccine formulated with AlPO 4 (no IL-12). Moreover, formulating the vaccines with 8-200 ng of IL-12 in the absence AlPO 4 did not alter the IgG subclass response. In contrast, these doses of IL-12 when combined with AlPO 4 resulted in substantially increased IgG1 and IgG2a titers to Pn6B. These titers were similar to those obtained with vaccine formulated with MPL®. IL-12 also increased the IgG2b and IgG3 titers induced by vaccine formulated with AlPO 4 ; however, these titers appeared to be substantially lower than those induced by vaccine formulated with MPL®.

To determine if the increases obtained with a combination of IL-12 and AlPO 4 were statistically significant, the Pn6B IgG titers of individual mice in selected groups were determined. The geometric mean titers (GMT) are presented Table 11. The data indicate that groups immunized with vaccines formulated without adjuvant or with AlPO 4 alone had similar GMT against Pn6B. Formulating the vaccine with AlPO plus 40 ng IL-12 resulted in a 29-fold increase in titer over that induced by vaccine containing no adjuvant. When all the data were tested by ANOVA (analysis of variance by JMP software; SAS Institute, Cary, N.C.), no statistically significant differences were found. Upon comparison of subsets of data, ANOVA indicated a statistically significant difference when comparing the week 5 responses induced by vaccine containing no adjuvant and vaccines formulated with AlPO 4 and various doses of IL-12. Of these, The vaccine formulated with AlPO 4 plus 40 ng IL-12 induced a significantly higher Pn6B titer than vaccine formulated without adjuvant. As a further indication of the heightened immunogenicity of that formulation, 7 of the 10 mice in that group had Pn6B titers greater than or equal to 50,000 compared to only 1 and 2 mice each in the groups vaccinated with conjugate formulated without adjuvant or with AlPO 4 alone.

TABLE 10
Effect of IL-12 on the IgG response to PnPs6B in mice immunized with a
bivalent PnPs6B/14 pneumococcal glycoconjugate vaccine
		Pn6B IgG Subclass Response at
	Pn6B IgG Titer*	Week 5*
Group	Adjuvant	Week 3	Week 5	IgG1	IgG2a	IgG2b	IgG3
P344	200 ng IL-12 +	630	161,867	19,474	22,664	2,954	7,333
P345	40 ng IL-12 +	2,609	429,006	61,364	24,172	4,117	9,830
P346	8 ng IL-12 + AlPO 4	1,977	284,206	46,734	32,859	3,195	8,764
P347	AlPO 4 (no IL-12)	279	120,999	8,767	2,199	688	301
P348	200 ng IL-12	<100	22,401	6,816	3,147	501	1,104
P349	40 ng IL-12	164	23,343	5,056	2,532	879	292
P350	8 ng IL-12	642	81,748	17,702	3,573	5,151	1,786
P351	None	<100	20,153	3,061	1,506	364	1,220
P352	100 μg MPL ®	2,872	840,513	84,660	30,813	43,505	25,749
*Pooled serum titers

TABLE 11
Pn6B IgG titers of individual mice
	Group
	P344	P345	P346
	AlPO 4 +	AlPO 4 +	AlPO 4 +	P347	P350	P351	P352
	200 ng	40 ng	8 ng	AlPO 4	8 ng	No	100 μg
Mouse #	IL-12	IL-12	IL-12	(no IL-12)	IL-12	Adjuvant	MPL ®
1	1,957	596,886	13,457	306,012	833,148	3,544	7,556
2	2,498	1,205	1,000,000	3,653	9,431	326	1,359,470
3	100	9,453	1,422	8,708	3,163	1,136	81
4	11,830	70,278	168,481	41,395	109,399	24,140	583,097
5	1,823	157,427	16,454	677,407	252	50,785	86,656
6	6,114	90,843	989	9,089	150,245	228	284
7	279	49,182	372,709	17,164	112	1,351	1,000,000
8	756,503	408,348	425	7,329	393	36,805	473,652
9	1,000,000	1,000,000	667,988	100	13,622	22,817	927,213
10	177	1,052,210	6,206	245	182,629	851	—
GMT	4,347	103,743	22,580	9,735	10,120	3,589	55,799
Mice with	2	7	4	2	4	1	6
titer
≧50,000
Statistical Comparisons (ANOVA: α = 0.05)
AlPO 4 + 40 ng IL-12 vs. no adjuvant: significant

Response to PnPs14 Conjugate

The IgG response to the PnPs14 component of the vaccine is shown in Table 12. The data indicate that IL-12 in the 8-40 ng dose range, either alone or when formulated with AlPO 4 , did not enhance the response to PnPs14 after primary or secondary vaccination. Moreover, subclass analysis indicated that IL-12 did not enhance the IgG2a titers when formulated with IL-12. In this study, MPL® did not have the profound adjuvant effect on the PnPs14 response there was observed in previous studies, at least when assaying pooled sera. To get an idea or the degree of variation or the response of each group, individual sera were assayed Pn14 IgG antibodies at a 1/300 dilution The results presented in Table 13 suggest that there was large range of responses in each group, i.e., the Coefficient of Variation (CV) ranged from 0.229 to 0.587, with the exception of the group immunized with vaccine containing MPL® where the CV was 0.051. Thus, it appeared that MPL®, but not IL-12, may have acted as an adjuvant or the Pn14 IgG response and reduced the mouse-to-mouse variation.

TABLE 12
Effect of IL-12 on the IgG subclass response to
Pn14 in mice immunized with a bivalent PnPs6B/14
pneumococcal glycoconjugate vaccine
	PnPs14 Ig*	PnPs14 IgG Subclass
	Titer*	at Week 5*
Adjuvant	Week 3	Week 5	IgG1	IgG2a	IgG2b	IgG3
200 ng IL-12 +	2,170	58,657	6,880	8,996	1,945	5,995
AlPO 4
40 ng IL-12 +	1,641	53,557	8,646	3,003	3,684	2,745
AlPO 4
8 ng IL-12 +	2,181	85,173	10,094	11,346	5,328	2,560
AlPO 4
AlPO 4 (no	2,102	201,082	54,989	4,030	6,402	3,745
IL-12)
200 ng IL-12	849	18,293	5,769	1,582	536	799
40 ng IL-12	1,544	11,442	4,350	714	514	455
8 ng IL-12	113	12,169	5,286	354	245	330
None	509	22,601	6,080	808	618	694
100 μg MPL ®	18,616	77,106	15,745	4,275	10,205	3,916
*Pooled serum titers

TABLE 13
Response of individual mice to Pn14 component
of Pn6B/Pn14 bivalent pneumococcal conjugate vaccine*
		O.D.	Standard	Coefficient or
Adjuvant	O.D. Range	Mean	Deviation	Variation
AlPO 4 + 200 ng IL-12	0.034-0.990	0.788	0.318	0.404
AlPO 4 + 40 ng IL-12	0.457-0.948	0.771	0.176	0.229
AlPO 4 + 8 ng IL-12	0.023-0.923	0.707	0.2811	0.397
AlPO 4 (no IL-12)	0.328-0.974	0.770	0.220	0.285
8 ng IL-12 (no alum)	0.009-0.812	0.505	0.292	0.587
No adjuvant	0.030-0.876	0.614	0.343	0.558
100 μg MPL ®	0.791-0.918	0.863	0.044	0.051
*Individual sera tested by ELISA at 1/300 dilution for IgG antibodies to Pn14.

Example 5

Comparison of the Effect of IL-12 in the Presence or Absence of Alum on the Murine Immune Response to Monovalent PnPs14-CRM 197 Conjugate Vaccine

STUDY DESIGN

BALB/c mice (8 per group) were immunized subcutaneously at week 0 with 1 μg PnPs14-CRM 197 conjugate formulated with or without 100 μg AlPO 4 and either no IL-12 or with 8, 40, 200, 1,000 or 5,000 ng IL-12. Normal mouse serum (0.25%) was included as a carrier protein to stabilize IL-12 at low concentrations. At week 1, lymph node cell suspensions were prepared from half the mice in each group and evaluated for antigen-specific cytokine production in vitro. Their spleens were also harvested and weighed. At week 3 the remaining mice were bled and re-immunized with the same vaccine formulation used in the initial vaccination. At week 5 the twice-immunized mice were bled, their spleens weighed and their splenocytes evaluated for cytokine production. PnPs14 and CRM 197 IgG and IgG subclass titers were determined on pooled sera. When the assays were performed using sera from individual mice, the results are expressed as geometric mean titers (GMT).

RESULTS

Effect of IL-12 on Spleen Weight One Week After Immunization

One week after the first immunization, mice receiving 5,000 ng IL-12, but not lower doses of IL-12, in the absence of AlPO 4 , had significantly higher spleen weights than those receiving vaccine containing neither alum nor IL-12 (Table 14). Vaccines containing AlPO 4 induced higher spleen weights when formulated with 40 to 5000 ng IL-12. Pair-wise comparisons indicated that vaccines formulated with 200 or 1000 ng IL-12 plus AlPO 4 induced higher spleen weights than those formulated with the same dose of IL-12 in the absence of AlPO 4 . Overall, the data indicate that formulating IL-12 with AlPO 4 greatly enhanced a biological activity of the cytokine, i.e., its ability to cause increased spleen weight one week after vaccination.

Effect of IL-12 on the IgG Response to PnPs14

Initially, pooled sera were assayed for IgG antibodies to PnPs14 (Table 15). The clearest indication of an adjuvant effect was noted after primary immunization with vaccine containing AlPO 4 and 8 to 40 ng IL-12. This combination resulted in a 17- to 21-fold increase in the IgG titer relative to mice immunized with vaccine formulated with neither AlPO 4 nor IL-12. The combination of AlPO 4 and IL-12 resulted in higher responses than when used individually; on their own AlPO 4 and the 40 ng dose of IL-12 caused 4-fold and 5-fold increase in week 3 IgG titers, respectively. Analysis of individual sera from mice immunized with AlPO 4 -containing vaccines (Table 16) showed that 8 ng IL-12 induced 5-fold higher PnPs14 IgG titers after primary vaccination than vaccine adjuvanted with only AlPO 4 . The difference in titers was statistically significant. Higher doses of IL-12 did not enhance the response. The 1,000 to 5,000 ng doses of IL-12 caused a marked decline in PnPs14 IgG titers. After the second immunization only the 40 ng dose of IL-12 caused a significant rise (3-fold) in the PnPs14 titer induced by the AlPO 4 -based vaccine.

The pooled serum data suggest that the combination of AlPO 4 and 8-40 ng IL-12 enhanced the IgG1 titers after primary immunization. After two vaccinations, IL-12 did not enhance the IgG1 titers to PnPs14 in mice immunized with conjugate in the absence of AlPO 4 as indicated by analysis of pooled (Table 15) and individual sera (Table 17) Moreover, among mice immunized with vaccine containing AlPO 4 , the addition of 8 to 200 ng IL-12 did not result in higher IgG1 titers after 2 vaccinations (Table 17).

The most profound of IL-12 was to substantially increase the PnPs14 IgG2a response at week 5. This was seen both when the vaccine contained AlPO 4 or was formulated without AlPO 4 (Table 18). In the absence of AlPO 4 , statistically significant increases (14- to 42-fold) in IgG2a GMT were obtained with 8 to 1,000 ng IL-12. Similarly, 8-1,000 ng IL-12 enhanced the ability of AlPO 4 -containing vaccines to induce IgG2a antibodies, although in this study only the titers induced by the 8 and 40 ng doses of IL-12 were statistically higher. Overall, the highest IgG2a titers were induced by conjugate formulated with AlPO 4 and 40 ng IL-12. This was significantly different from the IgG2a titers induced by 40 ng IL-12 in the absence of AlPO 4 , again indicating that the adjuvant activity of IL-12 was enhanced by alum.

IgG2b and IgG3 titers were assayed on pooled sera only (Table 15). Doses of IL-12 in the range of 8 to 1,000 ng when co-formulated with AlPO 4 , but not in its absence, promoted substantial increases in IgG3 titers after primary and secondary immunization. No consistent effect of IL-12 on the IgG2b titers was noted.

Effect of IL-12 on the IgG Response to CRM 197

The IgG response to CRM 197 was also evaluated to see if there were differences between the effect of IL-12 on the protein carrier versus the polysaccharide portion of the conjugate (Table 19). In the absence of AlPO 4 , 40 ng IL-12 appeared to modestly increase the IgG titers to CRM 197 after two vaccinations. However, the highest IgG titers to CRM 197 were obtained when the vaccine was formulated with both AlPO 4 and 8-40 ng IL-12. The heightened adjuvant activity of IL-12 co-formulated with AlPO 4 is indicated by the finding that, on their own, 40 ng IL-12 and AlPO 4 resulted in 6-fold and 17-fold increases in IgG titer at week 5, but when combined together the increase was 147-fold. IL-12 enhanced the IgG1 response to CRM 197 regardless of whether the vaccine was formulated with or without AlPO 4 (Tables 19 and 20). IL-12 substantially increased the week 5 IgG2a titers to CRM 197 after immunization with vaccines containing AlPO 4 (Table 19). Again the optimal dose of IL-12 appeared to be 40 ng. The cytokine appeared to increase the IgG2b titers induced by vaccine containing AlPO 4 .

Effect of IL-12 on Cytokine Profile of CRM 197 -specific T Cells

Cytokine production by spleen cells taken two weeks after secondary vaccination week (5) revealed effects of IL-12 on the priming of both IFN-γ and IL-5 producing cells. Splenocytes from mice immunized in the absence of AlPO 4 and IL-12 produced detectable levels of IL-5, but not IFN-γ, when stimulated with CRM 197 in vitro (Table 21). Formulating the vaccine with IL-12 appeared to enhance the induction IL-5 producing cells with peak activity occurring with 40 ng of the cytokine. Higher doses of IL-12 resulted in decreased production of IL-5, with virtually no cytokine being produced by mice immunized with conjugate vaccine containing 1,000 to 5,000 ng IL-12. Convincing IFN-γ production was detected only from the splenocytes of mice immunized with vaccines formulated with 5,000 ng IL-12. When the vaccine was formulated with AlPO 4 , the addition of 8 ng IL-12 resulted in priming of cells that produced copious amounts of IFN-γ, whereas in the absence of the cytokine only antigen-specific IL-5 production was detected. It appears that priming for maximal IFN-γ production occurs with 40 to 1,000 ng IL-12. Addition of 5,000 ng IL-12 abolished the ability of the vaccine to prime for IL-5-producing cells.

TABLE 14
Spleen weights of Balb/c mice one week after subcutaneous
immunization with 1 μg PnPs14-CRM - conjugate formulated
with cr without 110 μg AlPO and the indicated
doses of IL-12
	Spleen weight (grams)
Adjuvant Formulation		Standard
Group Code	IL-12 (ng)	AlPO	AVERAGE	Deviation
P641	0	—	0.179	0.0225
P642	2	—	0.148	0.0112
P643	40	—	0.162	0.0202
P644	200	—	0.175	0.0431
P645	1,000	—	0.196	0.0068
P646	5,000	—	0.257	0.0247
P647	0	—	0.151	0.0158
P648	0.151	0.0332
P649	40	—	0.217	0.0596
P650	200	—	0.290	0.0226
P651	1,000	—	0.277	0.0919
P652	5,000	—	0.305	0.0545

Statistical Comparisons (ANOVA; α=0.05)

P642, P643, P644, P645 vs P641: not significant

P646 vs P641: significant

P648 vs P647: not significant

P649, P650, P651, P652 vs P647: significant

P641 vs P647: not significant

P644 vs P650: significant

P642 vs P648: not significant

P645 vs P651: significant

P643 vs P649: not significant

P646 vs P652: not significant

TABLE 15
Anti-PnPs14 IgG response in Balb/c mice immunized with PnPs14-CRM 197
conjugate formulated with IL-12 and AlPO 4
Adjuvant	PnPs14 IgG Titers of Pooled Sera
Formulation	IgG	IgG1	IgG2a	IgG2b	IgG3
IL-12 (ng)	AlPO 4	Week 3	Week 5	Week 3	Week 5	Week 3	Week 5	Week 3	Week 5	Week 3	Week 5
0	−	1,691	24,498	479	9,967	139	492	<100	<100	295	1,516
8	−	4,679	32,966	841	9,860	377	1,902	108	609	390	1,354
40	−	6,484	50,096	1,235	17,631	207	1,209	58	714	1,633	4,017
200	−	5,330	51,240	385	7,568	715	3,748	290	1,397	1,091	4,519
1,000	−	6,347	69,673	1,286	12,814	859	6,532	124	<100	782	6,208
5,000	−	1,131	19,621	229	3,598	126	1,392	<100	<100	635	3,616
0	+	7,825	103,092	1,714	38,147	195	1,535	617	3,973	447	2,963
8	+	29,506	195,069	7,444	58,046	1,207	6,697	693	4,843	5,669	25,407
40	+	35,567	295,361	4,945	46,030	2,883	17,267	1,371	9,911	5,797	22,602
200	+	10,177	190,701	1,777	41,800	626	9,816	<100	1,479	3,443	23,648
1,000	+	2,422	245,683	90	31,373	167	13,847	<100	722	1,173	34,039
5,000	+	1,304	35,333	91	5,228	<100	1,429	<100	<100	772	8,065

TABLE 16
Effect of IL-12 on the IgG response to PnPs14 in
mice immunized with PnPs14-CRM - conjugate formulated with
AlPO
	PnPd14 IgG GMT (fold increase)
Group	IL-12 (ng)	AlPO 4	Week 3	Week 5
P647	0	+	3,037		27,027
P648	8	+	16,681	(5.5)	55,855	(2.1)
P649	40	+	6,667	(2.2)	88,271	(3.4)
P650	200	+	2,333	(0.8)	57,076	(2.1)
P651	1,000	+	611	(0.2)	30,886	(1.1)
P652	5,000	+	617	(0.2)	10,989	(0.4)

Statistical Comparisons (ANOVA; ∝=0.05)

Week 3 titers

P648 vs P647: significant

P651 vs P547: significant

P649, P650, P652 vs P647: not significant

Week 5 titers

P649 vs P547: significant

P648, P550, P651 vs P647: not significant

TABLE 17
PnPs14 IgG1 titers in mice twice immunized with
PnPs14-CRM 197 conjugate vaccine formulated with or without
AlPO 4 and various doses of IL-12
Adjuvant Formulation
				IgG1 GMT
				(Geometric
	Group Code	IL-12 (ng)	AlPO 4	Mean Titer)
	P641	0	−	9,492
	P642	8	−	5,964
	P643	40	−	14,028
	P644	200	−	4,628
	P645	1,000	−	5,815
	P646	5,000	−	1,757
	P647	0	+	15,283
	P648	8	+	35,730
	P649	40	+	31,855
	P650	200	+	34,166
	P651	1,000	+	15,347
	P652	5,000	+	4,022

Statistical Comparisons (ANOVA; α=0.05)

P642, P643, P644, P646, P647, P651 vs P641: not significant

P648, P549, P650 vs P641: significant

P548, P649, P650, P651 vs P547: not significant

P652 vs P647: significant

TABLE 18
PnPs14 IgG2a titers in mice twice immunized with
PnPs14-CRM 197 conjugate vaccine formulated with or without
AlPO 4 and various doses of IL-12
			IgG2a GMT at Week 5
Group Code	IL-12 (ng)	AlPO 4	(Fold Increase*)
P641	0	−	97
P642	8	−	1,418	(14.6)
P643	40	−	1,509	(15.6)
P644	200	−	2,228	(23.0)
P645	1,000	−	4,126	(42.5)
P646	5,000	−	289	(3.0)
P647	0	+	806
P648	8	+	6,841	(8.5)
P649	40	+	13,252	(16.4)
P650	200	+	4,740	(5.9)
P651	1,000	+	3,291	(4.1)
P652	5,000	+	368	(0.5)
*relative to control vaccines not containing IL-12

Statistical Comparisons (ANOVA; α=0.05)

642, P643, P644, P645 vs P641: significant

P646 vs P641: not significant

648, P649 vs P647: significant

650, P651, P652 vs P647: not significant

643 vs P649: significant

TABLE 19
Anti-CRM 197 IgG response in Balb/c mice immunized
with PnPs14-CRM 197 conjugate formulated with IL-12 and AlPO 4
	CRM 197 IgG Titer	IgG Subclasses at
Adjuvant	(Pooled Sera)	Week 5 (Pooled Sera)
IL-12 (ng)	AlPO 4	Week 3	Week 5	IgG1	IgG2a	IgG2b
0	−	3,843	8,965	703	1,269	792
8	−	2,456	14,389	4,674	<100	<100
40	−	3,200	53,758	14,073	3,403	<100
200	−	1,666	13,419	1,803	2,044	<100
1,000	−	4,999	3,663	<100	506	<100
5,000	−	2,841	3,641	<100	<100	<100
0	+	4,870	153,075	55,922	1,796	407
8	+	89,558	1,515,87	377,82	85,972	10,972
40	+	19,566	1,319,10	147,03	199,29	7,206
200	+	6,884	315,071	48,852	35,807	3,865
1,000	+	7,292	545,827	126,72	44,190	4,127
5,000	+	7,213	7,029	1,041	769	<100

TABLE 20
IgG1 titers to CRM 197 in Balb/c mice immunized
with PnPs14-CRM 197 conjugate formulated with IL-12 and AlPO 4
Group Code	IL-12 (ng)	AlPO 4	IgG1 GMT	Fold Increase
P641	0	−	317	—
P642	8	−	1,136	3.6
P643	40	−	9,141	28.8
P644	200	−	1,627	5.1
P645	1,000	−	100	0.3
P646	5,000	−	174	0.6
P647	0	+	22,061	—
P648	8	+	119,130	5.4
P649	40	+	73,226	3.3
P650	200	+	14,391	0.7
P651	1,000	+	33,468	1.5
P652	5,000	+	317	0.01

Statistical Comparisons (ANOVA; α=0.05)

P643, P644 vs P641: significant

P642, P645, 5646 vs P641: not significant

648, P649, P650, P651 vs P647: not significant

P642 vs P648, P643 vs P649, P644 vs P650, P645 vs P651: significant

TABLE 21
Cytokine production by splenocytes from mice immunized twice with PnPs14-
CRM 197 formulated with IL-12 in the presence and absence of AlPO 4
	Cells Stimu-	IL-12 Dose in Vaccine Formulated	IL-12 Dose in Vaccine Formulated
	lated With	Without AlPO 4 (ng)	With AlPO 4 (ng)
Cytokine	Antigen	μg/mL	0	8	40	200	1,000	5,000	0	8	40	200	1,000	5,000
IFN-γ	CRM 197	30	<0.06	<0.06	0.4	0.3	0.4	6.9	0.1	20.6	32.1	30.2	29.4	21.0
(U/mL)	CRM 197	10	<0.06	<0.06	0.3	0.2	0.3	3.4	0.1	16.5	31.7	30.2	27.6	21.0
	CRM 197	3	<0.06	<0.06	<0.06	<0.06	0.2	1.4	<0.03	15.7	30.9	28.7	26.7	20.1
	CRM 197	1	<0.06	<0.06	<0.06	<0.06	0.2	0.4	<0.03	12.8	30.9	28.2	27.9	18.0
	CRM 197	0.3	<0.06	<0.06	<0.06	<0.06	0.1	0.1	<0.03	6.3	27.5	26.2	26.5	6.5
	Lysozyme	30	<0.06	<0.06	<0.06	<0.06	<0.03	<0.03	<0.03	<0.0	<0.0	<0.0	<0.02	<0.02
	Con A	1	11.9	15.4	15.8	15.9	20.6	21.0	21.1	17.0	20.8	13.7	23.4	17.7
	Medium	—	<0.06	<0.06	<0.06	<0.06	<0.03	<0.03	<0.03	<0.0	<0.0	<0.0	<0.02	<0.02
IL-5	CRM 197	30	370	480	2560	960	60	70	2010	1440	5280	1640	880	<10
(pg/mL)	CRM 197	10	150	300	1110	260	<24	<24	1220	920	4590	410	430	<10
	CRM 197	3	30	90	910	200	<24	<24	1190	690	2830	1030	200	<10
	CRM 197	1	<4	50	200	40	<24	<24	880	400	2150	520	140	<10
	CRM 197	0.3	<4	30	70	<4	<24	<24	670	180	440	270	90	<10
	Lysozyme	30	<4	<4	<4	<4	<24	<24	<24	<24	<10	<10	<10	<10
	Con A	1	<4	<4	<4	<4	<24	<24	60	80	40	<10	<10	<10
	Medium	—	<4	<4	<4	<4	<24	<24	<24	<24	<10	<10	<10	<10

Example 6

Effect of IL-12/AlPO 4 on the Humoral Response to a Nonavalent Pneumococcal Glycoconjugate Vaccine

STUDY DESIGN

Evaluation of the effect of IL-12 on the IgG response to pneumococcal glycoconjugate vaccine was extended to a nonavalent vaccine composed of serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F, 23F. Swiss Webster mice were immunized with 0.1, 1, or 5 μg of vaccine (carbohydrate weight) at weeks 0 and 3. The vaccine was administered alone, with AlPO 4 (100 μg) or with AlPO 4 admixed with 50, 200 or 1,000 ng of IL-12. Normal mouse serum was not included in the vaccine. The IgG responses to serotypes 4, 6B, 9V, 14, 18C and to the carrier protein CRM 197 were evaluated at week 5 (i.e., 2 weeks after boosting by ELISA.

RESULTS

Response to CRM 197 at Week 5

Addition of IL-12 to a vaccine containing AlPO4 resulted in a dose-dependent increase in IgG2a and IgG2b antibodies to CRM 197 . This was seen at all doses of conjugate tested (Table 22). Increased IgG2a titers were evident in mice receiving 50 ng of the cytokine and were maximal at 1,000 ng. This contrasts with other studies where maximal IgG2a titers were obtained with 40-100 ng of cytokine added to the alum-based vaccine and where higher doses of IL-12 resulted in a diminished immune response. The reason for the differences in dose response between studies is not known. It may relate to differences in the vaccine, i.e., multivalent versus monovalent or that normal mouse serum included in the vaccine in previous studies to stabilize the cytokine at low concentrations was omitted.

Response to Pneumococcal Polysaccharides

Formulating the nonavalent vaccine with AlPO4 enhanced the IgG response to several serotypes including PnPs4, PnPs6B, PnPs9V and PnPs14, especially when the lowest dose of conjugate (0.1 μg) was used (Tables 24-27). Addition of IL-12 did not appear to further enhance the IgG response to these serotypes. In the case of the PnPs18C response, however, addition of 50 or 1,000 ng IL-12 to 5 μg of vaccine containing AlPO4 resulted in higher geometric mean IgG titers to this serotype and higher proportion of mice with PnPs18C IgG titers above 10,000 (Table 23). The responses to PnPs1, 5, 19F and 23F were not evaluated.

Addition OF IL-12 to nonavalent vaccines containing AlPO4 resulted in dose-dependent increases in IgG2a titers to PnPs4, PnPs6B, PnPs9V and PnPs14 (Tables 24-27). Generally, the increase in IgG2a paralleled that for the CRM 197 response with highest titers being obtained with 1000 ng of IL-12. In contrast to the experiments using monovalent PnPs14 conjugate or bivalent PnPs6B/PnPs14 vaccine, the 50 ng dose of IL-2 had little or no effect on the IgG2a response to these serotypes. The exception is the IgG2a response to PnPs14, as this dose of cytokine appeared, to enhance the response to this serotype (Table 27).

Overall, this study indicates that IL-12 will promote the complement-fixing IgG2a antibody subclass response to multiple pneumococcal serotypes present in a multivalent vaccine.

TABLE 22
Effect of IL-12 on the CRM 197 response of
mice immunized with nonavalent pneumococcal
glycoconjugate vaccine formulated with AlPO 4
Vaccine Formulation
Conjugate	IL-12	AlPO4	CRM 197 Response at Week 5
Dose (μg)	(ng)	(μg)	IgG	IgG1	IgG2a	IgG2b	IgG3
5.0	none	none	391,021	138,784	1,687	3,277	102
5.0	0	100	1,419,910	609,704	4,328	11,349	181
5.0	50	100	3,226,410	896,621	27,736	18,086	728
5.0	200	100	2,991,990	584,991	87,732	28,855	2,937
5.0	1,000	100	16,224,900	906,192	303,656	87,726	3,023
1.0	none	none	545,046	162,757	1,178	9,213	358
1.0	0	100	956,584	338,751	1,284	4,118	306
1.0	50	100	1,936,170	370,961	6,677	31,982	931
1.0	200	100	4,788,500	660,082	187,034	36,785	1,065
1.0	1,000	100	12,404,500	644,151	533,065	69,185	1,176
0.1	none	none	18,215	3,800	<100	<100	<100
0.1	0	100	561,952	157,362	1,437	7,744	<100
0.1	50	100	807,363	141,670	15,064	25,978	2,092
0.1	200	100	1,560,380	313,263	38.686	51.737	306
0.1	1,000	100	2,296,310	202,111	112,158	36,958	1,054

Mice were immunized with indicated dose of nonavalent pneumococcal glycoconjugate vaccine at weeks 0 and 3. The conjugates were formulated alone, with AlPO (100 μg) or with AlPO 4 plus IL-12. Sera from the week 5 bleed were analyzed for IgG antibodies to CRM 197 .

TABLE 23
Effect of IL-12 on the response to PnPs18C in
mice immunized with 5 μg nonavalent pneumococcal
glycoconjugate vaccine formulated with AlPO4
Vaccine Formulation	PnPs18C Response
Conjugate	IL-12	AlPO 4	IgG Titer	Mice With Titer
Dose (μg)	(ng)	(μg)	(GMT)	>10,000 (n = 5)
5	0	0	2,933	1
5	50	100	23,725	4
5	1,000	100	48,375	5

Mice were immunized with indicated dose of nonavalent pneumococcal glycoconjugate vaccine at weeks 0 and 3. The conjugates were formulated alone, with AlPO 4 (100 μg) or with AlPO 4 plus IL-12. Individual mouse Sera from the week 5 bleed were analyzed for IgG antibodies to PnPs18C.

TABLE 24
Effect of IL-12 on the PnPs4 response of mice
immunized with nonavalent pneumococcal glycoconjugate
vaccine formulated with AlPO4
Vaccine Formulation
Conjugate	IL-12	AlPO 4	PnPs4 Response at Week 5
Dose (μg)	(ng)	(μg)	IgG	IgG1	IgG2a	IgG2b	IgG3
5.0	none	none	55,068	13,731	<500	<500	<500
5.0	0	100	233,008	55,620	<500	1,157	990
5.0	50	100	285,806	64,493	1,050	1,329	2,634
5.0	200	100	203,236	56,654	1,789	692	2,693
5.0	1,000	100	371,329	35,778	4,048	1,080	3,820
1.0	none	none	77,714	9,070	<500	608	<500
1.0	0	100	141,371	14,829	<500	<500	542
1.0	50	100	97,999	14,336	449	814	1,034
1.0	200	100	137,674	17,380	752	569	816
1.0	1,000	100	214,739	25,056	4,685	1,260	4,055
0.1	none	none	4,726	706	<500	<500	<500
0.1	0	100	79,686	12,071	<500	869	<500
0.1	50	100	70,917	9,649	1,032	1,389	<500
0.1	200	100	46,503	7,779	885	1,056	572
0.1	1,000	100	87,762	6,788	1,725	<500	1,682

Mice were immunized with indicated dose of nonavalent pneumococcal glycoconjugate vaccine at weeks 0 and 3. The conjugates were formulated alone, with AlPO4 (100 μg) or with AlPO4 plus IL-12. Individual mouse Sera from the week 5 bleed were analyzed for IgG antibodies to PnPs4.

TABLE 25
Effect of IL-12 on the PnPs6B response of mice
immunized with nonavalent pneumococcal glycoconjugate
vaccine formulated with AlPO4
Vaccine Formulation
Con-
jugate		PnPs6B Response at Week 5
Dose	IL-12	AlPO 4	Total
(μg)	(ng)	(μg)	IgG	IgG1	IgG2a	IgG2b	IgG3
5.0	none	none	64,734	20,221	<100	195	325
5.0	0	100	103,686	39,061	138	2,498	1,801
5.0	50	100	487,798	127,753	916	3,200	13,758
5.0	200	100	214,743	59,979	924	959	6,459
5.0	1,000	100	427,514	94,478	4,426	2,552	13,142
1.0	none	none	165,558	37,646	<100	2,047	2,337
1.0	0	100	730,910	133,441	990	2,770	7,468
1.0	50	100	428,549	77,124	838	3,755	12,931
1.0	200	100	164,820	29,685	316	662	4,703
1.0	1,000	100	401,513	51,132	11,442	2,735	31,613
0.1	none	none	4,787	1,034	<100	<100	<100
0.1	0	100	370,177	71,287	603	11,372	5,712
0.1	50	100	137,091	25,447	1,029	3,346	3,411
0.1	200	100	128,428	31,634	434	2,698	1,891
0.1	1,000	100	524,385	67,301	9,611	11,587	8,711

Mice were immunized with indicated dose of nonavalent pneumococcal glycoconjugate vaccine at weeks 0 and 3. The conjugates were formulated alone, with AlPO4 (100 μg) or with AlPO4 plus IL-12. Sera from the week 5 bleed were analyzed for IgG antibodies to PnPs6B.

TABLE 26
Effect of IL-12 on the PnPs9V response of mice
immunized with nonavalent pneumococcal glyconconjugate
vaccine formulated with AlPO4
Vaccine Formulation	PnPs9V Response at Week 5
Conjugate	IL-12	AlPO 4	Total
Dose (μg)	(ng)	(μg)	IgG	IgG1	IgG2a	IgG2b	IgG3
5.0	none	none	36,831	15,568	306	250	317
5.0	0	100	78,614	37,544	359	667	286
5.0	50	100	117,345	61,031	1,073	834	2,089
5.0	200	100	134,333	35,031	2,973	748	2,594
5.0	1,000	100	197,407	40,368	15,353	2,147	1,945
1.0	none	none	81,932	34,845	546	2,232	735
1.0	0	100	100,448	55,608	660	1,274	699
1.0	50	100	157,316	47,285	1,084	2,036	4,730
1.0	200	100	154,672	48,318	1,765	860	2,044
1.0	1,000	100	168,614	54,223	10,037	1,469	3,006
0.1	none	none	<500	181	<100	<100	<100
0.1	0	100	86,952	26,425	206	485	1,285
0.1	50	100	20,746	6,381	579	726	353
0.1	200	100	19,966	5,501	778	325	235
0.1	1,000	100	50,219	3,511	1,290	1,036	714

Mice were immunized with indicated dose of nonavalent pneumococcal glycoconjugate vaccine at weeks 0 and 3. The conjugates were formulated alone, with AlPO4 (100 μg) or with AlPO4 plus IL-12. Sera from the week 5 bleed were analyzed for IgG antibodies to PnPs9V.

TABLE 27
Effect of IL-12 on the PnPs14 response of mice
immunized with nonavalent pneumococcal glyconconjugate
vaccine formulated with AlPO4
Vaccine Formulation
Con-
jugate		PnPs14 Response at Week 5
Dose	IL-12	AlPO 4	Total
(μg)	(ng)	(μg)	IgG	IgG1	IgG2a	IgG2b	IgG3
5.0	none	none	2,676	1,750	<100	<100	<100
5.0	0	100	11,792	15,704	124	580	1,723
5.0	50	100	56,712	31,056	6,144	2,854	11,840
5.0	200	100	5,049	3,050	1,588	<100	2,106
5.0	1,000	100	11,848	3,760	1,853	366	2,035
1.0	none	none	4,846	3,116	<100	409	699
1.0	0	100	20,605	31,022	291	2,383	9,286
1.0	50	100	8,338	4,722	1,354	715	10,079
1.0	200	100	5,618	3,252	1,014	<100	583
1.0	1,000	100	13,026	3,551	2,879	671	2,070
0.1	none	none	<100	105	<100	<100	<100
0.1	0	100	114	392	<100	<100	710
0.1	50	100	2,140	2,838	<100	245	3,592
0.1	200	100	2,200	426	<100	622	759
0.1	1,000	100	394	378	219	100	658

Mice were immunized with indicated dose of nonavalent pneumococcal glycoconjugate vaccine at weeks 0 and 3. The conjugates were formulated alone, with AlPO4 (100 μg) or with AlPO4 plus IL-12. Sera from the week 5 bleed were analyzed for IgG antibodies to PnPs14.

Example 7

The Effect of IL-12 and AlPO4 on the Immune Response to Neiserria meningitidis Type C (menC) Glyconconjugate Vaccine

STUDY DESIGN

This study evaluated IL-12 with a vaccine against Neiserria meningitidis type C (menC). Swiss Webster mice were immunized at weeks 0 and 3 with 0.1 μg or 1 μg of MenC glycoconjugate formulated alone, with AlPO 4 (100 μg) or a combination of IL-12 (50 ng) and AlPO4. Normal mouse serum was not added to the vaccine. Mice were bled at weeks 3 and 5 and sera analyzed for IgG antibodies to menC polysaccharide by ELISA.

RESULTS

When immunized with the higher dose of conjugate, equivalent menC IgG titers were generated regardless of the adjuvant formulation. The addition of IL-12/AlPO4 to the vaccine, however, resulted in higher IgG2a titers to the polysaccharide than if formulated with AlPO4 (but no IL-12) or no adjuvant.

In mice immunized with the lower dose of conjugate, higher mening C titers were obtained when the vaccine was formulated with AlPO4 (Table 28). The addition of IL-12 to the adjuvant did not enhance the overall IgG titer but did result in a >10-fold increase in IgG2a antibodies. These data show that IL-12 in combination with AlPO4 can promote the induction of complement-fixing IgG subclasses to menC glyconconjugate vaccine.

TABLE 28
Effect of IL-12/AlPO4 on the IgG response to
menC glyconconjugate vaccine
Vaccine Formulation
MenC		MenC Response
Conjugate	IL-12	AlPO 4	IgG	IgG Subclass at Week 5
(μg)	(ng)	(μg)	Week 3	Week 5	IgG1	IgG2a	IgG2b	IgG3
1.0	50	100	33,176	598,027	83,662	7,218	4,351	1,436
	0	100	34,553	404,111	71,017	1,383	3,085	1,006
	0	0	16,254	288,493	63,043	1,965	<100	502
0.1	50	100	2,584	68,678	9,604	3,440	1,967	512
	0	100	8,174	30,450	6,532	288	429	<100
	0	0	1,724	7,894	1,767	<100	<100	<100

Example 8

The Effect of IL-12 and AlPO4 on the Immune Response to Hemophilus influenzae Type b Glycoconjugate Vaccine (HbOC)

STUDY DESIGN

This study evaluated IL-12 with a vaccine against Hemophilus influenzae type b. Swiss Webster mice (10 per group) were immunized at weeks 0 and 3 with 0.1 μg or 1.0 μg of glycoconjugate vaccine consisting of capsular polysaccharide from Hemophilus influenzae type b (HibPs) conjugated to CRM 197 . The vaccine (HbOC) was administered alone or in combination with AlPO4 (100 μg) or a mixture of IL-12 (50 ng) plus AlPO4. Normal mouse serum was not added to the vaccine. The mice were bled at weeks 3 and 5. The antibody response to HibPs was measured using a Farr assay which measures all antibodies binding to the saccharide regardless of isotope, i.e., IgM, IgG and IgA. The IgG subclass response was measured by ELISA. Additionally, the IgG and IgG subclass response to CRM 197 was also determined by ELISA.

RESULTS

The titers of anti-HibPs antibodies in serum pooled from the week 3 bleed (primary response) were not different between mice immunized with vaccine formulated alone, with AlPO4 or IL-12 plus AlPO4 regardless of the dose of conjugate used for immunization (Table 29). Analysis of pooled serum from the week 5 bleed suggested that in mice immunized with 1 μg of HbOC with IL-12 plus alum resulted in at least a 10-fold higher anti-HibPs than when given with alum or without adjuvant (Table 30) However, analysis of individual mouse sera showed that this was due to a single mouse having a titer of approximately 10,000 μg/mL. When the results are expressed as geometric mean titer there was no evidence of an enhanced HibPs response due to IL-12. The IgG subclass response to HibPs was evaluated on pooled sera by ELISA The combination of IL-12 and AlPO4 appeared to enhance the IgG2a titer 3-fold in mice immunized with 1 μg of conjugate. However, this was no different than the titer obtained with vaccine adjuvanted with AlPO4 alone. In mice immunized with 0.1 μg of HbOC, IL-12 plus AlPO4 did not enhance the IgG2a titer to HibPs. That the IL-12/AlPO4 adjuvant combination was active was revealed by analysis of the anti-CRM 197 response (Table 31) where increased IgG2a titer to the carrier protein was seen in mice immunized with either dose of conjugate.

TABLE 29
Anti-HibPs antibody response of mice immunized
with HbOC formulated with IL-12 and AlPO4
	Anti-HibPs Antibody Response
	(μg/mL)
Vaccine Formulation	Week 3	Week 5
HbOC	IL-12	AlPO 4	Pooled	Pooled
(μg)	(ng)	(μg)	Serum	Serum	GMT*
1.0	50	100	9.73	469.16	26.92
	0	100	13.04	42.55	21.30
	0	0	5.12	33.19	2.25
0.1	50	100	3.18	30.95	ND
	0	100	4.06	15.11	ND
	0	0	3.03	14.05	ND

TABLE 30
Effect of IL-12 and AlPO4 on the IgG subclass
response to HbOC
	Anti-HibPs IgG Subclass
Vaccine Formulation	Response at Week 5 (ELISA
HbOC	IL-12	AlPO 4	Endpoint Titer)
(μg)	(ng)	(μg)	IgG1	IgG2a
1.0	50	100	754,745	26,899
	0	100	122,637	12,880
	0	0	73,114	8,570
0.1	50	100	46,673	17,290
	0	100	68,176	14,971
	0	0	35,237	11,418

TABLE 31
Anti-CRM 197 IgG response of mice immunized with
HbOC formulated with IL-12 and AlPO4
Vaccine Formulation
HbOC	IL-12	AlPO 4	Anti-CRM 197 Response at Week 5
(μg)	(ng)	(μg)	IgG	IgG1	IgG2a	IgG2b
1.0	50	100	1,775,700	681,944	39,672	40,527
	0	100	2,221,780	818,557	19,010	32,672
	0	0	3,979,530	1,466,010	8,059	15,961
0.1	50	100	761,027	292,448	38,258	21,008
	0	100	891,251	346,728	6,546	14,832
	0	0	874,805	151,397	1,899	3,517

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

Claims

1. A composition comprising a mixture of a pneumococcal capsular polysaccharide, an adjuvant amount of interleukin-12 and an aqueous suspension of alum, and optionally comprising a physiologically acceptable vehicle.

2. A composition according to claim 1, wherein the interleukin-12 is adsorbed onto the alum suspension.

3. A composition according to claim 1, wherein the interleukin-12 is human interleukin-12.

4. A composition according to claim 1, wherein the alum is aluminum hydroxide or aluminum phosphate.

5. A composition according to claim 1, wherein the pneumococcal capsular polysaccharide is selected from the group consisting of pneumococcal capsular polysaccharide serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F and 23F and combinations thereof.

6. A composition according to claim 1, wherein the pneumococcal capsular polysaccharide is conjugated to a carrier molecule.

7. A composition according to claim 6, wherein the carrier molecule is selected from the group consisting of tetanus toxin, diphtheria toxin, pertussis toxin and non-toxic variants thereof.

8. A composition according to claim 7, wherein the carrier molecule is CRM197.

9. A method of eliciting an immune response to a pneumococcal capsular polysaccharide, comprising administering to a mammalian host an effective amount of a vaccine composition comprising a mixture of a pneumococcal capsular polysaccharide, an adjuvant amount of interleukin-12 and an aqueous suspension of alum, and optionally comprising a physiologically acceptable vehicle.

10. A method according to claim 9, wherein the interleukin-12 is adsorbed onto the alum suspension.

11. A method according to claim 9, wherein the interleukin-12 is human interleukin-12.

12. A method according to claim 9, wherein the alum is aluminum hydroxide or aluminum phosphate.

13. A method according to claim 9, wherein the pneumococcal capsular polysaccharide is selected from the group consisting of pneumococcal capsular polysaccharide serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F and 23F and combinations thereof.

14. A method according to claim 9, wherein the pneumococcal capsular polysaccharide is conjugated to a carrier molecule.

15. A method according to claim 14, wherein the carrier molecule is selected from the group consisting of tetanus toxin, diphtheria toxin, pertussis toxin and non-toxic variants thereof.

16. A method according to claim 15, wherein the carrier molecule is CRM197.

17. An immunogenic composition comprising a mixture of a pneumococcal capsular polysaccharide, an adjuvant amount of interleukin-12 and an aqueous suspension of alum, and optionally comprising a physiologically acceptable vehicle.

18. An immunogenic composition according to claim 17, wherein the interleukin-12 is adsorbed onto the alum suspension.

19. An immunogenic composition according to claim 17, wherein the interleukin-12 is human interleukin-12.

20. An immunogenic composition according to claim 17, wherein the alum is aluminum hydroxide or aluminum phosphate.

21. An immunogenic composition according to claim 17, wherein the pneumococcal capsular polysaccharide is selected from the group consisting of pneumococcal capsular polysaccharide serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F and 23F and combinations thereof.

22. An immunogenic composition according to claim 17, wherein the pneumococcal capsular polysaccharide is conjugated to a carrier molecule.

23. An immunogenic composition according to claim 22, wherein the carrier molecule is selected from the group consisting of tetanus toxin, diphtheria toxin, pertussis toxin and non-toxic variants thereof.

24. An immunogenic composition according to claim 23, wherein the carrier molecule is CRM197.