IMPROVED METHODS FOR ENTEROVIRUS INACTIVATION, ADJUVANT ADSORPTION AND DOSE REDUCED VACCINE COMPOSITIONS OBTAINED THEREOF

Abstract

The present invention is directed to improved methods of Enterovirus inactivation by formaldehyde in presence of tromethamine buffer resulting in maximum recovery of D-antigen. Subsequent adsorption of said sIPV on aluminium hydroxide provides significantly dose reduced sIPV compositions.

Description

BACKGROUND OF THE INVENTION

The prevalence of polio virus has largely been decreased by the use of Oral Polio Vaccine (OPV), based on live-attenuated Sabin polio strains. However, OPV has limitations for the post-eradication era. Therefore, development of Sabin-IPV plays an important role in the WHO polio eradication strategy. The use of attenuated Sabin instead of wild-type Salk polio strains will provide additional safety during vaccine production. Moreover, to prevent the emergence of circulating vaccine-derived polioviruses (cVDPVs), the use of OPV should be discontinued following polio eradication, and replaced by IPV. These cVDPVs are transmissible and can become neurovirulent (similar to wild polioviruses) resulting in vaccine associated paralytic poliomyelitis. Such strains can potentially re-seed the world with polioviruses and negate the eradication accomplishments.

IPV is delivered by intramuscular (IM) or deep subcutaneous (SC) injection. IPV is currently available either as a non-adjuvanted stand-alone formulation, or in various combinations, including DT-IPV (with diphtheria and tetanus toxoids) and hexavalentDTPHepB-Hib-IPV vaccines (additionally with pertussis, hepatitis B, and Haemophilus influenzae b. The currently acceptable standard dose of polio vaccines contains D antigens as 40 Units of inactivated poliovirus type 1 (Mahoney), 8 units of inactivated poliovirus type 2 (MEF-I) and 32 units of inactivated poliovirus type 3 (Saukett) (e.g. Infanrix-IPV™). Existing preparations of stand-alone IPV do not contain adjuvant.

Most experts agree that worldwide use of IPV is preferable because of its proven protective track-record and safety. However, when compared to OPV, the cost-prize for IPV is significantly higher. This is mainly due to requirements for: (i) more virus per dose; (ii) additional downstream processing (i.e. concentration, purification and inactivation), and the related QC-testing (iii) loss of antigen or poor recovery in downstream and iv) containment. Until now, the financial challenge has been a major drawback for IPV innovation and implementation in low and middle-income countries. The production costs of sIPV are currently estimated equivalent to that for IPV, which is about 20-fold more expensive than OPV. The future global demand for IPV following eradication of polioviruses could increase from the current level of 80 million doses to 450 million doses per year. Consequently, approaches to “stretch” supplies of IPV are likely to be required.

Reduced-dose efficacious vaccine formulations which provide protection against infection using a lower dose of IPV antigen are desirable in situations where the supply of conventional vaccine is insufficient to meet global needs or where the cost of manufacture of the conventional vaccine prevents the vaccine being sold at a price which is affordable for developing countries. Also the exposure to lower dose of IPV; compared to the existing marketed formulations could be more safer. Thus, various strategies to make IPV available at more affordable prices need to be evaluated.

In case of pandemic influenza vaccines the use of adjuvants has permitted dose reduction, increased the availability and reduced cost of the vaccine. Therefore, it has been speculated that an adjuvanted vaccine formulation of sIPV would reduce cost and also increase the number of available sIPV doses worldwide.

Globally different research groups have been evaluating dose sparing for vaccines (Influenza vaccines in particular) by employing several adjuvants namely Alum, Emulsion, TLR-agonists (MPL, CpG, poly-IC, imiquimod), dmLT, 1,25-dihydroxyvitamin D3, CAF01, poly [di (carboxylatophenoxy)-phosphazene] (PCPP) and Venezuelan equine encephalitis (VEE) replicon particles. Most of the adjuvant types being studied have encountered following hurdles i) Unknown safety or classified as toxic by regulatory agencies ii) having limitations regards to route of administration iii) lacking manufacturing reproducibility iv) stability of adjuvant.

Emulsion adjuvants (MF-59, AS03, AF3) have been previously reported to provide a strong dose-reduction effect (>30 fold) for Influenza and Hepatitis B vaccines. These adjuvants work by forming a depot at the site of injection, enabling the meted release of antigenic material and the stimulation of antibody producing plasma cells. However, these adjuvants have been deemed too toxic for widespread human prophylactic vaccine use and are usually reserved for those severe and/or terminal conditions such as cancer where there is a higher tolerance of side-effects.

Further, Aluminum salts have been considered safe, are already being used in combination vaccines containing sIPV, have the lowest development hurdles and are inexpensive to manufacture. However aluminium adjuvants are not known for permitting significant dose-reduction.

One of the most critical steps in the production of vaccines against pathogens, in particular viral vaccines, is viral inactivation. In the case of virus inactivation, formalin is the most frequently used inactivating agent in the manufacture of vaccines. Formaldehyde inactivates a virus by irreversibly cross-linking primary amine groups in surface proteins with other nearby nitrogen atoms in protein or DNA through a —CH2-linkage. A potential problem with using formalin for viral inactivation is that this involves a series of chemical reactions that produce reactive products that can induce cross-linking of viral proteins and aggregation of virus particles. This could hamper the inactivating efficiency of the formalin and could also result in the partial destruction of the immunogenicity of the antigen in vaccine. Accordingly, it has been reported previously that formalin inactivation of polioviruses could affect the viral immunogenicity as well as antigenicity. Refer Morag Ferguson et al Journal of General Virology (1993), 74, 685-690. Most importantly, previously disclosed formaldehyde inactivation methods were particularly carried out in presence of phosphate buffer wherein significant D-antigen losses were observed along with epitope modification for Sabin Type I/II/III (D-antigen recovery post inactivation: 22% for sabin type I, 15% for sabin type II, 25% for sabin type III), thereby failing to preserve the epitopic conformation. It is therefore possible that antibodies produced by recipients of formalin-inactivated polioviruses (in presence of phosphate buffer) may not contribute to the protective immune response.

By combining formalin and UV-inactivation, scientists tried to overcome the limitations of isolated UV-inactivation or formalin-inactivation, respectively, when inactivating the particularly resilient poliovirus. See, e.g., McLean, et al., “Experiences in the Production of Poliovirus Vaccines,” Prog. Med. Virol., vol 1, pp. 122-164 (1958.) Taylor et al. (J. Immunol. (1957) 79:265-75) describe the inactivation of poliomyelitis virus with a formalin and ultraviolet combination. Molner et al. (Am. J. Pub. Health (1958) 48:590-8) describe the formation of a measurable level of circulating antibodies in the blood of subjects vaccinated with ultraviolet-formalin inactivated poliomyelitis vaccine. Truffelli et al. (Appl. Microbiol. (1967) 15:516-27) report on the inactivation of Adenovirus and Simian Virus 40 Tumorigenicty in hamsters by a three stage inactivation process consisting of formalin, UV light and β-propiolactone (BPL). Miyamae (Microbiol. Immunol. (1986) 30:213-23) describes the preparation of immunogens of Sendai virus by a treatment with UV rays and formalin. However previously discussed promising alternatives for formaldehyde like β-propiolactone (BPL) have been reported to produce an immune complex-reaction when combined with other components of the rabies vaccine. Additionally, it has been shown to produce squamous cell carcinomas, lymphomas and hepatomas in mice.

It is therefore particularly desirable to employ favorable formaldehyde inactivation conditions that maintain the structural integrity of antigenic structures of Sabin strains as well as utilize safe and cost-effective adjuvants that can result in significantly dose reduced (i.e. 8 to 10 fold) sIPV (Sabin IPV) vaccine compositions thereby reducing cost of manufacture, increasing vaccine supplies and making vaccines affordable for developing countries.

The present inventors have surprisingly found that D-antigen losses post-formaldehyde inactivation could be due to presence of phosphate buffer that unexpectedly causes undesirable aggregation of polio viruses. The instant invention provides an improved process of formaldehyde inactivation in presence of TRIS buffer thereby ensuring minimal epitopic modifications and subsequently minimizing D-antigen losses. Subsequently significantly dose reduced Sabin IPV vaccine compositions with atleast 8 fold dose reduction for Sabin Type I and 3 fold dose reduction for Sabin Type III can be obtained.

DESCRIPTION OF FIGURES

FIG. 1: Alum phosphate gel prepared in 0.9% NaCl (pH Vs Zeta potential at different concentrations of Alum phosphate gel)

FIG. 2: Alum phosphate gel prepared in WFI (pH Vs Zeta potential at different concentrations of Alum phosphate gel)

FIG. 3: Alum Hydroxide gel prepared in 0.9% NaCl (pH Vs Zeta potential at different concentrations of Alum hydroxide gel)

FIG. 4: Alum Hydroxide gel prepared in WFI (pH Vs Zeta potential at different concentrations of Alum hydroxide gel)

DETAILED DESCRIPTION

An important aspect of the instant invention is that said improved process of formalin inactivation and adsorption on alum salt comprises of following steps:

• a) Adding Sabin IPV purified bulk to TRIS buffer (30 to 50 mM) having pH between 6.8 to 7.2,
• b) Adding M-199 medium containing glycine (5 gm/1) to mixture of (a),
• c) Adding 0.025% formaldehyde while mixing,
• d) Incubating mixture obtained in Step (c) at 37° C. from 5 to 13 days on magnetic stirrer,
• e) Subjecting post-incubation mixture to intermediate 0.22μ filtration on day 7 and final filtration on day 13,
• f) Storing bulk obtained after step (e) at 2-8° C.,
• g) Performing D-Ag ELISA for D-Antigen unit determination,
• h) Taking the desired volume of autoclaved Al(OH)₃ to get the final concentration of Alum(Al++) between 0.8 to 1.2 mg/dose in a 50 ml Container,
• i) Adding sIPV bulk with adjusted D-Ag unit and making up the volume with diluent (10×M-199+0.5 Glycine %),
• j) Adjusting the final formulation pH and obtaining final formulation with pH between 6 and 6.5,
• k) Subjecting the formulation bulk to magnetic stirring overnight at 2-8° C. and wherein formalin inactivation of step (a) does not occur in presence of phosphate buffer

A first embodiment of instant invention is that said buffer to be used during formaldehyde inactivation can be selected from the group consisting of TRIS, TBS, MOPS, HEPES, and bicarbonate buffers.

A preferred aspect of first embodiment is that said formaldehyde inactivation can occur in presence of TRIS Buffer or TBS (TRIS Buffered saline) having concentration selected from 30 mM, 40 mM and 50 mM, preferably 40 mM and at a pH selected from 6.8, 6.9, 7, 7.1 and 7.2, preferably between 6.8 and 7.2 wherein said inactivation does not utilize any phosphate buffer.

A second embodiment of the instant invention is that adsorption of formalin inactivated sIPV can be done on aluminium hydroxide having concentration selected from 1.5 mg/dose, 1.8 mg/dose, 2.2 mg/dose, preferably between 2 mg/dose to 2.4 mg/dose and at a pH selected from 6.2, 6.3, 6.4 and 6.5, preferably 6.5.

A third embodiment of instant invention is that said improved process of formalin inactivation and aluminium hydroxide adsorption can result in D-Antigen recovery post-inactivation between 50% and 80% and percent adsorption of aluminium hydroxide can be between 85 and 99%.

One aspect of third embodiment is that present invention provides an improved process of formalin inactivation and aluminium hydroxide adsorption resulting in dose reduction of atleast 8 fold for Sabin Type I, atleast 3 fold for Sabin Type III as compared to standard dose of 40 DU-8DU-32DU. Second aspect of third embodiment is that instant invention provides improved formaldehyde inactivation and aluminium hydroxide adsorption methods that result in vaccine compositions comprising of i) inactivated poliovirus type 1 at a dose of atleast 5D-antigen units, ii) inactivated poliovirus type 2 at a dose of atleast 8D-antigen units and iii) inactivated poliovirus type 3 at a dose of atleast 10D-antigen units.

A fourth embodiment of instant invention is that said aluminium salt adjuvant is an aluminium hydroxide having concentration between 1.5 mg/0.5 ml dose and 2.5 mg/0.5 ml dose, preferably between 2.100 mg/0.5 ml dose and 2.4 mg/0.5 ml dose at a pH of about 6.5.

One aspect of fourth embodiment is that total aluminium content in the trivalent vaccine (Type 1, 2 and 3) can be between 800-1000 μg, preferably 800 μg Al³⁺+ per 0.5 mL dose, characterized in that atleast 400 μg Al³⁺ for Type 1, atleast 200 μg Al³⁺ for Type 2, atleast 200 μg Al³⁺ for Type 3.

Another aspect of fourth embodiment is that said dose reduced polio virus vaccine composition can consist of Type 1 and Type 3 and is devoid of Type 2 wherein the dose volume can be between 0.1 and 0.4 ml.

The dose reduced vaccine compositions prepared by instant methods can be i) “Standalone sIPV” wherein the antigens may comprise of sIPV type 1 or sIPV type 2 or sIPV type 3, or sIPV types 1 and 2, or sIPV types 1 and 3, or sIPV types 2 and 3, or sIPV types 1, 2 and 3 or ii) “Combination Vaccines containing sIPV” wherein said non-IPV antigens of combination vaccines can be selected from but not limited to diphtheria toxoid, tetanus toxoid, whole cell pertussis antigen(s), acellular pertussis antigen(s), Hepatitis B surface antigen, Haemophilus influenzae b antigen(s), Neisseria meningitidis A antigen(s), Neisseria meningitidis C antigen(s), Neisseria meningitidis W-135 antigen(s), Neisseria meningitidis Y antigen(s), Neisseria meningitidis X antigen(s), Neisseria meningitidis B bleb or purified antigen(s), Hepatitis A antigen(s), Salmonella typhi antigen(s), Streptococcus pneumoniae antigen(s).

The non-IPV antigen(s) may be adsorbed onto an aluminium salt such as aluminium hydroxide, an aluminium salt such as aluminium phosphate or onto a mixture of both aluminium hydroxide and aluminium phosphate, or may be unadsorbed.

Poliovirus may be grown in cell culture. The cell culture may be a VERO cell line or PMKC, which is a continuous cell line derived from monkey kidney. VERO cells can conveniently be cultured microcarriers. After growth, virions may be purified using techniques such as ultrafiltration, diafiltration, and chromatography. Prior to administration to patients, the viruses must be inactivated, and this can be achieved by treatment with formaldehyde.

Compositions may be presented in vials, or they may be presented in ready filled syringes. The syringes may be supplied with or without needles. A syringe will include a single dose of the composition, whereas a vial may include a single dose or multiple doses (e.g. 2 doses). In one embodiment the dose is for human. In a further embodiment the dose is for an adult, adolescent, toddler, infant or less than one year old human and may be administered by injection.

Vaccines of the invention may be packaged in unit dose form or in multiple dose form (e.g. 2 doses). The said multidose composition can be selected from a group consisting of 2 dose, 5 dose and 10 dose. For multiple dose forms, vials are preferred to pre-filled syringes. Effective dosage volumes can be routinely established, but a typical human dose of the composition for injection has a volume of 0.5 mL.

EXAMPLES

Example 1

Purification of Sabin IPV (sIPV)

1) Tangential Flow Filtration (TFF):

• • Clarified harvest pool was concentrated to 10× using tangential flow filtration system with 100 Kda cassettes (0.5 m²) and then diafiltered 3 times of harvest volume with phosphate buffer (40 mM, pH: 7.0)

2) Column Chromatography:

• • The purification was done by Ion Exchange Chromatography (IEC). 10×TFF concentrate was passed through DEAE Sepharose fast flow (Weak-Anion exchanger) packed in column xk-26 using Akta explorer (GE Healthcare). Negatively charged impurities was found to bind to the column whereas polio virus was collected in flow through with phosphate buffer 40 mM.

3) TRIS Buffer Exchange:

• • To minimize the loss of antigen in a quite cumbersome inactivation procedure (13 days), purified virus pool was buffer exchanged from phosphate buffer to TRIS buffer (40 mM, pH: 7) with TFF system (100 KDa, 0.1 m2). The purified virus pool was exchanged with three volumes of tris buffer.

Example 2

A) Inactivation of sIPV

• • 10× concentrated M-199 with 0.5% glycine was added so as to achieve final concentration 1×. Inactivation agent formalin (0.025%) was added into purified virus bulk while constant mixing. Inactivation was carried out at 37° C. while continuous stirring for 13 days containing 0.22 u filtration on 7th day and 13th day.

B) Inactivation of sIPV in TRIS Buffer and Phosphate Buffer

0.025% formaldehyde was used for inactivation for 13 days at 37° C.

TABLE 1
D-Antigen Content, Formalin inactivation in
presence of TRIS buffer and Phosphate buffer
	D-Antigen content (40 mM	D-Antigen content (40 mM
	Phosphate buffer during	Tris buffer during
	Inactivation)	Inactivation)
Type 1	52.70 DU/ml	408.19 DU/ml
Type 2	22.63	180.20
Type 3	4.21	21.50

When formaldehyde inactivation methods were particularly carried out in presence of phosphate buffer, significant D-antigen losses were observed for Sabin Type I. Whereas it was found that formaldehyde inactivation in presence of TRIS buffer resulted in minimum loss of D-antigen.

TABLE 2
Different concentrations of TRIS Buffer used during inactivation
	30 mM	40 mM	50 mM
	Type 1	500 DU/ml	576.80 DU/ml	585 DU/ml
	Type 2	140 DU/ml	165.16 DU/ml	155 DU/ml
	Type 3	16 DU/ml	21.17 DU/ml	19 DU/ml

• • TRIS Buffer at a concentration of 40 mM was found to be most efficient in terms of D-Antigen content preservation for sIPV 1, 2 and 3.

C) D-Antigen Content Determination by ELISA.

Day 1: Plate Coating:

• • 1. 100 ul of specific bovine anti polio was pippeted in PBS per well
  • 2. Microtiter plate was sealed and incubated overnight at room temperature.

Day 2: Blocking:

• • 1. The plates were washed (Washing/dilution buffer −0.05% tween 20 in 1×PBS) 3 times.
  • 2. 300 ul block buffer (1% BSA in PBS) was pipetted per well.
  • 3. The plate was sealed and incubated for 45 minutes at 37±1° C.

Sample Addition:

• • 1. The plate was washed 3 times.
  • 2. 100 ul of sample diluent was added in all wells except well of row A.
  • 3. 100 ul standard was added to first two wells of column 2 and 3.
  • 4. 100 ul sample was added to first two wells of column 4-12.
  • 5. Prediluting sample to a suitable concentration.
  • 6. 100 ul sample diluents was added to first two wells of column 1.
  • 7. Serial two fold dilution were made down the column by transferring 100 ul from each well to adjacent well of the same column and discarding 100 ul from the last well.
  • 8. Incubating at 37° C. for 2 hr.
  • 9. Plates were kept overnight at 4° C.

Day 3: Monoclonal Antibody Addition:

• • 1. The plate was washed 3 times.
  • 2. 100 ul diluted (1:240) type specific monoclonal antibodies were added.
  • 3. The plates were sealed and incubated for 2 hours at 37° C.

Conjugate:

• • 1. The plate were washed 3 times
  • 2. 100 ul diluted conjugate (Type1-1:2400, Type2-1:1500, Type3-1:4800) was added.
  • 3. The plate was sealed and incubated for 1 hour at 37° C.

Substrate Addition:

• • 1. 100 ul TMB substrate was added to all wells.
  • 2. Mixture incubated at room temperature for 10 minutes.
  • 3. Reaction was stopped by adding 100 ul 2M H2SO4.
  • 4. Plate was read at 450/630 nm.
  • 5. D antigen concentration was calculated using KC4 software.

Example 3

Adsorption of sIPV:

• • 1. Autoclaved 1% stock of Al(OH)₃ and AlPO₄ was used for the preparation of formulations.
  • 2. Desired volume of Al(OH)₃/AlPO₄ was taken to get the required concentration of alum in a 100 ml glass bottle.
  • 3. Inactivated polio virus bulk with known D-Ag Unit was added and volume make up was done with diluent.
  • 4. Final formulation pH was adjusted to 6.5 with 1 N HCl/NaOH.
  • 5. The formulation bulk was kept on magnetic stirrer overnight at 2-8° C.

Example 4

Preformulation Studies

Different concentrations of Al(OH)₃ & AlPO₄ were prepared in 0.9% saline and in WFI to check size and zeta potential with respect to change in pH.

It was observed that zeta potential of AlPO₄ decreases (negativity) with increase in pH from 5 to 7.5 in presence of WFI as well as in saline (Refer FIGS. 1 and 2).

Whereas, zeta potential of Al(OH)₃ in saline remains constant, independent of pH and Al(OH)₃ salt concentration (Refer FIGS. 3 and 4).

Example 5

Adsorption Studies of sIPV on Alum Phosphate and Alum Hydroxide

TABLE 3
Sabin Type 1, 2&3 (Titer 106.0/dose) adsorption
on alum (Alum phosphate and Alum Hydroxide)
			Virus
		Titer (per	Particles	% free in	% adsorbed
	Sample	does)	(in K)	SUP	on gel
Type 1,	Control	5.45	284	NA
AlOH3	Al+++	4.15	14	4.98	95.02
	125 ug/dose
	Al+++	3.85	7	2.49	97.51
	250 ug/dose
	Al+++	3.8	6.3	2.24	97.78
	500 ug/dose
Type 1,	Control	5.84	691	NA
AlPO4	Al+++	3.49	3	0.43	99.57
	125 ug/dose
	Al+++	3.09	1.2	0.17	99.83
	250 ug/dose
	Al+++	2.94	0.87	0.12	99.87
	500 ug/dose
Type 2,	Control	5.49	309	NA
AlOH3	Al+++	3.59	3.89	1.25	98.75
	125 ug/dose
	Al+++	3.49	3.09	1	99
	250 ug/dose
	Al+++	3.49	3.09	1	99
	500 ug/dose
Type 2,	Control	5.49	309	NA
AlPO4	Al+++	3.15	1.41	0.45	99.5
	125 ug/dose
	Al+++	3.09	1.23	0.39	99.6
	250 ug/dose
	Al+++	3.09	1.23	0.39	99.6
	500 ug/dose
Type 3,	Control	5.59	389	NA
AlOH3	Al+++	4.14	13.8	3.54	96.47
	125 ug/dose
	Al+++	3.94	8.7	2.23	97.77
	250 ug/dose
	Al+++	3.54	3.4	0.87	99.13
	500 ug/dose
Type 3,	Control	5.59	389	NA
AlPO4	Al+++	5.34	218	56.04	43.96
	125 ug/dose
	Al+++	5.24	173	44.47	55.53
	250 ug/dose
	Al+++	5.16	144	37.01	62.9
	500 ug/dose

It was found that Sabin polio virus type-3 shows only 50-60% adsorption with aluminium phosphate (AlPO₄). Whereas, Sabin polio virus type-3 shows atleast 90% adsorption with Al(OH)₃. Thus, Alum hydroxide was found to be more efficient as compared to Alum phosphate with respect to adsorption of Sabin Type 1, 2 and 3.

Example 6

Immunogenicity Studies of Alum Adsorbed sIPV

To check immune response of adjuvanted sIPV in rat (Sera Neutralisation Test) SNT test was carried out. Sera was separated and used to test the presence of neutralizing antibodies for type specific polio virus. Control sera used to validate the test. Virus back-titration was also performed to get the number of challenge virus particles added.

Animal Model: Wistar rat (8 weeks, approx 200 gm) 50% male and 50% female per group.

Route of Inoculation: Intra Muscular.

Volume: 0.5 ml

Blood withdrawal: on day 21.

Site of bleeding: Retro-Orbital plexus.

TABLE 4
Type 1
	Group 1	Group 2	Group 3	Group 4	Group 5	Group 6	Group 7	Group 15
	Comm.	5 DU	2.5 DU	1 DU	5 DU	2.5 DU	1 DU	−ve
	IPV	1.15 mgOH	1.15 mgOH	1.15 mgOH	1.8 mgPO4	1.8 mgPO4	1.8 mgPO	control
Rat	SNT	Sera		Sera		Sera		Sera		Sera	SNT	Sera		Sera		Sera
No	+ve	Titer	SNT	Titer	SNT	Titer	SNT	Titer	SNT	Titer	+ve	Titer	SNT	Titer	SNT	Titer
1	1	(1:2)	8	(1:256)	1	(1:2)	4	(1:16)	5	(1:32)	5	(1:32)	2	(1:4)	0	(<1:2)
2	1	(1:2)	5	(1:32)	1	(1:2)	7	(1:128)	8	(1:256)	4	(1:16)	1	(1:2)	0	(<1:2)
3	0	(<1:2)	7	(1:128)	3	(1:8)	0	(<1:2)	4	(1:16)	6	(1:64)	0	(<1:2)	0	(<1:2)
4	0	(<1:2)	11	(1:2048)	2	(1:4)	2	(1:4)	1	(1:2)	5	(1:32)	0	(<1:2)	0	(<1:2)
5	7	(1:128)	3	(1:8)	7	(1:128)	5	(1:32)	6	(1:64)	4	(1:16)	1	(1:2)	0	(<1:2)
6	4	(1:16)	7	(1:128)	7	(1:128)	1	(1:2)	5	(1:32)	6	(1:64)	3	(1:8)	0	(<1:2)
7	3	(1:8)	5	(1:32)	4	(1:16)	1	(1:2)	8	(1:256)	7	(1:128)	0	(<1:2)	0	(<1:2)
8	1	(1:2)	7	(1:128)	3	(1:8)	2	(1:4)	6	(1:64)	0	(<1:2)	0	(<1:2)	0	(<1:2)
9	3	(1:8)	8	(1:256)	2	(1:4)	3	(1:8)	8	(1:256)	4	(1:16)	4	(1:16)	0	(<1:2)
10	3	(1:8)	7	(1:128)	4	(1:16)	5	(1:32)	6	(1:64)	2	(1:4)	2	(1:4)	0	(<1:2)

It was surprisingly found that Alum hydroxide adjuvanted Type 1 Sabin IPV having 5 DU/dose gave better seroconversion as compared to Salk IPV vaccine with 40 DU/dose and Alum phosphate adjuvanted Sabin IPV having 5 DU/dose.

TABLE 5
Type 2
	Group 1	Group 2	Group 3
	Al(OH)3 Adjuvanted
	4 DU( 0.6 mgOH)	8 DU( 0.6 mgOH)	16 DU 0.6 mgOH
Rat		Sera		Sera		Sera
No	SNT +ve	Titer	SNT +ve	Titer	SNT +ve	Titer
1	3	(1:8)	4	(1:16)	7	(1:128)
2	4	(1:16)	6	(1:64)	5	(1:32)
3	0	(<1:2)	3	(1:8)	5	(1:32)
4	3	(1:8)	4	(1:16)	6	(1:64)
5	5	(1:32)	7	(1:128)	6	(1:64)
6	6	(1:64)	4	(1:16)	9	(1:512)
7	4	(1:16)	7	(1:128)	4	(1:16)
8	5	(1:32)	3	(1:8)	8	(1:256)
9	7	(1:128)	8	(1:256)	8	(1:256)
10	5	(1:32)	3	(1:8)	8	(1:256)

Type 2 sIPV having 8 DU/dose with adjuvant gave equivalent sero conversion as compared to Salk IPV vaccine with 8 DU/dose.

TABLE 6
Type 3
	Group 1	Group 2	Group 3
	Al(OH)3 Adjuvanted
	10 DU 0.6 mgOH	5 DU 0.6 mgOH	2.5 DU 0.6 mgOH
Rat		Sera		Sera		Sera
No	SNT +ve	Titer	SNT +ve	Titer	SNT +ve	Titer
1	3	(1:8)	2	(1:4)	0	(<1:2)
2	0	(<1:2)	5	(1:32)	1	(1:2)
3	2	(1:4)	3	(1:8)	1	(1:2)
4	4	(1:16)	2	(1:4)	0	(<1:2)
5	4	(1:16)	2	(1:4)	1	(1:2)
6	4	(1:16)	1	(1:2)	1	(1:2)
7	9	(1:512)	0	(<1:2)	2	(1:4)
8	7	(1:128)	2	(1:4)	2	(1:4)
9	1	(1:2)	0	(<1:2)	1	(1:2)
10	5	(1:32)	7	(1:128	1	(1:2)

It was found that Type 3 sIPV having 10 DU/dose with adjuvant gave equivalent sero conversion as compared to Salk IPV vaccine with 32 DU/dose.

TABLE 7
Maximum dose reduction observed for individual
Sabin Type 1, 2 & 3 after studies.
	sIPV	Standard dose	*SIIL Dose	Dose reduction
	Type 1	40 DU	5 DU	~8 Folds
	Type 2	8 DU	8 DU	Equivalent
	Type 3	32 DU	10 DU	~3 Folds

SIIL: Serum Institute of India In House dose reduced IPV preparation.

In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.

Claims

1. A method for producing a composition comprising Enteroviral particles, wherein the method comprises the steps of: a) producing a medium containing the Enteroviral particles;b) purification of the Enteroviral particles from the medium;c) stabilization of purified Enteroviral particles;d) formalin inactivation of the Enteroviral particles whereby during at least a part of the inactivation a buffer other than a phosphate buffer is present at a concentration sufficient to prevent or reduce aggregation of the Enteroviral particles thereby reducing the D-antigen losses post inactivation by 8 to 10 fold as compared to phosphate buffer; ande) adsorption of Enteroviral particles on aluminum salt adjuvant whereby percentage adsorption on alum is atleast 95%.

2. The method according to claim 1, wherein the buffer of step (d) is selected from the group consisting of TRIS, TBS, MOPS, HEPES and bicarbonate buffers.

3. The method according to claim 2, wherein the buffer is a TRIS buffer having a pH of about 6.8 to 7.2 and at a concentration in the range of 30 mM-70 mM, preferably 40 mM.

4. The method according to claim 1, wherein the aluminum salt adjuvant of step (e) is selected from a group of aluminum hydroxide, or aluminum phosphate, or a mixture of both.

5. The method according to claim 4, wherein the aluminum salt adjuvant is an aluminum hydroxide having concentration between 1.5 mg/0.5 ml dose and 2.5 mg/0.5 ml dose, preferably between 2.100 mg/0.5 ml dose and 2.4 mg/0.5 ml dose at a pH of about 6.5.

6. The method according to claim 5, wherein total aluminum content in the trivalent vaccine is 0.8-1.2 mg, preferably 0.8 mg Al3+ per 0.5 mL dose, characterized in that atleast 0.4 mg Al3+ for Type 1, atleast 0.2 mg Al3+ for Type 2, atleast 0.2 mg Al3+ for Type 3.

7. The method according to claim 1, wherein the composition comprising Enteroviral particles is a vaccine.

8. The method according to claim 7, wherein the Enteroviral particles are of an Enterovirus of polioviruses.

9. A The method according to claim 8, wherein the Enteroviral particles comprise polioviruses of the Sabin serotypes 1, 2 and 3.

10. The method according to claim 8, wherein the Enteroviral particles comprise polioviruses of Salk serotypes IPV type 1 (Mahoney strain), IPV type 2 (MEF-1 strain); and/or IPV type 3 (Saukett strain).

11. The method according to claim 7, wherein the vaccine is a dose reduced Inactivated Polio Vaccine (IPV).

12. The method according to claim 11, wherein the dose reduced Inactivated Polio vaccine comprises: i) inactivated poliovirus type 1 at a dose less than 15 D-antigen units instead of standard dose of 42 DU; and/orii) inactivated poliovirus type 2 at a dose less than 18 D-antigen units; and/oriii) inactivated poliovirus type 3 at a dose less than 15 D-antigen units instead of standard dose of 32 DU.

13. The method according to claim 15, wherein the method for preparing the dose reduced inactivated Polio vaccine containing Salk or Sabin polioviruses comprises the steps of: a) producing a medium containing the polioviruses;b) purification of the polio viruses from the medium;c) stabilization of purified polioviruses by addition of M-199 medium containing glycine;d) inactivation of the polio viruses by using formaldehyde 0.025% at 37° C. for 5 to 13 days in presence of TRIS buffer at a concentration between 30 mM to 60 mM to prevent or reduce aggregation of the poliovirus particles thereby reducing the D-antigen losses post inactivation by 8 to 10 fold as compared to phosphate buffer; ande) adsorption of inactivated polioviruses on Alum hydroxide adjuvant having concentration between 2 to 2.5 mg/dose, whereby percentage adsorption on Alum hydroxide is greater than 95% for Type 1, Type 2 and Type 3.

14. The method according to claim 15, wherein the method for preparing the dose reduced inactivated Polio vaccine containing Salk or Sabin polioviruses comprises the steps of: a) producing a medium containing the polioviruses;b) purification of the polio viruses from the medium;c) stabilization of purified polioviruses by addition of M-199 medium containing glycine;d) inactivation of the polio viruses by using formaldehyde 0.025% at 37° C. for 5 to 13 days in presence of TRIS buffer at a concentration between 30 mM to 60 mM to prevent or reduce aggregation of the poliovirus particles thereby reducing the D-antigen losses post inactivation by 8 to 10 fold as compared to phosphate buffer; ande) adsorption of inactivated polioviruses on Alum hydroxide adjuvant having concentration between 2 to 2.5 mg/dose, whereby percentage adsorption on Alum hydroxide is greater than 95% for Type 1 and Type 3.

15. The method according to claim 11, wherein the dose reduced Inactivated Polio vaccine can be selected from a group of: i) Sabin single dose composition having Sabin Type 1, Type 2, Type 3 combination selected from 5-16-10;ii) Sabin two dose composition having Sabin Type 1, Type 2, Type 3 combination selected from 5-16-10;iii) Sabin single dose composition having Sabin Type 1, Type 2, Type 3 combination selected from 2.5-8-5;iv) Sabin two dose composition having Sabin Type 1, Type 2, Type 3 combination selected from 2.5-8-5;v) Sabin single dose composition having Sabin Type 1, Type 2, Type 3 combination selected from 5-8-10;vi) Sabin two dose composition having Sabin Type 1, Type 2, Type 3 combination selected from 5-8-10;vii) Salk single dose composition having Sabin Type 1, Type 2, Type 3 combination selected from 7.5-16-10;viii) Salk two dose composition having Sabin Type 1, Type 2, Type 3 combination selected from 7.5-16-10;ix) Salk single dose composition having Salk Type 1, Type 2, Type 3 combination selected from 8-2-5;x) Salk two dose composition having Salk Type 1, Type 2, Type 3 combination selected from 8-2-5;xi) Salk single dose composition having Salk Type 1, Type 2, Type 3 combination selected from 10-2-5;xii) Salk two dose composition having Salk Type 1, Type 2, Type 3 combination selected from 10-2-5;xiii) Salk single dose composition having Salk Type 1, Type 2, Type 3 combination selected from 10-2-12;xiv) Salk two dose composition having Salk Type 1, Type 2, Type 3 combination selected from 10-2-12;xv) Salk single dose composition having Salk Type 1, Type 2, Type 3 combination selected from 5-2-5; andxvi) Salk two dose composition having Salk Type 1, Type 2, Type 3 combination selected from 5-2-5.

16. The method according to claim 15, wherein the dose reduced Salk or Sabin Inactivated Polio Vaccine does not comprise Type 2.

17. The method according to claim 15, wherein a multivalent vaccine consisting of dose reduced IPV can comprise of one or more antigens from a pathogen selected from a list consisting of: Haemophilus influenzae b, Neisseria meningitidis type A, Neisseria Meningitidis type C, Neisseria meningitidis type W, Neisseria meningitidis type Y, Neisseria meningitidis type X, Neisseria meningitidis type B, Streptococcus pneumoniae, Streptococcus agalactiae Salmonella typhi, Hepatitis A, Hepatitis B, RSV, Hepatitis C, diphtheria toxoid, tetanus toxoid, whole cell pertussis, acellular pertussis, Staphylococcus aureus, anthrax, Vibrio cholera, Zika, Ebola, Chikungunya, dengue, malaria, measles, mumps, rubella, BCG, Japanese encephalitis, Rotavirus, smallpox, Shigella, yellow fever, typhoid, CMV, Shingles, Varicella virus, HPV, HSV, and HIV.