Immunity enhancing lactic acid bacteria

Information

  • Patent Grant
  • 6379663
  • Patent Number
    6,379,663
  • Date Filed
    Wednesday, February 16, 2000
    24 years ago
  • Date Issued
    Tuesday, April 30, 2002
    22 years ago
Abstract
Novel bacteria Lactobacillus rhamnosus HN001 and HN 067, Lactobacillus acidophilus HN017, and Bifidobacterium lactis HN019 are claimed. Each strain provides immune enhancing effects when ingested.
Description




This is the U.S. National Phase under 35 U.S.C. § 371 of International Application PCT/NZ98/00122, filed Aug. 18, 1998 which claims priority of Australian Application Nos. AU PP 3225, filed Apr. 28, 1998 and AU PO 8699, filed Aug. 21, 1997.




TECHNICAL FIELD




This invention relates to novel strains of lactic acid bacteria and their use in enhancing immunity.




BACKGROUND ART




The consumption of products containing lactic acid bacteria (LAB) is associated with a range of health benefits including enhancement of immunity. There are thousands of strains of lactic acid bacteria but only some strains exhibit health-promoting properties. The ability of these bacteria to tolerate acids and bile salts, adhere to mucosal epithelial cells, and to survive passage through the gastrointestinal tract is considered an important criterion for selection of health-promoting strains. Only a few strains of lactic acid bacteria with proven health benefits have been identified to date.




Strains of LAB showing good adhesion to the cells of the mucosal epithelium of the small intestine thereby lending themselves to therapeutic applications are known from New Zealand Patent 248057. The micro-organisms described in this patent enhance both natural inununity (phagocyte function) and acquired immunity (antibody responses and lymphocyte proliferation responses).




It is desirable to have other LAB bacteria that enhance a broad spectrum of immune responses including phagocyte function.




It is an object of this invention to go some way towards achieving these desiderata or at least to offer the public a useful choice of immune enhancing lactic acid bacteria.




DISCLOSURE OF THE INVENTION




Accordingly, in one aspect the invention may be said broadly to consist of a biologically pure culture of


Lactobacillus rhamnosus


HN001, AGAL deposit number NM97/09514 dated Aug. 18, 1997.




In another aspect the invention may be said broadly to consist of a biologically pure culture of


Lactobacillus rhamnosus


HN067, AGAL deposit number NM97/01925 dated Feb. 17, 1998.




In another aspect the invention may be said broadly to consist of a composition of a biologically pure culture of any one of


Lactobacillus acidophilus


HN017, AGAL deposit number NM97/09515 dated Aug. 18, 1997


, Lactobacillus rhamnosus


HN001


, Lactobacillus rhamnosus


HN067 or


Bifidobacterium lactis


HN019, AGAL deposit number NM97/09513 dated Aug. 18, 1997 in an immunostimulating concentration, with a physiologically acceptable excipient or diluent.




In one embodiment said composition contains any two or more of said strains.




Preferably said physiologically acceptable excipient or diluent is a food.




Preferably said food is any one of cultured milk, yoghurt, cheese, milk drink or milk powder.




Alternatively said composition is a pharmaceutical composition and said excipient or diluent is pharmacologically acceptable excipient or diluent.




Immunity enhancing, physiologically acceptable, biologically pure strains of homologues or mutants of any one of the strains:






Lactobacillus acidophilus


HN017,






Lactobacillus rhamnosus


HN001,






Bifidobacterium lactis


HN 019, or






Lactobacillus rhamnosus


HN067.




In another embodiment the invention may be said broadly to consist of a method of enhancing natural and acquired immunity which comprises administering to a mammal any one of the above biologically pure cultures at an immunostimulating dosage rate.




In another embodiment substantially biologically pure cultures of two or three of the above-defined strains are present.




Preferably said culture is administered in the form of a composition with a physiologically acceptable excipient or diluent.




Preferably said physiologically acceptable excipient or diluent is a food.




Preferably said food is cultured milk, yoghurt, cheese, milk drink or milk powder.




This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

shows the effect of supplementation of mice with product fermented with


L. rhamnosus


HN001 or unfermented product containing


L. rhamnosus


HN001 on phagocyte activity of peripheral blood leukocytes as described in example 5. BALB/c mice were fed on milk based diets containing 10


9


cfa (per day)


L. rhamnosus


HN001 in either fermented or unfermented product for 14 days. Phagocytic activity of peripheral blood leukocytes was determined using flow cytometry and fluoroscein isothiocyanate-labelled


Escherichia coli


. Values are mean±standard error. Significant differences (ANOVA, the SAS program) from the control: **P<0.0001.





FIG. 2

shows the effect of supplementation of mice with live


L. rhamnosus


HN001 or heat killed L. rhamnosuis HN001 on phagocytic activity of peripheral blood leukocytes as described in example 7. BALB/c mice were fed on milk based diets and orally administered 10


9


cfu (per day) of either live or heat killed


L. rhamnosus


HN001 for 14 days. Phagocytic activity of peripheral blood leukocytes and peritoneal macrophages were determined using flow cytometry and fluoroscein isothiocyanate—labelled


Escherichia coli


. Values are mean±standard error. Significant differences (ANOVA, the SAS program) from the control, **P<0.0001.





FIG. 3

shows the effect of supplementation of mice with


L. rhamnosus


HN001 or


B. lactis


HN019 on bacteria translocation in mice challenged with


S. typhimurium


as described in example 8. Unsupplemented and


B. lactis


HN019, or


L. rhamnosus


HN001 supplemented BALB/c mice were orally challenged with


S. typhimurium


following continuous daily supplementation. Six days after challenge mice were humanely killed and their livers and spleens were harvested for monitoring bacterial translocation. Tissue suspensions from the harvested organs were then cultured on MacConkey agar plates for 24-48 hr prior to enumeration. Values are mean±standard error. Significant differences (ANOVA, the SAS program) from the control: *P<0.05.





FIG. 4

shows the effect of supplementation of mice with


L. rhamnosus


HN001 or


B. lactis


HN019 on the phagocytic activity of peripheral blood leukocytes from mice challenged with


S. typhimurium


as described in example 8. Unsupplemented and


B. lactis


HN019, or


L. rhamnosus


HN001 supplemented BALB/c mice were orally challenged with


S. typhimurium


following continuous daily supplementation. Phagocytic activity of peripheral blood leukocytes was determined six days after challenge using flow cytometry and fluoroscein isothiocyanate-labelled


Escherichia coli


. Values are mean±standard error. Values (mean±standard error) with different superscripts are significantly different (ANOVA, the SAS program): P<0.01.





FIG. 5

shows the effect of supplementation of mice with


L. rhamnosus


HN001 or


B. lactis


HN019 on the proliferative responses of spleen lymphocytes from mice challenged with S. typhimuritim as described in example 8. Unsupplemented and


B. lactis


HN019, or


L. rhamnosus


HN001 supplemented BALB/c mice were orally challenged with


S. typhimurium


following continuous daily supplementation. Six days after challenge the proliferative responses of spleen lymphocytes were measured colourimetrically following the incorporation of 5-bromo-2′-debxyuridine for the final 16 hrs of the 96 hr incubation. Values (mean±standard error) with different superscripts are significantly different (ANOVA, the SAS program): P<0.01).











MODES OF CARRYING OUT THE INVENTION




Freeze dried cultures of the four bacterial strains have been deposited at the Australian Government Analytical Laboratories (AGAL), The New South Wales Regional Laboratory, I Suakin Street, Pymble, NSW 2073, Australia. Details of the deposits are:




















Strain




Number




Date















L. acidophilus


HN017




NM97/09515




August 18, 1997









L. rhamnosus


HN001




NM97/09514




August 18, 1997









B. lactis


HN019




NM97/09513




August 18, 1997









L. rhamnosus


HN067




NM97/01925




February 11, 1998















The four strains identified above have been found to enhance a broad spectrum of immune responses including both natural and acquired immune responses.




EXAMPLE 1




Morphology and General Properties




RAPD analysis, 16S rRNA sequencing and SDS-PAGE analyses were used to confirm taxonornical characterisation of strains. It was also found that


L. acidophilus


HN017 was genetically different from


L. acidophilus


(LC1) of New Zealand Patent No. 248057.




RAPD analysis, 16S rRNA sequencing and SDS-PAGE analyses were used to confirm taxonomical characterisation of


L. rhamnosus


HN067; species-specific primers used for characterisation of


L. rhamnosus


HN067 at molecular level included Pr I (forward) 5-CAGACTGAAAGTCTGACGG-3 and Pha II (reverse) 5-GCGATGCGAATTTCTATTATT-3.




The morphology and sugar fermentation properties of this strain are detailed in Tables 1 and 2.












TABLE 1











Morphology and other characteristics
















L. acidophilus








L. rhamnosus








B. lactis








L rhamnosus








HN017




HN001




HN019




HN067









Short to medium




Short to medium




Microaerophilic to




Short to medium






rods with rounded




rods with square




anaerobic rods with




rods with square






ends, generally




ends in chains,




characteristic shapes




ends in chains,






occurring singly




generally 0.7 × 1.1 ×




such as middle




generally 0.7 × 1.1 ×






or in pairs or short




2.0-4.0 μm,




enlarged cells, ‘V’ or




2.0 to 4.0 μm,






chains, when




when grown in




palisade arrangement




when grown in






grown in MRS




MRS broth.




of cells when grown




MRS broth.






broth.




Gram positive,




on TPY agar slabs.




Gram positive,






Gram positive,




non-mobile, non-




In MR5 broth with




catalase negative,






non-spore




spore forming,




0.05% cysteine




non-mobile, non-






forming, catalase




catalase negative




hydrochloride, they




spore-forming,






negative




facultative




form middle-enlarged




facultative






facultatively




anaerobic rods




cells and club shaped




anaerobic rods






anaerobic rods




with optimum




(spatulated




with optimum growth






with optimum




growth




extremities) cells.




temperature of






growth




temperature of




Gram positive, non-




37 ± 1° C. and






temperature of




37 ± 1° C. and




motile and non-spore




optimum pH of 6.0






37 ± 1° C. and




optimum pH of




forming, catalase




to 6.5. These are






optimum pH of




6.0-6.5. These




negative rods with




facultatively






6.0-6.5. These




are facultatively




optimum growth




heterofermentative






are obligately




heterofermentative




temperature of




bacteria and no






homofermentative




bacteria and no




37 ± 1° C. and optimum




gas produced from






bacteria and no




gas produced from




pH of 6.0-7.0.




glucose.






gas is produced




glucose.




Fructose-6-phosphate






from glucose.





phospho-ketolase








positive.






















TABLE 2











Carbohydrate fermentation pattern of selected Lactobacillus and






Bifidobacterium strains















S1. No.




Name of the bacterium




Score*











1






L. acidophilus


HN017




5755546







2






L. rhamnosus


HN001




5757177







3






B. lactis


HN019




1051622







4






L. rhamnosus


HN067




5757175













API 50 CH sugar fermentation kit was used to determine the sugar-fermentation pattern.











*The scores are based on scores of 22 prominent sugars (Bergey's manual)













EXAMPLE 2




Adhesion to Intestinal Cells




The ability of probiotic strains to adhere to human intestinal epithelial cells (HT-29 and CaCo-2) was assessed in vitro using differentiated cell-lines. Monolayers of HT-29 and CaCo-2 cells were grown on cover slips and placed in multi-well dishes. 10


8


cfu/ml of LAB in 1 ml of spent culture supernatant was then added to cell layers along with 1 ml of DMEM medium and incubated for 1 hr at 37° C. in 10% CO


2


-90% air. Monolayers were washed 4 times with PBS, fixed in methanol, Gram strained and the number of bacteria adhering to epithelial cells determined microscopically. On average, 20 fields were counted and the results are summarised in Table 3.












TABLE 3











Adherence to HT-29 and CaCo-2 cell lines*















STRAIN




HT-29




CaCo-2













L. acidophilus


HN017




 98 ± 17




171 ± 16









L. rhamnosus


HN001




161 ± 18




218 ± 35









B. lactis


HN019




188 ± 27




194 ± 25













*Number (mean ± SEM) of bacteria/100 epithelial cells













EXAMPLE 3




Enhancement of Natural and Acquired Immunity




The immunoenhancing effects of the three strains


L. rhamnosus


HN001


, L. acidophilus


HN017 and


B. lactis


HN019 were examined by determining phagocyte (blood leukocytes and peritoneal macrophage) function, and quantifying concentrations of specific antibodies to protein antigens used for mimicking responses to vaccines in mice.




The following experimental protocol was used:




1. Six-to-seven week old BALBIc mice, weighing 20-30 g were used.




2. Mice were randomly allocated to different treatment groups (Table 4)




3. Mice were fed


L. acidophilus


HN017


, L. rhamnosus


HN001 or


B. lactis


HN019 (10


9


cfu/day) in 50 μl skim milk for 10 days. Control mice received 50 μl of skim milk powder only.




4. All mice received skim milk powder based diet throughout the experiment.




Blood leukocytes and macrophages from mice receiving


L. acidophilus


HN017


, L. rhamnosus


HN001 or


B. lactis


HN019 showed significantly greater phagocytic capacity compared with cells from control mice (Table 4). The production of oxygen radicals (oxidative burst) by leukocytes from probiotic fed mice was also higher than the control mice (data not shown).












TABLE 4











The effect of dietary


L. acidophilus


HN017,


L. rhamnosus


HN001 and








B. lactis


HN019 on phagocyte function in mice














% Blood




% Peritoneal







leukocytes with




macrophage with






Treatment




phagocytic activity




phagocyte activity









Control




14.33 ± 0.87 




66.1 ± 3.5 








L. acidophihilus


HN017




 22.7 ± 1.21**




79.0 ± 1.0**








L. rhamnosus


HN001




24.84 ± 0.93**




 0.5 ± 1.8**








B. lactis


HN019




23.19 ± 0.95**




77.4 ± 2.6* 














BALB/c mice were orally administered with 10


9


cfu (per day)


L. acidophilus


HN017


, L. rhamnosus


HN001 or


B. lactis


HN019 for 10 days. Phagocytic activity of blood leukocytes and peritoneal macrophages was determined using flow cytometry and fluorescein isothiocyanate—labelled


Escherichia coli


. Values are mean±standard error. Significant differences (Students t test) from the control: *P<0.05, **P<0.01.




The concentration of specific IgG antibodies in the sera and in the intestinal washings of mice receiving


L. acidophilus


HN017


, L. rhamnosus


HN001 or


B. lactis


HN019 was also greater than those of control mice (Table 5).












TABLE 5











The effect of dietary


L. acidophilus


HN017,


L. rhamnosus


HN001 and








B. lactis


HN019 on serum and mucosal antibody responses
















Serum




Mucosal








antibody response




antibody response







Treatment




(units/ml)




(units/ml)











Control




80.2 ± 6.0  




1350 ± 96.0 









L. acidophilus






134.6 ± 25.2* 




1548 ± 270.0







HN017









L. rhamnosus


HN001




118.5 ± 12.5** 




1512 ± 198.0









B. lactis


HN019




158.1 ± 51.6***




1548 ± 234.0















BALB/c mice were orally administered with 10


9


cfu (per day)


L. acidophilus


HN017


, L. rhamnosus


HN001 or


B. lactis


HN019 for 10 days. Mice were immunised with cholera toxin (an antigen used to mimic enteric infection) on days 0 and 7. The concentration of specific antibodies in serum and intestinal secretions were measured using ELISA on day 10. Values represent mean±standard error. Significant differences (Students t test) from control: *P=0.08; **P<0.05; ***P<0.01.




EXAMPLE 4




Immunostimulating Effects Following Supplementation with LAB for Four Weeks




The immunostimulating effects of


L. acidophilus


HN017


, L. rhamnosus


HN001 , and


B. lactis


HN019 were assessed in mice using the following experimental protocol:




1. Six-to-seven week old BALB/c mice, weighing 20-30 g were used.




2. Mice were randomly allocated (18/group) to different treatment groups.




3. After acclimatisation (for 7 days), mice were given 10


9


cfu (per day)


L. acidophilus


HN017


, L. rhamnosus


HN001 , or


B. lactis


HN019, in 50 μl skim milk, for 28 days (from day 0 to day 28). Control mice received 50 μl skim milk (without any micro-organisms) only.




4. Mice were offered a skim milk powder based-diet and water ad libitum, throughout the experiment.




5. Immunostimulating effects were assessed by monitoring phagocytic activity of blood leukocytes and peritoneal macrophages, NK-cell activity of splenic lymphocytes, lymphocyte proliferation (spleen cells) responses to a T-cell mitogen, ConA (an indicator of cell-mediated immunity) and antibody responses to Tetanus vaccine.




As seen in Table 6, leukocytes (neutrophils, monocytes and macrophages) from mice receiving


L. acidophilus


HN017


, L. rhamnosus


HN001, or


B. lactis


HN019 exhibited significantly greater phagocytic activity (an indicator of natural immunity) than leukocytes from control mice.












TABLE 6











The effect of dietary


L. acidophilus


HN017,


L. rhamnosus


HN001, and








B. lactis


HN019 in mice














% Blood




% Peritoneal







leukocytes with




macrophages with






Treatment




phagocytic activity




phagocytic activity









Control




15.5 




72.67 








L. acidophilus


HN017




29.4**




82.2* 








L. rhamnosus


HN001




24.2**




82.8** 








B. lactis


HN019




31.1**




83.0** 














Mice (18/group) were given 10


9


cfu (per day)


L. acidophilus


HN017


, L. rhamnosus


HN001 , or


B. lactis


HN019 in 50 μl skim milk for 28 days. Phagocytic activity of blood leukocytes/peritoneal macrophages was determined on day 28 using flow cytometry and fluorescein isothiocyanate-labelled


E. coli


. Values are least square means. Significant differences (the SAS analysis): *P<0.002, **P<0.0005.




Consumption of


L. acidophilus


HN017


, L. rhamnosus


HN001, or


B. lactis


HN019 for 28 days also resulted in an increase in the NK-cell activity, lymphocyte proliferation responses to ConA and antibody responses to Tetanus vaccine. For all these indicators of immunocompetence, mice receiving


L. acidophilus


NN017


, L. rhamnosus


HN001 , or


B. lactis


HN019 had higher responses than those of control mice (Table 7).




Together these results show that supplementation for extended periods with


L. acidophilus


HN017


, L. rhamnosus


HN001, or


B. lactis


HN019 is able to induce a sustained enhancement in several aspects of natural and acquired immunity.












TABLE 7











The effect of dietary


L. acidophilus


HN017,


L. rhamnosus


HN001, and








B. lactis


HN019 on NK cell activity and lymphocyte proliferation






responses to ConA and antibody responses to Tetanus vaccine.
















Lymphocyte




Antibody







NK cell




proliferation to




responses to






ConA




activity




ConA




Tetanus vaccine






Treatment




(%)




(absorbance)




(units/ml)









Control




 8.8




 1.4 ± 0.125




402.5 ± 41.4 








L. acidophilus


HN017




 9.9




1.6 ± 0.44




923.9 ± 116.0*








L. rhamnosus


HN001




11.5




1.8 ± 0.1*




711.5 ± 127.2*








B. lactis


HN019




10.5




1.7 ± 0.5




844.6 ± 134.7*














Mice (18/group) were given 10


9


cfu (per day)


L. acidophilus


HN017


, L. rhamnosus


HN001 , or


B. lactis


HN019 in 50 μl skim milk for 28 days (i.e. from days 0 to 28). NK-cell activity of splenic lymphocytes was determined on day 28 using flow cytometry and D275-labelled Yac-1 cells. Lymphocyte proliferation responses of splenic lymphocytes to ConA were assessed on day 28 using a commercial cell proliferation kit (Boehringer Mannheim, Germany). For antibody responses, mice were immunised with Tetanus vaccine (50 μl/dose, CSL, Australia) on days 7 and 21. The concentration of specific antibodies were determined using an ELISA; antigen supplied by the vaccine manufacturers (CSL, Australia) was used for coating plates. Values are least square means of 18 mice. Significant differences (the SAS analysis): *P <0.05.




EXAMPLE 5




Enhancement of Natural and Acquired Immunity Using Fermented Versus Unfermented Products




The aim was to assess the immunoenhancing efficacy of yoghurt made (fermented) using the probiotic strain


L. rhamnosus


HN001 compared to unfermented product containing


L. rhamnosus


HN001. The immunoenhancing effects were examined by determining the phagocyte function (peripheral blood leukocytes and peritoneal macrophages) and lymphocyte proliferative responses to a B-cell mitogen (LPS).




The following experimental protocol was used:




1. Six-to-seven week old BALB/c mice, weighing 20-30 g were used.




2. Mice were randomly allocated to different treatment groups.




3. Control mice received a whole milk powder-based diet throughout the experiment.




4. Test mice received 2.5 g yoghurt made using


L. rhamnosus


HN001 (10


9


cfu/day) or 2.5 g whole milk containing


L. rhamnosus


HN001 (10


9


cfu/day) per day as well as a whole milk powder based diet for 14 days.




Results




Mice receiving yoghurt made with


L. rhamnosus


HN001 or whole milk containing


L. rhamnosus


HN001 displayed a significantly higher level of phagocytic activity of peripheral blood leukocytes than was observed in mice receiving the control diet (FIG.


1


). This increase was seen irrespective of whether the


L. rhamnosus


HN001 was delivered in the yoghurt (fermented with


L. rhamnosus


HN001) or unfermented product containing


L. rhamnosus


HN001. There was no difference in the level of phagocytic activity between mice receiving the fermented yoghurt made using


L. rhamnosus


(HN001 ) compared to unfermented WMP product containing


L. rhamnosus


(HN001).




Both the unfermented and


L. rhamnosus


HN001 fermented product fed mice showed higher lymphocyte proliferative responses to LPS than the control mice (Table 8). There was no significant difference in the response between mice receiving unfermented product containing


L. rhamnosus


HN001 and mice receiving product fermented with


L. rhamnosus


HN001.












TABLE 8











The effect of fermented and unfermented


L. rhamnosus


HN001 on






lymphocyte proliferative responses in mice













Lymphocyte proliferation to LPS






Treatment




(absorbance)









Control (WMP)




0.4699 ± 0.028






WMP Fermented with




0.5361 ± 0.028








L. rhamnosus


HN001






Unfermented WMP with


L. rhamnosus






0.5518 ± 0.028*






HN001














BALB/c mice were fed on milk based diets containing 10


9


cfu (per day)


L. rhamnosus


HN001 in either unfermented product or yoghurt made with


L. rhamnosus


HN001 (fermented product) for 14 days. Control mice received milk-based diet without any LAB. Proliferative responses were measured colourimetrically following the incorporation of 5-bromo-2′-deoxyuridine for the final 16 hrs of the 96 hr incubation.




Values are means±standard error. Significant differences (Students t test) from the control: *P=0.05.




Together these results suggest that supplementation with


L. rhamnosus


HN001 enhances a range of immune functions including phagocytic activity and lymphocyte cell proliferation.


L. rhamnosus


HN001 presented in either fermented or unfermented product is effective at eliciting enhancement of immune function, with fermented product giving a greater response for some functions and unfermented being superior in others.




EXAMPLE 6




Enhancement of Natural and Acquired Immunity by


L. rhamnosus


HN067




Experiment 1.




The immunoenhancing effects of


L. rhamnosus


HN067 were examined by monitoring phagocytic capacity of peripheral blood leukocytes and peritoneal macrophages (indicator of non-specific immunity), and quantifying concentrations of specific antibodies to an immunisation antigen, cholera toxin (used for mimicking responses to enteric vaccines) in mice.




The following experimental protocol was used:




1. Six-to-seven week old BALB/c mice, weighing 20-30 g were used. They were fed on a skim milk-based diet throughout the experiment.




2. Mice in the test group (n=6) were orally administered


L. rhamnosus


HN067 (10


9


cfu/day) in 50 μl skim milk for 10 days. Control mice (n=6) received 50 μl of skim milk powder (without any LAB) only.




Results




Blood leukocytes and peritoneal macrophages from mice receiving


L. rhamnosus


HN067 showed significantly greater phagocytic activity (enhanced phagocyte function) compared with cells from control mice. The results are set out in Table 9 below.












TABLE 9











The effect of dietary


L. rhamnosus


HN067 on phagocyte function














% Blood




% Peritoneal







leukocytes with




macrophages with






Treatment




phagocylic activity




phagocytic activity









Control




13.1 ± 1.5




76.4 ± 1.9








L. rhamnosus


HN067




23.7 ± 1.5**




87.2 ± 1.9*














BALBIc mice (6/group) were fed on milk-based diet with or without oral administration of L. rhamnosus HN067 (10


9


cfu/day) for 10 days. Phagocytic activity of blood leukocytes and peritoneal macrophages were determined using flow cytometry and fluorescein isothiocyanate—labelled


E. coli


. Values represent least square mean±standard error LSM. Significant differences (the SAS program) from the control: *P=0.0005, **P=0.0001.




The concentration of specific antibodies to cholera toxin, an antigen used for oral immunisation, in the sera and in the intestinal washings of mice receiving


L. rhamnosus


HN067 was also significantly greater than those of control mice (Table 10).












TABLE 10











The effect of dietary supplementation with


L. rhamnosus


HN067 on






serum and mucosal antibody responses to cholera toxin















Mucosal antibody







Serum antibody response




response






Treatment




(units/ml)




(units/ml)









Control




63.1 ± 43.2 




1969.7 ± 279.5 








L. rhamnosus


HN067




246.5 ± 43.2**




2995.5 ± 465.2*














BALB/c mice were fed on milk-based diet with or without


L. rhamnosus


HN067 (10


9


cfu/day) for 10 days. Mice were immunised orally with cholera toxin (10 μg/dose), an antigen used to mimic enteric infection, on days 0 and 7. Antibody levels in serum and intestinal secretions were measured using ELISA on day 10. Values represent least square mean±standard error LSM. Significant differences (the SAS program) from control: *P=0.02; **P=0.0039.




Experiment 2.




The immunostimulating effects of


L. rhamnosus


HN067 were assessed in mice using the following experimental protocol:




1. Six-to-seven week old BALB/c mice, weighing 20-30 g were used. They were offered skim milk powder based diet and water ad libitum, throughout the experiment.




2. After acclimatisation for 7 days, mice in group 1 (n=20) were orally administered with 10


9


cfu (per day)


L. rhamnosus


(HN067) in 50 μl skim milk (group 1 n=20) for 14 days. Control mice (group 2, n=20) received skim milk without any microorganisms.




3. Immunostimulating effects were assessed by monitoring phagocytic activity of blood leukocytes and peritoneal macrophages, and spleen lymphocyte proliferation responses to phytohaemagglutinin (PHA) and lipopolysaccharide (LPS) (T and B-cell mitogens respectively).




Results




Blood leukocytes and peritoneal macrophages from mice receiving


L. rhamnosus


HN067 exhibited significantly greater phagocytic activity (an indicator of natural immunity) than leukocytes and macrophages from control mice (Table 11).












TABLE 11











The effect of dietary


L. rhamnosus


HN067 on phagocyte function in mice














% Blood




% Peritoneal







Leukocytes with




macrophages with






Treatment




phagocytic activity




phagocytic activity









Control




13.7 ± 0.07




64.6 ± 2.1








L. rhamnosus


HN067




22.5 ± 0.07**




75.8 ± 1.7*














BALB/c mice were fed on milk-based diet with or without oral administration of


L. rhamnosus


HN067 (10


9


cfu/day) for 14 days. Phagocytic activity of blood leukocytes/peritoneal macrophages were determined on day 14 using flow cytometry and fluorescein isothiocyanate-labelled


E. coli


. Values represent least square mean±standard error LSM. Significant differences (the SAS program): *P=0.002, **P=0.0001.




Mice receiving


L. rhamnosus


HN067 for 14 days also displayed higher lymphocyte proliferation responses to PHA and LPS compared with control mice (Table 12).












TABLE 12











The effect of


L. rhamnosus


HN067 supplementation on lymphocyte






proliferation responses to PHA and LPS













ConA




Lymphocyte




Lymphocyte






Treatment




proliferation to PHA




proliferation to LPS









Control




1.18 ± 0.08




0.99 ± 0.07








L. rhamnosus


HN067




1.37 ± 0.07*




1.24 ± 0.06**














BALB/c mice were fed on milk-based diet with or without oral administration of


L. rhamnosus


HN067 (10


9


cfu/day) for 14 days. Lymphocyte proliferation responses of spleen cells to PHA and LPS were assessed on day 14 using a commercial cell proliferation kit (Boehringer Mannheim, Germany). Values represent least square mean±standard error LSM. Significant differences (the SAS program): *P<0.08, **P<0.01.




In summary, mice receiving


L. rhamnosus


HN067 displayed significant enhancement of a range of host immune responses including leukocyte phagocytic function, antibody responses to oral immunisation, and lymphocyte proliferation responses to T and B-cell mitogens. Blood leukocytes (neutrophils and monocytes) and macrophages are major effectors of natural immunity and play a major role in protection against microbial infections. A correlation between in vitro lymphocyte proliferation responses to mitogens (T- and B-cell mitogens) and immunocompetence of an individual is also well documented. Therefore, these results suggest that supplementation with


L. rhamnosus


HN067 is able to enhance several aspects of natural and acquired immunity.




EXAMPLE 7




Enhancement of Natural and Acquired Immunity Using Live and Heat Killed


L. rhamnosus


HN001




The aim of the present study was to investigate the immunoenhancing effects of the probiotic strain


L. rhamnosus


HN001 when presented in either the live or heat killed form. The effect on immune function was assessed by determining phagocytic activity of peripheral blood leukocytes. The effect of live and heat killed


L. rhamnosus


HN001 on humoral immunity was investigated by immunising mice with cholera toxin, and measuring the concentrations of specific antibodies produced.




The following experimental protocol was used:




1. Six-to-seven week old BALB/c mice, weighing 20-30 g were used.




2. Mice were randomly allocated to different treatment groups.




3. Control mice received a skim milk powder based diet throughout the experiment.




4. Test mice receive either 10


9


cfu/day of live


L. rhamnosus


HN001 or 10


9


cfu/day heat killed


L. rhamnosus HN


001 per day as well as a skim milk powder-based diet for 14 days.




5. Mice were orally immunised with cholera toxin on day 0 and day 7 of feeding.




Results






L. rhamnosus


HN001 feeding significantly enhanced the level of phagocytic activity of peripheral blood leukocytes compared to mice receiving the control diet (FIG.


2


). This increase was seen irrespective of whether the


L. rhamnosus


HN001 was delivered in the live or heat killed form. There was no difference in the level of phagocytic activity between the mice receiving live


L. rhamnosus


HN001 compared to heat killed


L. rhamnosus


HN001.




Feeding of both live and dead


L. rhamnosus


HN001 induced an increase in both serum and mucosal antibody responses compared to the control mice. However, the level of response was significantly greater in the mice fed the live


L. rhamnosus


HN001 (Table 13).












TABLE 13











The effect of live and heat killed


L. rhamnosus


HN001 on serum and






mucosal antibody responses to Cholera Toxin in mice














Serum antibody




Mucosal antibody






Treatment




response (units/ml)




response (units/ml)









Control




88.69 ± 18.52




708.6 ± 146.9






Live


L. rhamnosus


HN001




214.89 ± 62.33*




 2054.5 ± 285.8***






Heat Killed




174.89 ± 44.78 




1533.6 ± 319.3 








L. rhamnosus


HN001














BALB/c mice were fed on milk-based diets and orally administered 10


9


cfu (per day)


L. rhamnosus


HN001 in either live or heat killed form for 14 days. Control mice received no LAB. Mice were orally immunised with Cholera Toxin on days 0 and 7. Antibody responses (serum and intestinal secretions) were measured using an ELISA on day 14. Values are mean±standard error. Significant differences (Students t test) from the control: *P=0.05, ***P=0.0005.




These results suggest that both live and heat killed


L. rhamnosus


HN001 are able to enhance aspects of natural and acquired immunity in mice.




EXAMPLE 8




Anti-infection properties of


B. lactis


HN019 and


L. rhamnosus


HN001




The aims of the current study were to:




1. Assess the protection efficacy of


B. lactis


HN019 and


L. rhamnosus


HN001 against the gastrointestinal pathogen


Salmonella typhimutrum.






2. Determine the role of immunostimulation induced by


B. lactis


HN019 and


L. rhamnosus


HN001 in protection against


S. typhimurium


infection in mice.




Anti-infection properties were assessed by measurement of bacterial translocation to the liver and spleen. The immunoenhancing effects were examined by determining the phagocyte function (peripheral blood leukocytes and peritoneal macrophages) and lymphocyte proliferative responses to a T-cell mitogen (PHA).




The following experimental protocol was used:




1. Six-to-seven week old BALBIc mice, weighing 20-30 g were used.




2. Mice were randomly allocated to 4 difference treatment groups and were individually housed.




3. Al mice received a skim milk powder based diet throughout the experiment.




4. Test mice commenced daily feeding of


B. lactis


HN019 or


L. rhamnosus


HN001 (10


9


cfu/day) 7 days prior to challenge, and continued for the duration of the trial.




5. Mice administered with


B. lactis


HN019 or


L. rhamnosus


HN001 and a control group (no LAB) were orally challenged with


Salmonella typhimurium


(ATCC 1772) 8×10


5


cfu/day for 5 days starting on day 7.




6. An uninfected control group did not receive


S. typhimurium


challenge.




7. On day 6 after challenge mice were used for the measurement of bacterial translocation to the liver and spleen, and for immune function assessment.




Results




Both the


B. lactis


HN019 and


L. rhamnosus


HN001 supplemented mice showed significantly lower levels of bacterial translocation into the liver and spleen than the


S. typhimurium


alone fed mice (FIG.


3


).




Challenge infection resulted in a significant suppression of phagocyte function (FIG.


4


); the phagocytic activity of control mice challenged with


S. typhimurium


was significantly lower than that of the uninfected mice. However, infection with


S. typhimurium


had no effect on the phagocytic ability of peripheral blood leukocytes of mice supplemented with


B. lactis


HN019 or


L. rhamnosus


HN001 . This was shown by similar levels of phagocytic activity in mice supplemented with


B. lactis


HN019 or


L. rhamnosus


HN001 and challenged with


S. typhimurium


and the normal uninfected control mice.




Both the


B. lactis


HN019 and


L. rhamnosus


HN001 supplemented mice showed higher lymphocyte proliferative responses to PHA than the


S. typhimurium


challenged control (FIG.


5


). There was no significant difference in the response between mice receiving


B. lactis


HN019 or


L. rhamnosus


HN001 and the uninfected control mice.




Together these results suggest that supplementation with


B. lactis


HN019 or


L. rhamnosus


HN001 is able to confer protection against enteric pathogens such as


Salmonella typhimurium


. Enhanced resistance to infection is accompanied by an increase in immune performance.



Claims
  • 1. A biologically pure culture of either Lactobacillus (L.) rhamnosus HN001 AGAL deposit number NM07/09514 or Lactobacillus (L.) rhamnosus HN067 AGAL deposit number NM97/01925.
  • 2. A composition comprising at least one of the strains selected from the group consisting of L. rhamnosus HN001 AGAL deposit number NM97/09514, L. rhamnosus HN067 AGAL deposit number NM97/01925, Bifidobacterium (B.) lactis HN019 AGAL deposit number NM97/09513 and L. acidophilus HN017 AGAL deposit number NM97/09515, in an amount effective to stimulate an immune response, and a physiologically acceptable excipient or diluent.
  • 3. The composition as claimed in claim 2 comprising at least two or more of said strains.
  • 4. The composition as claimed in claim 2 wherein said physiologically acceptable excipient or diluent is a food.
  • 5. The composition as claimed in claim 4 wherein said food is selected from the group consisting of cultured milk, yoghurt, cheese, milk drink and milk powder.
  • 6. The composition as claimed in claim 2 wherein said physiologically acceptable excipient or diluent is also a pharmacologically acceptable excipient or diluent.
  • 7. A physiologically acceptable pure culture of a strain, homologue, or mutant of at least one of the strains selected from the group consisting of:L. acidophilus HN017, L. rhamnosus HN001, B. lactis HN019, and L. acidophilus HN067, having all of the identifying characteristics of said strains.
  • 8. A method of enhancing natural and acquired immunity which comprises administering to a mammal in need thereof at least one a biologically pure culture of a strain of claim 1 or claim 7 in an amount effective to stimulate an immune response.
  • 9. The method of claim 8 wherein two or more of the strains are administered.
  • 10. A method of enhancing natural and acquired immunity which comprises administering to a mammal in need thereof a therapeutically effective amount of the composition of claim 2.
  • 11. The method of claim 8 wherein said physiologically acceptable excipient or diluent is a food.
  • 12. The method of claim 11 wherein said food is selected from the group consisting of cultured milk, yoghurt, cheese, milk drink and milk powder.
Priority Claims (2)
Number Date Country Kind
PO 8699 Aug 1997 AU
PP 3225 Aug 1998 AU
PCT Information
Filing Document Filing Date Country Kind
PCT/NZ98/00122 WO 00
Publishing Document Publishing Date Country Kind
WO99/10476 3/4/1999 WO A
US Referenced Citations (2)
Number Name Date Kind
5164183 Komoda et al. Nov 1992 A
5494664 Brassart et al. Feb 1996 A
Foreign Referenced Citations (6)
Number Date Country
0295794 May 1988 EP
09002959 Jan 1997 JP
248057 Jul 1993 NZ
WO 9418997 Sep 1994 WO
WO 9709448 Mar 1997 WO
WO 9823727 Jun 1998 WO