Abstract
An in vitro screening test using the murine Peyer's patch cell culture method was developed for detection of bifidobacteria which induce large quantities of IgA. Bifidobacteria grown for 48 h were added at a dose corresponding to an absorbance value of 0.275 at 660 nm to BALB/c mouse Peyer's patch cells, and 7 days later the quantities of IgA antibody in the culture supernatants were measured by an ELISA method. With this screening test, three strains of bifidobacteria capable of inducing large quantities of IgA were selected from 120 strains isolated from human faeces and identified as Bifidobacterium breve (two strains) and B. longum (one strain). When one of the three strains (B. breve Y1T 4064) was administered orally along with cholera toxin (CT) into mice, the amount of anti-CT IgA antibody in faeces and anti-CT IgA antibody production and proliferation in Peyer's patch cells tended to be greater and were significantly greater, respectively, than after administration of only CT or CT and B. breve Ka-6, which did not induce IgA.