The Immune Response in Mice Immunized with Lactobacillus acidophilus LF221 – A Potential Probiotic Strain
Irena Rogelj*, Mojca Narat and Irena Hočevar
Biotechnical Faculty, Zootechnical Department, Institute for Dairying, Groblje 3, SI–1230 Domžale, Slovenia
Article history:
Received December 4, 1998
Accepted June 14, 1999
Key words:
probiotics, bacteriocins, immune response, anti-lactobacilli antibodies
Summary:
Lactobacillus acidophilus LF221, a child’s faeces isolate, has some promising probiotic properties. Prior to its commercial use the immunological effects have to be assessed as well. Therefore, the effect of the bacteriocins producing LF221 (bac+), its mutant (bac–), and Lactobacillus casei ATCC393 strains on the specific immune response in NIH mice was studied. Mice were immunized intraperitoneally (i.p.) or orally with a dose of 2.41010 viable or dead cells. The blood samples were collected on 9th, 11th, 14th, 18th, 21st and 24th day after 1st immunization. The sera of mice immunized i.p. with viable cells of LF221 (bac+) were screened for specific anti-LF221 (bac+) IgA, IgG and IgM antibody reaction by a modified DIBA assay. With ELISA assay sera samples from all groups were tested for total and specific anti-lactobacilli IgA, IgG and IgM antibodies. Irrespective of the way of immunization, strain or cells preparation, the concentration of total serum IgA, IgG and IgM antibodies remained on the same level. The highest levels of specific anti-lactobacilli IgG and IgM antibodies after i.p. immunization were detected in mice immunized with viable cells of the strain LF221 (bac+), while activation of specific humoral immune response with dead cells was low. LF221 does not evoke the specific humoral immune response after oral application and is as such suitable for probiotic application.
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