title: Immunomodulatory effects of Lactobacillus plantarum colonizing the intestine of gnotobiotic rats.
abstract: We have studied the effect of the probiotic strain Lactobacillus plantarum 299v on the immune functions of gnotobiotic rats. One group of germ-free rats was colonized with the type 1-fimbriated Escherichia coli O6:K13:H1 and another group with the same E. coli strain together with L. plantarum 299v. One and 5 weeks after colonization, bacterial numbers were determined in the contents of the small intestine, caecum and mesenteric lymph nodes. Small intestinal sections were examined for CD8+, CD4+, CD25+ (IL-2R alpha-chain), IgA+ and MHC class II+ cells and mitogen-induced spleen cell proliferation was determined. Immunoglobulin levels and E. coli-specific antibodies were measured in serum. Rats given L. plantarum in addition to E. coli showed lower counts of E. coli in the small intestine and caecum 1 week after colonization compared with the group colonized with E. coli alone, but similar levels after 5 weeks. Rats colonized with L. plantarum + E. coli had significantly higher total serum IgA levels and marginally higher IgM and IgA antibody levels against E. coli than those colonized with E. coli alone. They also showed a significantly increased density of CD25+ cells in the lamina propria and displayed a decreased proliferative spleen cell response after stimulation with concanavalin A or E. coli 1 week after colonization. The results indicate that L. plantarum colonization competes with E. coli for intestinal colonization and can influence intestinal and systemic immunity.
authors.affiliation: Department of Clinical Immunology, Göteborg University, Göteborg. v.herias@immuno.gu.se
authors.forename: M V
authors.initials: MV
authors.lastname: Herías
authors.forename: C
authors.initials: C
authors.lastname: Hessle
authors.forename: E
authors.initials: E
authors.lastname: Telemo
authors.forename: T
authors.initials: T
authors.lastname: Midtvedt
authors.forename: L A
authors.initials: LA
authors.lastname: Hanson
authors.forename: A E
authors.initials: AE
authors.lastname: Wold
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D015703:Antigens, CD / Q000032:analysis; D001422:Bacterial Adhesion; D018988:Bacterial Translocation; D005260:Female; D010861:Fimbriae, Bacterial; D005856:Germ-Free Life; D007150:Immunohistochemistry; D007422:Intestines / Q000382:microbiology*; D007778:Lactobacillus / Q000502:physiology*; D008213:Lymphocyte Activation; D008297:Male; D051381:Rats
chemical_list: D000907:Antibodies, Bacterial; D015703:Antigens, CD