title: Lactobacillus rhamnosus GG secreting an antigen and Interleukin-2 translocates across the gastrointestinal tract and induces an antigen specific immune response.
abstract: Lactobacillus rhamnosus strain GG (LGG) is a probiotic organism. In this present study, LGG that express the green fluorescence protein (LGG-GFP) and IL-2 and GFP as a fusion protein (LGG-IL-2-GFP) were used to examine bacterial uptake and the immune response induced by oral immunization. Using TEM to examine the intestinal tissue, the Lactobacilli were localized in M cells and in venules. After oral immunization, most of the bacteria were excreted in feces only a small fraction (0.15%) was retained in the intestine at 48 hr. However, more LGG-IL-2-GFP was found in the MLN and spleen than LGG-GFP. The loop ligation method was used to evaluate LGG uptake and both LGG-GFP and LGG-IL-2-GFP were found to translocate at the same rate. Analysis of LGG internalization in J774 macrophage cells indicated that IL-2 increased survival of LGG and this may explain the increased presence of these bacteria in the MLN for a longer period. After oral immunization, specific mucosal antibody production as well as GFP specific CTL activity was demonstrated. IL-2 co-expression with GFP further enhanced antibody production and CTL activity. In conclusion, Lactobacillus rhamnosus GG expressing an antigen could generate an effective immune response to the antigen and IL-2 improved the response generated probably by increasing LGG expressing antigen survival in immune cells.
authors.affiliation: Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Matheswaran
authors.initials: M
authors.lastname: Kandasamy
authors.forename: Anita
authors.initials: A
authors.lastname: Selvakumari Jayasurya
authors.forename: Shabbir
authors.initials: S
authors.lastname: Moochhala
authors.forename: Boon
authors.initials: B
authors.lastname: Huat Bay
authors.forename: Yuan
authors.initials: Y
authors.lastname: Kun Lee
authors.forename: Ratha
authors.initials: R
authors.lastname: Mahendran
mesh_terms: D000818:Animals; D018988:Bacterial Translocation; D002460:Cell Line; D005260:Female; D041981:Gastrointestinal Tract / Q000276:immunology* / Q000382:microbiology*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology*; D052201:Lacticaseibacillus rhamnosus / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal
chemical_list: D007376:Interleukin-2; D049452:Green Fluorescent Proteins