The role of CD4+ T cells in iga production in murine peyer's patches following oral feeding of bifidobacterium components

Immunomodulatory effects, especially in murine Peyer's patch (PP) cells, were demonstrated following oral administration of Bifidobacterium immunomodulators (BIM) to BALB/c mice for 7 consecutive days. The BIM was derived from sonicated B. pseudocatenulatum 7041. We previously demonstrated that BIM administration augmented total IgA production including BIM-specific IgA by PP cells and enhanced the secretion of interferon-gamma (IFN-gamma), interleukin-5 (IL-5), IL-6 and IL-12 by the PP cells. In the present study, the immunoresponses of CD4(+) PP T-cells have been characterized to elucidate the influences of oral feeding of 131M. Also, we examined how CD4(+) PP T cells induced IgA production following oral BIM administration. After 7 days of oral administration of BIM, PP cells were obtained from each experimental mouse and CD4(+) T-cells were isolated using a magnetically activated cell sorting system. The expression of cell-surface antigens on CD4(+) PP cells was analyzed by flow cytometry. CD4(+) T cells were co-cultured with BIM in the presence of antigen-presenting cells and the cytokine secretion and IgA production were then measured by ELISA. On CD4(+) PP T-cells from BIM-fed mice, the expression of CD45RB(high), a naive marker, showed significant enhancement compared with controls. On the other hands, the secretion of cytokines (IFN-gamma, IL-6) by CD4(+) PP T-cells was increased by BIM administration. In addition, these cells increased BIM-specific IgA production but did not induce an increase in the total IgA production.