The role of lactic acid bacteria in gut mucosal immunity was investigated by comparing the enhanced effects in the Peyer's patches and spleen of BALB/c mice fed daily with Lactobacillus paracasei subsp. paracasei NTU 101 for 3 to 9 weeks. After feeding with Lactobacillus, the percentage of CD4+ T cells in both Peyer's patches and the spleen was significantly increased; however, expression of CD 154 molecules, which play a pivotal role in cell-to-cell communication, on CD4+ T cells and the percentage of B220+ B cells increased only in Peyer's patches. Compared with systemic serum IgA, Peyer's patch-derived immunomodulation induced higher levels of intestinal IgA+-producing cells in the lamina propria. Our data also showed that feeding with Lactobacillus induced stronger CD4+ T cell-dendritic cell interaction, enhanced CD4+ T cell and B cell proliferation, and increased IL-1beta, IL-10, IL-12, IFN-gamma, and TNF-alpha mRNA expression in Peyer's patches, but not in the spleen. Here, we demonstrate that following Lactobacillus treatment, Peyer's patches exhibited a more distinct capacity to induce CD4+ T cell-dendritic cell interactions, lymphocyte proliferation, and cytokine secretion than the spleen, and thereby promoted greater intestinal IgA production that could enhance immunosurveillance to prevent intestinal infections or other intestinal pathologies.
2010 Elsevier B.V. All rights reserved.