Influence of an Enterococcus faecium probiotic on the development of Peyer's patches B cells in piglets

To study the interactions between a probiotic bacterium and the host's immune system, we undertook a feeding trial with Enterococcus faecium SF68 (NCIMB 10415). Starting at an age of 1 day, piglets received a daily oral dose of the probiotic bacteria. Immune cells were isolated from the blood and the distal continuous Peyer's patch (PP) of the piglets. While the percentage of B cells in the distal continuous PP was not influenced by the probiotic treatment, an elevated expression of CD1 on Peyer's patch B cells was observed after probiotic treatment. Furthermore, the fraction of CD4-CD8+ cells was decreased in this organ. In blood lymphocyte fractions of the probiotic-treated piglets, the proportion of CD16-positive cells was also diminished, whereas the portion of γδ T cells and CD4-positive T cells increased. The data indicate that early administration of the probiotic Enterococcus faecium can modulate the composition of blood lymphocyte populations in piglets.