Association of Lactobacillus spp. with Peyer's patches in mice

Sixteen strains of Lactobacillus isolated from humans, mice, and food produ cts were screened for their capacity to associate with Peyer's patches in m ice. In preliminary experiments, in vitro binding to tissue pieces was asse ssed by scanning electron microscopy, and it was demonstrated qualitatively that 5 of the 16 strains showed some affinity for the Peyer's patches, irr espective of their association with the nonlymphoid intestinal tissue. Lact obacillus fermentum KLD was selected for further study, since, in addition to its intrinsically high adhesion rate, this organism was found to exhibit a preferential binding to the follicle-associated epithelium of the Peyer' s patches compared with its level of binding to the mucus-secreting regions of the small intestine, Quantitative assessment of scanning electron micro graphs of tissue sections which had been incubated with L. fermentum KLD or a nonbinding control strain, Lactobacillus delbruckii subsp. bulgaricus, s upported these observations, since a marked difference in adhesion was note d (P < 0.05). This preferential association of strain KLD with the Peyer's patches was also confirmed with radiolabeled lactobacilli incubated with in testinal tissue in the in vitro adhesion assay. Direct recovery of L. ferme ntum KLD from washed tissue following oral dosing of mice revealed a distin ct association (P < 0.05) between this organism and the Peyer's patch tissu e. In contrast, L, delbruckii subsp, bulgaricus showed negligible binding t o both tissue types in both in vitro and in vivo adhesion assays. It was co ncluded that L, fermentum KLD bound preferentially to Peyer's patches of BA LB/c mice.