EFFECT OF YOGURT FEEDING ON THE SMALL AND LARGE-INTESTINE ASSOCIATED LYMPHOID-CELLS IN MICE

The effect of giving yogurt supplements to BALB/c mice on the various gut-associated lymphoid cells was studied. Animals were fed for 2, 5, 7 and 10 consecutive days. The different lymphoid cell types were iden tified and counted by haematoxylin-eosin staining of histological slic es. The numbers of cells secreting IgA, IgG and IgM and the numbers of T lymphocytes were determined by direct immunofluorescence. The degre e of activation of the intestinal macrophages in the small intestine w as assessed by measuring the beta-glucuronidase (EC 3.2.1.31) released into the intestinal fluid, and also by a histochemical method. Throug hout the feeding period, there were no histological alterations in the gut, but there was marked cell infiltration, mainly of plasma cells a nd lymphocytes. The number of macrophages on the small intestine incre ased significantly after feeding for 2 d, while the beta-glucuronidase activity was only slightly higher that of the controls. after a 7 d f eeding period, the number of IgA secreting cells increased. while the values for cells secreting IgM and IgG and for T lymphocytes remained similar to those of the controls. The effect of giving yogurt on lymph oid cells associated with the large intestine was mainly on the number s of IgA secreting B cells and T lymphocytes, with a marked increase d uring the whole feeding period in the latter type of cell. Since givin g yogurt mainly enhanced the IgA secreting B cells in both small and l arge intestines, this increase would strengthen the host's defence mec hanisms in the intestinal mucosa. Although the number of macrophages w as increased, there was no enhancement in their activity, which might have harmed the host by producing an inflammatory response.