EFFECT OF VIABLE LACTOBACILLUS-CASEI FEEDING ON THE IMMUNITY OF THE MUCOSAE AND INTESTINAL MICROFLORA IN MALNOURISHED MICE

The effect feeding of viable L. casei on the immunity of the mucosae o f mal-nourished mice was studied. The animals were fed with 1.2 x 10(9 ) L. casei cells suspended in 10% non-fat milk (NFM) for 2 consecutive days. Phagocytic activity of peritoneal macrophages, number of cells in peripheral blood, intestinal flora and preventive ability of L. cas ei against infections with Salmonella (S.) typhimurium were also inves tigated. The influence of such feeding on the immunity of the mucosa w as determined by the number of IgA-producing cells and by the levels o f IgA and IgM specific for S. typhimurium measured in the intestinal f luid. The L. casei feeding given to mat-nourished animals slightly inc reased the number of circulating leukocytes and the phagocytic activit y of peritoneal macrophages. This feeding also restored the strict ana erobic population in the small intestine, but failed to prevent bacter ial translocation. L. casei induced an increase in the number of IgA-p roducing cells as well as in the levels of IgM. However, this microorg anism did not increase the IgA levels, nor was it effective against an infection with S. typhimurium. It is possible that the administration of L. casei to a malnourished host, which can be beneficial in certai n aspects, would not be advisable prior to an adequate refeeding of th e host. In this case its supplementary oral administration might induc e a fairly satisfactory immunity in the mucosa.