Inhibition of plasmid-encoded adhesion of Yersinia enterocolitica by non-immunoglobulin fraction of human milk.

The inhibitory effect of human milk on plasmid-encoded adhesion of Yersinia enterocolitica to rabbit ileal brush border membrane vesicles immobilized on polystyrene was evaluated. Adhesion was reduced to about 50% after incubation of equal volumes of bacteria and undiluted human milk, but a significant reduction was also detectable after incubation with milk samples at a final 1:10 dilution. Removal of immunoglobulins from human milk by means of immunoadsorption did not change the inhibitory effect on adhesion. Both milk fat, proteins, and factors resistant to proteolytic and heat treatment contributed to the reduction in adhesion.