Inhibition of Escherichia coli by bovine colostrum and post-colostral milk. I. Complement-mediated bactericidal activity of antibodies to a serum susceptible strain of E. coli of the serotype O 111.
Bovine colostral whey diulted in unheated bovine milk or in Kolmer saline containing 5 per cent pre-colostral calf serum was bactericidal for Escherichia coli NCTC 9703 (serotype O 111). Whey diluted in saline without pre-colostral calf serum was inactive. Bactericidal activity was abolished by heating at 56 degrees for 30 minutes or by pre-incubating with N-acetyl-L-tyrosine ethylester, indicating that complement present in milk or pre-colostral calf serum was involved in the bactericidal activity. Undiluted colostral whey was inactive even in the presence of up to 20 per cent pre-colostral calf serum, probably due to a prozone effect. Milk heated at 80 degrees for 10 minutes was also shown to have a limited anti-complementary effect. Post-colostral milk from some cows had bactericidal activity, whereas similar milks from other cows were either inactive or active only after addition of pre-colostral calf serum, indicating that antibodies to E. coli or complement or both may or may not be present in the post-colostral milk of different cows. The implications of these findings in relation to the bacterial flora of the intestinal tract of neonates are discussed.
D000818:Animals; D000907:Antibodies, Bacterial; D000937:Antigen-Antibody Reactions; D000942:Antigens, Bacterial; D001431:Bacteriological Techniques; D001770:Blood Bactericidal Activity; D002417:Cattle; D003126:Colostrum / Q000276:immunology*; D003169:Complement Inactivator Proteins; D003165:Complement System Proteins; D004926:Escherichia coli / Q000254:growth & development / Q000276:immunology*; D005260:Female; D006358:Hot Temperature; D008892:Milk / Q000276:immunology*; D012703:Serotyping; D013997:Time Factors
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D003169:Complement Inactivator Proteins; D003165:Complement System Proteins