Protection of suckling mice from the heat-stable enterotoxin of Escherichia coli by human milk.
Human milk contained a factor or factors that protected suckling mice from lethal fluid loss due to Escherichia coli heat-stable toxin. This protective effect was present throughout lactation. The factor was heat stable, acid and alkali stable (pH 2 and 12), and of low molecular weight. Ion-exchange chromatography indicated that it was uncharged at neutral pH. The factor was insensitive to proteinase K digestion and partitioned in the aqueous phase in 2:1 (vol/vol) chloroform-methanol. Acid hydrolysis (2 N HCl at 100 C for 3 hr) destroyed the protective effect. Neither an amino acid mix simulating human milk nor lactose in phosphate-buffered saline was protective. These data indicate that the protective factor in human milk is neither a lipid nor a protein but appears to be a carbohydrate.
D000596:Amino Acids / Q000032:analysis / Q000494:pharmacology; D000818:Animals; D000833:Animals, Suckling; D001427:Bacterial Toxins; D002241:Carbohydrates / Q000032:analysis* / Q000494:pharmacology; D003126:Colostrum / Q000032:analysis*; D019286:Endopeptidase K; D010450:Endopeptidases / Q000494:pharmacology; D004768:Enterotoxins / Q000037:antagonists & inhibitors*; D029968:Escherichia coli Proteins; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007785:Lactose / Q000494:pharmacology; D051379:Mice; D008895:Milk, Human / Q000032:analysis*; D008970:Molecular Weight
D000596:Amino Acids; D001427:Bacterial Toxins; D002241:Carbohydrates; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C034151:heat stable toxin (E coli); D010450:Endopeptidases; D019286:Endopeptidase K; D007785:Lactose