g(m3)-ganglioside and Escherichia-coli-Infections

Diarrhea caused by enterotoxigenic Escherichia coli (ETEC) is the main infectious disease of newborn calves. The first step of infection involves bacterial attachment to the intestinal mucosa. This adhesion is mediated by fimbriae that recognize some glycoconjugates on the host cell surface, in particular, several gangliosides. Because milk also contains gangliosides, these have been suggested to serve as ligands for bacterial fimbriae and thus prevent the bacterial attachment to mucosa. The most relevant ETEC strains in calves, including those with K99 and F41 fimbriae, were assayed to determine whether they are able to bind gangliosides isolated from several stages of bovine lactation. Both GM3 and GD3, the main gangliosides of milk, were recognized by ETEC strains, although the different fimbriae showed diverse levels of affinity. Unexpectedly, the adhesion to colostral gangliosides was considerably weaker than that to gangliosides from the other stages of lactation. Because the carbohydrate moiety did not change and because differences in the percentages of unsaturated FA and sphingosine between colostrum and other stages were observed, we conclude that the differences in adhesion could be due to a different composition of the ganglioside ceramide.

Topics: Animals; Antigens, Surface; Bacterial Adhesion; Bacterial Toxins; Carbohydrate Sequence; Cattle; Cattle Diseases; Ceramides; Diarrhea; Escherichia coli; Escherichia coli Infections; Female; G(M3) Ganglioside; Gangliosides; In Vitro Techniques; Milk; Molecular Sequence Data; Molecular Structure

Enterotoxigenic Escherichia coli possessing K99 fimbriae (E. coli K99) causes diarrhea in piglets of less than 1 week old. The first stage of the bacterial infection is adhesion by the fimbriae on the small intestinal mucosa and the adhesion is followed by colony formation. K99 fimbriae bind specifically to N-glycolylneuraminyl-lactosyl-ceramide, GM3(NeuGc) [Ono, E. et al. (1989) Infect. Immun. 57,907-911]. We examined the postnatal change of the content and the molecular species of GM3(NeuGc) in the small intestinal mucosa of 0- to 14-day-old piglets and adult pigs. GM3(NeuGc) was a major ganglioside of piglet intestinal mucosa. GM3(NeuGc) content was maximal at birth and gradually decreased to 1/16 in adult animals (5 months old). The ceramide moiety of piglet intestinal GM3(NeuGc) was characterized by the presence of 2-hydroxylated palmitic acid. 125I-labeled bacteria strongly bound to GM3(NeuGc) containing 2-hydroxylated palmitic acid and phytosphingosine compared with GM3(NeuGc) containing any other ceramide moiety. The time when this particular GM3(NeuGc) appears coincides with the time that the infection occurs, and it may explain the susceptibility of newborn piglets to E. coli K99 infection.

Topics: Animals; Animals, Newborn; Chromatography, Thin Layer; Enterotoxins; Escherichia coli; Escherichia coli Infections; G(M3) Ganglioside; Gangliosides; Intestinal Diseases; Intestinal Mucosa; Intestine, Small; Swine