Human colostrum contains IgA antibodies reactive to colonization factors I and II of enterotoxigenic Escherichia coli.
Diarrhea is an important cause of morbidity and mortality amongst infants of low socio-economic levels in developing countries and in travelers who visit such areas. Enterotoxigenic E. coli strains express two sets of virulence-associated factors: enterotoxins (heat-stable toxins or heat-labile toxins) and colonization factors. Studies have shown that breast-feeding protects infants against infectious diseases, such as diarrhea, as it presents a great variety of immunological components. The aim of this study was to analyze the reactivity of immunoglobulin A from human colostrum to colonization factor antigens I and II. The colostrum ability in preventing enterotoxigenic E. coli adhesion to Caco-2 cells was also evaluated. Colostrum samples were collected from 32 healthy women, and a human colostrum pool was prepared. Enterotoxigenic E. coli strains expressing colonization factor antigens I and II were utilized. The colostrum pool and individual samples showed variable antienterotoxigenic E. coli immunoglobulin A titers, that were reactive with colonization factor antigen I and CS1/CS3 (colonization factor antigen II). The human colostrum pool and individual samples inhibited enterotoxigenic E. coli colonization factor antigen I and II adhesion to Caco-2 cells, at variable levels, and this ability was a result of immunoglobulin A antibodies reactive to these colonization factors. The immunoglobulin A-depleted pool lost this inhibitory ability. As bacterial adhesion is the initial mechanism of enterotoxigenic E. coli infection, breast-feeding could protect the offspring against diarrhea caused by this agent.
Corrêa
Simone
S
Department of Immunology, Universidade de São Paulo, São Paulo, Brazil.
Palmeira
Patricia
P
Carneiro-Sampaio
Magda Maria Sales
MM
Sanae Nishimura
Lucília
L
Guth
Beatriz Ernestina Cabilio
BE
D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology; D001422:Bacterial Adhesion; D018938:Caco-2 Cells; D003126:Colostrum / Q000276:immunology*; D004768:Enterotoxins / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology* / Q000472:pathogenicity; D005260:Female; D036781:Fimbriae Proteins / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology*
D000942:Antigens, Bacterial; D004768:Enterotoxins; D007070:Immunoglobulin A; C022924:colonization factor antigens; D036781:Fimbriae Proteins