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.

Colostrum from healthy Brazilian women inhibits adhesion and contains IgA antibodies reactive with Shiga toxin-producing Escherichia coli.

UNLABELLED: Although Shiga toxin-producing Escherichia coli (STEC) has been isolated in Brazil, severe manifestations of the infection, such as haemorrhagic colitis and haemolytic-uraemic syndrome, are extremely rare in our population. Enteropathogenic Escherichia coli (EPEC) is the main aetiological agent of acute infantile diarrhoea in Brazil. There are many similarities between STEC and EPEC, such as the ability to produce attaching and effacing (A/E) lesions and some virulence-associated factors. Our aim was to investigate the presence of anti-STEC antibodies in healthy people living in an EPEC endemic area. Colostrum samples collected from 51 women living in low socio-economic conditions were analysed. Two STEC strains: O111:H- (Stx1) and O157:H7 (Stx2), and one EPEC strain (O111:H-) were used in the bacterial adhesion assays to HEp-2 cells, in the Stx1 and Stx2 cytotoxicity assays on Vero cells, in immunoblotting and in ELISA assays. All the samples strongly inhibited the adhesion of the three strains and contained SIgA antibodies reactive with antigens of EPEC O111:H-, STEC O111:H- and STEC O157:H7, mainly STEC and EPEC 94 kDa adhesin intimin. High titres of anti-LPS O111 antibodies were found in many samples. Nevertheless, the cytotoxic effect of both Stx1 and Stx2 on Vero cells was not neutralised by any sample. CONCLUSION: Our results suggest that Brazilian people may be exposed to Shiga toxin-producing Escherichia colimore frequently than previously thought or alternatively there may be a cross reactive immunity between enteropathogenic Escherichia coliand Shiga toxin-producing Escherichia coli.

Phagocytic activity of human colostrum macrophages

1. We evaluated the ability of human colostrum adhering cells to phagocytize sheep red blood cells (E) incubated with rabbit anti-E IgG antibody (A) and zymosan particles incubated with fresh human serum or with the aqueous phase of colestrum. 2. The cells were found to have considerably intense phagocytuc ability, i.e., 96,8% phagocytized EA parcicles, 83.2% phagocytized zymosan particles opsonized with fresh human serum, and 73.3% phagocytized zymosan particles opsonized with the aqueous phase of colostrum. Thus, the aqueous phase of colostrum can opsonize zymosan particles, an activity attributed to the complement system. 3. Total hemolytic complement (V+CH50) and the C3 component in a pool of normal human serum were two-fold higher than in a pool of the aqueous phase of colostum. 4. These results indicate the existence of Fcgama and C3 receptors on the membrane of human colostum macrophages and suggest that these cells may be biologically active

Tratamento global da criança asmática no período intercrítico / Global treatment of the asthmatic child in intercrusis period

Os autores relatam a experiência da Unidade de Imunopatologia do Instituto da Criança"Prof. Pedro de Alcântara", do Hospital das Clínicas da FMUSP, no tratamento de crianças asmáticas no período intercrítico abordando os aspectos de higiene ambiental, dietoterapia, psicoprofilaxia, ginástica respiratória, drogas e imunoterapia. O objetivo deste trabalho é tornar mais acessível ao pediatra geral o acompanhamento das crianças asmáticas, patologia muito freqüente na clínica pediátrica, o que exige um preparo para conduçäo adequada destes pacientes e obtençäo de bons resultados