INHIBITION OF ENTEROPATHOGENIC ESCHERICHIA-COLI ADHESION TO HEP-2 CELLS BY COLOSTRUM AND MILK FROM MOTHERS DELIVERING LOW-BIRTH-WEIGHT NEONATES

Breast milk samples from three groups of Brazilian women were evaluate d for their inhibitory effect on enteropathogenic Escherichia coli (EP EC) adhesion to HEp-2 cells: G1, mothers delivering preterm babies of appropriate birth weight (n = 12); G2, mothers delivering term babies of low birth weight (n = 11); G3, the control group, mothers deliverin g term babies of appropriate birth weight (n = 39). Colostrum samples were obtained at 48-72 h and milk samples on the 7th, 30th and 60th da ys after delivery. All samples showed strong inhibitory activity (66%- 100%), without significant differences among the three groups and four periods. Total IgA and anti-EPEC IgA concentrations were significantl y higher in colostrum than in milk samples in the three groups studied . The levels of colostral IgA and anti-EPEC IgA observed in G1 and G2 were significantly higher compared to the control group. Western blott ing assays showed that individual samples as well as pools of colostru m or milk samples contain IEA antibodies to many EPEC outer membrane p roteins. A 94 kDa band with molecular weight consistent with the EPEC adhesin named intimin, was recognized by all samples analysed. Bands o f different molecular weight were also recognized by some samples of c olostrum and milk, such as a band of similar to 18.4 kDa, with molecul ar weight equivalent to bundle-forming pilus subunits. Conclusion Our results suggest that colostrum and milk from mothers of premature and small-for-date term neonates are as effective in protecting the newbor n against EPEC infections as those from mothers of term babies of appr opriate birth weight.