Antibodies to heat-labile Escherichia coli enterotoxins in human milk and sera. A study of Ethiopian and Swedish mothers and their children.

Maternal serum and cord blood from 50 Ethiopian, 10 Costa Rican and 20 Swedish newly delivered mothers and their babies was examined for the presence of antibodies against heat labile (LT) enterotoxin from a human strain of E. coli. 96% of the Ethiopian, 80% of the Costa Rican and 30% of the Swedish mothers and infants had detectable antibody levels. The titres were significantly higher in the Ethiopian material. Furthermore, antibody titres to E. coli enterotoxin were determined in breast milk collected from Ethiopian mothers at 48 h and at 1 month after delivery. One third of these mothers had detectable levels of antibodies in samples from early lactation. Experiments performed with LT enterotoxin from another human and with LT from a porcine E. coli strain confirmed the results. Neutralization tests with cholera enterotoxin as antigen were all negative in sera and milk samples from all these groups. The material has been collected in three different geographical areas which are nonendemic for cholera.