Antibody responsiveness to the enteropathogenic Escherichia coli bundle-forming pilus subunit A in lactating mothers and asymptomatic children.

UNLABELLED: The objective of this study was to examine the antibody responsiveness to the bundle-forming pilus subunit A of enteropathogenic Escherichia coli in human colostrum (n = 36) and serum (n = 90) of paediatric ambulatory patients, 3-24 months of age. Affinity purified recombinant bundle-forming pilus subunit A was used in immunoblot analysis to detect antigen-specific serum immunoglobulins G and A, and colostrum immunoglobulin A. Circulating immunoglobulin G antibody activity to the bundle-forming pilus subunit A was readily detected in all children. The frequency of immunoglobulin A antibody activity to the bundle-forming pilus subunit A in serum was 83.3%. Immunoglobulin A antibody activity to the bundle-forming pilus subunit A was detected in 75% of colostrum samples. The high frequency of immunoglobulin A antibody activity to the bundle-forming pilus subunit A observed in serum reveals a predominance of typical enteropathogenic Escherichia coli priming/infection in the study population. CONCLUSION: these findings demonstrate that the bundle-forming pilus subunit A is immunogenic, for both immunoglobulins G and A, in both pregnant/lactating women and asymptomatic children.

Prevalent transfer of human colostral IgA antibody activity for the enteropathogenic Escherichia coli bundle-forming pilus structural repeating subunit A in neonates.

The frequency of IgA antibody activity to the structural protein subunit BfpA of the enteropathogenic Escherichia coli bundle-forming pilus was determined in 40 mother-infant pairs by immunoblot analysis using affinity purified recombinant BfpA to monitor for IgA in maternal colostrum and in feces of the neonates. Fecal samples were collected from exclusively breastfed term infants < 24-h after the first breastmilk feeding and colostral samples from their mothers. Infants were monitored prospectively with monthly visits to ascertain dietary practices and diarrheal illnesses. The percentage of colostral anti-BfpA IgA positive patients that were also coproantibody positive was 67.5%. The median duration of lactation was 108 days and the incidence of infantile diarrheal disease was 7.5%. Thus, colostral anti-BfpA IgA antibody activity survives passage through the gut of breastfed neonates, persisting in their feces. It is suggested that oral passive immunotherapy may be used to prevent and/or treat typical EPEC infection during infancy.