CD79A and infection: Anti-CTB and anti-TcpA IgG and IgA antibodies were only stimulated by infection, and their presence could be used to distinguish infection from vaccination, though misclassification with this approach could occur with children, who may have higher levels of anti-CTB antibodies (due to enterotoxigenic Escherichia coli [ETEC] infection) and are generally less likely to generate anti-TcpA antibodies than adults (14).