Demonstration of specific IgA in human feces after immunization with live Ty21a Salmonella typhi vaccine

An enzyme-linked immunosorbent assay was applied to evaluate the appearance of specific IgA in fecal eluates of 11 normal subjects given oral live Salmonella typhi Ty21a vaccine. All subjects after immunization showed a detectable rise in levels of specific IgA to both lipopolysaccharide and flagellar antigens of S. typhi.