Shigella-specific IgA in saliva of children with bacillary dysentery

To study the secretory immune response after Shigella infection, the anti-lipopolysaccharide and anti-Shiga-toxin response in saliva, obtained from children with confirmed shigellosis and healthy children, were determined by enzyme-linked immunosorbent assay and by Western blot. Children with infection showed high titers compared to healthy controls. After Shigella dysenteriae type 1 infection a significant change in titer could be observed in a large number of cases, in contrast to Shigella flexneri infection. It appeared that, in children living in endemic areas, infection with one serotype can give a rise in antibody titer to another serotype. This could be ascribed to polyclonal B cell activation since children in endemic areas routinely show relatively high titers to Shigella antigens. We conclude that the dynamics of salivary anti-Shigella LPS and anti-Shiga-toxin in children with dysentery indicate that it can be applied to studies of immune response in shigellosis for epidemiological and vaccination purposes.