Investigation of the role of Vi antibodies and antibodies of IgA type in the low specific bactericidal activity of the serum in typhoid carriers.

Absorption of sera of typhoid carriers with Vi antigen resulting in the decrease of gamma A antibodies led to a significant increase in the specific bactericidal activity of the serum. On the basis of these findings the authors discuss the origin and the cause of the low values of this activity in sera of typhoid carriers and the possible meaning of this phenomenon in the pathogenesis of typhoid carriership.