Measurement of antibody-producing capacity in man. I. The normal response to flagellin from Salmonella adelaide.

Abstract

The immune response to a single subcutaneous injection of 5 μg of flagellin from Salmonella adelaide was examined in 108 human subjects. Titrations were performed by tanned cell haemagglutination before and 1, 2, 6 and 10 weeks after injection. The class of antibody was assessed by mercaptoethanol treatment of serum. Antibody which was entirely IgM was present in 86% of sera before immunization: this is referred to as `natural' antibody. After injection of flagellin the response was predominantly IgM, but both IgM and IgG antibody reached peak titres at 2 weeks and both persisted throughout the response. By contrast after a second injection of flagellin the response was almost entirely IgG antibody.