Characterization of Antibodies Produced in Natural and Experimental Coxsackievirus Infections

Abstract

Neutralizing, hemagglutination-inhibiting (HI), complement-fixing (CF) and precipitating coxsackievirus antibodies produced in natural infections of man and experimental infections of rhesus monkeys were characterized with respect to their sedimentation properties in sucrose density gradients and sensitivity to 2-mercaptoethanol (ME). Early appearing neutralizing and HI antibodies consisted largely of 19 S immunoglobulins; these were replaced by 7 S antibody globulins in convalescent-phase sera. Determining the ME sensitivity of neutralizing and HI antibodies in sera from human coxsackievirus infections did not give a particularly reliable indication of the current infecting virus type; in some instances homotypic antibody did not show significant reductions in titer after ME treatment, and in other instances heterotypic antibody was ME-sensitive to the same extent as homotypic antibody. Complement-fixing antibodies to the coxsackieviruses were invariably ME-resistant and demonstrable only in the 7 S immunoglobulin fraction, even in initial infections with a coxsackievirus. In both natural and experimental infections specific precipitating antibody was ME-sensitive and present in the 19 S immunoglobulin fraction, while group precipitating antibody was ME-resistant and present in the 7 S fraction.