Production of low-avidity antibody by infants after infection with serogroup B meningococci

Experimental serogroup a meningococcal vaccines have induced only poor immu ne responses and have had little protective efficacy in children younger th an 1 year of age. We used ELISA with potassium thiocyanate to compare the a verage avidity of antibody produced by infants with that of children order than 10 years after systemic disease. Infants produced specific antibody of lower average avidity than older children-a finding that correlates with a bsence of serum bactericidal activity in the serum samples of the same infa nts.