Immune response to tetravalent meningococcal vaccine: opsonic and bactericidal functions of normal and properdin deficient sera.

Neisseria meningitidis serogroup W-135 appears to be a fairly common cause of infection associated with properdin deficiency or dysfunction, and anticapsular antibodies might be protective in these patients. For this reason, bactericidal and opsonophagocytic activities for serogroup W-135 were investigated before and four weeks after vaccination of two properdin-deficient adults with tetravalent meningococcal vaccine. In addition, the response of IgM, IgG and IgA class antibodies to the serogroups A, C, Y and W-135 was determined by ELISA. There was no evidence of poor antibody responses in the properdin-deficient persons. Vaccination promoted classical pathway-mediated killing in serum and opsonization of serogroup W-135 to the same extent as that seen in vaccinated controls. The increase of alternative pathway-mediated killing in the properdin-deficient sera was moderate, but vaccination clearly enhanced alternative pathway-mediated opsonophagocytosis in the sera. It was also shown that vaccination markedly reduced the requirement for properdin in alternative pathway-mediated killing of the meningococci.