Group B meningococcal opsonins in serum measured by polymorphonuclear leukocyte chemiluminescence

Serum opsonic activity against a strain of group B meningococci was measured by the initial increment in polymorphonuclear leukocyte chemiluminescence. Chemiluminescence was markedly enhanced by serum and was dependent upon both thermostable and thermolabile factors. It was higher in convalescent sera from patients with meningococcal disease than from other patients and normal controls. Absorption of sera with the homologous strain substantially decreased the opsonic activity. Convalescent serum from a patient with group C meningococcal pericarditis showed high opsonic activity towards a group B meningococcal strain. A convalescent serum showed significantly higher activity towards its homologous group B strain than towards another group B meningococcal strain. As measured by chemiluminescence, properties besides group specificity are of importance in opsonization of meningococci. The simplicity and precision of the chemiluminescence measurements seem to offer an improved tool for the study of meningococcal disease immunology.