Evaluation of monoclonal antibodies in serovar classification of group B streptococci (GBS). Brief report.

We have produced murine MAbs against the c protein from GBS and selected one anti-c alpha and one anti-c beta MAb for serovar classification of c-protein-producing strains. A total of 61 GBS isolates, classified by serotype-specific rabbit antisera, were tested in an immunofluorescent assay and whole-cell ELISA. The MAbs permitted classification of the isolates into 13 serovars. A total of 34 strains contained the c alpha antigen, seven strains the c beta antigen, and 20 strains both the c alpha and the c beta antigen. The distribution of GBS with regard to c-protein serovars was identical to that recorded when rabbit anti-c alpha and -c beta sera were used. The results show that the MAbs are directed against common epitopes on c alpha and beta, respectively. The MAbs will be useful in the serovar determination of clinical GBS isolates and in the study of the structure and immunobiology of c proteins.