IMMUNOREACTIVITY OF 5 MONOCLONAL-ANTIBODIES AGAINST THE 37-KILODALTONCOMMON CELL-WALL PROTEIN (PSAA) OF STREPTOCOCCUS-PNEUMONIAE

Five monoclonal antibodies (MAbs) were produced against the Streptococ cus pneumoniae pneumococcal surface adhesin A (PsaA) 37-kDa common cel l wall protein. These antibodies were used in a dot immunoblot and Wes tern blot study of clinical isolates of S. pneumoniae to detect the pr esence of the protein. By both assays, the MAbs reacted with clinical isolates representing the 23 type-specific serotypes present in the li censed pneumococcal polysaccharide vaccine. Western blot analysis conf irmed the presence of a protein migrating in the gel with a molecular mass of 37 kDa. An extension of the study by using dot immunoblot anal ysis that included an analysis of the 90 serotypes of S. pneumoniae sh owed that all five MAbs reacted with 89 of the 90 serotypes tested. MA b 1B6, the exception, did not react with S. pneumoniae serotype 16F. D ot immunoblot analysis of the MAbs with Enterococcus faecalis and viri dans streptococci showed varied reactivity patterns, depending on the species. The MAbs against the 37-kDa antigen did not react with Escher ichia coli, respiratory pathogens, or nonpathogens representing 22 gen era and 29 species of bacteria. All five MAbs also reacted with five m ultidrug-resistant strains of S. pneumoniae. In summary, these MAbs ma y be useful for detection of pneumococcal antigen and may lead to the development of diagnostic assays for pneumococcal disease.