[Type-specific antibody to type Ia, Ib, II and III group B Streptococcus in maternal and neonatal sera measured by...

In order to determine the type-specific antibody to group B streptococcus (GBA) type Ia, Ib, II and III, the ELISA system was established in Research laboratories, Toyo Jozo Co., Ltd. We assayed type-specific antibody by this ELISA system in both maternal and neonatal (or cord) sera. The cut off levels were determined by the antibody levels of maternal and neonatal sera of 26 infected cases and 90 GBS carriers, that type Ia, Ib, II were 0.20 and type III was 0.15. Prevalence of type-specific antibody levels were studied in 356 maternal sera (14 affected cases, 100 GBS carriers and 242 non carriers). Antibody levels were positive in 47.2% of maternal sera to type Ia, 34.0% to type Ib, 46.9% to type II and 45.5% to type III. Antibody levels to type Ia, Ib, II and III were positive, respectively, in 100%, 88.2%, 25.0% and 42.9% of the sera of carrier mothers whose infants were not affected. Antibody levels in 50 pair sera of maternal and cord blood were well correlated.