[Antibodies to group B streptococci in maternal and cord sera]

Group B Streptococcus (GBS) antibody concentrations were studied in 214 pregnant women, of which 91 were carriers and 123 were noncarriers. The method using EIA was designed to measure antibodies to Type Ia, Ib, Ic, II, III and Group B. By means of AGG (Agglutination), antibodies to Type Ib, II, and Group B could also be measured. 1) The Group B antibody concentration in pregnant carriers of GBS (mean: 13.9 microliters with EIA, 4.77 microliters with AGG) was significantly greater than that in noncarriers (mean: 10.6 microliters with EIA, 3.64 microliters with AGG). 2) In most of the cases studied, the cord serum concentration was similar to the maternal concentration when EIA was used. On the other hand the antibody concentrations in cord serum were lower than those in the maternal serum when AGG was used. 3) In a premature baby (1,768g) and in a baby with Downs' syndrome the cord serum concentration was lower than the maternal concentration, while in a large baby (4,074g) the cord serum concentration was higher than the maternal concentration. 4) Using EIA, the type-specific antibody which coincided with the type of strain isolated from each vaginal carrier showed a higher concentration than any other type-specific antibody.