Low levels of antibodies to surface antigens of group B streptococci in commercial IgG preparations.

53 different batches of commercial IgG were tested for antibodies to group B streptococci (GBS) types Ia, Ib, II and III. The levels of antibodies varied widely. Comparison of the anti-GBS antibody levels in these preparations with those found in normal blood donor sera showed that the commercial IgG contained approximately 2.6 times less type-specific antibodies. We conclude that the commercial IgG now available is not optimal for passive immunization against GBS infections in neonates.