Low Levels of Antibodies to Surface Antigens of Group B Streptococci in Commercial IgG Preparations

Abstract

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 approximatively 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.

Group B Streptococcal Infections

“…Administration of sufficient human type-specific antibodies against CPS to animals before lethal challenge with GBS of the homologous serotype is protective [350,[587][588][589][590][591]. Despite this sound theoretical rationale, commercial preparations of IVIG contain relatively low concentrations of antibodies to group B streptococcal polysaccharides [590][591][592][593][595][596][597][598][599][600], suggesting that prohibitively large doses would be required and raising concern for reticuloendothelial blockade [589,592]. In addition, functional activity of licensed IVIG preparations can vary by manufacturer and lot [588,589,[595][596][597][598][599][600][601], and any increase in antibodies after infusion would be transient only [596,602].…”