Isotype composition of antibodies to streptococcus group B type III polysaccharide and to tetanus toxoid in maternal, cord blood sera and in breast milk

Abstract

Neonates are protected against group B streptococcal (GBS) infections and tetanus by transplacentally transferred serum antibodies. Antibodies of the immunoglobulin (Ig) G, IgM and IgA classes and IgG subclasses to the capsular polysaccharide (CPS) of type III group B streptococci (GBS III) and to tetanus toxoid (TT) were measured in sera from healthy women of fertile age and in paired maternal and cord blood sera from term and preterm pregnancies. GBS III CPS antibodies of the IgG class were found in sera from 97 out of 100 women of fertile age, but only 15 of them had antibodies above the proposed protective level (greater than or equal to 2 micrograms/ml). TT IgG antibodies above the protective level (0.01 units/ml) were found in all sera. The IgG antibodies against GBS III CPS were mainly composed of the IgG2 subclass and to a lesser extent of IgG1. Almost all women had IgG1 antibodies against TT and 40% had IgG4 antibodies. Total IgG and IgG1 antibodies against GBS III CPS were higher in cord blood sera from 37 term neonates than in sera from their mothers whereas IgG2 antibody levels were similar. Total IgG and IgG1 antibodies against TT were also higher in the 20 term neonates tested than in their mothers. In contrast, total IgG and IgG1 to both GBS III CPS and TT and IgG2 to GBS III CPS were lower in cord blood sera from preterm neonates than in sera from their mothers. IgA antibodies to GBS III CPS were detected in 63% of breast milk samples while IgA antibodies against TT were detected in only 4%.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies to group B streptococci in neonates and infants

“…In one study of 28 adult women, IgM antibodies were more prevalent than IgG antibodies against GBS CPS type III [1] while another study found no IgM antibodies against GBS type III in 35 sera from healthy adults [11]. A third study of 100 healthy women of fertile age (using the same biotinavidin ELISA as in the present study) showed the same prevalence (97%) of detectable IgG and IgM antibodies against GBS type III [13]. Data showing that there is a good correlation between total antibodies as measured by RABA in maternal and cord sera [3±5], indicate that IgG predominates in adult sera, since IgM does not pass the placenta.…”

“…IgG to GBS types Ia, II and III and IgM to GBS type III were measured by enzyme-linked immunosorbent assay (ELISA) in duplicate in serial three fold dilutions [6,12,13]. The detection limit was 0.05 lg/ml.…”

Cellular Activation, Phagocytosis, and Bactericidal Activity Against Group B Streptococcus Involve Parallel Myeloid Differentiation Factor 88-Dependent and Independent Signaling Pathways

“…This is particularly true of GBS infections in preterm infants who lack a competent adaptive immune response (3). An effective first-line defense must be accomplished in the earliest stages of microbial invasion before the microbial sensing system is overwhelmed by large numbers of invading bacteria (4).…”

c-Jun Kinase Is a Critical Signaling Molecule in a Neonatal Model of Group B Streptococcal Sepsis

“…Several immune mechanisms have been shown to limit the ability of colonizing bacteria to invade the host. In young children, the primary mechanism for limiting bacterial invasion relies on the innate immune system, because the adaptive immune system of newborn and particularly preterm infants is significantly impaired due to decreased synthesis of IgG and constraints in the V H gene repertoire (4,5). Both the epithelial lining of mucosal surfaces and macrophages resident in the adjacent tissue carry the major responsibility of discriminating bacteria from self structures and orchestrating a balanced immune response in the earliest stages of microbial invasion (6).…”