title: Development of IgM antibody to group B Streptococcus type III in human infants.
abstract: An ELISA was developed to measure IgM antibody to albumin-coupled native capsular polysaccharide of type III group B streptococcus (GBS). The assay was standardized by two double-label methods that agreed within 33%. In quantitative assays, the range of IgM antibody to type III GBS in the sera of 94 adult pregnant women was 1.2-50.6 micrograms/ml (median, 5.4), while each of 38 cord serum samples contained less than 0.03 micrograms/ml IgM antibody. Neonatal rats were passively immunized with a serially diluted human serum containing 15 micrograms/ml IgM and undetectable IgG antibody to type III GBS. The rats were protected against lethal infection with an IgM antibody concentration of 0.5 micrograms/ml. In single serum samples from 31 healthy infants less than 2 years old and serial specimens from 5 infants with type III GBS infections, specific IgM antibody was detectable by 3 months of age. Levels greater than or equal to 0.5 micrograms/ml were present in all samples from infants greater than 7 months of age. The acquisition of specific IgM antibody is inversely correlated with the age-limited incidence of type III GBS infections in young children.
authors.affiliation: Department of Pediatrics, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois.
authors.forename: K M
authors.initials: KM
authors.lastname: Boyer
authors.forename: M E
authors.initials: ME
authors.lastname: Klegerman
authors.forename: S P
authors.initials: SP
authors.lastname: Gotoff
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D000831:Animals, Newborn; D000907:Antibodies, Bacterial / Q000096:biosynthesis* / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D006801:Humans; D007116:Immunization, Passive; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000096:biosynthesis* / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D011247:Pregnancy / Q000097:blood / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D013292:Streptococcus agalactiae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M