title: Functional activity of class-specific antibodies to type III, group B streptococcus.
abstract: The functional activity of naturally acquired IgG and IgM with specificity for the capsular polysaccharide of type III, group B Streptococcus (III-GBS) was compared. Sera collected during convalescence from 14 infants who had developed specific antibodies following III-GBS infection were employed for separation of IgG from IgM by ion-exchange chromatography. Bactericidal killing of III-GBS was similar for IgG- and IgM-rich samples (37 and 42%, respectively) in reactions containing a mean of 1.0 or 1.9 micrograms/ml of III-GBS specific IgG or IgM antibody. Purified IgA lacked opsonophagocytic activity for III-GBS. These results indicate that III-GBS-specific IgG and IgM antibodies in infant sera promote opsonophagocytosis at low concentrations, and that their functional capacity is comparable.
authors.affiliation: Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: J R
authors.initials: JR
authors.lastname: Campbell
authors.forename: C J
authors.initials: CJ
authors.lastname: Baker
authors.forename: T G
authors.initials: TG
authors.lastname: Metzger
authors.forename: M S
authors.initials: MS
authors.lastname: Edwards
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology*; D000918:Antibody Specificity; D001770:Blood Bactericidal Activity; D002852:Chromatography, Ion Exchange; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000302:isolation & purification; D007075:Immunoglobulin M / Q000276:immunology / Q000302:isolation & purification; D007223:Infant; D013292:Streptococcus agalactiae / Q000145:classification / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M