title: Natural acquired humoral immunity against serotype-specific group B Streptococcus rectovaginal colonization acquisition in pregnant women.
abstract: Group B Streptococcus (GBS) rectovaginal colonization in pregnant women is associated with invasive GBS disease in newborns, preterm delivery and stillbirths. We studied the association of GBS serotype-specific capsular polysaccharide (CPS) antibody on new acquisition and clearance of rectovaginal GBS colonization in pregnant women from 20 weeks until 37 to 40 weeks' gestation. Serum serotype-specific CPS IgG antibody concentration was measured by multiplex enzyme-linked immunosorbent assay and opsonophagocytic activity (OPA) titres. Rectovaginal swabs were evaluated for GBS colonization, using standard culture methods and serotyping by latex agglutination, at five to six weekly intervals. Higher serotype III CPS antibody concentration was associated with lower risk of rectovaginal acquisition of serotype III during pregnancy (p 0.009). Furthermore, serotype-specific OPA titres to Ia and III were higher in women who remained free of GBS colonization throughout the study compared to those who acquired the homotypic serotype (p <0.001 for both serotypes). Serum CPS IgG values of ≥1μg/mL for serotype V and ≥3μg/mL for serotypes Ia and III were significantly associated with protection against rectovaginal acquisition of the homotypic serotype. A GBS vaccine that induces sufficient capsular antibody in pregnant women, including high OPA titres, could protect against rectovaginal colonization during the latter half of pregnancy.
authors: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation, Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
authors: G
authors: G
authors: Kwatra
authors: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation, Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
authors: P V
authors: PV
authors: Adrian
authors: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation, Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
authors: T
authors: T
authors: Shiri
authors: Department of Obstetrics and Gynecology, University of The Witwatersrand, South Africa.
authors: E J
authors: EJ
authors: Buchmann
authors: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation, Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
authors: C L
authors: CL
authors: Cutland
authors: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Department of Science and Technology/National Research Foundation, Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa; National Institute for Communicable Diseases, Division of National Health Laboratory Service, Johannesburg, South Africa. Electronic address: shabirm@nicd.ac.za.
authors: S A
authors: SA
authors: Madhi
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D016667:Bacterial Capsules / Q000276:immunology; D001431:Bacteriological Techniques; D002353:Carrier State / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D056724:Immunity, Humoral; D007074:Immunoglobulin G / Q000097:blood; D007231:Infant, Newborn; D007841:Latex Fixation Tests; D010587:Phagocytosis; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D012007:Rectum / Q000382:microbiology; D065288:Serogroup; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000276:immunology* / Q000302:isolation & purification; D014621:Vagina / Q000382:microbiology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G
keywords: Antibody; colonization; group B Streptococcus; opsonophagocytic activity; pregnant women