Association between antibodies against group B Streptococcus surface proteins and recto-vaginal colonisation during pregnancy

Abstract

Group B Streptococcus (GBS) recto-vaginal colonisation in pregnant women is the major risk factor for early-onset invasive GBS disease in their newborns. We aimed to determine the association between serum antibody levels against 11 GBS surface proteins and recto-vaginal acquisition of GBS colonisation during pregnancy. Sera collected from pregnant women at 20–25 weeks and ≥37 weeks of gestation age were measured for IgG titres against GBS surface proteins using a multiplex immunoassay. Women were evaluated for recto-vaginal colonisation every 4–5 weeks. We observed that the likelihood of becoming colonised with GBS during pregnancy was lower in women with IgG titres ≥200 U/mL against gbs0233 (adjusted OR = 0.47 [95% CI: 0.25–0.89], p = 0.021) and ≥85 U/mL for gbs1539 (adjusted OR = 0.44 [95% CI: 0.24–0.82], p = 0.01) when comparing between women who acquired GBS colonisation and those that remained free of GBS colonisation throughout pregnancy. IgG titres (U/mL) specific to BibA and Sip were higher in pregnant women colonised with GBS (380.19 and 223.87, respectively) compared to women with negative GBS cultures (234.42 and 186.21, respectively; p < 0.01) at ≥37 weeks gestation. Antibodies induced by gbs0233 and gbs1539 were associated with a reduced likelihood of recto-vaginal GBS acquisition during pregnancy and warrant further investigation as vaccine targets.

Immunogenic Proteins of Group B Streptococcus—Potential Antigens in Immunodiagnostic Assay for GBS Detection

“…This indirect use indicates the usability of BibA protein as detection antigen in ELISA for GBS carriage and/or infection diagnosis [60]. A similar conclusion can be drawn from the research whose aim was to examine the association between antibodies against Streptococcus agalactiae surface proteins and recto-vaginal colonization during pregnancy, in which titers of IgG antibodies were measured in Luminex multiplex immunoassay [61].…”

A Phase 2, Randomized, Control Trial of Group B Streptococcus (GBS) Type III Capsular Polysaccharide-tetanus Toxoid (GBS III-TT) Vaccine to Prevent Vaginal Colonization With GBS III

“…Our study provides proof-of-concept that GBS conjugate vaccine-induced antibodies against type III GBS can delay colonization at mucosal sites. These findings are consistent with and amplify those of 2 observational cohort studies in South African pregnant women that showed that women with high naturally acquired antibodies to CPS-specific IgG [26] or to surface proteins of GBS had a reduced risk of acquiring vaginal and rectal GBS colonization [27]. Decreasing GBS colonization through immunization could have a significant public health impact by reducing pregnancy loss, preterm gestation, and third trimester stillbirth, which are sequelae that cannot be prevented by IAP to prevent mother-to-infant transmission [8].…”

Group B Streptococcal Colonization, Molecular Characteristics, and Epidemiology

“…Other promising vaccine targets that have been identified by reverse vaccinology include the Sip and BibA proteins ( Maione et al, 2005 ; Santi et al, 2007 , 2009b ). It has been recently shown that a reduced likelihood of maternal GBS acquisition during pregnancy is directly associated with Sip and BibA induced antibodies ( Dzanibe et al, 2017 ). The successful development and introduction of a GBS vaccine may, therefore, result in converting GBS into a predominantly harmless commensal of the mucosa.…”