Association between functional antibody against Group B Streptococcus and maternal and infant colonization in a Gambian cohort. Issue 22 (19th May 2017)

• Record Type: Journal Article
• Authors: Le Doare, Kirsty; Faal, Amadou; Jaiteh, Mustapha; Sarfo, Francess; Taylor, Stephen; Warburton, Fiona; Humphries, Holly; Birt, Jessica; Jarju, Sheikh; Darboe, Saffiatou; Clarke, Edward; Antonio, Martin; Foster-Nyarko, Ebenezer; Heath, Paul T.; Gorringe, Andrew; Kampmann, Beate
• Is Part Of: Vaccine. Volume 35:Issue 22(2017)
• Page Start: 2970
• Page End: 2978
• Publication Date: 2017-05-19
• Subjects: Neonatal -- Group B Streptococcus -- Meningitis -- Vaccines; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2017.04.013
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: As maternally-derived anti-GBS antibody increases infant colonization risk decreases. There is a serotype-specific threshold above which an infant is uncolonised with GBS. Higher anti-GBS antibody is associated with infant clearance of GBS between birth and 3 months. Abstract: Background: Vertical transmission of Group B Streptococcus (GBS) is a prerequisite for early-onset disease and a consequence of maternal GBS colonization. Disease protection is associated with maternally-derived anti-GBS antibody. Using a novel antibody-mediated C3b/iC3b deposition flow cytometry assay which correlates with opsonic killing we developed a model to assess the impact of maternally-derived functional anti-GBS antibody on infant GBS colonization from birth to day 60–89 of life. Methods: Rectovaginal swabs and cord blood (birth) and infant nasopharyngeal/rectal swabs (birth, day 6 and day 60–89) were obtained from 750 mother/infant pairs. Antibody-mediated C3b/iC3b deposition with cord and infant sera was measured by flow cytometry. Results: We established that as maternally-derived anti-GBS functional antibody increases, infant colonization decreases at birth and up to three months of life, the critical time window for the development of GBS disease. Further, we observed a serotype (ST)-dependent threshold above which no infant was colonized at birth. Functional antibody above the upper 95th confidence interval for the geometric mean concentration was associated with absence of infant GBS colonization at birth for STII (p < 0.001), STIII (p = 0.01) and STV (p < 0.001). Increased functional antibody was also associated with clearance of GBS between birth and day 60–89. Conclusions: Higher concentrations of maternally-derived antibody-mediated complement deposition are associated with a decreased risk of GBS colonization in infants up to day 60–89 of life. Our findings are of relevance to establish thresholds for protection following vaccination of pregnant women with future GBS vaccines.