IgG coating of Lactobacillus crispatus is associated with cervicovaginal immune homeostasis and reduced preterm birth rates, identifying S-layer proteins as candidate antibody targets
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Background
Maternal host immune system responses to cervicovaginal microbiota influence the risk of
microbial-driven spontaneous preterm birth (sPTB). Immunoglobulins are present in cervicovaginal fluid (CVF). There are decreased IgG concentrations in women with CST I compared to CST IV, but their role in sPTB is unclear. Here we investigate immunoglobulin
coating of vaginal bacteria in 100 women at high-risk of sPTB (48 sPTB vs 53 term).
Results
Lactobacillus-dominated communities, especially L. crispatus-dominated, had higher proportions of IgG coating than high diversity, Lactobacillus-depleted communities. There was a positive correlation between IgG and IgG2 coating, indicating IgG2 was the main
bound subclass. The percentage of bacterial coating by IgG and IgG2 was higher in women who delivered at term compared to preterm, and IgG coating negatively correlated with concentrations of CVF proinflammatory immune mediators. IgG and IgG2 both bound to L.
crispatus surface layer proteins (SLPs), identifying SLPs as potential targets of antibody binding associated with immune homeostasis and term birth.
Conclusions
Our results reveal an association between vaginal bacterial antibody coating and mucosal
microbe-immune homeostasis with reduced cervicovaginal inflammation and term birth.
These represent a potential component of host-microbe interactions associated with pregnancy outcome.
Maternal host immune system responses to cervicovaginal microbiota influence the risk of
microbial-driven spontaneous preterm birth (sPTB). Immunoglobulins are present in cervicovaginal fluid (CVF). There are decreased IgG concentrations in women with CST I compared to CST IV, but their role in sPTB is unclear. Here we investigate immunoglobulin
coating of vaginal bacteria in 100 women at high-risk of sPTB (48 sPTB vs 53 term).
Results
Lactobacillus-dominated communities, especially L. crispatus-dominated, had higher proportions of IgG coating than high diversity, Lactobacillus-depleted communities. There was a positive correlation between IgG and IgG2 coating, indicating IgG2 was the main
bound subclass. The percentage of bacterial coating by IgG and IgG2 was higher in women who delivered at term compared to preterm, and IgG coating negatively correlated with concentrations of CVF proinflammatory immune mediators. IgG and IgG2 both bound to L.
crispatus surface layer proteins (SLPs), identifying SLPs as potential targets of antibody binding associated with immune homeostasis and term birth.
Conclusions
Our results reveal an association between vaginal bacterial antibody coating and mucosal
microbe-immune homeostasis with reduced cervicovaginal inflammation and term birth.
These represent a potential component of host-microbe interactions associated with pregnancy outcome.
Date Acceptance
2026-09-10
Citation
Microbiome
ISSN
2049-2618
Publisher
BMC
Journal / Book Title
Microbiome
Copyright Statement
Copyright This paper is embargoed until publication. Once published the Version of Record (VoR) will be available on immediate open access.
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Publication Status
Accepted