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Mucosal Immunol. 2015 Nov;8(6):1339-48. doi: 10.1038/mi.2015.23. Epub 2015 Apr 8.

Characterization of host immunity during persistent vaginal colonization by Group B Streptococcus.

Author information

1
Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, USA.
2
BioScience Center, San Diego State University, San Diego, California, USA.
3
Department of Pediatrics, University of California San Diego School of Medicine, La Jolla, California, USA.

Abstract

Streptococcus agalactiae (Group B Streptococcus, GBS) is a Gram-positive bacterium, which colonizes the vaginal tract in 10-30% of women. Colonization is transient in nature, and little is known about the host and bacterial factors controlling GBS persistence. Gaining insight into these factors is essential for developing therapeutics to limit maternal GBS carriage and prevent transmission to the susceptible newborn. In this work, we have used human cervical and vaginal epithelial cells, and our established mouse model of GBS vaginal colonization, to characterize key host factors that respond during GBS colonization. We identify a GBS strain that persists beyond a month in the murine vagina, whereas other strains are more readily cleared. Correspondingly, we have detected differential cytokine production in human cell lines after challenge with the persistent strain vs. other GBS strains. We also demonstrate that the persistent strain more readily invades cervical cells compared with vaginal cells, suggesting that GBS may potentially use the cervix as a reservoir to establish long-term colonization. Furthermore, we have identified interleukin-17 production in response to long-term colonization, which is associated with eventual clearance of GBS. We conclude that both GBS strain differences and concurrent host immune responses are crucial in modulating vaginal colonization.

PMID:
25850655
PMCID:
PMC4598252
DOI:
10.1038/mi.2015.23
[Indexed for MEDLINE]
Free PMC Article

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