Vaginal microbe-binding antibody interactions with a Lactobacillus crispatus live biotherapeutic following treatment for bacterial vaginosis.
Rachel Liu, Eric Armstrong, Anke Hemmerling et al.
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In 30 seconds
This randomized controlled trial examined whether vaginal antibodies binding Lactobacillus crispatus CTV-05 affect colonization after bacterial vaginosis treatment. Among 65 women randomized to LACTIN-V or placebo after metronidazole, investigators assessed pre-existing and treatment-associated IgA and IgG. Binding antibodies were common before treatment, with IgA predominating. Neither total nor CTV-05-binding antibody levels predicted resistance to colonization; baseline CTV-05-binding IgA was associated with greater colonization permissiveness. LACTIN-V did not alter overall vaginal antibody concentrations or induce CTV-05-binding antibodies.
Key findings
- Among 65 women, vaginal CTV-05-binding IgA and IgG were commonly detected before bacterial vaginosis treatment, with IgA predominating.
- Neither total nor CTV-05-binding IgA or IgG predicted resistance to CTV-05 colonization.
- Baseline CTV-05-binding IgA was associated with colonization permissiveness.
- LACTIN-V did not change overall vaginal antibody concentrations or induce CTV-05-binding IgA or IgG.
Why it matters
Variable colonization is a challenge for vaginal live biotherapeutics. These findings suggest that pre-existing antibodies binding L. crispatus are not necessarily a barrier to colonization and may be associated with greater permissiveness. The absence of antibody induction after LACTIN-V also informs understanding of host immune responses to this product, while not establishing why colonization succeeds or fails.
What to keep in mind
The study assessed antibody associations in 65 women; the abstract does not report effect estimates or establish that antibodies cause differences in colonization.