510. Secretory IgA in the Vaginal Mucosa Inhibits Herpes Simplex Virus Infection

Abstract Background HSV2 increases HIV risk and is twice as common among women. We previously showed that cervicovaginal secretions exhibit innate anti-HSV2 activity was lower in adolescents women with HIV-- conditions associated vaginal dysbiosis increased HSV shedding. Our current study aims to test the hypothesis low anti-HSV explore molecules mechanisms contribute. Methods Cervicovaginal lavage (CVL) (10 ml normal saline wash) collected from 20 who presented clinical bacterial vaginosis (BV) (Day 0) then 1 4 weeks after completing a 7-day oral metronidazole course; parent results were reported (PMID 34003290). Anti-HSV2 of CVL (diluted 1:4) determined by plaque reduction assay. IgG, IgA, cytokines antimicrobial peptides quantified ELISA or multiplex Luminex select microbiota quantitative real-time PCR. enriched for IgA IgG using protein L (binds all Ig) Protein G only IgG). HSV-specific antibodies assessed ELISA. Statistical analyses including Spearman correlation coefficients (SCC) performed GraphPad Prism version 9.1.2 software. Results highly variable at Day 0 (mean 18.6% SD 36.7) trended increase treatment 22.56% 33.8). The correlated positively Nugent scores (SCC= -0.28, p= 0.03) qPCR levels BV-associated microbes (SCC = -0.2 -0.3, p< -0.1) but (r= 0.49, 0.01) 0.33, 0.01). isolated pools high inhibitory greater than 40% (n= 8). mapped fraction (56.5% inhibition) compared non-Ig (0% even though, expected, concentration higher (8.3μg/mL vs 4.9 μg/mL). did not correlate Ig CVL. Conclusion findings suggest secretory contributes may trap viral particles prevent entry. speculate sialidases, which cleave are elaborated microbiota, contribute observed high-risk cohorts. Disclosures Betsy Herold, MD, Viracor (Eurofins): Advisor/Consultant|X-Vax, Technologies: Grant/Research Support|X-Vax, Serve on Scientific Advisory Board X-Vax, Technologies receiving reserach funding related worl.