Loss of Innate Host Defense Following Unprotected Vaginal Sex

Multiple defense mechanisms protect the female genital tract from pathogens, but the impact of sexual intercourse on defense is unknown.

As part of a hypothesis-generating study, 17 women provided cervicovaginal lavage (CVL) at baseline (abstinent x 72 hours), and 2-6 hours and 10-14 hours after vaginal intercourse with and without a male condom (5 visits total). Vaginal pH, concentrations of immune molecules, and antimicrobial activity at post-coital visits were compared to baseline.

Vaginal pH and transforming growth factor (TGF)-β1 increased, but human beta-defensin (HBD)-2, HBD-3, and interleukin (IL)-8 decreased after unprotected sex. CVL E. coli inhibitory activity decreased significantly from baseline at the 2-6 hour post-unprotected sex visit (median 63% [range -34-99] vs. 5% [-51-100]; p=0.02) and remained low at the 10-14 hour visit (6% [-19-92]; p=0.02). Pooled human seminal plasma enhanced E. coli growth in vitro in a dose dependent manner and, when added to CVL samples with high anti-E. coli activity, reversed the inhibition.

Unprotected vaginal sex results in a reduction in endogenous anti-E. coli activity, which may reflect, in part, enhancement of bacterial growth by seminal plasma. This finding may contribute to the risk of E. coli vaginal colonization following sexual intercourse.

Full PDF article at: http://goo.gl/XM4JJs

By: Nakra NA1, Madan RP1, Buckley N1, Huber AM1, Freiermuth JL1, Espinoza L2, Walsh J2, Parikh UM3, Penrose KJ3, Keller MJ2, Herold BC1

• 1Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY.
• 2Department of Medicine, Albert Einstein College of Medicine, Bronx, NY.
• 3Department of Medicine, University of Pittsburgh, Pittsburgh, PA.  

More at:  https://twitter.com/hiv_insight