Inducible immunity to Trichomonas vaginalis in a mouse model of vaginal infection.

Abstract

Trichomonas vaginalis is a protozoan parasite that causes a common sexually transmitted disease, trichomoniasis. Despite its high prevalance, the pathogenesis and immunogenicity of T. vaginalis are not well understood. Because currently available therapies are not always effective in treatment or in disease control and because of the impact of T. vaginalis on the health of women, a vaccination strategy could be an effective method of prevention. We studied the protective effects of subcutaneous immunization with T. vaginalis using a mouse model of vaginal infection. Balb/c mice were either immunized with T. vaginalis suspended in Freund's complete adjuvant (FCA) at day $-$56 and boosted with Freund's incomplete adjuvant (FIA) at day $-$28, or immunized only at day $-$28 with either Tv/FCA or Tv/FIA. Control mice were sham immunized and boosted with phosphate-buffered saline suspended in FCA and FIA respectively. At day 0 all mice were intravaginally inoculated with T. vaginalis. Mice immunized and boosted had significantly less intravaginal infection and had an elevated serum and vaginal antibody response compared to single immunization or control mice. Immunization with whole T.vaginalis appears to confer protection against intravaginal challenge with T. vaginalis in this animal model of infection.