INDUCIBLE IMMUNITY TO TRICHOMONAS-VAGINALIS IN A MOUSE MODEL OF VAGINAL INFECTION

We studied the protective effect of subcutaneous immunization with Tri chomonas vaginalis in a mouse model of vaginal infection, BALB/c mice were immunized with various doses of T. vaginalis (4.5 x 10(5), 9 x 10 (6), and 1 x 10(8) organisms per ml) suspended in Freund's complete ad juvant 56 days prior to vaginal infection and were given booster injec tions of the same doses of T. vaginalis in Freund's incomplete adjuvan t 4 weeks later. Control mice were immunized and given booster injecti ons of phosphate-buffered saline suspended in Freund's complete and in complete adjuvants. The mice were tail bled and vaginal washes were pe rformed at weekly intervals for 4 weeks to determine the isolation of T. vaginalis and the serum and vaginal antibody reactivity, Mice which had been immunized and given booster immunizations had significantly fewer intravaginal infections and had increased serum and vaginal anti body responses compared with those of control mice (P < 0.01), Mice th at were vaginally infected, treated with metronidazole, and then reinf ected vaginally did not develop protective immunity. Subcutaneous immu nization with whole T. vaginalis organisms appears to confer protectio n against intravaginal challenge with T. vaginalis, protection which i s not achieved as a result of prior vaginal infection.