Relationship of the virulence of Trichomonas vaginalis and the major histocompatibility complex in murine trichomonad infection

Abstract

A biological assay based upon the induction of abscesses in mice injected subcutaneously with Trichomonas vaginalis was shown to be a valid method for comparing the virulence of two isolates of T. vaginalis cultured from two patients, one suffering from severe vaginitis and the other exhibiting only mild disease. The data showed excellent correlation between the physical dimensions of abscesses in mice injected with each trichomonad isolate and the severity of vaginitis produced in the women from whom the isolates were obtained. The assay employed in our study incorporated measurement of the mean abscess volumes from day 1 to day 6 post-inoculation with T. vaginalis. We found that the abscess assay was clearly superior to a murine intraperitoneal assay for virulence evaluation of trichomonad isolates. We then used the murine abscess assay to determine the susceptibility of different strains of mice to infection with a virulent T. vaginalis isolate so as to test whether the genetic constitution of the host would influence the pathogenesis of the disease. BALB/c (H-2d) mice were susceptible to infection with T. vaginalis, but both CBA/CaH (H-2k) and BALB/c-H-2k mice were shown to be resistant. The quantitation of abscess formation in these inbred and congeneic resistant mouse strains demonstrates that the severity of infection with T. vaginalis is governed by genes mapping within the major histocompatibility complex.

Complement-Mediated Regulation of <i>Trichomonas vaginalis</i> Infection in Mice

“…The formation of subcutaneous abscesses in mice in this study was consistent with that depicted in studies using different mouse strains [12].…”

“…No other pathogenic microorganisms were isolated from either patient. T. vaginalis strain WAA-38 was classified as highly virulent and strain WAA-51 only weakly virulent based upon the induction of subcutaneous abscesses in mice resulting from the subcutaneous injection of both strains of trichomonad [12]. The trichomonads were inoculated into Feinberg-Whittington medium (F-W) without added agar and maintained at 37°C.…”

“…The murine abscess assay [12] used in these experiments was based upon the method originally devised by Honigberg et al [16]. 8 !…”

“…To obtain a more comprehensive comparison between the patterns of responsiveness in the subcutaneous assay than was possible by simply comparing mean volumes from individual days, the following procedure was adopted [12,18]. Individual curves were constructed from single mean volumes, randomly chosen, at each time point from day 1 to day 6 of the assay.…”

Host genetic backgrounds: the key to determining parasite-host adaptation

“…Furthermore, the elevation of IgM, IgG1 and IgG2b in patient urine samples was found to be related to more severe symptoms ( Imam et al., 2007 ). In addition, the virulence of T. vaginalis could be modulated by MHC, the sensitivity of T cells and the activation of phagocytes in hosts ( Caterina et al., 1996 ). A mouse strain harboring H-2 d was shown to be susceptible to infection with T. vaginalis , but strains with H-2 k were resistant ( Caterina et al., 1996 ).…”