Trichomonas vaginalis α-Actinin 2 Modulates Host Immune Responses by Inducing Tolerogenic Dendritic Cells via IL-10 Production from Regulatory T Cells

Trichomonas vaginalis is a pathogen that triggers severe immune responses in hosts. T. vaginalis alpha-actinin 2, Tv alpha-actinin 2, has been used to diagnose trichomoniasis. This study was undertaken to examine the role of Tv alpha-actinin 2 as an antigenic molecule to induce immune responses from humans. Western blot analysis using anti-Tv alpha-actinin 2 anti-bodies indicated its presence in the secreted proteins of T. vaginalis. ELISA was employed to measure cytokine production by vaginal epithelial cells, prostate cells, mouse dendritic cells (DCs), or T cells stimulated with T. vaginalis or Tv alpha-actinin 2 protein. Both T. vaginalis and rTva-actinin 2 induced cytokine production from epithelial cell lines, including IL-10. Moreover, CD4(+)CD25(-) regulatory T cells (Treg cells) incubated with rTv alpha-actinin 2-treated DCs produced high levels of IL-10. These data indicate that Tv alpha-actinin 2 modulates immune responses via IL-10 production by Treg cells.