Potential role of mycoplasma hominis in interleukin (IL)-17-producing CD4 + t-cell generation via induction of IL-23 secretion by human dendritic cells

Abstract

Background.Mycoplasma hominis, a human urogenital pathogen, is involved in genital and extragenital infections and arthritis, particularly in immunocompromised patients. The interleukin (IL) 23/T helper (Th) 17 axis is associated with inflammatory and autoimmune diseases. The aim of this study was to assess the IL-23 response to M. hominis in human dendritic cells (DCs) and the CD4 + T-cell differentiation in response to M. hominis-infected DCs.Methods.Human monocyte-derived DCs were cultured with phosphate-buffered saline, lipopolysaccharide, or M. hominis PG21. Cocultures with heterologous T cells were performed. Extracts from M. hominis were separated and incubated with DCs. Isolates from different clinical syndromes were tested.Results.M. hominis induced the maturation of human DCs with predominant IL-23 secretion in a Toll-like receptor 2-dependent manner. The in vitro immunomodulatory capacity of M. hominis was contained in a lipoprotein-enriched fraction from the mycoplasma. M. hominis-activated DCs induced IL-17-producing CD4 + T cells. Interestingly, clinical isolates differed in their ability to promote IL-23 secretion by DCs.Conclusions.Taken together, our findings demonstrate a major role for the IL-23/Th17 axis in the defense against M. hominis and indicate a potential role for these bacteria in inflammatory and autoimmune diseases. © The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved.