The potential protective role of the combination of IL-22 and TNF-α against genital tract Chlamydia trachomatis infection

• MOECs expressed murine β-defensin 2 and the antimicrobial chemokines CXCL-9, -10, and -11.
• MOECs treated with IL-22 and TNF-α or a Th22 cell supernatant could recruit Th1 cells.
• MOECs treated with IL-22 and TNF-α or a Th22 cell supernatant could inhibit Chlamydia trachomatis growth.
• IL-22 and TNF-α or a Th22 cell supernatant exert a positive role in controlling genital epithelial damage.

Th22 cells are a novel class of lymphocytes characterized by the secretion of both IL-22 and TNF-α. In summary, Th22 cells have little or no direct impact on other immune cells, but exert selective effects on epithelia. It is not known, however, whether Th22 cells play a role in genital mucosal immunity. Here, we demonstrate that IL-22 and TNF-α synergistically induce several immunomodulatory molecules, such as the antimicrobial peptide mBD-2 (murine β-defensin 2) and the antimicrobial chemokines CXCL-9, -10, and -11 in primary murine oviduct epithelial cells (MOECs). The induction of innate immunity is relevant in an in vitro infection model, in which MOECs stimulated with Th22 cell supernatants or recombinant IL-22 and TNF-α effectively inhibit the growth of Chlamydia trachomatis and maintain the survival of the epithelia compared with IL-22 or TNF-α alone. In summary, we demonstrate that the Th22 cell cytokines IL-22 and TNF-α play important roles in genital tract infection. The potential for Th22 cell cytokines to modulate innate immune mediators may lead to the development of new topical agents to treat and/or prevent immune-mediated sexually transmitted diseases (STDs). In summary, we demonstrate that IL-22 and TNF-α represent a potent, synergistic cytokine combination for inducing genital mucosal immunity.