Anti-IL36G (C-terminal) polyclonal antibody

Background. Increasing evidence suggests depot medroxyprogesterone acetate (DMPA) and intravaginal practices may be associated with human immunodeficiency virus (HIV-1) infection risk; however, the mechanisms are not fully understood. This study evaluated the effect of DMPA and intravaginal practices on the genital proteome and microbiome to gain mechanistic insights. Methods. Cervicovaginal secretions from 86 Kenyan women, including self-reported DMPA users (n = 23), nonhormonal contraceptive users (n = 63), and women who practice vaginal drying (n = 46), were analyzed using tandem-mass spectrometry. Results. We identified 473 human and 486 bacterial proteins from 18 different genera. Depot medroxyprogesterone acetate use associated with increased hemoglobin and immune activation (HBD, HBB, IL36G), and decreased epithelial repair proteins (TFF3, F11R). Vaginal drying associated with increased hemoglobin and decreased phagocytosis factors (AZU1, MYH9, PLAUR). Injury signatures were exacerbated in DMPA users who also practiced vaginal drying. More diverse (H index: 0.71 vs 0.45; P =.009) bacterial communities containing Gardnerella vaginalis associated with vaginal drying, whereas DMPA showed no significant association with community composition or diversity. Conclusions. These findings provide new insights into the impact of DMPA and vaginal drying on mucosal barriers. Future investigations are needed to confirm their relationship with HIV risk in women.

IL-36 is the common name for the three IL-1 family members IL-36 alpha, IL-36 beta, and IL-36 gamma, formerly known as IL-1F6, IL-1F8, and IL-1F9, respectively. IL-36 appears to have pro-inflammatory activities; however, the physiological function of these cytokines remains unknown. Expression of IL-36 by keratinocytes implies its possible involvement in innate immune responses in the skin. We observed that, of the three IL-36 isoforms, human keratinocytes express high levels of IL-36 gamma. IL-36 gamma mRNA expression was dramatically induced by the Toll-like receptor ligands polyinosinic-polycytidylic acid (poly(I: C)) and flagellin. Surprisingly, the IL-36 gamma protein was released by cells treated with poly(I: C), but remained intracellular in cells treated with flagellin only. poly(I: C), but not flagellin, induced cell death and caspase-3/7 activation. Inhibition of caspase-3/7 and caspase-1 blocked extracellular release of IL-36 gamma from poly(I: C)-treated cells. Furthermore, caspase-1 inhibition prevented poly(I: C)-induced caspase-3/7 activation. Interestingly, transcription of the gene IL36G was dependent on caspase-1, but not caspase-3/7, activation. This demonstrates that the pathways leading to IL36G transcription and caspase-3/7 activation branch after caspase-1. This divergence of the pathways allows the cells to enter a state of de novo protein synthesis before committing to pyroptosis. Overall, our observations suggest that IL-36 gamma may be an alarmin that signals the cause, e. g., viral infection, of cell death.