Paucity of CD4+ Natural Killer T (NKT) Lymphocytes in Sooty Mangabeys Is Associated with Lack of NKT Cell Depletion after SIV Infection

摘要: Lack of chronic immune activation in the presence persistent viremia is a key feature that distinguishes nonpathogenic simian immunodeficiency virus (SIV) infection natural hosts from pathogenic SIV and HIV infection. To elucidate novel mechanisms downmodulating infection, we investigated killer T (NKT) lymphocytes sooty mangabeys. NKT are potent immunoregulatory arm innate system recognize glycolipid antigens presented on nonpolymorphic MHC-class I-like CD1d molecules. In cross-sectional analysis 50 SIV-negative naturally SIV-infected mangabeys, ligand α-galactosylceramide loaded tetramers co-staining with Vα24-positive invariant were detected at frequencies ≥0.002% circulating approximately half animals. contrast to published reports Asian macaques, mangabey consisted CD8+ CD4/CD8 double-negative CXCR3-positive CCR5-negative suggesting they trafficked sites inflammation without being susceptible Consistent these findings, there was no difference frequency or phenotype between On stimulation human molecules, underwent degranulation secreted IFN-γ, TNF-α, IL-2, IL-13, IL-10, indicating both effector functional capabilities. The unique absence CD4+ combined their IL-10 cytokine-secreting ability preservation following raises possibility might play role