Differential Expressions of Selected Activating and Inhibitory Receptors on K562-Stimulated Natural Killer (NK) Cells in HIV-1 and HIV-2 Infections

Context: The functional activity of NK cells depends on the balance between the engagement of activating and inhibitory receptors on the cell surface with their ligands, which enables them to kill infected cells. Objectives: The aim of this study was to evaluate and compare expressions of selected activating and inhibitory receptors on stimulated NK cells in HIV-1 and HIV-2 infections. Methods: PBMCs were analysed for activating (NKp30, NKp44, NKp46) and inhibitory (CD158a, CD158b, p70) receptor expressions in 30 HIV-1, 30 HIV-2 and 30 HIV uninfected healthy control (HC) subjects by flow cytometry after stimulating with K562 cells. Results: There was an expression of other receptors following an already in vitro engagement of NK cells with K562 cells. Higher expression of the activating receptors, NKp44 (p = 0.029) and NKp46 (p = 0.032) on NK cells from HIV-2 compared to HIV-1 infected individuals but similar NKp30 expression (p = 0.980). The levels of expression of inhibitory receptor CD158a were similar between HIV-1 and HIV-2 infected subjects (p = 0.309) but there was significant up-regulation of inhibitory receptors p70 (p = 0.010) and CD158b (p = 0.05) in HIV-1 compared to HIV-2 subjects. Conclusion: Despite the in vitro engagement of NK cells with stimulating K562 cells, our data showed differential expressions of other selected activating and inhibitory receptors in HIV-1 and HIV-2 infected subjects.