Natural killer (NK) cells are the major antiviral effector population of the innate immune system. We previously found that S100A9 is a novel ligand of the receptor CD85j and that S100A9 tetramers enhance the anti-HIV activity of NK cells. Also, we found that dendritic cells (DCs) infected by the HIV vaccine candidate, MVA HIV , prime NK cells to specifically control HIV infection in autologous CD4 + T cells. In this study, we analyzed whether stimulation of NK cells by S100A9 tetramers prior to the priming by MVA HIV- infected DCs modulates the subsequent anti-HIV activity of NK cells. We found that S100A9 tetramers activate NK cells and that DCs enhance the anti-HIV activity of NK cells. Interestingly, we observed that stimulation of NK cells by S100A9 tetramers, prior to the priming, significantly increased the subsequent anti-HIV activity of NK cells and that the enhanced anti-HIV activity was observed following different conditions of priming, including the MVA HIV- priming. As S100A9 tetramers alone directly increase the anti-HIV activity of NK cells and as this increased anti-HIV activity is also observed following the interaction of NK cells with MVA HIV- infected DCs, we propose S100A9 tetramers as potential adjuvants to stimulate the anti-HIV activity of NK cells.
Moreno-Nieves, U. Y., Didier, C., Lévy, Y., Barré-Sinoussi, F., & Scott-Algara, D. (2015). S100A9 tetramers, which are ligands of CD85j, increase the ability of MVA HIV- primed NK cells to control HIV infection. Frontiers in Immunology, 6(SEP). https://doi.org/10.3389/fimmu.2015.00478