6533b7d1fe1ef96bd125d673

RESEARCH PRODUCT

NKG2D stimulation of CD8(+) T cells during priming promotes their capacity to produce cytokines in response to viral infection in mice

subject

description

NKG2D is an activating receptor that is expressed on most cytotoxic cells of the immune system, including NK cells, γδ and CD8+ T cells. It is still a matter of debate whether and how NKG2D mediates priming of CD8+ T cells in vivo, due to a lack of studies where NKG2D is eliminated exclusively in these cells. Here we studied the impact of NKG2D on effector CD8+ T-cell formation. NKG2D-deficiency that is restricted to murine CD8+ T cells did not impair antigen-specific T-cell expansion following mCMV and LCMV infection, but reduced their capacity to produce cytokines. Upon infection, conventional dendritic cells induce NKG2D ligands, which drive cytokine production on CD8+ T cells via the Dap10 signaling pathway. T-cell development, homing and proliferation were not affected by NKG2D deficiency and cytotoxicity was only impaired when strong T-cell receptor stimuli were used. Transfer of antigen-specific CD8+ T cells demonstrated that NKG2D-deficiency attenuated their capacity to reduce viral loads. The inability of NKG2D-deficient cells to produce cytokines could be overcome with injection of IL-15 super-agonist during priming. In summary, our data shows that NKG2D has a non-redundant role in priming of CD8+ T cells to produce antiviral cytokines. Upon viral infection, classical Dendritic cells induce expression of the NKG2D ligand H60. NKG2D stimulation during priming enhances the ability of CD8 T cells to produce cytokines but not increases cytotoxic potential upon T cell receptor engagement in the periphery.