[HTML][HTML] A conserved HIV-1-derived peptide presented by HLA-E renders infected T-cells highly susceptible to attack by NKG2A/CD94-bearing natural killer cells

ZB Davis, A Cogswell, H Scott, A Mertsching… - PLoS …, 2016 - journals.plos.org
ZB Davis, A Cogswell, H Scott, A Mertsching, J Boucau, D Wambua, S Le Gall, V Planelles
PLoS pathogens, 2016journals.plos.org
Major histocompatibility class I (MHC-I)-specific inhibitory receptors on natural killer (NK)
cells (iNKRs) tolerize mature NK cell responses toward normal cells. NK cells generate
cytolytic responses to virus-infected or malignant target cells with altered or decreased MHC-
I surface expression due to the loss of tolerizing ligands. The NKG2A/CD94 iNKR
suppresses NK cell responses through recognition of the non-classical MHC-I, HLA-E. We
used HIV-infected primary T-cells as targets in an in vitro cytolytic assay with autologous NK …
Major histocompatibility class I (MHC-I)-specific inhibitory receptors on natural killer (NK) cells (iNKRs) tolerize mature NK cell responses toward normal cells. NK cells generate cytolytic responses to virus-infected or malignant target cells with altered or decreased MHC-I surface expression due to the loss of tolerizing ligands. The NKG2A/CD94 iNKR suppresses NK cell responses through recognition of the non-classical MHC-I, HLA-E. We used HIV-infected primary T-cells as targets in an in vitro cytolytic assay with autologous NK cells from healthy donors. In these experiments, primary NKG2A/CD94+ NK cells surprisingly generated the most efficient responses toward HIV-infected T-cells, despite high HLA-E expression on the infected targets. Since certain MHC-I-presented peptides can alter recognition by iNKRs, we hypothesized that HIV-1-derived peptides presented by HLA-E on infected cells may block engagement with NKG2A/CD94, thereby engendering susceptibility to NKG2A/CD94+ NK cells. We demonstrate that HLA-E is capable of presenting a highly conserved peptide from HIV-1 capsid (AISPRTLNA) that is not recognized by NKG2A/CD94. We further confirmed that HLA-C expressed on HIV-infected cells restricts attack by KIR2DL+ CD56dim NK cells, in contrast to the efficient responses by CD56bright NK cells, which express predominantly NKG2A/CD94 and lack KIR2DLs. These findings are important since the use of NK cells was recently proposed to treat latently HIV-1-infected patients in combination with latency reversing agents. Our results provide a mechanistic basis to guide these future clinical studies, suggesting that ex vivo-expanded NKG2A/CD94+ KIR2DL- NK cells may be uniquely beneficial.
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