CD107a degranulating assay on distinct NK cell subsets expressing single inhibitory receptors.

<p>CD107a degranulating ability of activated NK cell subsets from each patient was analyzed in the presence of autologous melanoma cells, either adding or not an anti-pan HLA class I blocking mAb. E/T ratio = 1.5∶1. A representative analysis of patient CA is shown in panel <b>A</b>. In order to assess the link between HLA class I expression on melanoma cells and their susceptibility to autologous NK cell-mediated lysis, the degranulation of NK cell subsets, expressing a single inhibitory receptor for distinct HLA class I molecules, was analyzed. Staining NK cells with mAbs against a specific KIR or NKG2A and with a mixture of mAbs against the other inhibitory receptors allowed to gate on the specific subset and evaluate its CD107a expression after co-culture with autologous melanoma cells. <b>B</b>: Melanoma specific deletion of a HLA class I allele in the same patient CA. HLA-Bw4 was here detected by flow cytometry on the surface of lymphocytes but not of the autologous melanoma. As a comparison, another conserved HLA-A allele is shown. In accordance with Bw4 deletion, KIR3DL1+ NK cell subset exerts a strong cytolytic activity against autologous melanoma cells, which is not significantly increased following anti-HLA class I masking.