Role of HLA class I alteration in melanoma susceptibility to lysis by autologous NK cells.

<p>Summary of CD107a degranulating assays (performed as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0008132#pone-0008132-g002" target="_blank">figure 2A</a>) analyzed on NK cell subsets in the presence of autologous melanoma cells from six patients. Degranulation was analyzed on (i) NK cell subsets expressing the single inhibitory receptors, (ii) NK cell subsets expressing one or more inhibitory receptors (“Total HLA-inhibited”), (iii) NK cell subsets expressing no inhibitory receptors for self HLA (“Total HLA non-inhibited”) and (iv) the whole NK cell population. Data represent percentages of CD107a expression in the presence of autologous target (grey columns) or in the presence of autologous target plus anti-HLA class I mAb (black columns). Values were calculated by subtracting the spontaneous CD107a expression in the absence of the target. NK cell subsets expressing no receptors for self-HLA are depicted on a grey background. n.d. indicates that the specific NK cell subset was not detectable in a given patient. For each patient, on the right side of the figure, patient HLA class I antigens that are relevant for inhibiting NK cell activity are shown and antigens that have undergone deletions on autologous melanoma cells are marked by a slash. For HLA class I A,B,C, both molecular and serological typing were performed (see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0008132#pone-0008132-t001" target="_blank">Table 1</a>), while HLA-E was detected only at mRNA level. For each HLA class I antigen, matched inhibitory receptor is also specified. Results are expressed as means of 3 to 6 independent experiments. E/T ratio was 1.5∶1.