Expression of killer inhibitory receptors on cytotoxic cells from HIV‐1‐infected individuals
Dysfunction of cytotoxic activity of T and natural killer (NK) lymphocytes is a main immunological feature in patients with AIDS, but its basis are not well understood. It has been recently described that T and NK cell‐mediated cytotoxicity can be regulated by HLA killer inhibitory receptors (KIR). In this work, we have determined on cytotoxic T cells and NK cells from HIV‐1‐infected individuals the expression of the following KIR molecules: p58, p70, and ILT2 (immunoglobulin‐like family KIR) as well as CD94 and NKG2A (C‐lectin‐type family KIR). With some exceptions, no significant changes were found on the expression of immunoglobulin‐like KIR in either CD8+ or CD56+ cells. Interestingly, the percentages of CD8+ and CD56+ cells expressing CD94 were significantly increased in these individuals. We also show that, in vitro, IL‐10 up‐regulates CD94 expression on CD8+ and CD56+ cells obtained from normal individuals, suggesting that the augmented expression observed in HIV‐infected individuals could be related to the high levels of IL‐10 previously described in HIV‐1‐infected individuals.