Siglec‐7 Defines a Highly Functional Natural Killer Cell Subset and Inhibits Cell‐Mediated Activities

Sialic acid‐binding immunoglobulin‐like lectin‐7 (Siglec‐7) is an inhibitory receptor expressed on natural killer (NK) cells. In this study, we investigated the relationship between Siglec‐7 expression and NK cell functions. Siglec‐7 was highly expressed on NK cells and was preferentially expressed by mature NK cells from peripheral blood of healthy adults. Siglec‐7+ NK cells displayed higher levels of activating receptors CD38, CD16, DNAM1, NKp30 and NKp46, but lower levels of inhibitory receptors such as NKG2A and CD158b, compared with Siglec‐7– NK cells. Functional tests showed that Siglec‐7+ NK cells displayed more CD107a degranulation and IFN‐γ production than Siglec‐7– NK cells. Siglec‐7 inhibited NK cell functions when interacting with specific antibodies. These data suggest that Siglec‐7 defines a highly functional NK cell subset and suppresses NK cell‐mediated functions when cross‐linked with specific antibodies.