Siglec-7 is an inhibitory receptor on human mast cells and basophils

摘要

Allergic effector cells, such as mast cells (MCs), eosinophils, and basophils, are key cellular targets whose activation must be inhibited to resolve or prevent allergic reactions. One approach to inhibiting these cells is to activate inhibitory receptors (IRs) expressed on their surface.1 Sialic acid-binding Ig-like lectin 7 (Siglec-7, also called p75/AIRMl and CD328) was first described in human natural killer (NK) cells2 and later in granulocytes, monocytes, a minor subset of CD8+ T cells,3 and most recently in eosinophils.4 Siglec-7 preferentially binds to a2,8-disialyl and branched a2,6-sialyl carbohydrate structures,5 and association of its immunoreceptor tyrosine-based inhibition motif with the inhibitory phosphatase Src homology region 2 domain-containing phosphatase-1 (SHP-1) transduces an inhibitory signal.2 Here, we show for the first time that Siglec-7 is also expressed on human MCs and basophils; functionally, our data suggest that Siglec-7 plays a significant role in inhibiting IgE-mediated MC activation, but only moderately affects IgE-mediated activation in primary human basophils.