Antibody S22019F Selectively Recognises KIR2DS1 and Enables Analysis of KIR2DS1⁺ NK Cells and T Cells

Killer cell immunoglobulin-like receptors (KIR) and their cognate HLA ligands regulate the functions of natural killer (NK) cells. However, extensive sequence homology within the KIR family limits the ability of monoclonal antibodies to selectively recognise individual receptors, and no KIR2DS1-specific reagent is available to date. Here, we comprehensively delineate the binding profile of the monoclonal antibody S22019F. Using Ba/F3 cells, NK cell clones, and primary NK cells, we demonstrate that S22019F selectively binds KIR2DS1. Moreover, functional assays reveal that binding of S22019F to KIR2DS1 is preserved upon activation by its HLA-C ligand. We further confirm that S22019F does not cross-react to KIR2DL3*005 allotypes and we extend its application to the analysis of KIR2DS1⁺ T cells. Collectively, these findings underscore the value of S22019F as a reagent that selectively recognises KIR2DS1, enabling improved analyses of KIR2DS1-bearing lymphocytes in fundamental and clinical research.