Difference in target cell recognition of naive and activated human natural killer cells: role of Haymaker (p38.5) in tumoricidal activity.

The human Haymaker gene, at 19q13.2 in the Leukocyte Receptor-Receptor-Related Complexes, encodes a 38.5-kDa non-MHC protein found on the plasma membrane of tumor cell lines that are highly susceptible to lysis by naive (unstimulated) natural killer (nNK) cells.