The PK136 monoclonal antibody (mAb) reacts with mouse NK1.1 which is expressed by NK cells on certain strains of mice (C57BL⁄6, CE, C58, Ma⁄My, NZB, SJL, ST). Useful applications for the PK136 mAb include immunoprecipitation, immunostaining for flow cytometry, complement-dependent microcytotoxicity, depletion of NK cells4, and redirected lysis.