NKp44 does not elicit IPC-mediated cytotoxicity. (A,C) Redirected lysis of the FcR-bearing cell line P815 in the presence of an anti-NKp44 antibody was determined by a 4-hour (A) or 18-hour (C) chromium release assay. Activated NK cells (A) or the NK cell line NK92 (C) were included as controls. (B) Direct killing of K562 cells by IPCs or NK92 was tested in a 4-hour chromium release assay. (D) Intracellular granzyme B expression in IPCs. Bold profile shows anti-granzyme-B staining; thin profile represents an isotype-matched control antibody.