PRF1 and Chediak-Higashi syndrome: Furthermore, although many of the fundamental immunologic principles can be applied from mouse models to human subjects, several significant differences exist between human and mouse NK cells, such as initial functionality and cytotoxicity, differences in translation and expression of lytic proteins (perforin and granzymes) or cell-surface receptors, and pathways regulating NK cell activation.35, 36, 37 Therefore we sought to create a human CHS model to determine the underlying biochemical cause of the impaired cytotoxicity in CHS cytotoxic lymphocytes.