Granulysin is a member of the saposin-like protein family of lipid binding proteins (SAPLIP). It is expressed by NK cells and cytolytic T lymphocytes (CTL) as 15- and 9-kD forms. The 9-kda form is derived from the 15-kD form by cleavage at both amino- and carboxy-termini. Granulysin has broad cytolytic activities against a variety of tumor cells and microbes, including Gram-positive and -negative bacteria, fungi, and parasites. It also functions as a chemoattractant for inflammatory cells and activates the cells to express cytokines and chemokines.