Cytolytic granules in cytotoxic T cells and NK cells

Cytolytic granules contain membrane perturbing molecules that allow fusion of the killer cell with the target cell. These include perforins and granulysin. Fusion allows the release of granule contents into the target cell, and molecules such as granzymes induce apoptosis.

The membrane attack complex is part of the complement pathway and is not found in cytolytic granules.