Question

Cytotoxic T-lymphocytes produce a substance called _______, which creates holes in the cell membranes of target cells

Answer 1

The answer is perforin. This is a pore creating cytolytic protein located in the granules of cytotoxic T lymphocytes (CTLs) and NK cells. Upon degranulation, perforin attaches to the target cell's plasma membrane, and oligomerises in a Ca2+ dependent way to create pores on the target cell.