Question

What chemical do cytotoxic T cells release?

Answer 1

Cytotoxic T-cells produce the cytotoxic proteins perforin and granzymes.

Explanation:

Cytotoxic T-cells are cells of the immune system that can recognize and kill aberrant cells. For example cells that are infected by a virus or cancer cells.

Cytotoxic T-cells (`"T"_C`-cells) get activated by recognizing an antigen on the surface of a 'sick' cell. Upon activation the `"T"_C`-cell releases lytic granules. These granules are modified lysosomes that contain specific proteins:

1. Perforin: a protein that polymerizes and forms a pore in the membrane of the sick target cell.

2. Granzymes: name for a group of different proteases (enzymes that break down proteins), specifically serine proteases.

Granzymes can enter the cell through the perforin pores. The proteases target proteins that are involved in apoptosis = programmed cell death. So the granzymes give the cell the signal to kill itself in an orderly manner.