Question

The principal mechanism through which cytotoxic T cells act is by the calcium-dependent release of specialized lytic granules upon recognition of antigen on the surface of a target cell. These granules are modified lysosomes that contain at least two distinct classes of cytotoxic effector protein that are expressed selectively in cytotoxic T cells. Such proteins are stored in the lytic granules in an active form, but conditions within the granules prevent them from functioning until after their release. One of these cytotoxic proteins, known as perforin, polymerizes to generate transmembrane pores in target cell membranes. The other class of cytotoxic proteins is comprised of at least three proteases called what?

Bence Jones proteins
RANTES
Caspases
Addressins
Granzymes

Answer 1

Cytotoxic T cells use perforin and granzymes to induce apoptosis in infected cells. Perforin forms pores in the target cell membrane, and granzymes enter through these pores to trigger programmed cell death.

Step-by-step explanation:

The principal mechanism through which cytotoxic T cells act involves the calcium-dependent release of specialized lytic granules upon the recognition of antigen on the surface of a target cell. These granules contain cytotoxic effector proteins that exist in an active state within the granules, but are rendered inactive until released. One such protein, known as perforin, polymerizes to form transmembrane pores on the target cell membranes, allowing the entrance of other cytotoxic proteins.

The other class of cytotoxic proteins released by cytotoxic T cells are called granzymes, which comprise at least three specific proteases. These granzymes enter the target cell through the perforin-formed pores and induce apoptosis, effectively leading to the death of the infected or abnormal cell without releasing pathogens that could infect neighboring cells.