Mastering A&P Immune System Practice Test 2026 - Free Immune System Practice Questions and Study Guide

Perforins play a critical role in the immune response, particularly in the activity of cytotoxic T cells and natural killer (NK) cells. Their primary function is to perforate the membranes of target cells that are infected by viruses or that have become cancerous. When these immune cells encounter a target, they release perforins, which create pores in the lipid bilayer of the target cell's membrane. This compromises the integrity of the membrane, leading to cell lysis and death.

This mechanism is essential for the elimination of infected or abnormal cells, contributing to the effectiveness of the cellular immune response. By inducing cell death in this manner, perforins help to limit the spread of infections and aid in the overall defense of the host organism against pathogens. This distinguishes their function from other processes, such as antibody generation or activation of B cells, which involve different immune mechanisms.