What is the primary function of cytotoxic T immune cells?

Cytotoxic T immune cells, also known as CD8+ T cells, play a crucial role in cell-mediated immunity by specifically targeting and killing infected or aberrant cells. Their primary function is to recognize cells that exhibit abnormal antigens — typically those infected by viruses or transformed by cancer — and induce apoptosis (programmed cell death) in these cells. This targeted attack helps eliminate pathogens from the body and is vital for controlling viral infections and maintaining immune surveillance against tumors.

While the production of antibodies is a function primarily associated with B cells, cytotoxic T cells focus on direct action against infected or dysfunctional cells. They do not directly enhance phagocytosis, which is largely done by other immune cells such as macrophages and neutrophils, nor do they primarily aid in pathogen recognition — a function that is more characteristic of helper T cells and antigen-presenting cells. Therefore, the specialization of cytotoxic T cells in directly targeting and dismantling infected cells underscores the critical nature of their role in adaptive immunity.