Which immune cells are specifically targeted by CTLs?

Cytotoxic T lymphocytes (CTLs) are specialized immune cells that play a crucial role in the adaptive immune response, particularly in the defense against viral infections and certain intracellular pathogens. The primary function of CTLs is to recognize and eliminate infected host cells that display foreign antigens on their surface.

When a host cell becomes infected with a virus or other intracellular pathogen, it presents viral peptides on its surface using Major Histocompatibility Complex (MHC) class I molecules. CTLs possess specific T cell receptors (TCRs) that can recognize these foreign antigens presented by MHC class I. Upon recognition, CTLs initiate a response that can lead to the death of the infected cell through various mechanisms, including the release of perforin and granzymes, which induce apoptosis (programmed cell death).

This targeted action makes CTLs vital for controlling and eliminating infections from within host cells, safeguarding the body against diseases caused by viruses and some proteins produced by bacteria. Understanding the specificity of CTLs for infected cells displayed with foreign antigens is essential for comprehending how the immune system effectively combats infections.