Читать книгу Immunology - Richard Coico - Страница 46

When naïve CD8⁺ cells encounter antigen‐presenting cells expressing antigenic peptides that bind to their TCR, they are activated and differentiate into cytotoxic killer cells (CTL). Activation also induces the generation of long‐lived memory CTLs to equip the host with sustainable immunity to the antigenic stimulus (e.g., viruses and other intracellular pathogens). Phenotpically, CTLs express αβ TCR, CD3, and CD8 and produce signature cytokines that include IL‐2 and interferon (IFN)‐γ. Their most distinguishing property is the presence of cytoplasmic granules filled with proteins including perforin and granzymes that, when released upon CTL–target cell interaction, kill the target cells. Target cells susceptible to CTL killing include virus‐infected cells and tumor cells (Figure 2.11).