CD8-positive alpha-beta T cell (CD8+ T cell) (CD8+ T cell)

CD8-positive alpha-beta T cells, also known as cytotoxic T lymphocytes (CTLs), are a subset of T cells that play a vital role in the adaptive immune system by directly killing infected or cancerous cells. They recognize specific peptide antigens presented by Major Histocompatibility Complex (MHC) class I molecules via their alpha-beta T-cell receptors (TCRs) [Janeway's Immunobiology, 2017]. Upon recognition, these cells release cytotoxic proteins such as perforin and granzymes, which trigger apoptosis in the target cell, and secrete cytokines like interferon-gamma to coordinate the broader immune response [StatPearls, 2023]. In the context of therapeutic intervention, CD8+ T cells are the primary effectors for immune checkpoint inhibitors, which prevent T-cell exhaustion and enhance anti-tumor immunity [Nature Reviews Cancer, 2018]. They are also the basis for CAR-T cell therapies, where they are genetically engineered to target specific tumor antigens. However, their overactivation or dysfunction can lead to autoimmune diseases, chronic inflammation, or severe systemic toxicities like cytokine release syndrome [PubMed: 27149144]. These cells are characterized by the expression of the CD8 glycoprotein, which acts as a co-receptor for the TCR during MHC I binding [UniProt: P01732]. Monitoring the infiltration and activation state of these cells in the tumor microenvironment is a key biomarker for predicting response to immunotherapy [Nature, 2021].

Other names

Cytotoxic T lymphocyteCTLCD8+ T-cellKiller T cellCD8-positive T-lymphocyteCD8+ alpha-beta T cell

Therapeutic strategies involving these cells include checkpoint inhibition to reverse exhaustion, cytokine-mediated stimulation to enhance proliferation, and genetic engineering (CAR-T) to redirect specificity toward tumor-associated antigens [Nature Reviews Immunology, 2015; Nature Reviews Cancer, 2018].