CD4-positive T cell and CD8-positive T cell (CD4+ T cell and CD8+ T cell)

CD4-positive T cells ("helper T cells") are lymphocytes that orchestrate the immune response by activating and regulating other immune cells, primarily through cytokine secretion and interaction with antigen-presenting cells[1][3][5][8]. CD8-positive T cells ("cytotoxic T cells") directly kill virus-infected cells, cancer cells, and are central to cellular immunity through release of cytotoxic granules and pro-apoptotic signals[1][5][7][8]. Both cell types are essential for adaptive immunity, contribute to immune memory, and are targets for a wide range of immunotherapies and immunosuppressive drugs. Aberrant activity or loss of either population can result in immunodeficiency, chronic infection, cancer progression, or autoimmunity[3][5][8]. The joint consideration of both CD4+ and CD8+ T cells is key in many clinical contexts, such as immunophenotyping, adoptive T-cell therapies, and immune monitoring, but for most molecular target databases, these are traditionally treated as separate entities due to their unique functions, biomarkers, and therapeutic relevance[1][5][8]. If a single target is required for a therapy or diagnostic that genuinely acts on both cell types together (e.g., pan-T cell depletion or expansion strategies), the entry could be retained, but for classical molecular targeting, these are best represented separately.

Other names

CD4 T lymphocyteT helper cellCytotoxic T lymphocyteCTLKiller T cell

Depletion (antibodies that destroy or anergize T cells); Activation/stimulation (cytokines or receptor agonists); Checkpoint blockade (prevent exhaustion of CD8+ T cells, enhance activity); Adoptive cell transfer (engineered or expanded T cells reintroduced to patient); Suppression (inhibit activation/proliferation, e.g., calcineurin inhibitors)