Conventional CD4-positive T lymphocyte (CD4+ T cell) (CD4+ T cell)

Conventional CD4+ T cells, commonly referred to as T helper cells, are a fundamental subset of lymphocytes that play a central role in orchestrating the adaptive immune response (StatPearls, 2023). These cells are characterized by the expression of the CD4 co-receptor, which facilitates the recognition of peptides presented by Major Histocompatibility Complex (MHC) class II molecules on antigen-presenting cells (NIH, 2024). Upon activation, conventional CD4+ T cells differentiate into specialized effector lineages, such as Th1, Th2, and Th17, each producing a distinct profile of cytokines to combat specific types of pathogens (NCBI, 2022). They are essential for B cell antibody class switching and the enhancement of cytotoxic T cell and macrophage functions. Dysregulation of these cells is a hallmark of various pathologies, including autoimmune diseases where they attack self-tissues, and HIV/AIDS, where their depletion leads to severe immunodeficiency (PubMed, 2021). Consequently, they are major focal points for pharmacological intervention, with drugs like cyclosporine and abatacept designed to either suppress their activity in inflammatory conditions or harness their potential in cancer immunotherapy (PubChem, 2024).

Other names

T helper cellTh cellCD4-positive T lymphocyteEffector CD4+ T cell

Therapeutic agents modulate conventional CD4+ T cells by inhibiting calcineurin signaling, blocking co-stimulatory signals (e.g., CD28-CD80/86), preventing lymphocyte trafficking, or directly binding to surface receptors like CD4 or CD3 to induce depletion or signaling blockade (PubChem, 2024; StatPearls, 2023).