T-helper type 1 immune response

The T-helper type 1 (Th1) immune response is a specialized arm of the adaptive immune system mediated by Th1 cells, a subset of CD4+ helper T cells. Th1 responses are primarily responsible for cell-mediated immunity, which targets intracellular pathogens such as viruses, certain bacteria (e.g., Mycobacterium tuberculosis), and protozoa. Key cytokines produced are interferon-gamma (IFN-γ), interleukin-2 (IL-2) and tumor necrosis factor-beta (TNF-β). Effector functions include activating macrophages to enhance their microbicidal activity, stimulating cytotoxic T lymphocytes (CD8+ T cells) to kill infected host cells and promoting opsonizing antibody production by B-cells. The differentiation into the Th1 lineage is regulated mainly by transcription factors STAT4 and T-bet. While essential for defense against many pathogens, excessive or misdirected Th1 responses can contribute to tissue damage and autoimmune diseases.

Other names

Th1 responseT helper 1 responseType 1 T helper responseTh1 immune response