https://doi.org/10.1351/goldbook.13718
Helper T lymphocyte (Th) producing mainly interleukin-2 (IL-2), interferon (IFN-$\ce{\upgamma\!}$), and tumor necrosis factor $\ce{\upbeta\!}$ ($\ce{TNF\mbox{-}\upbeta\!}$), and thereby responsible for phagocyte-dependent host responses.
Note: Th1-dominated responses are seen in autoimmune diseases in which cytotoxic T cells and macrophages play a major role, e.g., multiple sclerosis, diabetes mellitus type 1, Hashimoto thyroiditis, and Crohn disease. Switching from Th1 to Th2 response can prevent Th1-mediated tissue destruction in animal models.