What are two phases of Th1 HS?

Sensitisation (TH1 cells that are activated by intracellular pathogens, including bacteria, fungi and protozoa, as well certain chemicals ( hair dyes, nickel salts) leading to clonal expansion and differentiation of antigen-specific cells into TH1 clone, CD4+ TH1 cells secrete IL2 and interferon gamma, further inducing the release of other TH1 cytokines, thus mediating the immune response) Effector phase ( Antigen-specific TH1 cells that were primed by a previous exposure to the antigen, enter the site of antigen injection, recognize complexes of peptide: MHC class II molecules on APCs, undergo further clonal expansion and release inflammatory cytokines, such as IFN-γ, TNF-β)