Final answer:
Naïve T helper (TH) cells differentiate into TH1, TH2, TH17, and Treg subtypes depending on the specific cytokines they are exposed to.
Step-by-step explanation:
Naïve T helper (TH) cells differentiate into TH1, TH2, TH17, and Treg subtypes depending on the specific cytokines they are exposed to. The differentiation is directed by antigen-presenting cell (APC)-secreted cytokines. For example, TH1 cells are stimulated by APC-secreted cytokines and secrete cytokines that enhance the activities of macrophages and other T cells, while TH2 cells stimulate naïve B cells to secrete antibodies. TH17 cells are specifically responsible for the body's defense against chronic mucocutaneous infections, and Treg cells play a role in maintaining immune tolerance.