Final answer:
The TCR of a helper T cell binds to antigens presented with MHC II molecules. This binding triggers immune responses, including the release of cytokines.
Step-by-step explanation:
The TCR (T cell receptor) of a helper T cell binds to antigens presented with MHC II (major histocompatibility complex II) molecules.
MHC II molecules are found on antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells.
When the TCR binds to the MHC II-antigen complex, it triggers a series of immune responses, including the release of cytokines that help coordinate the immune response.