Tcells communicate to the rest of the body using

secreting chemical messengers

Explanation:

Helper T cell is a type of cell that provides help to other cells in the immune response by recognizing foreign antigens and secreting cytokines that activate T and B cells.

The helper T cell contains the T cell receptors which binds to the antigen-complexed class II MHC molecule on the B cell surface resulting in helper T activation. The activated helper T cen will noe provide a second activation signal to the B cell, which can occur through a variety of proteins.

In order for helper T cell to communicate to the rest of the body, it must share information through chemical messenger it screated.