Can you identify the major theme illustrated by each of the following examples? If necessary, you may review the themes in Chapter 1 of your book. Match the themes on the left with the examples on the right. Not all themes will be used. ResetHelp T cell activation requires specific types of communication. Antigen receptors on T cells only recognize fragments of antigens, and the fragments must be displayed, or presented, on the surface of body cells by special proteins before T cells are activated. A T cell bearing a receptor that matches this antigen fragment binds to both the antigen and self-protein. This three-part interaction among a self-protein, an antigen fragment, and an antigen receptor is required for a T cell to function.