When a presented antigen fragment interacts with the T cell receptor of a helper T cell,the co-receptor that must also participate to finalize recognition is _________.

Question

Quizplus · Accepted Answer

CD4 is the co-receptor that must participate in the recognition process when an antigen fragment interacts with the T cell receptor of a helper T cell. The CD4 co-receptor binds to the MHC II molecule on the surface of the antigen-presenting cell, stabilizing the interaction between the T cell and antigen-presenting cell, and initiating signaling cascades that ultimately lead to T cell activation. CD8 is a co-receptor that helps to finalize recognition in cytotoxic T cells and binds to MHC I molecules on infected or cancerous cells. MHC I molecules are not involved in the recognition of antigen fragments by helper T cells.

When a Presented Antigen Fragment Interacts with the T Cell