In Antigen Presentation to Helper T Cells (TH Cells), Both

Question

In antigen presentation to helper T cells (TH cells), both the TCR and co-receptor proteins…
A) are expressed on the dendritic cell.
B) bind to the class II MHC protein.
C) bind to the presented peptide antigen.
D) All of the above.

Accepted Answer

Note that T cell receptors (TCRs) bind to both the presented peptide and the polymorphic parts of the class II MHC protein, whereas the CD4 co-receptor binds only to the invariant part of the MHC protein.