All of the following protein-protein interactions are involved in activation of naive helper T cells by antigen-presenting cells (APCs)EXCEPT:
A)Binding of peptide-MHC complexes on the APC to the TCR on the T cell
B)Binding of CD4 on the T cell to nonpolymorphic regions of class II MHC molecules on the APC
C)Binding of integrins on the T cell with adhesion ligands on the APC
D)Binding of B7-2 on the APC with CD28 on the T cell
E)Binding of CD40L on the T cell with CD40 on the APC

Question

Quizplus · Accepted Answer

CD40L is not expressed on naive T cells and is only up-regulated subsequent to activation by an antigen-presenting cell (APC).In the naive helper T cell,the TCR binds to the MHC-peptide complex whereas the CD4 coreceptor engages a conserved region on the MHC II molecule.Integrins on the T cell interact with adhesion ligands on the APC.This region of binding between the T cell and the APC is known as the immunologic synapse and also includes costimulatory interactions,such as CD28 on the T cell binding to B7 on the APC.

All of the Following Protein-Protein Interactions Are Involved in Activation