An MHC- II Molecule on an Antigen-Presenting
Cell Dendritic Cell Presenting a Bound Viral Epitope to a Naive T4-Lymphocyte with a Matching
TCR/CD4 on its Surface
Naive T4-lymphocytes via the unique
T-cell receptors and CD4 molecules on their surface recognize peptide epitopes
from exogenous antigens bound to MHC-II molecules on antigen presenting dendritic cells. Different T-cell receptors recognize different epitopes.