FIGURE 3.

Involvement of CD8 in CD3Δc induction by cognate ligand in a role beyond affinity. The relative affinity for the OT-I TCR of variant peptides when loaded either in K^b WT or K^b MUT molecules is: K^b WT/pFARL < K^b WT/pG4 < K^b WT/pQ7 < K^b WT/pQ4H7 < K^b MUT/pOVA < K^b WT/pOVA. Preselection OT-I DP thymocytes were cocultured with these peptide-loaded APCs and the CD3-PD assay was performed (top). A fraction of the postnuclear lysate of each sample was used to determine the total CD3 content by Western blot of CD3ζ (bottom).