Thymic selection stifles TCR reactivity with the main chain structure of MHC and forces interactions with the peptide side chains.
Huseby ES, Kappler JW, Marrack P. Thymic selection stifles TCR reactivity with the main chain structure of MHC and forces interactions with the peptide side chains. Mol Immunol. 2008 Feb; 45(3):599-606.