TCR Antagonism by Peptide Requires High TCR Expression

TCR antagonism by peptide requires high TCR expression.

Current models of T cell activation focus on the kinetics of TCR-ligand interactions as the central parameter governing T cell responsiveness. However, these kinetic parameters do not adequately predict all T cell behavior, particularly the response to antagonist ligands. Recent studies have demonstrated that TCR number is a critical parameter influencing the responses of CD4(+) T cells to weak...

Altered Peptide Ligand-Mediated TCR

Using Dual-TCR-Expressing T Cells Study of the Mechanism of TCR Antagonism

Altered Peptide Ligands Carrying Single Residue Substitutions in an Antigenic Peptide Characterization and Frequencies of TCR Agonism and TCR Antagonism With or Without Partial Activation’

A CD4+ human T cell clone YN5-32 recognized a streptococcal M12p54-68 peptide in the context of HLA-DR4 and produced a large amount of IFN-y. We investigated responses of YN5-32 to 156 independent analogue peptides carrying single residue substitutions at residues 57 (position 1 (PI)) to 65 (p9) of the peptide. Approximately 30% of analogues at either Leu5’ (pl), Ala6’ (*), or As@ (p6) residues...

CD5 Expression Is Developmentally Regulated By T Cell Receptor (TCR) Signals and TCR Avidity

Recent data indicate that the cell surface glycoprotein CD5 functions as a negative regulator of T cell receptor (TCR)-mediated signaling. In this study, we examined the regulation of CD5 surface expression during normal thymocyte ontogeny and in mice with developmental and/or signal transduction defects. The results demonstrate that low level expression of CD5 on CD4(-)CD8(-) (double negative,...