Peptide-MHC Class I Tetrameric Complexes Display Exquisite Ligand Specificity

Display Exquisite Ligand Specificity Peptide-MHC Class I Tetrameric Complexes

Specificity of CTL interactions with peptide-MHC class I tetrameric complexes is temperature dependent.

Tetrameric peptide-MHC class I complexes ("tetramers") are proving invaluable as reagents for characterizing immune responses involving CTLs. However, because the TCR can exhibit a degree of promiscuity for binding peptide-MHC class I ligands, there is potential for cross-reactivity. Recent reports showing that the TCR/peptide-MHC interaction is dramatically dependent upon temperature led us to...

Antigen specificity acquisition of adoptive CD4+ regulatory T cells via acquired peptide-MHC class I complexes.

The Ag-specific CD4(+) regulatory T (Tr) cells play an important role in immune suppression in autoimmune diseases and antitumor immunity. However, the molecular mechanism for Ag-specificity acquisition of adoptive CD4(+) Tr cells is unclear. In this study, we generated IL-10- and IFN-gamma-expressing type 1 CD4(+) Tr (Tr1) cells by stimulation of transgenic OT II mouse-derived naive CD4(+) T c...

The Complex Route to MHC Class I-Peptide Complexes

The loading of peptides into the groove of MHC class I molecules prior to antigen presentation is a complex process. In this issue of Cell, Park et al. (2006) show that peptide loading gets a helping hand from a resident ER enzyme called protein disulfide isomerase, a chaperone that has oxidoreductase activity.

Catalysis of peptide dissociation from class II MHC-peptide complexes.

Certain peptides such as dynorphin A [dynA-(1-13)] enhance the release of antigenic peptides bound to class II MHC molecules at neutral pH. This enhanced release has been termed push off. Previous work has shown that the antigenic pigeon cytochrome c peptide PCC-(89-104) has at least two conformational isomers when bound to the class II MHC protein I-Ek. We have accordingly studied the push off...