Recognition of an MHC Class I-Restricted Antigenic Peptide Can Be Modulated by para-Substitution of Its Buried Tyrosine Residues in a TCR-Specific Manner

Conformational dependence of TCR contact residues of the H-2Kb molecule on the two buried tyrosine side chains of the vesicular stomatitis virus (VSV)-8 peptide was investigated by systematic substitutions of the tyrosines with phenylalanine, p-fluorophenylalanine (pFF), or p-bromophenylalanine (pBr...

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Bibliographic Details
Published in:The Journal of immunology (1950) 1999-05, Vol.162 (10), p.5998-6008
Main Authors: Saito, Naoyuki G, Chang, Hsiu-Ching, Paterson, Yvonne
Format: Article
Language:English
Subjects:
Animals
Antigens, Viral - chemistry
Antigens, Viral - immunology
Computer Simulation
Female
H-2 Antigens - immunology
Mice
Mice, Inbred C57BL
Models, Molecular
Nucleocapsid - chemistry
Nucleocapsid - immunology
Nucleocapsid Proteins
Oligopeptides - chemistry
Oligopeptides - immunology
Peptide Fragments - chemistry
Peptide Fragments - immunology
Receptors, Antigen, T-Cell - immunology
Tyrosine - immunology
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Summary:Conformational dependence of TCR contact residues of the H-2Kb molecule on the two buried tyrosine side chains of the vesicular stomatitis virus (VSV)-8 peptide was investigated by systematic substitutions of the tyrosines with phenylalanine, p-fluorophenylalanine (pFF), or p-bromophenylalanine (pBrF). The results of peptide competition CTL assays revealed that all of the peptide variants, except for the pBrF analogues, had near-native binding to the H-2Kb molecule. Epitope-mapped anti-H-2Kb mAbs detected conformational differences among H-2Kb molecules stabilized with these VSV-8 variants on RMA-S cells. Selective recognition of the VSV-8 analogues was displayed by a panel of three H-2Kb-restricted, anti-VSV-8 TCRs. Thus, these substitutions result in an antigenically significant conformational change of the MHC molecular surface structure at both C and D pockets, and the effect of this change on cognate T cell recognition is dependent on the TCR structure. Our results confirm that the structure of buried peptide side chains can determine the surface conformation of the MHC molecule and demonstrate that even a very subtle structural nuance of the buried side chain can be incorporated into the surface conformation of the MHC molecule. The ability of buried residues to modulate this molecular surface augments the number of residues on the MHC-peptide complex that can be recognized as "foreign" by the CD8+ T cell repertoire and allows for a higher level of antigenic discrimination. This may be an important mechanism to expand the total number of TCR specificities that can respond to a single peptide determinant.
ISSN:0022-1767
1550-6606
DOI:10.4049/jimmunol.162.10.5998