Alterations in TCR-MHC contacts subsequent to cross-recognition of class I MHC and singly substituted peptide variants.
Vesicular stomatitis virus (VSV) elicits H-2Kb-restricted CTLs specific for the immunodominant VSV octapeptide RGYVYQGL. To study the structural features important for interaction between the TCR beta-chain and the peptide/MHC complex, we immunized TCR alpha-chain transgenic mice with the VSV peptide and raised a panel of anti-VSV CTL clones with identical TCR alpha-chains. Consistent with our previous analysis of uncloned populations of primary CTLs, the anti-VSV CTL clones were all Vbeta13+ and expressed TCR beta-chains with highly homologous complementarity-determining region 3 (CDR3) loops. Although the clones expressed similar TCRs, they differed in their ability to cross-react with VSV peptide variants singly substituted at TCR contact positions 4 and 6. These findings allowed us to identify short stretches of amino acids in the C-terminal region of the CDR3beta loop that, when altered, modify the cross-reaction capability of the TCR to position 4 and position 6 variant peptides. To further probe the structural correlates of biologic cross-reactivity, we used cross-reactive CTL clones and cell lines expressing point mutations in H-2Kb to investigate the effect of single amino acid changes in the peptide on the pattern of recognition of the TCR for the peptide/MHC complex. Single conservative substitutions in the peptide were sufficient to alter the recognition contacts between a cross-reactive TCR and the MHC molecule, supporting the idea that the TCR can make overall structural adjustments in MHC contacts to accommodate single amino acid changes in the peptide.
Ono
T
T
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
DiLorenzo
T P
TP
Wang
F
F
Kalergis
A M
AM
Nathenson
S G
SG
D019943:Amino Acid Substitution / Q000235:genetics* / Q000276:immunology; D000818:Animals; D002460:Cell Line; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D006183:H-2 Antigens / Q000235:genetics / Q000378:metabolism*; D008024:Ligands; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008958:Models, Molecular; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism*; D014721:Vesicular stomatitis Indiana virus / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism
D006183:H-2 Antigens; D008024:Ligands; D010446:Peptide Fragments; D016693:Receptors, Antigen, T-Cell, alpha-beta; D014764:Viral Proteins