Identification of conserved T cell receptor CDR3 residues contacting known exposed peptide side chains from a major histocompatibility complex class I-bound determinant
✍ Scribed by Janice M. Kelly; Sandra J. Sterry; Stephen Cose; Stephen J. Turner; John Fecondo; Stuart Rodda; Pamela J. Fink; Francis R. Carbone
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 1022 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0014-2980
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✦ Synopsis
Identification of conserved T cell receptor CDR3 residues contacting known exposed peptide side chains from a major histocompatibility complex class I-bound determinant*
We have analyzed the T cell receptor (TCR) repertoire found in the major histocompatibility complex class I-restricted cytotoxic T lymphocyte (CTL) response to the protein ovalbumin (OVA). Despite skewing towards the expression of Vf35.2+ TCR by OVA-specific CTL from C57BL/6 mice, we found a relatively high degree of diversity in V(D)J usage in both TCR aand fi-chains. Closer examination showed that the majority of these sequences encoded negatively and positively charged residues at their respectiveTCR a-and f3-chain VJ or VDJ junctions. These junctions form the third complementaritydetermining regions (CDR3) of the TCR polypeptides involved in the direct interaction with the class I-bound peptide. Crystallographic analyses of Kbpeptide complexes predict that the major determinant from OVA, peptide OVA257-264 (SIINFEKL), contains two exposed charged side chains which can contact theTCR. These are the negatively charged glutamic acid at determinant position 6 (P6) and the positively charged lysine at W . To examine whether the TCR a-chain makes contact with P7 lysine, we established a single chain TCR transgenic C57BL/6 mouse line where all T cells express a TCR f3-chain derived from the Vf35.2+ clone B3. OVA-specific T cells derived from in vivo primed transgenic mice preferentially expressed TCR a-chains that also contained negatively charged junctional residues despite some further variation in V a and J a sequences. Stimulation of naive TCR f3-chain transgenic T cells with a W substitution peptide analogue induced a T cell response that was no longer cross-reactive with the wild-type OvA257-264 determinant, sugesting that theTCR a-chain from the T cell clone B3 can determine the specificity for this residue. Consequently, these results reveal the existence of conserved residues in the CDR3 of TCR a-and f3-chains specific for OVA257-264 and identify their possible orientation over the peptide-class I complex.