Cytotoxic T lymphocytes that react with a complex of Ld and a ubiquitous self-peptide derived from the enzyme α-ketoglutarate dehydrogenase (p2Ca, LSPFPFDL) can be readily elicited by the addition of synthetic peptide to cultures of BALB/c speen cells. As with other Ld restricted CTL, the p2Ca-specific cells use predominantly the Vβ8.3 region. In addition, the p2Ca-specific cells use almost exclusively one of three Jβ gene segments. Selection for these Jβ regions appears to be related to the presence of a glutamic acid residue that is encoded at the 5' end of the Jβ and is present within the CDR3. As p2Ca does not contain a complementary charged residue, this finding may suggest that the β-chain CDR3 from p2Ca-specific CTL contacts one of the five basic residues located on the Ld helices. Together, the results support the possibility that CDR1 and/or CDR2 (within Vβ8.3) and the CDR3 may each contact the Ld molecule. In contrast to the Vβ and Jβ regions, the VβDβJβ junctions and Vα Jα repertoires were diverse. The diversity could explain why p2Ca-specific CTL have relatively high precursor frequencies allowing them to be generated rapidly in primary cultures.
- T cell receptor
- major histocompatibility complex
- thymic selection
ASJC Scopus subject areas
- Molecular Biology