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T cell receptor gene segment utilization by HLA-DR1-alloreactive T cell clones
M J Geiger1, J Gorski, D D Eckels
1Immunogenetics Research Section, Blood Research Institute of the Blood Center of Southeastern Wisconsin, Milwaukee 53233.
Journal of Immunology (Baltimore, Md. : 1950)
|October 1, 1991
Summary
Alloreactive T cells recognize foreign MHC molecules during tissue transplantation. This study found that while TCR gene usage didn't correlate with MHC recognition, variable junctional sequences suggest T cells may also detect bound peptides.
Area of Science:
- Immunology
- Molecular Biology
- Transplantation Science
Background:
- Allograft rejection occurs due to T cell recognition of histoincompatible MHC molecules.
- The precise mechanisms of T cell receptor (TCR) interaction with allo-MHC are not fully understood.
Purpose of the Study:
- To investigate the relationship between TCR gene usage and allo-MHC restriction patterns.
- To analyze the sequence diversity within TCR alpha and beta chains in alloreactive T cells.
Main Methods:
- Utilized one-way polymerase chain reaction to amplify alpha- and beta-chain mRNA from HLA-DR1-alloreactive T lymphocyte clones.
- Sequenced and analyzed variable (V), joining (J), and diversity (D) gene segments, focusing on complementarity-determining regions (CDRs).
Main Results:
- Identified novel V alpha and J alpha gene sequences.
- Found no direct correlation between specific TCR gene usage and DR1 alloreactivity.
- Observed limited diversity in CDR1 and CDR2 regions but high variability in CDR3 (junctional) sequences.
Conclusions:
- TCR CDR1 and CDR2 regions likely interact with conserved features of the DR1 molecule.
- Highly variable CDR3 sequences suggest that alloreactive T cells may also recognize bound endogenous peptides presented by MHC molecules.
- This dual recognition mechanism could contribute to the complexity of allograft rejection.