T cell receptor usage by HLA-DR3-specific T cell clones isolated from a renal allograft

Mixed lymphocyte cultures can predict TCR Vbeta repertoires of T cells infiltrating kidney transplants during acute rejection episodes

Alloreactive T cell populations can show skewing of T-cell antigen receptor (TCR) Vbeta gene usage. The aims of the experiments were to compare in vivo and in vitro T cell alloresponses against donor alloantigens for TCR Vbeta gene usage. T-cell cultures from renal biopsies taken during acute rejection and pretransplant mixed lymphocyte cultures (MLC) were established from five renal transplant patients. TCR Vbeta gene usage, assessed with Vbeta family specific antibodies, showed that up to five different Vbeta families were significantly expanded. In four of five cases, there was close concordance between Vbeta families expanded from the biopsy and in MLC. T-cell clones from one renal biopsy were specific for the mismatched donor alloantigen and showed similar TCR Vbeta gene usage to the original T-cell line. The results show very similar patterns of TCR Vbeta gene usage in alloreactive T cells generated ex vivo or in vitro.

Coronary arteries from human cardiac allografts with chronic rejection contain oligoclonal T cells: persistence of identical clonally expanded TCR transcripts from the early post-transplantation period (endomyocardial biopsies) to chronic rejection (coronary arteries)

Chronic cardiac allograft rejection presents pathologically as graft arteriosclerosis (GA) characterized by recipient T cell and monocyte infiltration. To determine whether oligoclonal T cells are present in coronary arteries of cardiac allografts from patients with GA, we conducted sequencing analysis of beta-chain TCR transcripts from these explanted coronary arteries using the nonpalindromic adaptor-PCR. Substantial proportions of identical beta-chain TCR transcripts in three of five patients were observed, clearly demonstrating the presence of oligoclonal T cells. TCR transcripts from the arteries of two other patients were relative heterogeneous. High proportions of identical CDR3 beta-chain TCR motifs were found in each patient. GENEBANK/EMBL/SWISS PROT database comparison of all sequences revealed that these beta-chain TCR transcripts were novel. Using Vbeta-specific PCR (independent amplification), we found in patient GA03 that the TCR transcript that was clonally expanded in the left anterior descending artery after nonpalindromic adaptor-PCR was also clonally expanded in the right coronary artery of the same allograft. These results demonstrate that this TCR transcript was clonally expanded at different anatomic sides of the cardiac allograft in a systemic manner. In two patients identical beta-chain TCR transcripts that were found to be clonally expanded in the coronary arteries of their explanted cardiac allografts were also found to be clonally explanted in endomyocardial biopsies collected 17 and 21 mo earlier from each patient. The presence of oligoclonal populations of T cells in the rejected graft suggest that these T cells have undergone specific Ag-driven proliferation and clonal expansion early on within the graft and persist throughout the post-transplantation period.