CHARACTERIZATION OF CMVpp65-SPECIFIC CD8+ T LYMPHOCYTES USING MHC TETRAMERS IN KIDNEY TRANSPLANT PATIENTS AND HEALTHY PARTICIPANTS1
2000; Wolters Kluwer; Volume: 69; Issue: 11 Linguagem: Inglês
10.1097/00007890-200006150-00005
ISSN1534-6080
AutoresMats Engstrand, Claire Tournay, Marie Alix Peyrat, Britt‐Marie Eriksson, Jonas Wadstr m, Benita Zweygberg Wirgart, Francois Romagn, Marc Bonneville, Thomas H. T tterman, Olle Korsgren,
Tópico(s)T-cell and B-cell Immunology
ResumoBackground. Cytomegalovirus (CMV) is a ubiquitous herpesvirus that infects 50–90% of individuals in different populations. After primary infection, the virus persists latently in myeloid cells under the control of specific T-cells. Reactivation of CMV infection may cause lethal organ dysfunction and is frequently seen in immunosuppressed individuals. CD8+ cytotoxic T-cells (CTL) have a primary role in suppressing CMV reactivation, and the dominating CTL response is directed against pp65. Methods. MHC tetramers, that is, complexes between HLA class I (or class II) molecules and antigenic peptides conjugated to fluorochromes allow the direct visualization of antigen-specific receptor-carrying T-cells using flow cytometry. We constructed a novel MHC tetramer for identification of CMVpp65-specific CD8+ T-cells using HLA-A2 molecules folded with the immunodominant NLVPMVATV peptide. Results. The A2/pp65 tetramer specifically stained CMV-directed T-cell lines, and sorted cells showed CMV-specific cytotoxicity. High proportions (0.1–9%) of the CD8+ T-cells were A2/pp65 tetramer+ in healthy HLA-A2+ CMV carriers and in immunosuppressed kidney transplant patients with latent infection. Patients with reactivated CMV infection exhibited up to 15% A2/pp65 tetramer+ cells, which seemed to correlate with CMV load over time. A2/pp65 tetramer+ cells expressed T-cell activation markers. Conclusions. The construction of a novel A2/pp65 MHC tetramer enabled the design of a rapid and precise flow cytometric method allowing quantitative and qualitative analysis of CMV-specific T-cells. The number of A2/pp65 tetramer binding CTLs in blood may prove to be clinically relevant in assessing the immune response to CMV.
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