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Abstract

Title: Increased Expression of Human T Lymphocyte Virus Type I (HTLV-I) Tax11-19 Peptide-Human Histocompatibility Leukocyte Antigen A*201 Complexes on CD4+ CD25+ T Cells Detected by Peptide-specific, Major Histocompatibility Complex-restricted Antibodies in Patients with HTLV-I-associated Neurologic Disease.
Author: Yamano Y, Cohen CJ, Takenouchi N, Yao K, Tomaru U, Li HC, Reiter Y, Jacobson S
Journal: J Exp Med 199(10):1367-1377
Year: 2004
Month: May

Abstract: Human T lymphocyte virus type I (HTLV-I)-associated chronic inflammatory neurological disease (HTLV-I-associated myelopathy/tropical spastic paraparesis [HAM/TSP]) is suggested to be an immunopathologically mediated disorder characterized by large numbers of HTLV-I Tax-specific CD8(+) T cells. The frequency of these cells in the peripheral blood and cerebrospinal fluid is proportional to the amount of HTLV-I proviral load and the levels of HTLV-I tax mRNA expression. As the stimulus for these virus-specific T cells are immunodominant peptide-human histocompatibility leukocyte antigen (HLA) complexes expressed on antigen-presenting cells, it was of interest to determine which cells express these complexes and at what frequency. However, until now, it has not been possible to identify and/or quantify these peptide-HLA complexes. Using a recently developed antibody that specifically recognizes Tax11-19 peptide-HLA-A*201 complexes, the level of Tax11-19-HLA-A*201 expression on T cells was demonstrated to be increased in HAM/TSP and correlated with HTLV-I proviral DNA load, HTLV-I tax mRNA load, and HTLV-I Tax-specific CD8(+) T cell frequencies. Furthermore, CD4(+) CD25(+) T cells were demonstrated to be the major reservoir of HTLV-I provirus as well as Tax11-19 peptide-HLA-A*201 complexes. These results indicate that the increased detection and visualization of peptide-HLA complexes in HAM/TSP CD4(+) CD25(+) T cell subsets that are shown to stimulate and expand HTLV-I Tax-specific CD8(+) T cells may play an important role in the pathogenesis of HTLV-I-associated neurological disease.