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The HTLV receptor is an early T-cell activation marker whose expression requires de novo protein synthesis

Manel, N.; Kinet, S.; Battini, J. L.; Kim, F. J.; Taylor, N.; Sitbon, M.

Blood

2003-03-01 / vol 101 / pages 1913-8

Abstract

The human T-cell leukemia virus type 1 (HTLV) is the first isolated human retrovirus, but its receptor has yet to be identified, in part due to its ubiquitous expression. Here we report that quiescent CD4 and CD8 T lymphocytes do not express this receptor, as monitored with a soluble receptor-binding domain derived from the HTLV envelope. However, HTLV receptor is an early activation marker in neonatal and adult T lymphocytes, detected as early as 4 hours following T-cell-receptor (TCR) stimulation. This induced surface expression of the HTLV receptor requires de novo protein synthesis and results in a wide distribution on the surface of activated lymphocytes. Moreover, the distribution of the HTLV receptor is independent of TCR/CD3-capped membrane structures, as observed by confocal immunofluorescence microscopy. To determine whether HTLV receptor up-regulation specifically requires TCR-mediated signals or, alternatively, is dependent on more generalized cell cycle entry/proliferation signals, its expression was monitored in interleukin 7 (IL-7)-stimulated neonatal and adult T cells. Neonatal, but not adult, lymphocytes proliferate in response to IL-7 and HTLV receptor expression is restricted to the former population. Thus, HTLV receptor expression appears to be an early marker of cell cycle entry. Up-regulation of the HTLV receptor, via signals transmitted through the IL-7 cytokine receptor as well as the TCR, is likely to contribute to the mother-to-infant transmission and spreading of HTLV-1.

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Tags

Female; Humans; Signal Transduction; Pregnancy; Infant, Newborn; Receptors, Antigen, T-Cell/immunology; Microscopy, Fluorescence; Adult; Recombinant Fusion Proteins/metabolism; Cell Cycle; Gene Expression Regulation/drug effects; Biological Markers; *Lymphocyte Activation/drug effects; Disease Transmission, Vertical; Gene Products, env/metabolism; Genes, env; HTLV-I Infections/*transmission; Interleukin-7/pharmacology; Leukemia Virus, Murine/genetics; Maternal-Fetal Exchange; Microscopy, Confocal; Receptor-CD3 Complex, Antigen, T-Cell/immunology; Receptors, Interleukin-7/physiology; Receptors, Virus/*biosynthesis/genetics; T-Lymphocyte Subsets/drug effects/immunology/*metabolism

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