The HTLV receptor is an early T-cell activation marker whose expression requires de novo protein synthesis.
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.
Manel
Nicolas
N
Institut de Génétique Moléculaire de Montpellier, CNRS UMR 5535/IFR 24, F-34293 Montpellier Cedex 5, France.
Kinet
Sandrina
S
Battini
Jean-Luc
JL
Kim
Felix J
FJ
Taylor
Naomi
N
Sitbon
Marc
M
D000328:Adult; D015415:Biomarkers; D002453:Cell Cycle; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D015686:Gene Products, env / Q000378:metabolism; D015752:Genes, env; D015490:HTLV-I Infections / Q000635:transmission*; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D015851:Interleukin-7 / Q000494:pharmacology; D009052:Leukemia Virus, Murine / Q000235:genetics; D008213:Lymphocyte Activation / Q000187:drug effects; D008431:Maternal-Fetal Exchange; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D011247:Pregnancy; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D020395:Receptors, Interleukin-7 / Q000502:physiology; D011991:Receptors, Virus / Q000096:biosynthesis* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*
D015415:Biomarkers; D015686:Gene Products, env; C080823:HTLV-I receptor; D015851:Interleukin-7; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D011948:Receptors, Antigen, T-Cell; D020395:Receptors, Interleukin-7; D011991:Receptors, Virus; D011993:Recombinant Fusion Proteins