title: High-affinity binding of melatonin by human circulating T lymphocytes (CD4+).
abstract: This paper shows the presence of high-affinity binding sites for melatonin in human circulating T lymphocytes, but not in B lymphocytes. The binding of melatonin to T cells was dependent on time, stable, reversible, saturable, specific, and inversely correlated to the production of melatonin, expressed as the nocturnal 12 h production of its urinary metabolite 6-sulfatoxymelatonin. The affinity of these binding sites (Kd = 0.27 nM) suggests that they may recognize the physiological concentrations of melatonin in serum. Moreover, among the lymphocyte subpopulations studied, binding of melatonin was mostly found in CD4+ cells rather than in CD8+ cells. Results suggest that CD4+ cells may be the target of melatonin among the human circulating lymphocytes.
authors.affiliation: Department of Medical Biochemistry and Molecular Biology, University of Seville School of Medicine, Spain.
authors.forename: M G
authors.initials: MG
authors.lastname: Gonzalez-Haba
authors.forename: S
authors.initials: S
authors.lastname: Garcia-Mauriño
authors.forename: J R
authors.initials: JR
authors.lastname: Calvo
authors.forename: R
authors.initials: R
authors.lastname: Goberna
authors.forename: J M
authors.initials: JM
authors.lastname: Guerrero
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D006801:Humans; D008550:Melatonin / Q000031:analogs & derivatives / Q000378:metabolism* / Q000652:urine
chemical_list: C054513:6-sulfatoxymelatonin; D008550:Melatonin