Induction of high-affinity paf receptor expression during T cell activation.
Activated human T cells via the CD2 or the CD3 pathways exhibited a higher capacity than resting T lymphocytes to incorporate and metabolize [3H]pafacether (paf) at 37 degrees C. Resting T lymphocytes lacked specific binding capacity for paf, yet high-affinity paf receptors (paf-R) were induced on CD3- or CD2-dependent activation. This up-regulation in the number of paf-R became apparent by day 1 of culture, reached a maximum of about 25,000 sites cell by days 4 to 6 and subsequently declined. Interestingly, human recombinant interleukin-2 in a dose-dependent manner prevented the decrease of high-affinity paf-R expression on T cells. By contrast, the receptor affinity was constant throughout the culture period. Thus, paf-R at different stages of T cell activation were indistinguishable with respect to receptor-ligand interaction, and differed only in their number. Together, these data demonstrate that after activation human T cells develop membrane high-affinity paf-binding sites. They also suggest for the first time that expression of the paf-R are coupled to T cell activation and/or differentiation.
Institut National de la Santé et de la Recherche Medicale U 200, Université Paris-Sud, Clamart, France.
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Calabresse
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Nguer
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Pellegrini
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J
Benveniste
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Richard
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Thomas
D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D018801:CD2 Antigens; D017252:CD3 Complex; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation; D010972:Platelet Activating Factor / Q000378:metabolism; D010980:Platelet Membrane Glycoproteins; D011869:Radioligand Assay; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D043562:Receptors, G-Protein-Coupled; D011971:Receptors, Immunologic / Q000502:physiology; D013601:T-Lymphocytes / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation
D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D017252:CD3 Complex; D007376:Interleukin-2; D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D011948:Receptors, Antigen, T-Cell; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D011971:Receptors, Immunologic; C039351:platelet activating factor receptor