Kinetics of expression and subset distribution of the TNF superfamily members CD40 ligand and Fas ligand on T lymphocytes in cattle.
CD40 and Fas are members of the tumor necrosis factor receptor (TNFR) superfamily. CD40 and Fas play key roles in T cell-B cell interactions. Cross linkage of these molecules induces cell activation and cell death, respectively. The interaction of CD40 with its ligand (CD40L), which is expressed on activated T cells, plays a pivotal role in the generation of the T-dependent (TD) immune response, and FasL-bearing T cells, which have been shown to be predominantly of either the TH0 or TH1 type, have the potential to induce the apoptotic death of Fas expressing B cells. We investigated bovine CD40L mRNA expression in established T cell clones by RT-PCR and Southern blotting. T cells analyzed included CD4+ TH0 and TH1 cell subpopulations, CD8+, and gamma/delta T cells stimulated with either specific antigen or Con A. All CD4+ clones but not all CD8+ or gamma/delta T cell receptor (TCR)-bearing clones expressed mRNA for CD40L. To determine the activation requirements for CD40L expression in cattle, we examined the kinetics and induction requirements for CD40L transcription in peripheral blood T cells using a phorbol ester and/or ionomycin, immobilized mouse anti-bovine CD3, or Con A. Our results demonstrate that CD40L mRNA appears relatively early after activation (1 h) and peaks at 2-4 h poststimulation. A rise in intracellular calcium concentration mediated by ionomycin treatment alone was sufficient to induce CD40L mRNA expression at relatively high levels. Ionomycin treatment in combination with other agonists (anti-CD3, PMA) did not enhance CD40L mRNA expression above levels obtained with ionomycin alone. The bovine Fas ligand gene was partially cloned and mRNA expression determined by RT-PCR in a panel of T cell clones. Our results demonstrate that TH0 and TH1 bovine T cell clones expressed Fas ligand transcripts although only one gamma/delta T cell clone did. This expression was upregulated within 3 h after mitogen stimulation and reduced by 24 h.
Hirano
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A
Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri-Columbia 65211, USA.
Brown
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WC
Trigona
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Tuo
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W
Estes
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DM
D000818:Animals; D001483:Base Sequence; D023201:CD40 Ligand; D002118:Calcium / Q000378:metabolism; D002417:Cattle / Q000235:genetics / Q000276:immunology*; D002999:Clone Cells; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D053222:Fas Ligand Protein; D015870:Gene Expression; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D007700:Kinetics; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology; D051379:Mice; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism
D017931:DNA Primers; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D007476:Ionophores; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D023201:CD40 Ligand; D015759:Ionomycin; D002118:Calcium