title: The T-cell receptor associated zeta-chain is required but not sufficient for CD26 (dipeptidylpeptidase IV) mediated signaling.
abstract: CD26 or dipeptidylpeptidase IV (DPP IV) is a cell surface protease involved in T-cell activation. Triggering or costimulation of T-cells via CD26 was shown to be dependent on the expression of the T-cell receptor (TCR) associated zeta-chain with at least one functional immune receptor tyrosine based activation motif (ITAM). Here we tested T-cell lines expressing chimeric proteins (hCD25-zeta) consisting of human IL-2 receptor-alpha chain derived extracellular sequences (hCD25) fused to mouse-specific zeta-chain segments, for their capacity to transfer CD26 mediated signals. Although these 'minimal receptor' expressing T-cell lines were capable of transmitting signals from other costimulatory molecules (e.g. CD2), crosslinking of CD26 did not induce IL-2 secretion. Co-cross-linking of hCD25 and CD26 molecules, however, resulted in the stimulation of the T-cells. Thus, although the zeta-chain is a prerequisite for CD26 mediated signaling events, the sole expression of zeta-protein as a signaling molecule is not sufficient for CD26 mediated triggering but permits CD26 induced costimulation in TCR negative cells.
authors.affiliation: Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: von Bonin
authors.forename: C
authors.initials: C
authors.lastname: Steeg
authors.forename: H W
authors.initials: HW
authors.lastname: Mittrücker
authors.forename: B
authors.initials: B
authors.lastname: Fleischer
mesh_terms: D002478:Cells, Cultured / Q000276:immunology / Q000378:metabolism; D018819:Dipeptidyl Peptidase 4 / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D008565:Membrane Proteins / Q000502:physiology*; D011863:Radioimmunoassay; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism / Q000502:physiology*; D015375:Receptors, Interleukin-2 / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection / Q000235:genetics / Q000502:physiology
chemical_list: D007376:Interleukin-2; D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins; C054979:antigen T cell receptor, zeta chain; D018819:Dipeptidyl Peptidase 4