title: IL-8-induced signal transduction in T lymphocytes involves receptor-mediated activation of phospholipases C and D.
abstract: We have characterized the IL-8-induced signal transduction processes in T lymphocytes. A basal level of IL-8 receptor expression was shown on mixed PBL, as identified by using phycoerythrin (PE)-coupled IL-8, and this expression was increased following IL-2 stimulation. Scatchard analysis of T cells revealed competitive binding of IL-8 with a Kd of 0.55 nM, with approximately 1200 receptors per cell, on freshly isolated T cells. After 24 h in culture following purification, reverse transcriptase PCR (RT-PCR) analyses show the mRNA for only the type B IL-8R on these cultured T lymphocytes and the cell line MOLT-4. Stimulation of T lymphocytes or T cell clones with IL-8 led to generation of inositol trisphosphate and calcium flux. In addition, when T cells were prelabeled with [3H]oleic acid, IL-8 caused a long lasting, time- and dose-related increase in [3H]phosphatidylethanol (PtE), indicating activation of phospholipase D (PLD). By contrast, this IL-8-dependent PLD activity was undetectable in IL-8-stimulated neutrophils. PLD activation appeared to be downstream of protein kinase C, because several inhibitors abrogated the increase in [3H]PtE, whereas guanosine-5'-O-(3-thiotriphosphate (GTP(gamma)S) and inositol trisphosphorothioate (IP3S3) both increased the generation of [3H]PtE. Together, these results demonstrate that the IL-8RB receptor is sufficient to mediate phospholipase C (PLC) and PLD activation in T lymphocytes, but not in neutrophils, and indicate an important difference in receptor usage and signal transduction pathways between IL-8-stimulated lymphocytes and neutrophils.
authors.affiliation: Glaxo Institute for Molecular Biology, Geneva, Switzerland.
authors.forename: K B
authors.initials: KB
authors.lastname: Bacon
authors.forename: L
authors.initials: L
authors.lastname: Flores-Romo
authors.forename: P F
authors.initials: PF
authors.lastname: Life
authors.forename: D D
authors.initials: DD
authors.lastname: Taub
authors.forename: B A
authors.initials: BA
authors.lastname: Premack
authors.forename: S J
authors.initials: SJ
authors.lastname: Arkinstall
authors.forename: T N
authors.initials: TN
authors.lastname: Wells
authors.forename: T J
authors.initials: TJ
authors.lastname: Schall
authors.forename: C A
authors.initials: CA
authors.lastname: Power
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D002634:Chemotaxis, Leukocyte; D004790:Enzyme Induction / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000502:physiology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D016209:Interleukin-8 / Q000494:pharmacology*; D010739:Phospholipase D / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D018123:Receptors, Interleukin / Q000502:physiology*; D023062:Receptors, Interleukin-8A; D015398:Signal Transduction; D016176:T-Lymphocyte Subsets / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism*
chemical_list: D016209:Interleukin-8; D018123:Receptors, Interleukin; D023062:Receptors, Interleukin-8A; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D015544:Inositol 1,4,5-Trisphosphate; D011493:Protein Kinase C; D010738:Type C Phospholipases; D010739:Phospholipase D; D019204:GTP-Binding Proteins; D002118:Calcium