title: Signal transduction in Sjögren's syndrome T cells. Abnormalities associated with a newly described human A-type retrovirus.
abstract: OBJECTIVE
  To study the effects of a novel A-type retrovirus, detected in cocultures of lip biopsy specimens from Sjögren's syndrome (SS) patients and a human T cell line, on the infected T cells.
  
  
  METHODS
  Interleukin-2 (IL-2) and IL-6 secretion were measured by bioassay and enzyme-linked immunosorbent assay, respectively, in the infected and noninfected cell lines. Surface antigen expression was determined by flow cytometry, using monoclonal antibodies. Protein kinase C (PKC) activity was measured using an enzyme assay kit, and calcium mobilization was assessed with a fluorescent probe.
  
  
  RESULTS
  Infected cells expressed less CD4 and IL-6 receptor, but more HLA-DR, compared with noninfected cells. Infected cells also produced less IL-2 and displayed reduced PKC activation and calcium mobilization. A similar defect in calcium mobilization was detected in T cells from SS patients.
  
  
  CONCLUSIONS
  These data suggest a possible involvement of the newly described retrovirus in T cell abnormalities.
authors.affiliation: Clinical Immunology Section, Audie L. Murphy Memorial Veterans Hospital, San Antonio, Texas.
authors.forename: E
authors.initials: E
authors.lastname: Flescher
authors.forename: M J
authors.initials: MJ
authors.lastname: Dauphinée
authors.forename: D
authors.initials: D
authors.lastname: Fossum
authors.forename: J
authors.initials: J
authors.lastname: Ledbetter
authors.forename: N
authors.initials: N
authors.lastname: Talal
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D011493:Protein Kinase C / Q000378:metabolism; D012190:Retroviridae / Q000502:physiology*; D015398:Signal Transduction; D012859:Sjogren's Syndrome / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D007376:Interleukin-2; D015850:Interleukin-6; D011493:Protein Kinase C; D002118:Calcium