Abnormal pattern of tyrosine phosphorylation in unstimulated peripheral blood T lymphocytes from patients with systemic lupus erythematosus

Academic Article

Abstract

  • Previous reports have shown abnormal responses mediated via the TCR/CD3 pathway in T lymphocytes from systemic lupus erythematosus (SLE) patients. Recently, we and others have reported augmented TCR/CD3-mediated responses in lupus T cells. It is possible that the pattern of downstream biochemical signals triggered by TCR/CD3 ligation may be altered in T lymphocytes from patients with SLE, thus leading to abnormal distal cell responses. In this paper we have examined the phosphorylation of proteins on tyrosine residues in peripheral blood T lymphocytes from a group of SLE patients and controls. We found a lower frequency of constitutively tyrosine-phosphorylated 119- and 113-kDa substrates and an enhanced frequency of tyrosine-phosphorylated 66- and 25-kDa proteins in unstimulated cultures of SLE T lymphocytes, suggesting an altered pattern of tyrosine phosphorylation in T cells from patients in vivo. Additionally, the protein tyrosine phosphatase (PTP) activity of CD45 immunoprecipitates was lower in unstimulated lupus T cells and was enhanced after stimulation via the CD3 pathway in lupus but not control T lymphocytes. The present results seem to suggest abnormal regulation of in-vivo tyrosine phosphorylation in T cells from patients with SLE.
  • Published In

  • Lupus  Journal
  • Digital Object Identifier (doi)

    Author List

  • Blasini AM; Alonzo E; Chac√≥n R; Riera R; Stekman IL; Rodriguez MA
  • Start Page

  • 515
  • End Page

  • 523
  • Volume

  • 7
  • Issue

  • 8