부산대학교 도서관

We have recently observed an abnormal pattern of protein tyrosine phosphoryl-ation in resting T lymphocytes obtained from peripheral blood of patients with systemic lupus erythematosus (SLE). To examine whether these findings may be related to dysregulated protein tyrosine kinase (PTK) function, we tested the relative amount and enzyme activity of the main PTKs involved in the earliest signalling steps triggered via the CD3 pathway. Cell lysates from peripheral blood T cells in SLE patients showed lower amounts of p59fynand p56lckas shown by immunoblot. In contrast, the amount of ZAP-70, a PTK of thesykfamily, was comparable in both groups. However, p59fynimmuno-precipitates obtained from unstimulated peripheral blood SLE T cells showed enhanced PTK activity as compared to controls, whereas the PTK activity of p56lckand ZAP-70 molecules was comparable in both groups. The unchecked activity of the TCR/CD3-associatedsrckinase p59fynmay alter the balance needed for regulated T cell responses in SLE patients.