A RECEPTOR THAT SUBSERVES REOVIRUS BINDING CAN INHIBIT LYMPHOCYTE-PROLIFERATION TRIGGERED BY MITOGENIC SIGNALS

A novel surface receptor complex involved in inhibition of T-cell prol iferation is described, Biochemical isolation revealed two non-covalen tly associated proteins of about M(r) 65,000 (p65) and 95,000 (p95). T hese polypeptides may be related, The p65 form is expressed after cell ular activation and replication and is recognized by monoclonal antibo dy (mAb) 87.92.6 or reovirus hemagglutinin as unnatural ligands, The p 95 species is associated with tyrosine kinase enzymatic activity, Rece ptor ligation results in rapid alteration of the phosphotyrosine conte nt of cellular substrates, and this activity correlates with antiproif erative effects, The inhibition of proliferation is a time-dependent r eversible arrest at the G(1)-S phase of the cell cycle. Activation thr ough the T-cell receptor, protein kinase C, or addition of cytokines d oes not reverse the antiproliferative effect, This receptor complex ma y define novel features of T-cell proliferation.