T cell factor-mediated suppression of immunoglobulin secretion by a human B lymphoblastoid cell line

The Epstein Barr Virus-transformed B lymphoblastoid cell line JR-2, which spontaneously secretes IgG detectable by a hemolytic plaque technique, is suppressed by the concanavalin A-induced T cell-derived nonspecific suppressor factor T-SF in a dose-dependent manner. This suppression is reversible after 24 hr and is not due to a cytotoxic mechanism. The T-SF does not affect proliferation of JR-2. Suppression by the T cell factor is inhibited or blocked by 2-mercaptoethanol or L-rhamnose and is also induced by gel chromatography fractions of the T cell supernatants containing molecules of 20,000 to 25,000 daltons. The JR-2 line appeared to be uniquely sensitive to the T-SF in that other potential suppressor T cell-derived factors were not active and 15 other B lymphoblastoid cell lines were not significantly inhibited by the T-SF.