INDUCTION OF A PROTEOGLYCAN CORE PROTEIN MESSENGER-RNA IN MOUSE T-LYMPHOCYTES

The mouse T lymphocyte cell line EL4.E1 synthesizes a proteoglycan cor e protein (PGCP) mRNA which is identical to serglycin mRNA found in mo use bone marrow-derived mast cells and a mouse mastocytoma cell line. PGCP mRNA was strongly induced in EL4.El cells by phorbol myristate ac etate, which also induces mRNAs for several cytokines in these cells. In contrast to the induction of cytokine mRNAs, however, the induction of PGCP mRNA was not inhibited by Cyclosporine. PGCP mRNA was also in ducible by allogeneic stimulation of normal mouse spleen cells, and by Con A stimulation of an Interleukin 2-producing T hybridoma cell line . A number of other cell lines expressed an identical or similar, mRNA , including two cytotoxic T cell lines, and three tumor cell lines rel ated to bone marrow-derived cells. The levels of several proteoglycans have previously been reported to increase in cells of bone marrow ori gin under activating conditions, but this appears to be the first repo rt of an induction of the corresponding PGCP mRNA by immune stimulatio n of T lymphocytes.