Single base oligodeoxyguanosine upregulates Fas ligand release by nonspecific cytotoxic cells

Nonspecific cytotoxic cells (NCC) are a type of teleost NK-like cell. In the present study a novel stimulus secretion model is described for catfish NCC utilizing single base oligodeoxyguanosine. Binding of guanosine 20-mers (dG20) to NCC up-regulated expression of cytosolic FasL detected by an anti-human FasL monoclonal antibody (mab). In vitro treatment of purified NCC with dG20 produced a 7-fold increase in expression of soluble Fas ligand (sFasL) after 3 h. Antibody binding to NCC was saturable and approximately 30-35% of total NCC were positive for sFasL expression. The teleost FasL equivalent produced programmed cell death of appropriate FasR positive targets. Supernatants from dG20 activated NCC produced hypoploidy and annexin-V binding by FasR bearing HL-60 cells. Treatment of activated supernatants with immobilized anti-FasL mab neutralized these activities. These studies demonstrated that an NK like cell (NCC) produces and secretes sFasL following binding by single base oligodeoxyguanosine. (C) 2003 Elsevier Ltd. All rights reserved.