ENHANCEMENT OF MOUSE NATURAL-KILLER CELL-ACTIVITY BY TYPE-II INTERFERON

Abstract

That interferons are key molecules in the physiological regulation of natural killing (NK) activity is based on the strong enhancing effect exerted by bypt I interferon on NK cells. The study examined whether type II interferon, released upon activation of T lymphocytes by a mitogen, had the same enhancing effect. Crude PHA[phytohemagglutinin]-induced interferon was purified on affinity chromatography columns (Blue Sepharose) and the eluted fractions were tested in parallel for antiviral activity and in vitro boosting effect on spleen cell natural cytotoxicity. Both activities were unseparable. Acid pretreatment of purified type II interferon and addition of anti-type II interferon serum decreased the enhancement of the spleen cell cytotoxic response. Responder cells to type II interferon are NK cells (surface Ig-negative, Thy-1-negative, devoided of avid Fc receptors) asassessed by classical spleen cell fractionation procedures based on cell surface markers. Comparison between the dose-response curves obtained with type I and type II interferons suggest that both interferon preparations stimulate NK activity comparably. Interferon molecules (type I and type II) dispaly a positive immunoregulatory function on NK cells.