Human Leucocyte Interferon: Analysis of Effect on MLC and Effector Cell Generation

Abstract

Mixed lymphocyte cultures (MLC) showed decreased thymidine incorporation when interferon (IF) was added to the culture medium. The cell-mediated lympholysis (CML) potential generated MLC grown in the presence of IF was substantiallly augmented at a certain concentration range. Highly purified leukocyte IF had this effect, whereas mock preparations did not. The CML[cell-mediated lympholysis]-augmenting property was found in the anti-viral fraction after separation of semi-purified leukocyte IF. The effects were not due to a shift in kinetics after culturing in the presence of IF. The killer-enhancing properties of IF did not seem due to an enhanced expression of HLA antigens, the selective inhibition of CML suppressor cells or a change in the specificity of recognized target cells. The results of secondary in vitro MLC-CML experiments in which primary MLC was carried out in the presence or absence of IF indicated that the compound acts (in vitro) through preferential selection of cells that are less sensitive to inhibition by IF and more likely to kill.