Printed in Great Britain 34I Biological Properties of Human Leukocyte Interferon Components

Human leukocyte interferon, purified approximately Iooo-fold by affinity chromatography on immobilized anti-interferon globulins and SDS-Sephadex filtration, was resolved into one major and one minor component by adsorption chromatography on hydroxylapatite and electrophoresis in polyacrylamide gels. These components were indistinguishable in their capacity to protect bovine, porcine and murine cells, and the antiviral activities of both were equally sus-ceptible to reduction by fl-mercaptoethanol. They were neutralized to the same degree by rabbit anti-leukocyte interferon but were not neutralized by rabbit anti-fibroblast interferon serum. Mice immunized with either component developed antibodies to both but failed to form antibodies against human fibroblast inter-feron. Our present evidence indicates that the two components possess at most only minor structural and antigenic dissimilarities