SEPARATION OF HUMAN-LEUKOCYTE INTERFERON COMPONENTS BY CONCANAVALIN-A-AGAROSE AFFINITY CHROMATOGRAPHY AND THEIR CHARACTERIZATION

Human leukocyte interferon (HL-IF), produced by mixed leukocytes infected with Newcastle disease virus, was resolved into three distinct fractions when chromatographed on concanavalin A-agarose. The major portion (70-75%) of interferon appeared in the breakthrough (BT fraction). The bound interferon (25-30%) was displaced from the column as two peaks: the first was eluted with 0.1 M methyl a-D-mannoside, yielding 15-20% of the interferon activity (α-MM fraction), and the second by including ethylene glycol (70%) in the eluant, yielding the remaining 5-15% of the interferon (EG fraction). No interferon was retained when HL-IF produced in the presence of glycosylation inhibitors (tunica-mycin or 2-deoxy-D-glucose) was chromatographed on concanavalin A-agarose, suggesting that the fraction of interferon retained by this lectin is glycosylated. The three fractions of interferon (BT, α-MM, and EG) were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, cross-species antiviral activity, and neutralization by specific antisera. The BT fraction contains exclusively the 16000 molecular weight component of human leukocyte interferon. The majority of the a-MM fraction (90%) is the 21 000 molecular weight component. However, the EG fraction contains the 16000 and 21 000-23 000 molecular weight components in essentially equal proportions. On the basis of cross-species antiviral activity and neutralization by specific antisera, the BT and α-MM fractions are leukocyte-type interferon and the EG fraction seems to be primarily of fibroblast type. © 1979, American Chemical Society. All rights reserved.