THE INTERFERON-INDUCING 22K PROTEIN FROM HUMAN-LEUKOCYTES - AMINO-ACID SEQUENCE AND IDENTITY WITH INTERLEUKIN-1

22K is an antivirally active protein produced by mitogcn-stimulated human leucocytes. Its antiviral effect is mediated by its ability to induce synthesis of small amounts of intcrfcron-β (HuIFN-β) in human fibroblasts This factor has been punfied to apparent clectrophoretic homogeneity and the sequence at its ammo terminal has been determined The pure 22K material scored negative in assays for interlcukin-2(IL-2). NK-ccll activation, lymphotoxin, inhibition of cell growth. It scored positive in assays for intcrlcukin-l (IL-1) and macrophagc/granulocytc colony-stimulating factor (CSF-GM) The pure factor also caused skin reactivity after mtracutaneous injection in rabbits Finally, on intravenous injection it was strongly pyrogenic and caused alterations in peripheral leucocyte counts, effects that arc both suggestive for endogenous Icucocytic pyrogen