19.2 -19.7 kDa

 cDNA of interferons were obtained from human leukocyte mRNA, and expressed in E.coli

 > 95% by SDS-PAGE stained by Coomassie Blue

 Activities of the interferons are measured using a cytopathic inhibition assay on Bovine Kidney Cells (MDBK) with Vesicular Stomatis Virus (VSV); human lung carcinoma cell line A549 with encephalomyocarditis virus (EMCV)

 Phosphate buffered saline (PBS) containing 0.1% bovine serum albumin (BSA) 

  < 1 EU/μg

Purified from E. coli by a combination of ion exchange, hydrophobic interaction and size exclusion chromatography

 For retention of full activity store at -70 ºC or below and avoid repeated freeze-thaw cycles