Homogeneous preparations of il-28 and il-29

Abstract

Homogeneous preparations of IL-28A, IL-28B, and IL-29 have been produced by mutating one or more of the cysteine residues in the polynucleotide sequences encoding the mature proteins. The cysteine mutant proteins can be shown to either bind to their cognate receptor or exhibit biological activity. One type of biological activity that is shown is an antiviral activity.

What is claimed is: 
     
         1 . A method of treating a patient having a hepatitis C virus infection comprising administering to the patient a therapeutically effective amount of a composition comprising a polypeptide that comprises an amino acid sequence having at least 97% sequence identity to SEQ ID NO: 159, wherein in said amino acid sequence the amino acid residue that corresponds to position 166 of SEQ ID NO:159 is Ser, Ala, Thr, Val, or Asn, and wherein the polypeptide has anti-hepatitis C activity,
 and a pharmaceutically acceptable vehicle,   wherein after administration of the composition the hepatitis C infection is reduced.   
     
     
         2 .- 20 . (canceled)