Pharmaceutical composition containing IFN-γ inducing polypeptide or factor for treating and/or preventing IFN-γ susceptive diseases

A pharmaceutical composition for inducing human IFN-γ, enhancing cytotoxicity of human killer cells or inducing formation of human killer cells, comprising a pharmaceutically acceptable carrier, and as an effective ingredient, 0.000001 w/w % to 100 w/w % on a dry solid basis of a polypeptide of SEQ ID NO:1, where amino acid residue 73 of SEQ ID NO:1, as represented by Xaa, is Ile or Thr, or a homologous polypeptide thereof, wherein the polypeptide and the homologous polypeptide thereof has the following physicochemical properties:

• (a) an amino acid sequence selected from the group consisting of SEQ ID NO:1, where amino acid residue 73, as represented by Xaa, is Ile or Thr, and a homologous sequence thereof where one amino acid residue in SEQ ID NO:1 is replaced with a different amino acid, or one amino acid residue is added to or deleted from the N-terminus or the C-terminus of SEQ ID NO:1, wherein said homologous polypeptide has substantially the same physicochemical properties and biological activity as the polypeptide of SEQ ID NO:1;
• (b) Molecular weight 18,500±3,000 daltons on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE);
• (c) Isoelectric point (pI) 4.9±1.0 on chromatofocusing;
• (d) Biological activity Inducing IFN-γ production by human immunocompetent cells;
• and
• (d) Acute toxicity Having an LD50 of at least about one mg/kg when tested in mice.