Chimeric cytokine of IL-7 and beta-chain of HGF and methods of use
The present invention relates to a single-chain or chimeric polypeptide comprising a cytokine and a growth factor linked by at least one amino acid residue, and wherein the chimeric polypeptide enhances the proliferation and/or differentiation of hematopoietic precursor cells. In particular the invention relates to, a chimeric polypeptide comprising the beta-chain of hepatocyte growth factor, and IL-7 linked by at least one amino acid, and wherein the chimeric polypeptide demonstrates pre-pro-B proliferation and growth stimulating activity.
1. A chimeric polypeptide comprising: an IL-7 polypeptide; and a hepatocyte growth factor-beta chain (HGFβ) polypeptide, wherein the IL-7 and HGFβ polypeptides are joined covalently to form a single contiguous polypeptide chain, and wherein the chimeric polypeptide is capable of inducing the proliferation and differentiation of pre-pro-B-cells.
2. The chimeric polypeptide of claim 1 , wherein the chimeric polypeptide comprises a heterologous polypeptide.
3. The chimeric polypeptide of claim 1 , wherein the single contiguous polypeptide chain further comprises a linker comprising an amino acid sequence disposed between the IL-7 and HGFβ polypeptides.
4. The chimeric polypeptide of claim 1 , wherein the chimeric polypeptide comprises a polypeptide having at least 95% sequence identity with SEQ ID NO: 7.
5. The chimeric polypeptide of claim 1 , wherein the chimeric polypeptide comprises a polypeptide having at least 95% sequence identity with SEQ ID NO: 14.
6. The chimeric polypeptide of claim 3 , wherein the linker comprises an amino acid sequence having from 1 to 50 amino acids.
7. The chimeric polypeptide of claim 1 , further comprising: an amino acid linker, wherein the IL-7 polypeptide is a polypeptide having at least 95% sequence identity with the amino acid sequence set forth in SEQ ID NO: 7; and the hepatocyte growth factor-beta chain (HGF j3) polypeptide is a polypeptide having at least 95% sequence identity with the amino acid sequence set forth in SEQ ID NO: 14, and wherein the linker, the IL-7 polypeptide, and HGFβ polypeptide are joined within a contiguous polypeptide chain.
8. The chimeric polypeptide of claim 7 , wherein the linker comprises from 5 to 50 amino acids.
9. The chimeric polypeptide of claim 8 , wherein the linker comprises from 5 to 20 amino acids.
10. The chimeric polypeptide of claim 8 , wherein the linker further comprises an amino acid consensus sequence for at least one of phosphorylation, acetylation, methylation, protease cleavage, isomerization, ubiquitination, protein binding , or a combination thereof.
11. The chimeric polypeptide of claim 9 , wherein the linker comprises the amino acid sequence as set forth in SEQ ID NO.:15.
12. A method of inducing the proliferation and differentiation of a hematopoietic progenitor cell, comprising administering an effective amount of the chimeric polypeptide of claim 1 , in combination with at least one pharmaceutically acceptable excipients[s], to an undifferentiated pre-pro-B-cell.