Functional phage display of ciliary neurotrophic factor

Area of Science:

• Biotechnology
• Molecular Biology
• Protein Engineering

Background:

• Human ciliary neurotrophic factor (hCNTF) is a crucial survival factor for neuronal cells.
• The alpha-helical cytokine superfamily includes important signaling proteins.
• Bacteriophage display is a powerful tool for protein engineering and selection.

Purpose of the Study:

• To display functional human ciliary neurotrophic factor (hCNTF) on the surface of filamentous bacteriophage fd.
• To demonstrate the biological activity and specific binding of phage-displayed hCNTF.
• To establish a method for affinity purification and selection of hCNTF variants using phage display.

Main Methods:

• Gene fusion of hCNTF cDNA with the pIII coat protein gene of bacteriophage fd.
• Construction of a phagemid vector with appropriate origins of replication.
• Packaging of phagemid particles using M13KO7 helper phage for phage display.
• Characterization of fusion phage binding to anti-CNTF antibodies and CNTF alpha-receptor.
• Assessment of biological activity of phage-displayed hCNTF.
• Affinity purification of fusion phage using immobilized CNTF alpha-receptor.

Main Results:

• Successfully displayed biologically active hCNTF on the surface of filamentous bacteriophage fd.
• Fusion phage exhibited specific binding to anti-CNTF antibodies and the CNTF alpha-receptor.
• Phage-displayed hCNTF demonstrated comparable biological activity to soluble hCNTF.
• Developed an affinity purification method for CNTF-displaying virions.

Conclusions:

• CNTF can be displayed on phage in a correctly folded and functionally active form.
• Phage display of hCNTF is a viable technology for protein engineering.
• This method facilitates the selection of high-affinity CNTF variants from mutant libraries.