Cell Surface Display of Human Immunodeficiency Virus Type 1 gp120 on Escherichia coli by Using Ice Nucleation Protein

A new system designed for cell surface display of recombinant proteins on Escherichia coli has been evaluated for expression of eukaryotic viral proteins. Human immunodeficiency virus type 1 (HIV-1) gp120 was fused to the C terminus of ice nucleation protein (INP), an outer membrane protein of Pseudomonas syringae. Western blotting, immunofluorescence microscopy, fluorescence-activated cell-sorting analysis, whole-cell enzyme-linked immunosorbent assay, and ice nucleation activity assay confirmed the successful expression of HIV-1 gp120 on the surface of Escherichia coli. This study shows that the INP system can be used for the expression of eukaryotic viral proteins. There is also a possibility that the INP system can be used as an AIDS diagnostic system, an oral vaccine delivery system, and an expression system for various heterologous higher-molecular-weight proteins.