Construction of a display vector based on the CS3 pili of enterotoxigenic Escherichia coli
Objective To construct the display vector based on the CS3 pili of enterotoxigenic Escherichia coli. Methods The secondary structure antigen epitopes, hydrophilicity and flexibility of CS3 subunit were predicted with the Goldkey software. Based on the prediction, the site for inserting heterologous epitopes was chosen. Mutation was done using the overlapping extention PCR. The gene fragment coding for the VP1 of foot mouth disease virus (FMDV) was synthesized and inserted into CS3. The surface expression of hybrid protein was examined using whole cell ELISA, electron microscopy and immuno electron microscopy. Mice were immunized by injecting the recombinant bacteria intraperitoneally to evaluate the immunogenicity of the hybrid proteins. Results The VP1 of FMDV was displayed on the surface of the recombinant cells. The fusion proteins were expressed as hybrid pili. Mice produced antibody response against CS3 and the VP1 of FMDV. Conclusion The CS3 pili can be a vector to express the foreign epitopes on the surface of the recombinant cells, and it may probably be an expression vector for the construction of the live gene engineering vaccine.