Expression, purification of the UL3 protein of herpes simplex virus type 1, and production of UL3 polyclonal antibody

Herpes simplex virus type 1 (HSV-1) is a common pathogen which causes infections of the mucocutaneous membranes. The UL3 protein belongs to a group of HSV-1 late proteins. To date, the function of the UL3 protein in cell culture, animal models, and natural infection is unknown. To investigate further the function of the UL3 protein, this study was undertaken to express the UL3 protein and raise a polyclonal antibody. The UL3 gene was cloned in the prokaryotic expression vector pET-28a (+) to yield pET-28a (+)-UL3. The His6-tagged UL3 protein was expressed in Escherichia coli (E. coli) BL21 (DE3) cells and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). After purification by nickel affinity chromatography and refolding, the recombinant protein was used to raise the anti-UL3 polyclonal antibody. Western blot analysis demonstrated that the UL3 protein was recognized by the polyclonal antibody, and immunofluorescent assay also showed that the antibody was able to recognize the UL3 protein in the cells infected with HSV-1.