Prokaryotic expression and immunogenicity in rabbit of Ebola virus VP40 matrix protein

Ebola hemorrhagic fever is among severe and fatal viral hemorrhagic fevers and a global health concern. Here, we constructed a prokaryotic expression plasmid pET32a-VP40 for the large-scale expression of VP40 in E. coli Rosetta (DE3) cells. Water-soluble protein was obtained through optimization of the expression temperature, time and IPTG concentrations. After purification through Ni-NTA affinity chromatography, VP40 protein was applied to immunize rabbit for the analysis of immunogenicity and the production of polyclonal antibodies. Western blot showed that recombinant VP40 protein could be recognized by anti-His6-tag MAb and rabbit polyclonal antibodies against VP40 protein. Polyclonal antibody titers in ELISA reached 1:51200. Moreover, the produced rabbit polyclonal antibodies could react specifically with VP40 protein expressed in BHK-21 cells by transfection of pcDNA-eGFP-VP40 in IPMA. The preparation of VP40 protein and its polyclonal antibodies laid the basis for developing immunoassays for EBOV detection.