High-level expression in Escherichia coli of the gene coding for the major structural protein (p72) of African swine fever virus

The gene encoding the major structural protein (p72) of African swine fever virus (ASFV) has been expressed in Escherichia coli using a T7 RNA polymerase system. The use of a recombinant plasmid which contains the entire gene inserted between the T7 promoter and the transcription terminator of the expression vector allowed us to obtain a high expression level of the intact viral protein. This polypeptide, which appears in the insoluble fraction of the bacterial extracts, showed an intense reaction with the antibodies present in the sera of ASFV-infected animals, as demonstrated by Western blot and enzyme-linked immunosorbent assay. The recombinant protein was purified by size-exclusion highperformance liquid chromatography and used to develop a serological test of the disease.