Functional and immunological properties of the baculovirus-expressed hemagglutinin of African swine fever virus.

A recombinant baculovirus harboring the hemagglutinin (HA) gene of African swine fever virus, with homology to the T-lymphocyte surface antigen CD2, was constructed. The efficient expression of the HA gene was determined by immunofluorescence and Western blot studies on insect cells infected with the recombinant baculovirus. The baculovirus-expressed HA showed hemadsorption and erythrocyte-agglutinating activities characteristic of the CD2 homolog protein induced by the virus in infected macrophages. Pigs immunized with the recombinant HA developed hemagglutination-inhibition and temporary infection-inhibition antibodies that recognize a 75-kDa structural protein and were protected against lethal infection.