Proteins specified by African swine fever virus. I. Analysis of viral structural proteins and antigenic properties.

At least 28 polypeptides have been identified in intracellular virus, with molecular weights ranging from 11,500 to 243,000 daltons. By treatment with Nonidet P-40 and 2-mercaptoethanol it is possible to obtain subviral particles that have lost some proteins and have a density in CsCl of 1.31 g/cm3 which is higher than that of the complete virus (1.23 g/cm3). After addition of NaCL the virus loses its major protein VP73 which indicates that it is localized in the viral envelope. Cores obtained after this treatment are made up of at least 14 proteins. Incorporation of 3H-fucose and 3H-glucosamine in intracellular virus occurs in three minor components. The protein VP42 is possibly the cell actin and appears to be strongly associated with the virus. It is not possible to eliminate it under conditions where the viral envelopes disappear morphologically. At least the proteins VP172, VP162, VP146 and VP73 act as antigens in the natural infection.