Neutralization of African swine fever virus by sera from African swine fever-resistant pigs.

Sera from African swine fever-resistant pigs with infection-inhibitory activity decreased virus replication in infected porcine buffy coat cultures. This same effect was observed even after virus was adsorbed. The infection-inhibition was not reversed by removing the immune serum from the assay cultures. Reduction of African swine fever virus replication by immune sera was demonstrated by fluorescent focus assay on MS cell line cultures. Virus-neutralization tests showed a persistent fraction of non-neutralized virus, which was not demonstrable by infection-inhibition tests. One hypothesis for explaining this difference is proposed.