Cellular immunity demonstrated in pigs infected with African swine fever virus.

Twenty-two pigs infected with African swine fever virus (ASFV) were used to demonstrate delayed hypersensitivity (DH) in vitro by the leukocyte migration-inhibition test. The results indicated that ASFV-infected pigs developed DH against ASFV antigen (ASF antigen) as early as 20 days after inoculation, and the presence of viremia did not interfere with the leukocyte migration-inhibition test. Three ASFV-infected pigs that were also sensitized to mycobacterium developed DH against both ASF antigen and mycobacterium. The conclusion was that the cellular immune system is not impaired by ASFV infection in pigs.