Interferon-gamma production by African swine fever virus-specific lymphocytes.

Peripheral blood mononuclear cells (PBMC) from inbred pigs that were immunized with autologous macrophages infected with the African swine fever (ASF) virus BA71V, a nonvirulent virus isolate, proliferated and produced interleukin-2 in response to homologous and heterologous isolates of the ASF virus. They produced, however, interferon (IFN) only when challenged in vitro with homologous or attenuated isolates of the ASF virus, but not with heterologous or virulent isolates. The IFN was pH 2 labile and was neutralized by specific serum to porcine recombinant IFN gamma.