Porcine leukocyte cellular subsets sensitive to African swine fever virus in vitro.

African swine fever virus infected most, if not all, of the macrophages (monocytes) and ca. 4% of the polymorphonuclear leukocytes from porcine peripheral blood. B and T lymphocytes, either resting or stimulated with phytohemagglutinin, lipopolysaccharide, or pokeweed mitogen, were not susceptible to the virus. All of the mitogens used inhibited African swine fever multiplication in susceptible cells. The number of virus passages in vitro and the virulence degree of the virus did not affect the susceptibility of porcine B or T lymphocytes to African swine fever virus.