Abstract
The ability of spleen macrophages to support Friend leukaemia virus replication was studied by testing for infectivity in adherent cells obtained from mice at various times after infection. Virus-releasing macrophages appeared early after infection and reached a high proportion. The released virus was probably synthesized de novo since macrophage infectivity was strongly reduced by treatments which affected cellular viability or synthetic activities and electron microscopy showed C-type particles budding from macrophages.