Effect of beta-interferon on in vitro spreading of mouse peritoneal macrophages

The influence of a homologous beta-interferon preparation (MuIFN-beta) on in vitro adherence and the early and late phase of spreading of mouse peritoneal macrophages (MPM) was tested. MPM from mice pre-treated with 2 x 10(4) U of MuIFN-beta did not differ in ability to adhere to a glass surface, compared to controls. However, when the early phase of MPM spreading was tested, the percentage of spreading cells from mice injected with MuIFN-beta or Newcastle disease virus was almost doubled as compared to MPM from control mice. To assay the late phase of MPM spreading, MPM from unstimulated mice were seeded on glass surfaces and cultivated with or without MuIFN-beta for 1-24 hours. MuIFN-beta enhanced the spreading of MPM with maximal difference 3-5 hours after seeding. The effect was dose-dependent up to 10(2)U per ml of MuIFN-beta. The effect was also species--specific and neutralized by addition of anti-MuIFN-beta globulin. Morphometric measurements of the spreading of MPM indicated that after 24 hours of MuIFN-beta treatment the mean area occupied was 50 per cent larger than that of controls.