An In Vitro Measure of Cellular Immunity to Fibroma Virus

A modification of the macrophage migration inhibition test using infected monolayers as a source of antigen was applied to the in vitro study of cellular immunity to fibroma virus infection. The capacity of infected monolayers or infected cell homogenates to inhibit migration of peritoneal exudate cells from fibroma virus-infected rabbits paralleled the onset of a cutaneous delayed hypersensitivity response and resistance to re-infection in the intact animal. Studies using antigens prepared at different intervals after infection of cells with the virus suggest that the test is measuring specific antigen(s) associated with the cell surface and probably not a component of the intact infectious virion. Immune serum did not prevent the antigen from inhibiting migration of sensitized cells, but instead enhanced the inhibition. The data obtained demonstrate that the macrophage migration test has practical application in the study of cell-mediated immunity to animal virus infections.