Strain Difference in Immune Response of the Rat to NRK Cells Infected with Spleen Focus-forming Virus of the Friend Leukaemia Virus Complex

Abstract

SUMMARYFive rat strains were studied for immune responsiveness to SFFV-NRK, a normal rat kidney cell line non-productively infected with spleen focus-forming virus (SFFV) of the Friend leukaemia virus (FLV) complex. Antisera from ACI, JAR, Fischer and SD strains precipitated SFFV-specific gene product, gp55, whereas those from LEW did not. In the cross of Fischer x LEW, immune responsiveness to gp55 was controlled by a single or a few dominant genes. The immune responsiveness was neither related to the susceptibility to FLV infection, nor to the amount of SFFV-related RNA in spleen cells. Unresponsiveness of LEW rats to gp55 was not absolute; when LEW rats were immunized with FLV preparations from infected mice or xenotropic virus-infected NRK cells, they produced antibody that could precipitate gp55,