Genetic studies on natural resistance to Moloney lymphoma (YAC) isografts. I. Introduction of a non-H-2-linked resistance gene on strain A/Sn background

YAC is a Moloney-virus-induced lymphoma of strain A/Sn origin that is highly sensitive to natural killing (NK) in vitro and NK-mediated hybrid resistance in vivo. Previous studies have shown that hybrid resistance is under polygenic control that includes both H-2-linked and non-H-2-linked factors. For further analysis on the genetics and immunology of hybrid resistance, we are at present developing congenic resistant lines on an A/Sn strain background. Following an outcross to a strain that conveys strong hybrid resistance on the F₁ offspring, the mice are challenged with small viable inocula of YAC. Survivors are backcrossed to A/Sn. This is followed by repeated YAC challenge and backcrossing. We now report the successful establishment of a first resistant strain, designated A.LRA. It is relatively resistant to small inocula of YAC cells due to a single, non-H-2-linked dominant gene introduced from the C57L strain.