Spontaneous, transplantable leukemias of DBA/2 mice express an antigen (ML) which cross-reacts with antigens of murine mammary tumor virus (MuMTV). The MuMTV cross-reactive antigen of the DBA/2 leukemias (ML cells) was found to be a glycoprotein of 78,000 molecular weight containing antigenic determinants of the major MuMTV glycoprotein gp52. No MuMTV particles were produced by the ML cells, al...

The data presented in this paper clearly indicate that the isolated carbohydrate and nucleoprotein constituents of Pneumococcus differ both serologically and antigenically one from the other. Moreover, each of these fractions of the cell separately exhibits immunological properties distinct from those manifested by the whole organism of which they form a part. The carbohydrate is a protein-free...