Specific antigen of murine erythroblasts.

A new antigan has been revealed by means of antisera against Rauscher virus in mice with Rauscher virus-induced leukemia. This antigen appears to be different from both Rauscher type-specific antigen and MULV-gs-1 (p-30), as shown by studies of electrophoretic mobility and immunochemical specificity. Except in leukemic mice it was also found in low levels in both serum and spleen extracts of healthy mice of a number of strains. Furthermore, this antigen was regularly demonstrated by immunofluorescence on the surface of erythroblasts, but not on the surface of erythrocytes, lymphocytes, polymorphonuclear cells and thymocytes, and was shown to be different from fetal hemoglobin. Therefore, it is referred to as antigen of erythroblasts (Ag-Eb), which seems to represent a surface marker for a certain differentiation stage of erythroid cells.