Immunochemical properties of antigens present on immature erythrocytes from mouse and rat.

Rabbit antisera directed against erythrocytes from anemic mice or from newborn rats, once absorbed on homologous normal adult erythrocytes, recognize antigens present respectively on immature erythrocytes from anemic adult mice or rats (Im M and Im R antigens). Using iodinated immature erythrocytes from both species, homologous sera precipitated two populations of antigens showing 230,000 D and 95,000 D molecular weights. Im M antigens (230,000 and 95,000 D) were partially precipitated using anti-Im R serum. After total absorption of the sample by anti-Im R serum, both 230,000 and 95,000 D antigens were still immunoprecipitated using anti-Im M serum. Similar results were obtained using Im R antigens and anti-Im M serum then anti-Im R serum. This demonstrates that some Im specificities are common to rat and mouse while others, showing identical molecular weights, are species-specific.