A Transplantable Plasma-Cell Leukemia in Mice Associated With the Production of β-Paraprotein

Abstract

The first 8 transfer generations of a spontaneous plasma-cell leukemia originating in a 27-month-old (CBA × DBA/2)F₁ mouse are described. Percentage of takes was 57 to 100. Survival time in the first passage was 148 to 437 days, gradually shortened to 55 to 193 days in the seventh passage. Total serum protein was normal. Paper electrophoresis showed a marked increase of the β-globulin fraction. Immunoelectrophoresis revealed that the paraprotein was a γ-protein of β-mobility, a β_2-III-fraction of increased concentration and mobility was found, probably due to a reaction of the host toward the implanted neoplasm. In starch-gel electrophoresis the paraprotein migrated more slowly than the normal β-globulin, and the β_2-III-fraction migrated faster. From the sixth passage the amount of paraprotein in serum decreased. Blood changes consisted in relative granulocytosis, in the last days of survival associated with the outburst of plasma cells. The outstanding macroscopic lesions were enlargement of the thymus, liver, spleen, and lymph nodes. Microscopic changes were typical leukemic infiltrations in all predilection sites of leukemia. Differentiation grade of the plasma cells in the spontaneous case and in transplanted mice of the first 2 passages was grade II–III; in the next 5 passages, grade III; and in the 8th transfer, grade III–IV. The relative granulocytosis developed simultaneously with the early manifestations of the leukemic lesions in the organs; paraprotein was released into the blood when the leukemic lesions had developed to a moderate degree, increasing in amount with further development of the leukemic process. Plasma cells did not enter the blood stream until the leukemic infiltrations had become extremely marked. No paraprotein was observed in the urine of leukemic mice.