Depletion of lymphocyte subpopulations in primary and secondary lymphoid organs of mice by a transplanted granulocytosis-inducing mammary carcinoma.

Transplanted CE mammary carcinoma causes a marked increase in the production of neutrophilic granulocytes in mice associated with the expansion of hemopoietic marrow into the peripheral skeleton. Changes in lymphocyte populations in the femoral marrow, the expanding peripheral marrow, and the spleen were examined for a period of 3 weeks post-tumor transplantation using fluoresceinated antisera specific for B- and T-cells. As tumor growth and granulocytic hyperplasia progressed, B- and T-cells became reduced in femoral marrow and the spleen, but lymphocytes of undefined function, devoid of T- and B-cell surface antigens (null cells), transiently increased in femoral marrow and in the spleen. In the expanding peripheral marrow, such null cells increased and remained as the predominant cell type until granulocytic hyperplasia took place. These changes suggest shifts in the site of myelogenous lymphocyte production or in the differentiation program of lymphocytes. The thymus invariably showed marked atrophy which, as shown in adrenalectomized animals, could not be explained entirely by tumor-induced stress. Thus, the massive granulocytopoietic effects of CE mammary carcinoma are coupled with marked changes in lymphocyte populations due, most likely, to the tumor's influence on primary lymphoid organs.