Splenic lymphocytic response to acute haemolysis

Adult albino rats, weighting 150--250 g, were administered a sublethal dose of copper sulphate, phenylhydrazine and anti-rat erythrocyta 1 serum by the intracardiac route to produce equivalent haemolysis of 3 mg se-bilirubin in 24 hr. The animals were sacrificed at intervals of 1, 2, 3, 5 and 7 days and the spleen was studied with particular reference to the lymphatic sheath. Copper sulphate treatment was followed by an initial increase in the number of lymphocytes within the perivascular sheath, indicating a rapid mobilization of thymic lymphocytes. Later these lymphocytes displayed blastic transformation and increased mitotic activity. After phenylhydrazine treatment activity was slight. Antiserum caused a complete loss of lymphocytes which were then replaced and germinal centers were formed. Erythrophagocytosis did not play a part in the conversion seen after phenylhydrazine treatment. The response to antiserum was slow. As copper increases the glycolytic activity of the cell on raising the copper level the quiescent small lymphocytes are converted into metabolically active blast cells.