Stimulation of autologous blood lymphocytes by malignant lymphoma cells and homogenates.

The blastogenic response to autologous blood lymphocytes to whole-cell suspensions and to homogenates obtained from malignant lymphoma tissue has been investigated. Spleens were obtained from patients in whom laparotomy was performed for staging of malignant lymphoma. Cell suspensions prepared from tumour nodules were treated with mitomycin C and allowed to react with separated autologous blood lymphocytes for 6 days. Lymphocyte stimulation was measured by liquid scintillation counting after exposure to 3H-TdR. Cultures were also prepared in which autologous lymphocytes were treated with spleen tumour homogenate. Control experiments used spleens from staging procedures in which no tumour deposits were present, and normal spleens removed incidentally during other operations. In the controls, the uptake of TdR was never more than twice that of unstimulated lymphocytes. Greater degrees of lymphocyte stimulation were seen in 6 out of 14 patients, using whole tumour cells, and in 7 out of 16 patients, using tumour homogenates. The results indicate an antigenic difference between tumour and host cells, and suggest that lymphocytes can react to a tumour-associated antigen.