Evaluation of PHA-P reactivity of lymphocytes in tumor development by acid phosphatase activity.

Abstract

Phytohemagglutinin (PHA-P) reactivity of lymphocytes was examined during development of solid Ehrlich Ascites-Tumor (EAT) and Sarcoma 180 in mice. Because PHA-P stimulated lymphocytes produce — dose depedent — a soluble factor activating macrophages, the PHA-P effect was evaluated by lysosomal acid phosphatase activity of these cells. The experiments showed in each of the two transplantable tumors a drastic decrease of the stimulatory PHA-P effect. The extent of this decrease was dependent on tumor weight (tumor development). In sarcoma 180 assay, the stimulatory PHA-P effect decreased continuously, beginning after tumor transplantation. In EAT assay, however, such a significant decrease was observed only from day 10 onwards. In EAT, the phosphatase activity of non PHA-P stimulated lymphocytes showed approximatively normal values after tumor transplantation; in a later state of tumor development the activity decreased. In contrast, cells of sarcoma 180 bearing animals not stimulated in vitro with PHA-P showed a continuous increase in phosphatase activity, which decreased only at a very late state of tumor development. In Sarcoma 180 growing more quickly than EAT, the enhancement of phosphatase activity over a relative long period of tumor growth was presumably due to cell activation in vivo by biological growth processes.