In Vitro Lymphocyte Responses to Malignant, Benign Neoplastic and Normal Tissue Extracts

To identify tumor antigens and tumor immunity in man, we have investigated the use of the blastogenic response of lymphocytes to tissue extracts. Extracts of malignant, benign, and normal tissues of 60 patients with cancer were used to stimulate their own lymphocytes, the lymphocytes of other patients with the same tumor and those of normal subjects. Autochthonous extracts of the neoplastic tissue stimulated blas-togenesis in 56% of patients and a linear dose-response curve was observed. This suggested the presence of TSA and specific tumor immunity, even in patients with advanced metastatic disease. However, stimulation of autochthonous lymphocytes by extracts of skin in 50% of patients cast doubt on the tumor specificity of the response to extracts. The release of nonspecific mitogens, or of usually concealed autoantigens, or the presence of tumor antigens in the skin of patients with malignant disease were hypothesized as the possible cause. Because of this lack of specificity it seemed that tumor extracts, used alone, will have limited value in the investigation of tumor immunity in man using the blastogenesis test.