In Vitro Responses of Lymphocytes from Cancer-Bearing Patients to Autochthonous Tumor Tissues 1

Abstract

There is an increasing clinical interest in the immune response of tumor-bearing patients towards their autochthonous tumor-specific antigens (1-3). Based upon animal studies, there is a growing conviction that the immune response to tumors is a major part of the host defence against the growth of neoplastic cells. However, the term “immune response” involves two types of immune reactivity—humoral and cellular—and current evidence suggests that both responses do not function similarly in tumor immunity. In general, experimental induction of tumor-specific antibodies has been associated with enhanced tumor growth (4); cellular immunity has more often been associated with tumor rejection (3, 4). Although there are a number of studies which demonstrate that man develops humoral immunity toward autochthonous tumors (5), there are few studies on human cellular immune response toward tumor in such patients. Studies estimating cellular immune responsiveness have been limited by the technical difficulties in measuring a response against tumor antigens. In animal tumor systems, cellular hypersensitivity experiments have been carried out using syngeneic transplantation (5), skin sensitivity (5), or lymphocyte-target cells assays in tissue culture (6, 7). In man, syngeneic experiments are unlikely; skin testing has had limited investigation (13) and has suffered from the question of non-specific inflammation and the need to use soluble preparations of tumor. Tissue culture experiments have generally been too demanding for extensive investigation, although recently a few investigators have begun to utilize these methods (8, 9, 14-16). A number of studies have recently demonstrated that peripheral blood lymphocyte transformation and proliferation in tissue culture, induced by antigens, is primarily a manifestation of cellular immunity (10, 11). We have, therefore, attempted to use this experimental system to demonstrate that a delayed hypersensitivity reaction occurs in man against tumor-specific antigens.