The in vitro generation of effector lymphocytes and their employment in tumor immunotherapy

The theory of immune surveillance against progressive neoplasia has been widely contested in recent years. The doubts casted on its axioms and corollaries have undermined much of the conceptual framework for efforts at tumor immunotherapy, and placed into serious question the validity of continued attempts in this direction. The probable irrelevance of most investigational models in tumor immunology to the natural history of neoplastic disease has been accentuated by the recent findings that signify the inability of neoplasms arising spontaneously in inbred experimental animals to evoke defensive immune reactions. These observations brought about a shift in analogies. Human cancers have come to be considered as analogous, immunologically, to spontaneous tumors of laboratory mice and rats rather than to those that have been the stock in trade of the experimental tumor immunologist. Currently, the climate of opinion regarding the role of immunologic responsiveness in cancer defenses has become pervasively unfavorable. Some investigators still entertain the possibility that immune surveillance may be prominent in the protection against cancers that do not normally come to appearance in nature, but that for those that do, immunologic function is thought to be excluded—as absent or inadequate—from the confrontation.