Tumor vaccines

Abstract

Vaccination against tumor, either as a prophylactic procedure or as a mode of treatment, has been a distant goal of immunologists for many years. Ideally, the less specific therapies such as chemotherapy would be replaced by an anti-tumor immune response in the host that would be present on a continuing basis. However, progress has been hampered by a lack of understanding of the role of viruses in human tumor development and the molecular nature of tumor-associated antigens. Recent developments using the techniques of molecular biology and monoclonal antibody reagents are beginning to remedy this deficiency so that vaccination has become a real possibility for certain human cancers. The natural fluctuations in growth rates of some human tumors, and the observation that tumors can occasionally remain dormant for years, has led to the idea that the host has an intrinsic ability to control tumor growth, and that this ability is a property of the immune system. Attempts to enhance this putative control are being made by treating the host with defined biological modifiers that stimulate cells involved in immunity in vivo, and by seeking and expanding such cells in vitro before reinfusing them into the host. These attempts to harness the immune system to attack tumor cells that have evaded the host's defenses might be considered optimistic, but they will at least tell us a great deal about tumor cell behavior and the ability of the host to influence it.