Effects of Anti-DNA and Anti-RNA Antibodies Bound to Melphalan and Methotrexate on C3H Mammary Adenocarcinoma and L 1210 Leukaemia

Abstract

Approaches to immunotherapy of neoplastic diseases can be improved by two kinds of methods: one non-specific, the other has specific aims. Our studies concerned mostly the latter. It is known that the biological substrates of neoplastic processes are contained in DNA and RNA molecules of cancer cells. DNA and RNA are involved whatever the etiology of neoplasms: on the one hand, the possible modification of the genome by direct mutation of DNA or by incorporation of oncogenic viruses; on the other hand, the oncorna viruses and messenger RNA as possible causes of neoplastic transfromation of cells. Based on this hypothesis, previous work on animal tumours has shown the cytostatic effect of DNA isolated from the same tumours and chemically modified. It has been postulated that the modified DNA acted as a vaccine in active immunotherapy of the host from which tumour DNA was extracted. With passive immunotherapy, a new approach has also been obtained by getting DNA antiserum from rabbits with the DNA isolated from tumours as antigens and chemically combined with rabbit gammaglobulins; the DNA being considered as a hapten. In another study, RNA extract from tumours was used in the same way and chemically modified for active immunotherapy assays and to produce interferon-like substances.