Characteristics of Tumors Induced in Mammals, Especially Rodents, by Viruses of the Avian Leukosis Sarcoma Group

Abstract

Publisher Summary This chapter analyzes the characteristics of avian leukosis sarcoma viruses (ALSV)-induced tumors in mammals, especially in rodents. ALSV, belonging to avian tumor viruses (ATV), represent a group of sarcoma and leukosis viruses capable of inducing various forms of predominantly malignant diseases in their natural hosts, chickens. Tumors can be induced by strains of ALSV with the help of heteroinduction. The first successful experiments on the induction of tumors and cystic hemorrhagic disease in rats were carried out in 1957 and 1958. It was shows that RSV was able to cause two types of pathological change in the same host: one, proliferative, leading to malignant tumors, and the other, lytic, represented by the development of cystichemorrhagic disease. There are four types of interaction between avian sarcoma viruses and mammalian tumor cells: virus-producing type, virogenic type, nonvirogenic type, and abortive type. Virus-producing type is found in mammalian tumors with the continuous production and release of infective virions. Virogenic tumor cells do not contain, do not produce, and consequently do not release infectious ALSV particles. A second characteristic property of virogenic mammalian tumor cells is that they can, under favorable conditions, transfer viral genetic material into susceptible avian cells, and as a result of this an avian cell is transformed into a malignant virus-producing or nonproducing cell. In case of nonvirogenic type of interactions, the isolation or production of infectious virus cannot be achieved by any known means currently. Abortive tumor cells can survive or multiply for various periods of time in the infected cells.