title: Tolerance, viral shedding, and neoplasia in chickens infected with non-defective reticuloendotheliosis viruses.
abstract: Chickens inoculated as embryos with non-defective reticuloendotheliosis viruses (ndREVs) generally developed a "tolerant" infection characterized by lack of immunofluorescent antibody and by a viremia that persisted through 93 weeks. Chickens inoculated at hatching generally developed a "non-tolerant" infection characterized by antibody development that gradually waned as the chickens aged and by a transient or intermittent viremia. Although chickens tolerantly infected with ndREV strain T were immunodepressed, tolerance to ndREVs did not depend on immunodepression, because 17-to-20-week-old chickens tolerantly infected with ndREV strain CS were normal in antibody response to sheep red blood cells and Brucella abortus and in mitogen-stimulated blastogenesis of blood lymphocytes. Tolerantly infected dams shed low levels of gs antigen and virus into eggs at high frequencies; however, in two trials, congenital transmission of virus by strain-CS-infected dams was documented in only 2 of 42 and 1 of 132 progeny chicks. Eggs and progeny chicks from non-tolerantly infected dams were always negative for virus and gs antigen. After long latent period (17 to 93 weeks), ndREV-infected chickens developed lymphomas involving the bursa of Fabricius and other visceral organs at high frequency and developed sarcomas, carcinomas, and inflammatory nerve lesions at a lower frequency. The ability of ndREVs to induce tolerant and non-tolerant infection, virus- and antigen-shedding into eggs, and chronic neoplastic disease resembled that of lymphoid leukosis virus, another common avian retrovirus. Certain differences in epidemiological properties of these 2 viruses are discussed.
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D002645:Chickens / Q000276:immunology*; D005260:Female; D007108:Immune Tolerance; D008297:Male; D009369:Neoplasms / Q000209:etiology / Q000662:veterinary; D011201:Poultry Diseases / Q000150:complications / Q000276:immunology*; D001356:Reticuloendotheliosis virus / Q000276:immunology* / Q000302:isolation & purification; D012190:Retroviridae / Q000276:immunology*; D014412:Tumor Virus Infections / Q000150:complications / Q000276:immunology / Q000662:veterinary*
chemical_list: D000914:Antibodies, Viral