Pathogenesis of Avian Lymphoid Leukosis. II. Immunologic Reactivity During Lymphomagenesls

Summary

The immunologic competence of chickens infected with avion leukosis virus (strain RPL-12) was studied. Circulating γ-globulin levels, natural agglutinins, and humoral responses to a variety of antigens were measured. Cellular immunity was assessed by graft rejection and graft-versus-host reactivity of peripheral leukocytes. Infection at hatching with the oncogenic virus caused no significant impairment in immunologic reactivity by any parameter measured. The apparent disparity between these results and those previously reported was thought to be due to the increased age of the birds at time of testing in this study as well as to the unusually low mortality from leukosis. Those birds that eventually died from disseminated leukosis had an impaired ability to produce antibody against bovine serum albumin and Brucella abortus. Infected birds attained adult levels of IgG more rapidly than controls, but otherwise showed no difference either in IgG or IgM levels. RSV-neutralizing antibody was found in 50% of infected birds. Immunohistochemical studies of the disseminated tumor indicated that it did not produce immunoglobulin. The significance of these findings is discussed in terms of the role of alterations in immunologic reactivity in the pathogenesis of this and other experimental malignancies.