Dissociation of antiviral and antitumor immunity in resistance to Marek's disease.

Immunization of chickens either with gluteral-dehyde-inactivated chicken kidney cells infected with Marek's disease (MD) virus or with glutaraldehyde-inactivated cells of MD lymphoma-derived continuous lymphoblastoid cell lines protected against MD. The former type of immunity was associated with an immunologic suppression of virus replication and virus antigen production after challenge with virulent virus, but lymphocytes specifically cytotoxic to cells bearing MD tumor antigens were not detected. In the latter type of immunity, virus multiplication was not affected; some evidence of the stimulation of cell-mediated antitumor immunity was found. The results supported the view that immunity to MD may be directed against either virus-specific or tumor-specific antigens and that in natural resistance to MD both mechanisms may be operative.