Anti-idiotype antibodies to Marek's disease-associated tumour surface antigen in protection against Marek's disease.

Marek's disease-associated tumour surface antigen (MATSA) removed by enzymatic (papain) digestion of Marek's disease tumour cells was fractionated by gel filtration chromatography. The first peak (F1) was used to raise antibody in rabbits. Monoclonal antibody (RPH-6) directed against MATSA and the anti-F1 IgG were used as idiotypic antibodies to raise polyclonal anti-idiotype serum in heterologous hosts; rabbit and goat, respectively. The anti-idiotypes (anti-Id) were purified by affinity chromatography and characterized by competitive binding assay using immunofluorescent (IF) tests. Day-old white Leghorn chicks were immunized with anti-Id to MATSA (Group 1) or anti-Id to F1 (Group 3) and challenged with virulent Marek's disease virus (MDV) on the tenth day post immunization. In positive control groups, the day-old chicks were inoculated with anti-BALB/c mouse globulin (Group 2) and anti-rabbit globulin (Group 4) and challenged with virulent MDV on the tenth day post inoculation. As compared with positive control groups, the vaccinated groups (1 and 3) had considerably lower level of MATSA positive cells during the post challenge observation period. The protection level against MD in the immunized groups was 66.6% (Group 1) and 86.6% (Group 3).