Delayed hypersensitivity and leucocyte migration inhibition in chickens with BCG or Marek's disease infection

Production of Migration Inhibition Factor in vitro by lymphocytes from chickens with delayed hypersensitivity was examined. Chickens were sensitized with Bacille Calmette-Guerin (BCG) and others with Marek's Disease (MD) virus. Peripheral blood was used as a source of cells for in vitro radial migration inhibition. Using purified Band 24 antigen from Mycobacterium bovis and >>A<< antigen from MD virus, migration inhibition was demonstrated in BCG and MD sensitized chickens respectively, and not in controls. Results correlated well with intra-dermal skin reactions. Old Tuberculin and crude MD antigens inhibited radial migration of leucocytes from control chickens. The use of peripheral blood as a source of lymphocytes facilitates repeated sampling, both prior to and following sensitization. As a result, the role of the bursa and thymus in the induction and maintenance of delayed hypersensitivity can be studied in vitro. Furthermore, the role of cellular immunity and humoral antibodies as contributors to oncogenicity and/or protection in MD can be examined.