Bursal lymphocyte proliferation in the presence of phorbol myristate acetate: Effect of IBDV strains on the proliferation response

Phorbol myristate acetate (PMA) was shown to be highly mitogenic for bursal lymphocytes (optimal concentration 2 μg/ml). Groups of 1-day-old chickens were inoculated with infectious bursal disease virus (IBDV, vaccine or virulent strains). Seven days after infection bursae were removed and the proliferation response of the bursal lymphocytes to PMA was determined. A significant reduction in the proliferation response was observed in the IBDV-inoculated birds. The results confirm that PMA is mitogenic for bursal lymphocytes and also demonstrate the usefulness of this in vitro assay for investigations into immune dysfunction in the bursa of Fabricius.