Ovoinhibitor in the chicken bursa of Fabricius: identification, isolation, and localization.

A monoclonal antibody (Mab) developed against a partially purified bursal protein extract was found to bind specifically to a single cell type in the cortico-medullary border region of the chicken bursa of Fabricius. These cells were microscopically similar to the bursal secretory dendritic-like cells. A product with an apparent molecular weight of approximately 56 kDa on SDS-polyacrylamide gel electrophoresis was immunopurified from bursal extracts by utilizing this Mab.