Duck hepatitis B virus is tropic for exocrine cells of the pancreas

Earlier observations had established that duck hepatitis B virus (DHBV) is tropic for pancreatic endocrine cells, including cells localized to islets and to acini. Because cells identifiable as endocrine represented only a minor fraction of the total acinar-associated, infected subpopulation, the possibility was addressed in the present study that this subpopulation also comprises exocrine cells. Fixed preparations of cells from pancreas of congenitally DHBV-infected young ducks were reacted in double immunofluorescence assay with anti-virus serum and either anti-avian pancreatic polypeptide (APP) serum, a probe for a major subclass of acinar-associated endocrine cells, or anti-chymotrypsin serum, a probe for exocrine cells. Approximately 2-5% of the cells in these preparations were viral antigen-positive, comprising a minor fraction positive for APP and a much larger fraction positive for chymotrypsinogen. The detection of the latter establishes that DHBV is tropic for exocrine cells.