Light microscopic observations of an intraepithelial granular cell type in the bovine parotid gland

Bovine parotid gland intralobular ducts were frequently found to contain an intraepithelial granular cell type, adjacent to the basement membrane. Granular cells were non-migratory and polymorphic in appearance, with strong cytoplasmic basophilia and acidophil metachromatic granules. Such cells were not found in the bovine mandibular and sublingual glands. It is proposed that the granular cell may be similar or identical to the globule leucocyte cell type and functionally associated with the parotid gland. A possible role for parotid gland granular cells in ruminant mucosal immunity is also discussed.