Immunohistochemical study on the presence of immunoglobulins in globule leucocytes in the tracheal epithelium of rats.

In the present study, the presence of immunoglobulins was immunohistochemically investigated in globule leucocytes in the tracheal respiratory epithelium of conventional rats, athymic nude rats and a germ-free rat. It was not possible to demonstrate any immunoglobulins in tracheal globule leucocytes. This and other dissimilarities with intestinal globule leucocytes are briefly discussed. On the other hand, peroxidase-antiperoxidase staining revealed the presence of surface immunoglobulins on the membrane of subepithelial mast cells. The previously postulated mast cell origin of the tracheal globule leucocytes is doubted, and the possibility that globule leucocytes should belong to the group of natural killer cells is discussed.