UPTAKE OF FERRITIN AND BORDETELLA-AVIUM IN BRONCHUS-ASSOCIATED LYMPHOID-TISSUE OF TURKEYS

The uptake of macromolecular and particulate materials in bronchus-ass ociated lymphoid tissue (BALT) in turkeys was examined using transmiss ion electron microscopy. Tracer materials used were live and ultraviol et-killed (UV-killed) Bordetella avium and ferritin. Suspensions of ba cteria and ferritin were instilled via intratracheal catheterization a nd allowed to remain in contact with the respiratory surfaces for 0, 1 0, 30, 60, 90, and 120 min. Ferritin and B. avium were taken up by bot h ciliated and non-ciliated cells of the epithelium overlying BALT (BA LT epithelium). Ferritin was found in organelles associated with endoc ytosis (i.e. apical vesicles, endosomes, cytoplasmic vacuoles) and was apparently transported across epithelial cells, since it was also fou nd in intercellular spaces. Bacteria were found in vacuoles within BAL T epithelial cells, but not free in intercellular spaces. Some macroph ages in BALT epithelium also contained bacteria. No differences were o bserved between uptake of live and UV-killed bacteria. We conclude tha t both ciliated and non-ciliated cells of BALT epithelium in turkeys a re able to take up macromolecular and particulate materials. Bacteria are also accessible to intraepithelial macrophages, although whether t hey are taken up directly from the bronchial surface or whether they p ass through epithelial cells first could not be determined. This evide nce suggests that antigens, including respiratory pathogens, could gai n access to cells of the avian immune system by transepithelial passag e in BALT.