Transport of colloidal carbon from the lymphoid follicles to other tissue compartments in the chicken bursa of Fabricius.
Transport of colloidal carbon out of the medulla of the lymphoid follicles in the chicken bursa of Fabricius was studied on light and electron microscopy. A group of chickens received a single dose of the tracer per anum, and they were sacrificed within 15 min to 72 h after the application. In 1 h, the tracer was observed in many cells and tissue compartments of the bursa. Another group of chickens was heavily loaded with the tracer per anum, and the changes in the amount and distribution of carbon in different parts of the bursa were followed during an observation period of 70 d. In the follicular medulla, macrophages gradually endocytosed carbon from the intercellular spaces, and some of these cells apparently migrated out of the medulla. Part of the carbon-containing stromal macrophages invaded the interfollicular surface epithelium and obviously reached the bursal lumen via this route. The third group of chickens received one dose of the tracer intravenously, and they were sacrificed 24 h and 1 wk afterwards. Only a negligible amount of carbon was shown to be trapped into the bursal tissue following such an intravenous administration. It is concluded that colloidal carbon is transported out of the follicular medulla to other parts of the bursal tissue and even back to the lumen, the bursal macrophages, or at least part of them, functioning as carriers in this transportation.
D000818:Animals; D001692:Biological Transport; D002060:Bursa of Fabricius / Q000502:physiology*; D002244:Carbon; D002645:Chickens; D003102:Colloids; D008214:Lymphocytes / Q000502:physiology*; D008264:Macrophages / Q000502:physiology*; D008297:Male; D013997:Time Factors
D003102:Colloids; D002244:Carbon