Transferrin binding and iron uptake by mouse lymph node cells during transformation in response to concanavalin A

Mouse lymph node cells cultured with Concanavalin A (Con A) in serum-free medium containing 59Fe-transferrin took up 59Fe more rapidly than cells cultured without Con-A. Uptake of iron commenced rapidly and preceded the onset of DNA synthesis in stimulated cells. Total uptake of transferrin during culture was much lower than that of iron, indicating that cells could remove iron from transferrin. The released transferrin appeared to be undergraded. Lymphoblasts bound six times more transferrin per cell than small lymphocytes. Lymphocytes also took up iron from citrate and nitrilotriacetate complexes, and iron so acquired was not readily removed by desferrioxamine, indicating that it was not bound extracellularly.