Replacement of transferrin in serum-free cultures of mitogen-stimulated mouse lymphocytes by a lipophilic iron chelator.

Proliferation of mouse lymph node lymphocytes in response to concanavalin A in serum-free medium is normally dependent upon the presence of transferrin. In the absence of transferrin, little proliferation occurred, but the response was restored by addition of the iron complex of pyridoxal isonicotinoyl hydrazone (FePIH), a lipophilic iron chelator. Since cellular acquisition of PIH-bound iron is known not to involve the transferrin receptor, these results indicate that transferrin promotes lymphocyte proliferation solely because of its iron-donating properties, and does not provide any additional signalling event for proliferation.