The blockage of the human transferrin receptor by a monoclonal antibody, EA.3, induces growth inhibition in leukemia cell lines.

In our program to produce monoclonal antibodies against hemopoietic functional antigens we have obtained an hybridoma cell line EA.3 reacting with human transferrin receptor. This monoclonal antibody is an IgM that displays "in vitro" antiproliferative activity against leukemic cells due to its competition with transferrin on the receptor. Cell cytotoxicity was demonstrated either with the blockage of BrdU incorporation in HL-60 cells and with leukemic CFU inhibition. In contrast, K562 cells were insensitive to the blockage of the transferrin receptor induced by this MAb.