To confirm that fucoidan binds TCR/CD3 on the T cell surface, we stably overexpressed RFP (red fluorescent protein) labeled human CD3E, a major component of the TCR/CD3 complex (Gil et al., 2002), in Jurkat T cell leukemia cells exhibiting higher transfection efficiencies than primary T cells. This evidence concerns the gene CD3E and T-cell leukemia.