Transferrin , Derived From an OKT 8 - Positive Subpopulation of T Lymphocytes , Suppresses the Production of Granulocyte - Macrophage

Purified human transferrin. when saturated with iron or zinc, decreased the production of granulocyte-macrophage colony-stimulating factors (GM-CSF) by human T lymphocytes that had been stimulated by phytohemagglutin or concanavalin-A. The iron-saturated transferrin was more active than the zinc-saturated transferrin. This effect was not seen for copper-saturated transferrin or for apotransferrin. and the inhibitory effect was seen whether production of GM-CSF occurred in the absence or presence of serum. If the lymphocytes were pretreated with monoclonal antibody against transferrin receptors. no suppressive effect with transferrin was seen. Transferrin did not have a direct effect on the granulocyte-macrophage colony