Differential Susceptibility of Activated Macrophage Cytotoxic Effector Reactionsto the Suppressive Effects of Transforming Growth Factor-Beta1

摘要

We examined the effects of TGF-Beta1 on induction of several activated macrophageantimicrobial activities against the protozoan parasite Leishmania, and on induction of tumoricidal activity against the fibrosarcoma tumor target 1023. TGF-Beta by itself did not affect the viability of either the intracellular or extracellular target in concentrations up to 200 ng/ml. As little as 1 ng/ml TGF-Beta, however, suppressed more than 70% of the intracellular killing activity of macrophages treated with lymphokines. In contrast, more than 100 ng/ml TGF-Beta was required to suppress intracellular killing by cells activated with an equivalent amount of recombinant IFN-gamma. Addition of TGF-Beta for up to 30 min after exposure to activation factors significantly reduced macrophage killing of intracellular parasites.