The metabolism of the amino acid L-arginine is emerging as a crucial mechanism for the regulation of immune responses. Here, we characterized the impact of L-arginine deprivation on T cell and macrophage (MPhi) effector functions: We show that whereas L-arginine is required unconditionally for T cell activation, MPhi can up-regulate activation markers and produce cytokines and chemokines in the absence of L-arginine. Furthermore, we show that L-arginine deprivation does not affect the capacity of activated MPhi to up-regulate L-arginine-metabolizing enzymes such as inducible NO synthase and arginase 1. Thus, our results show that to exert their effector functions, T cells and MPhi have different requirements for L-arginine.
Journal of leukocyte biology
Department of Immunology, Faculty of Medicine, Imperial College London, UK.
J Leukoc Biol. 2009 Feb;85(2):268-77
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