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Nat Rev Immunol. 2005 Aug;5(8):641-54.

Regulation of immune responses by L-arginine metabolism.

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Cancer Center of Veneto Region, Department of Oncological and Surgical Sciences, Padua University, Via Gattamelata 64, Padua, Italy.


L-Arginine is an essential amino acid for birds and young mammals, and it is a conditionally essential amino acid for adult mammals, as it is important in situations in which requirements exceed production, such as pregnancy. Recent findings indicate that increased metabolism of L-arginine by myeloid cells can result in the impairment of lymphocyte responses to antigen during immune responses and tumour growth. Two enzymes that compete for L-arginine as a substrate - arginase and nitric-oxide synthase - are crucial components of this lymphocyte-suppression pathway, and the metabolic products of these enzymes are important moderators of T-cell function. This Review article focuses on the relevance of L-arginine metabolism by myeloid cells for immunity under physiological and pathological conditions.

[Indexed for MEDLINE]

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