Regulation of immune responses by L-arginine metabolism

Nat Rev Immunol. 2005 Aug;5(8):641-54. doi: 10.1038/nri1668.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Arginase / metabolism
  • Arginine / metabolism*
  • Humans
  • Immunity, Cellular
  • Myeloid Cells / enzymology*
  • Nitric Oxide Synthase / metabolism
  • Reactive Nitrogen Species / metabolism
  • Reactive Oxygen Species / metabolism
  • Suppressor Factors, Immunologic / metabolism
  • T-Lymphocytes / immunology*


  • Reactive Nitrogen Species
  • Reactive Oxygen Species
  • Suppressor Factors, Immunologic
  • Arginine
  • Nitric Oxide Synthase
  • Arginase