title: Differences in iNOS and arginase expression and activity in the macrophages of rats are responsible for the resistance against T. gondii infection.
abstract: Toxoplasma gondii infects humans and warm blooded animals causing devastating disease worldwide. It has long been a mystery as to why the peritoneal macrophages of rats are naturally resistant to T. gondii infection while those of mice are not. Here, we report that high expression levels and activity of inducible nitric oxide synthase (iNOS) and low levels of arginase-1 (Arg 1) activity in the peritoneal macrophages of rats are responsible for their resistance against T. gondii infection, due to high nitric oxide and low polyamines within these cells. The opposite situation was observed in the peritoneal macrophages of mice. This discovery of the opposing functions of iNOS and Arg 1 in rodent peritoneal macrophages may lead to a better understanding of the resistance mechanisms of mammals, particularly humans and livestock, against T. gondii and other intracellular pathogens.
authors.affiliation: State Key Laboratory of Biocontrol, School of Life Sciences, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, People's Republic of China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Zhao
authors.forename: Xing-Quan
authors.initials: XQ
authors.lastname: Zhu
authors.forename: Qing-Shi
authors.initials: QS
authors.lastname: Ren
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Nie
authors.forename: Jiang-Mei
authors.initials: JM
authors.lastname: Gao
authors.forename: Xiao-Jie
authors.initials: XJ
authors.lastname: Gao
authors.forename: Ting-Bao
authors.initials: TB
authors.lastname: Yang
authors.forename: Wen-Liang
authors.initials: WL
authors.lastname: Zhou
authors.forename: Ji-Long
authors.initials: JL
authors.lastname: Shen
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Fang-Li
authors.initials: FL
authors.lastname: Lu
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Chen
authors.forename: Geoff
authors.initials: G
authors.lastname: Hide
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Ayala
authors.forename: Zhao-Rong
authors.initials: ZR
authors.lastname: Lun
mesh_terms: D000818:Animals; D001119:Arginase / Q000235:genetics* / Q000378:metabolism; D060467:Disease Resistance / Q000502:physiology*; D015870:Gene Expression; D058507:Host Specificity; D006801:Humans; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000201:enzymology* / Q000276:immunology / Q000469:parasitology; D051379:Mice; D008815:Mice, Inbred Strains; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012376:Rodent Diseases; D014122:Toxoplasma / Q000502:physiology; D014124:Toxoplasmosis, Animal / Q000201:enzymology* / Q000276:immunology / Q000469:parasitology
chemical_list: D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D001119:Arginase