title: Pattern of macrophage activation in yersinia-resistant and yersinia-susceptible strains of mice.
abstract: Th1 cells, in cooperation with activated macrophages, are required to overcome Yersinia enterocolitica infection in mice. The pathway macrophages utilize to metabolize arginine can alter the outcome of inflammation in different ways. The objective of this study was to verify the pattern of macrophages activation in Y. enterocolitica infection of BALB/c (Yersinia-susceptible) and C57BL/6 (Yersinia-resistant) mice. Both strains of mice were infected with Y. enterocolitica O:8 WA 2707. Peritoneal macrophages and spleen cells were obtained on the 1st, 3rd and 5th day post-infection. The iNOS and the arginase activities were assayed in supernatants of macrophage cultures, by measuring their NO/citrulline and ornithine products, respectively. TGFbeta-1 production was also assayed. The Th1 and Th2 responses were evaluated in supernatants of lymphocyte cultures, by IFN-gamma and IL-4 production. Our results showed that in the early phase of Y. enterocolitica infection (1st and 3rd day), the macrophages from C57BL/6 mice produced higher levels of NO/citrulline and lower levels of ornithine than macrophages from BALB/c mice. The infection with Y. enterocolitica leads to an increase in the TGF-beta1 and IL-4 production by BALB/c mice and to an increase in the IFN-gamma levels produced by C57BL/6 mice. These results suggest that Y. enterocolitica infection leads to the modulation of M1 macrophages in C57Bl/6 mice, and M2 macrophages in BALB/c mice. The predominant macrophage population (M1 or M2) at the 1st and 3rd day of infection thus seems to be important in determining Y. enterocolitica susceptibility or resistance.
authors.affiliation: Department of Biological Sciences, UNESP--São Paulo State University, School of Pharmaceutical Sciences, Araraquara, SP, Brazil.
authors.forename: Ana Rita Paladino
authors.initials: AR
authors.lastname: Tumitan
authors.forename: Luis Gustavo Silva
authors.initials: LG
authors.lastname: Monnazzi
authors.forename: Fabrício Rodrigues
authors.initials: FR
authors.lastname: Ghiraldi
authors.forename: Eduardo Maffud
authors.initials: EM
authors.lastname: Cilli
authors.forename: Beatriz Maria
authors.initials: BM
authors.lastname: Machado de Medeiros
mesh_terms: D000818:Animals; D001119:Arginase / Q000378:metabolism; D002956:Citrulline / Q000378:metabolism; D005260:Female; D008262:Macrophage Activation / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D009952:Ornithine / Q000378:metabolism; D015009:Yersinia Infections / Q000276:immunology* / Q000382:microbiology; D015008:Yersinia enterocolitica / Q000472:pathogenicity*
chemical_list: D002956:Citrulline; D009569:Nitric Oxide; D009952:Ornithine; D052247:Nitric Oxide Synthase Type II; D001119:Arginase