title: Alternative activation and increase of Trypanosoma cruzi survival in murine macrophages stimulated by cruzipain, a parasite antigen.
abstract: We studied the macrophage (Mo) activation pathways through Mo interaction with immunogenic Trypanosoma cruzi antigens as cruzipain (Cz) and R13. J774 cells, peritoneal and spleen Mo from normal mice, were used. Although Mo classic activation was observed in the presence of lipopolysaccharide, evaluated through nitric oxide (NO) and interleukin (IL)-12 production, Cz and R13 did not activate Mo in this way. To study the alternative pathway, we examined the arginase activity in Mo cultured with Cz. An increase of arginase activity was detected in all Mo sources assayed. An increase of IL-10 and transforming growth factor-beta in culture supernatants from Mo stimulated with Cz was observed. The study of expression of B7.1 and B7.2 in spleen Mo revealed that Cz induces preferential expression of B7.2. In vitro studies revealed that Cz stimulated J774 cells and then, infected with trypomastigotes of T. cruzi, developed a higher number of intracellular parasites than unstimulated infected Mo. Thus, Cz favors the perpetuation of T. cruzi infection. In addition, a down-regulation of inducible NO synthase was observed in J774 cells stimulated with Cz. These results suggest that Cz interaction with Mo could modulate the immune response generated against T. cruzi through the induction of a preferential metabolic pathway in Mo.
authors.affiliation: Inmunología, Departamento Bioquímica Clínica, Facultad Ciencias Químicas, Universidad Nacional Córdoba, Argentina.
authors.forename: Cinthia
authors.initials: C
authors.lastname: Stempin
authors.forename: Laura
authors.initials: L
authors.lastname: Giordanengo
authors.forename: Susana
authors.initials: S
authors.lastname: Gea
authors.forename: Fabio
authors.initials: F
authors.lastname: Cerbán
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis; D000953:Antigens, Protozoan / Q000276:immunology*; D001119:Arginase / Q000378:metabolism; D018122:B7-1 Antigen / Q000096:biosynthesis; D051940:B7-2 Antigen; D002448:Cell Adhesion; D002470:Cell Survival; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000276:immunology*; D004790:Enzyme Induction; D016753:Interleukin-10 / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D008262:Macrophage Activation / Q000276:immunology*; D008264:Macrophages / Q000201:enzymology / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000201:enzymology / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D019001:Nitric Oxide Synthase / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D015800:Protozoan Proteins; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014349:Trypanosoma cruzi / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D000953:Antigens, Protozoan; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497965:Cd86 protein, mouse; D008562:Membrane Glycoproteins; D009573:Nitrites; D015800:Protozoan Proteins; D016212:Transforming Growth Factor beta; D016753:Interleukin-10; D018664:Interleukin-12; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D003546:Cysteine Endopeptidases; C063214:cruzipain; D001119:Arginase