RESUMEN
Os antígenos recombinantes Cytoplasmic Repetitive Antigen e Flagellar Repetitive Antigen de Trypanosoma cruzi foram inoculados em camundongos BALB/c e C57BL/6 e o seu efeito avaliado a nível hematológico e histopatológico. Os resultados mostraram que o padrão histológico normal dos órgãos e o perfil hematológico dos camundongos não foram modificados sugerindo que esses antígenos não parecem causar dano ao animal.
Asunto(s)
Animales , Masculino , Ratones , Antígenos de Protozoos , Enfermedad de Chagas , Proteínas Recombinantes , Trypanosoma cruzi , Antígenos de Protozoos , Enfermedad de Chagas , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Proteínas RecombinantesRESUMEN
Interleukin-12 (IL-12) is essential to resistance to Trypanosoma cruzi infection because it stimulates the synthesis of interferon-gamma (IFN-gamma) that activates macrophages to a parasiticidal effect. Investigation of mice deprived of IL-12 genes (IL-12 knockout mice) has confirmed the important role of IL-12 and IFN-gamma in controlling parasitism in T. cruzi infection. However, it has not yet been addressed whether a shift towards a T helper type 2 (Th2) pattern of cytokine response occurred in these mice that might have contributed to the aggravation of the infection caused by IL-12 deprivation. We examined the course of T. cruzi (Y strain) infection and the regulation of cytokine responses and nitric oxide production in C57BL/6 IL-12 p40-knockout mice. The mutant mice were extremely susceptible to the infection as evidenced by increased parasitaemia, tissue parasitism and mortality in comparison with the control C57BL/6 mouse strain (wild-type) that is resistant to T. cruzi. A severe depletion of parasite-antigen-specific IFN-gamma response, without an increase in IL-4 or IL-10 production, accompanied by reduced levels of nitric oxide production was observed in IL-12 knockout mice. We found no evidence of a shift towards a Th2-type cytokine response. In IL-12 knockout mice, the residual IFN-gamma production is down-regulated by IL-10 but not by IL-4 and nitric oxide production is stimulated by tumour necrosis factor-alpha. Parasite-specific immunoglobulin G1 antibody levels were similar in IL-12 knockout and wild-type mice, whereas IL-12 knockout mice had much higher levels of immunoglobulin G2b.
Asunto(s)
Enfermedad de Chagas/inmunología , Interleucina-12/inmunología , Células Th2/inmunología , Trypanosoma cruzi/inmunología , Enfermedad Aguda , Animales , Anticuerpos Antiprotozoarios , Células Cultivadas , Susceptibilidad a Enfermedades , Femenino , Interferón gamma/biosíntesis , Interleucina-10/biosíntesis , Interleucina-12/genética , Interleucina-4/biosíntesis , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Óxido Nítrico/biosíntesis , Parasitemia/inmunología , Factor de Necrosis Tumoral alfa/inmunologíaRESUMEN
The Cytoplasmic Repetitive Antigen and Flagellar Repetitive Antigen recombinant antigens of Trypanosoma cruzi were inoculated into BALB/c and C57BL/6 mice and its effects evaluated at hematological and histopathological levels. The results showed that the histological pattern of the organs and the hematological profile of mice were not modified suggesting that these antigens are not harmful for the animal.