Ribeir?o, V

Ribeir?o, V. is still a major health problem for many Latin American countries, afflicting millions of individuals and causing thousands of deaths every year (34). The poor prospect of treatment raises the possibility that immune interventions, such as immunization, could be used as an additional approach to improve disease prevention and treatment efficacy. Based on the concept of immune interventions, independent researchers found that the immunization of mice with plasmids containing open reading frames (ORFs) generated not only immune responses mediated by antibodies, CD4+ and CD8+ type 1 T cells, but also remarkable protective immunity against otherwise lethal infection with (reviewed in references 15 and 32). Although prophylactic vaccination was performed in most studies, immunotherapy also proved feasible in certain experimental models (16). Among the ORFs described as capable of eliciting protective immunity, there are members of the TS (11, 21, 22, 27, 37), the trypomastigote surface antigens (16, 33, 45), or the complement regulatory protein (40). Other protective ORFs encoded amastigote surface protein 1 (ASP-1) or ASP-2 expressed in the intracellular stages of the parasite (2, 6, 10, 24, 43). In addition to the members of the TS Ranolazine dihydrochloride family of surface proteins, ORFs encoding other classes of antigens have also been reported for their ability to elicit protective immune responses against experimental mouse infection. Among those are, for example, the ORFs encoding cruzipain (9, 38), the LYT-1 antigen (21), the flagellar calcium-binding protein (Tc24) (16), and a fusion protein containing heat shock protein 70 (HSP70) and the paraflagellar rod protein 2 (PAR-2) (35) or HSP70 and KMP11 (36). The examples shown above provided strong support to the fact that plasmid DNA immunization against infection can be a useful and relatively simple approach to identify protective target antigens in the mouse model. However, it is important to notice that most studies used C57BL/6 or BALB/c TNFRSF5 mice for the purpose of vaccination. Although these mice die when challenged with the infective trypomastigotes of certain parasite strains, they are not as susceptible to infection as other mouse strains, such as, for example, A/Sn mice. In order to study the antigens which provide the protective immunity required for Ranolazine dihydrochloride vaccination, we have been using this mouse strain highly susceptible to Chagas’ disease. Infection with relatively small doses of the parasites of the Y strain of leads to 100% death in a period of 30 days or less. Due to its high susceptibility, we believe that this experimental model is an interesting one to study antigens capable of generating a high degree of protective immunity against infection. In this mouse model, we have recently described how vaccination with a plasmid containing the ORF encoding an amastigote-specific antigen (ASP-2) generated specific CD4+ Th1 and CD8+ Tc1 immune responses. Most importantly, immunization with this plasmid promoted the survival of approximately 65% of the mice against a lethal infection (43). Protective immunity of this magnitude could not be duplicated by immunization with a plasmid encoding a trypomastigote-specific antigen (TS) (43, 44). Based on the data obtained following infection in this mouse model, we considered that perhaps antigens expressed by the intracellular amastigote forms of would Ranolazine dihydrochloride be better targets for protective immune responses. Also, host cells containing amastigote nests are critically involved in chronic-phase Chagas’ disease pathology. These infected cells stimulate inflammatory responses considered the main cause of chronic chagasic pathology and targets for host protective or, eventually, pathological immune responses (7, 41). Based on our interest in the amastigote antigens, the present study had a dual purpose. First, we screened 14 ORFs/antigens putatively expressed by amastigotes of for their. Ranolazine dihydrochloride