Pereira Isabela Resende, Vilar-Pereira Glaucia, Marques Virgínia, da Silva Andrea Alice, Caetano Bráulia, Moreira Otacilio Cruz, Machado Alexandre Vieira, Bruna-Romero Oscar, Rodrigues Maurício Martins, Gazzinelli Ricardo Tostes, Lannes-Vieira Joseli
Laboratório de Biologia das Interações, Instituto Oswaldo Cruz/Fiocruz, Rio de Janeiro, Rio de Janeiro, Brazil.
Departamento de Patologia, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil.
PLoS Pathog. 2015 Jan 24;11(1):e1004594. doi: 10.1371/journal.ppat.1004594. eCollection 2015 Jan.
Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, is a prototypical neglected tropical disease. Specific immunity promotes acute phase survival. Nevertheless, one-third of CD patients develop chronic chagasic cardiomyopathy (CCC) associated with parasite persistence and immunological unbalance. Currently, the therapeutic management of patients only mitigates CCC symptoms. Therefore, a vaccine arises as an alternative to stimulate protective immunity and thereby prevent, delay progression and even reverse CCC. We examined this hypothesis by vaccinating mice with replication-defective human Type 5 recombinant adenoviruses (rAd) carrying sequences of amastigote surface protein-2 (rAdASP2) and trans-sialidase (rAdTS) T. cruzi antigens. For prophylactic vaccination, naïve C57BL/6 mice were immunized with rAdASP2+rAdTS (rAdVax) using a homologous prime/boost protocol before challenge with the Colombian strain. For therapeutic vaccination, rAdVax administration was initiated at 120 days post-infection (dpi), when mice were afflicted by CCC. Mice were analyzed for electrical abnormalities, immune response and cardiac parasitism and tissue damage. Prophylactic immunization with rAdVax induced antibodies and H-2Kb-restricted cytotoxic and interferon (IFN)γ-producing CD8+ T-cells, reduced acute heart parasitism and electrical abnormalities in the chronic phase. Therapeutic vaccination increased survival and reduced electrical abnormalities after the prime (analysis at 160 dpi) and the boost (analysis at 180 and 230 dpi). Post-therapy mice exhibited less heart injury and electrical abnormalities compared with pre-therapy mice. rAdVax therapeutic vaccination preserved specific IFNγ-mediated immunity but reduced the response to polyclonal stimuli (anti-CD3 plus anti-CD28), CD107a+ CD8+ T-cell frequency and plasma nitric oxide (NO) levels. Moreover, therapeutic rAdVax reshaped immunity in the heart tissue as reduced the number of perforin+ cells, preserved the number of IFNγ+ cells, increased the expression of IFNγ mRNA but reduced inducible NO synthase mRNA. Vaccine-based immunostimulation with rAd might offer a rational alternative for re-programming the immune response to preserve and, moreover, recover tissue injury in Chagas' heart disease.
恰加斯病（CD）由原生动物克氏锥虫引起，是一种典型的被忽视的热带疾病。特异性免疫可促进急性期存活。然而，三分之一的CD患者会发展为慢性恰加斯心肌病（CCC），这与寄生虫持续存在和免疫失衡有关。目前，对患者的治疗管理仅能减轻CCC症状。因此，疫苗作为一种替代方法出现，以刺激保护性免疫，从而预防、延缓疾病进展甚至逆转CCC。我们通过用携带无鞭毛体表面蛋白-2（rAdASP2）和转唾液酸酶（rAdTS）克氏锥虫抗原序列的复制缺陷型人5型重组腺病毒（rAd）对小鼠进行疫苗接种来检验这一假设。对于预防性疫苗接种，在未接触过抗原的C57BL/6小鼠用rAdASP2+rAdTS（rAdVax）按照同源初免/加强方案进行免疫，然后用哥伦比亚菌株进行攻击。对于治疗性疫苗接种，在感染后120天（dpi）开始给予rAdVax，此时小鼠已患有CCC。对小鼠进行电异常、免疫反应、心脏寄生虫感染及组织损伤分析。用rAdVax进行预防性免疫可诱导抗体以及H-2Kb限制性细胞毒性和产生干扰素（IFN）γ的CD8+T细胞，减少急性期心脏寄生虫感染以及慢性期的电异常。治疗性疫苗接种可提高存活率，并在初免（160 dpi时分析）和加强免疫（180和230 dpi时分析）后减少电异常。与治疗前小鼠相比，治疗后小鼠的心脏损伤和电异常较少。rAdVax治疗性疫苗接种可保留特异性IFNγ介导的免疫，但降低对多克隆刺激（抗CD3加抗CD28）的反应、CD107a+CD8+T细胞频率和血浆一氧化氮（NO）水平。此外，治疗性rAdVax重塑了心脏组织中的免疫，减少了穿孔素+细胞数量，保留了IFNγ+细胞数量，增加了IFNγmRNA的表达，但降低了诱导型一氧化氮合酶mRNA的表达。基于rAd的疫苗免疫刺激可能为重新编程免疫反应以保护并恢复恰加斯心脏病中的组织损伤提供一种合理的替代方法。
