Bontempi Iván Alejandro, Vicco Miguel Hernán, Cabrera Gabriel, Villar Silvina Raquel, González Florencia Belén, Roggero Eduardo Angel, Ameloot Paul, Callewaert Nico, Pérez Ana Rosa, Marcipar Iván Sergio
Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Argentina.
IDICER-CONICET and Instituto de Inmunología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Argentina.
Vaccine. 2015 Mar 3;33(10):1274-83. doi: 10.1016/j.vaccine.2015.01.044. Epub 2015 Jan 25.
Recombinant protein vaccines are safe but elicit low immunological responses. The new generation of adjuvants is currently reversing this situation. Here, a new antigen-adjuvant combination for protection against experimental Chagas disease was assessed. The antigen used in the formulation was a glycosylated mutant inactive trans-sialidase (mTS) that was previously proven to be highly protective against Trypanosoma cruzi infection; here, we show that it can be produced in large quantities and high quality using Pichia pastoris. The adjuvant used in the formulation was ISCOMATRIX (IMX), which was found to be effective and safe in human clinical trials of vaccines designed to control other intracellular infections. Fifteen days after the third immunization, mice immunized with mTS-IMX showed a TS-specific IgG response with titers >10(6) and high avidity, an increased IgG2a/IgG1 ratio, significant delayed-type hypersensitivity (DTH) reactivity, a balanced production of IFN-γ and IL-10 by splenocytes and a strong IFN-γ secretion by CD8(+) T lymphocytes. When these mice where challenged with 1000 trypomastigotes of T. cruzi, all mTS-IMX immunized mice survived, whereas mice immunized with mTS alone, IMX or PBS exhibited high mortality. Remarkably, during acute infection, when the parasitemia is highest in this infection model (day 21), mTS-IMX immunized mice had ∼50 times less parasitemia than non-immunized mice. At this moment and also in the chronic phase, 100 days after infection, tissue presented ∼4.5 times lower parasite load and associated inflammatory infiltrate and lesions. These results indicate that protection against Chagas disease can be achieved by a protein antigen-adjuvant mTS formulation that is compatible with human medicine. Therefore, the current formulation is a highly promising T. cruzi vaccine candidate to be tested in clinical trials.
重组蛋白疫苗安全，但引发的免疫反应较低。新一代佐剂目前正在扭转这种局面。在此，评估了一种用于预防实验性恰加斯病的新型抗原 - 佐剂组合。制剂中使用的抗原是一种糖基化突变失活转唾液酸酶（mTS），先前已证明其对克氏锥虫感染具有高度保护作用；在此，我们表明它可以利用毕赤酵母大量且高质量地生产。制剂中使用的佐剂是ISCOMATRIX（IMX），在旨在控制其他细胞内感染的疫苗人体临床试验中发现其有效且安全。第三次免疫后15天，用mTS - IMX免疫的小鼠表现出TS特异性IgG反应，滴度>10(6)且亲和力高，IgG2a/IgG1比值增加，显著的迟发型超敏反应（DTH）反应性，脾细胞产生的IFN - γ和IL - 10平衡，以及CD8(+) T淋巴细胞强烈分泌IFN - γ。当用1000个克氏锥虫的锥鞭毛体攻击这些小鼠时，所有用mTS - IMX免疫的小鼠都存活下来，而单独用mTS、IMX或PBS免疫的小鼠死亡率很高。值得注意的是，在急性感染期间，即该感染模型中寄生虫血症最高的时期（第21天），用mTS - IMX免疫的小鼠的寄生虫血症比未免疫的小鼠低约50倍。此时以及在慢性期，感染后100天，组织中的寄生虫负荷以及相关炎症浸润和病变降低约4.5倍。这些结果表明，通过与人类医学兼容的蛋白抗原 - 佐剂mTS制剂可以实现对恰加斯病的保护。因此，当前制剂是一种非常有前景的克氏锥虫疫苗候选物，有待在临床试验中进行测试。
