Laboratório de Vacinologia, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, RS, Brazil.
Laboratório de Vacinologia, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, RS, Brazil.
Microb Pathog. 2023 Nov;184:106378. doi: 10.1016/j.micpath.2023.106378. Epub 2023 Oct 4.
In the last 20 years, various research groups have endeavored to develop recombinant vaccines against leptospirosis to overcome the limitations of commercially available bacterins. Numerous antigens and vaccine formulations have been tested thus far. However, the analysis of cellular response in these vaccine formulations is not commonly conducted, primarily due to the scarcity of supplies and kits for the hamster animal model. Our research group has already tested the Q1 antigen, a chimeric protein combining the immunogenic regions of LipL32, LemA, and LigANI, in recombinant subunit and BCG-vectored vaccines. In both strategies, 100 % of the hamsters were protected against clinical signs of leptospirosis. However, only the recombinant BCG-vectored vaccine provided protection against renal colonization. Thus, the objective of this study is to characterize the cellular immune response in hamsters immunized with different vaccine formulations based on the Q1 antigen through transcriptional analysis of cytokines. The hamsters were allocated into groups and vaccinated as follows: recombinant subunit (rQ1), recombinant BCG (rBCG:Q1), and saline and BCG Pasteur control vaccines. To assess the cellular response induced by the vaccines, we cultured and stimulated splenocytes, followed by RNA extraction from the cells and analysis of cytokines using real-time PCR. The results revealed that the recombinant subunit vaccine elicited a Th2-type response, characterized by the expression of cytokines IL-10, IL-1α, and TNF-α. This pattern closely resembles the cytokines expressed in severe cases of leptospirosis. On the other hand, the rBCG-vectored vaccine induced a Th1-type response with significant up-regulation of IFN-γ. These findings suggest the involvement of the cellular response and the IFN-γ mediated inflammatory response in the sterilizing immunity mediated by rBCG. Therefore, this study may assist future investigations in characterizing the cellular response in hamsters, aiming to elucidate the mechanisms of efficacy and establish potential correlates of protection.
在过去的 20 年中，为了克服市售菌苗的局限性，各个研究小组都在努力开发针对钩端螺旋体病的重组疫苗。迄今为止，已经测试了许多抗原和疫苗制剂。但是，由于仓鼠动物模型的供应品和试剂盒稀缺，通常不会对这些疫苗制剂中的细胞反应进行分析。我们的研究小组已经在重组亚单位和卡介苗载体疫苗中测试了 Q1 抗原，这是一种由 LipL32、LemA 和 LigANI 的免疫原性区域组成的嵌合蛋白。在这两种策略中，100%的仓鼠都免受钩端螺旋体病的临床症状的影响。但是，只有重组卡介苗载体疫苗能提供针对肾脏定植的保护。因此，本研究的目的是通过细胞因子的转录分析，描述基于 Q1 抗原的不同疫苗制剂在免疫仓鼠时的细胞免疫反应。将仓鼠分组并进行以下疫苗接种：重组亚单位（rQ1）、重组卡介苗（rBCG：Q1）、生理盐水和卡介苗 Pasteur 对照疫苗。为了评估疫苗引起的细胞反应，我们培养并刺激了脾细胞，然后从细胞中提取 RNA 并使用实时 PCR 分析细胞因子。结果表明，重组亚单位疫苗引起了 Th2 型反应，其特征是表达细胞因子 IL-10、IL-1α 和 TNF-α。这种模式与钩端螺旋体病的严重病例中表达的细胞因子非常相似。另一方面，rBCG 载体疫苗诱导了 Th1 型反应，IFN-γ 的表达显著上调。这些发现表明细胞反应和 IFN-γ 介导的炎症反应参与了 rBCG 介导的杀菌免疫。因此，本研究可能有助于未来对仓鼠细胞反应的特征进行研究，旨在阐明功效的机制并建立潜在的保护相关性。
