Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil.
Programa de Pós-Graduação Interunidades em Biotecnologia USP-I.Butantan-IPT, São Paulo, Brazil.
Front Immunol. 2019 Jun 26;10:1460. doi: 10.3389/fimmu.2019.01460. eCollection 2019.
The live attenuated mycobacterial strain BCG, in use as vaccine against tuberculosis, is considered the gold standard for primary therapy of carcinoma of the bladder. Despite its limitations, to date it has not been surpassed by any other treatment. Our group has developed a recombinant BCG strain expressing the detoxified S1 pertussis toxin (rBCG-S1PT) that proved more effective than wild type BCG (WT-BCG) in increasing survival time in an experimental mouse model of bladder cancer, due to the well-known adjuvant properties of pertussis toxin. Here, we investigated the capacity of rBCG-S1PT to stimulate human immune responses, in comparison to WT-BCG, using an stimulation assay based on human whole blood cells that allows for a comprehensive evaluation of leukocyte activation. Blood leukocytes stimulated with rBCG-S1PT produced increased levels of IL-6, IL-8, and IL-10 as compared to WT-BCG, but comparable levels of IL-1β, IL-2, IFN-γ, and TNF-α. Stimulation of blood cells with the recombinant BCG strain also enhanced the expression of CD25 and CD69 on human CD4 T cells. PBMC stimulated with rBCG-S1PT induced higher cytotoxicity to MB49 bladder cancer cells than WT-BCG-stimulated PBMC. These results suggest that the rBCG-S1PT strain is able to activate an immune response in human leukocytes that is higher than that induced by WT-BCG for parameters linked to better prognosis in bladder cancer (regulation of immune and early inflammatory responses), while fully comparable to WT-BCG for classical inflammatory parameters. This establishes rBCG-S1PT as a new highly effective candidate as immunotherapeutic agent against bladder cancer.
减毒分枝杆菌菌株卡介苗（BCG）被用作结核病疫苗，被认为是膀胱癌初始治疗的金标准。尽管存在局限性，但迄今为止，尚无其他治疗方法能够超越它。我们的研究小组开发了一种表达减毒 S1 百日咳毒素的重组卡介苗菌株（rBCG-S1PT），与野生型 BCG（WT-BCG）相比，在膀胱癌实验小鼠模型中，rBCG-S1PT 增加了生存时间，这是由于百日咳毒素具有众所周知的佐剂特性。在这里，我们研究了 rBCG-S1PT 刺激人免疫反应的能力，与 WT-BCG 相比，使用基于人全血细胞的刺激测定法，该方法允许对白细胞激活进行全面评估。与 WT-BCG 相比，用 rBCG-S1PT 刺激的血液白细胞产生了更高水平的 IL-6、IL-8 和 IL-10，但产生了可比水平的 IL-1β、IL-2、IFN-γ和 TNF-α。重组 BCG 菌株刺激血液细胞也增强了人 CD4 T 细胞上 CD25 和 CD69 的表达。与 WT-BCG 刺激的 PBMC 相比，用 rBCG-S1PT 刺激的 PBMC 对 MB49 膀胱癌细胞的细胞毒性更高。这些结果表明，rBCG-S1PT 菌株能够在人类白细胞中激活免疫反应，其水平高于 WT-BCG 诱导的免疫反应，对于与膀胱癌预后更好相关的参数（免疫和早期炎症反应的调节），而对于经典炎症参数则与 WT-BCG 完全相当。这确立了 rBCG-S1PT 作为一种新的高效候选物，可作为膀胱癌的免疫治疗剂。
