乙肝DNA疫苗联合佐剂的免疫效果评价及抗H7N9流感病毒新策略的研究

发布时间：2018-05-12 05:33

本文选题：佐剂 + 乙肝DNA疫苗　；参考：《中国农业大学》2014年博士论文

【摘要】：感染性疾病一直严重威胁着人类的健康和公共卫生的安全,已知60%以上的感染性疾病都是由病毒感染所引起的,而我国是乙肝重灾区,将近9.3%的人口是乙肝病毒携带者,每年有近20万人死于HBV感染相关的疾病。2013年3月突如其来的H7N9禽流感病毒已造成超过419人感染,其中约127人死亡,严重威胁着人们的生命安全和社会的安定。但是目前我们对病毒感染性疾病的预防和治疗尚缺乏有效的应对办法,因此研发安全有效的防治措施具有非常重要的意义。由于DNA疫苗可以同时激活体液免疫和细胞免疫反应,因此被广泛应用于慢性乙肝等病毒感染性疾病的治疗,但在临床研究过程中发现DNA疫苗在大动物和人体内引起的免疫反应相对较弱。本实验室之前的研究发现临床上正在应用的两种小分子药物：西咪替丁和吡喹酮可以通过不同的方式增强乙肝DNA疫苗的治疗效果,本研究主要探讨西咪替丁联合吡喹酮是否可以产生协同效果进一步增强乙肝DNA疫苗的治疗效果。结果显示,西咪替丁联合吡喹酮作为乙肝DNA疫苗的佐剂可以显著降低体内CD4+CD25+Foxp3+调节性T细胞的数量和功能,从而增强乙肝DNA疫苗所诱导的抗原特异性CD8+T细胞的杀伤功能,进一步研究发现CD8+T细胞主要通过分泌IFN-y和IL-17A来发挥其杀伤作用,在HBsAg转基因小鼠模型中进一步证明了其治疗效果。鉴于这两种药物的既往临床安全性,有望作为乙肝DNA疫苗的候选佐剂。 IL-17是一种主要由Th17细胞分泌的新型细胞因子,被认为是连接固有免疫和适应性免疫反应的桥梁,而且在多种自主免疫性疾病(如银屑病、炎症性肠炎、多发性硬化症和类风湿性关节炎等)的发病过程中起到非常重要的作用。之前研究发现如果体内的IL-17A缺失后,小鼠对流感病毒的易感性明显增强,伴随着小鼠的体重和存活率下降,表明IL-17A在病毒感染过程中具有非常重要的作用。本研究通过检测不同流感病毒感染后患者血清中各种细胞因子的变化水平,我们发现血清中IL-17A的浓度越高,流感患者的病情相对较轻,预示着IL-17A可能参与到流感病毒感染的过程中并起到保护性的效果。在小鼠H7N9流感病毒的攻毒模型基础上,我们进一步证明IL-17A可以促进体内细胞因子IFN-γ的表达,从而抑制流感病毒的复制,降低肺部的病毒载量,增强小鼠抵抗H7N9禽流感病毒感染的能力。而且IL-17A在体外同样能够促进人外周血中的CD8+T细胞分泌IFN-γ的能力。本研究结果为研发基于IL-17A的新型抗H7N9禽流感病毒感染策略提供了新思路。
[Abstract]:Infectious diseases have been a serious threat to human health and public health. More than 60% of the known infectious diseases are caused by viral infection. In China, hepatitis B is a major disaster area, and nearly 9.3% of the population is hepatitis B virus carriers. Nearly 200000 people die each year from diseases associated with HBV infection. In March 2013, the sudden H7N9 avian influenza virus has infected more than 419 people, of whom about 127 have died, threatening people's lives and social stability. However, the prevention and treatment of viral infectious diseases is still lack of effective response, so it is of great significance to develop safe and effective prevention and treatment measures. Because DNA vaccine can activate both humoral and cellular immune responses, it has been widely used in the treatment of chronic hepatitis B and other viral infectious diseases. However, the immune response caused by DNA vaccine in large animals and humans is relatively weak. Previous studies in our laboratory have found that cimetidine and praziquantel, two small molecular drugs in clinical use, can enhance the efficacy of hepatitis B DNA vaccines in different ways. The aim of this study was to investigate whether cimetidine combined with praziquantel could produce synergistic effect to further enhance the therapeutic effect of hepatitis B DNA vaccine. The results showed that cimetidine combined with praziquantel as adjuvant of hepatitis B DNA vaccine could significantly reduce the number and function of CD4 CD25 Foxp3 regulatory T cells in vivo and enhance the antigen-specific CD8 T cell killing function induced by hepatitis B DNA vaccine. It was further found that CD8 T cells secreted IFN-y and IL-17A to exert their killing effect, which further proved its therapeutic effect in HBsAg transgenic mice. In view of the clinical safety of these two drugs, they are expected to be used as adjuvants for hepatitis B DNA vaccine. IL-17 is a novel cytokine secreted mainly by Th17 cells, which is considered to be a bridge between innate and adaptive immune responses, and is found in many autoimmune diseases such as psoriasis, inflammatory enteritis. Multiple sclerosis and rheumatoid arthritis, etc.) play a very important role in the pathogenesis. Previous studies showed that the susceptibility of mice to influenza virus was significantly increased after the absence of IL-17A in vivo, and the weight and survival rate of mice decreased, indicating that IL-17A plays a very important role in the process of virus infection. In this study, we detected the levels of cytokines in the serum of patients infected with different influenza viruses. We found that the higher the concentration of IL-17A in serum, the lighter the condition of influenza patients. This indicates that IL-17A may be involved in the process of influenza virus infection and play a protective role. Based on the model of H7N9 influenza virus in mice, we further prove that IL-17A can promote the expression of cytokine IFN- 纬 in vivo, thus inhibit the replication of influenza virus and reduce the viral load in lung. Enhance the ability of mice to resist H7N9 avian influenza virus infection. Moreover, IL-17A can also promote the ability of CD8 T cells to secrete IFN- 纬 in human peripheral blood in vitro. The results of this study provide a new idea for the development of new anti-H7N9 avian influenza virus infection strategy based on IL-17A.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R512.62;R511.7

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