Pro-Apoptotic Tuberculosis Vaccine

描述(由申请人提供)：针对包括结核分枝杆菌在内的巨噬细胞内的病原体，开发有效疫苗的主要障碍是如何以刺激保护性细胞免疫反应的方式递送抗原。最近涉及结核分枝杆菌反义突变体的研究表明，它们减少了铁联合因子超氧化物歧化酶(SOD)的产生，在小鼠中诱导了强烈的CD4+和CD8+T细胞反应，并显示出作为疫苗原型的良好活性。这些效应似乎与揭开通常被超氧化物歧化酶抑制的先天免疫反应有关，超氧化物歧化酶是结核分枝杆菌和其他致病分枝杆菌的一种重要的胞外酶。增强的先天宿主免疫反应可能允许微生物抗原通过MHC I类途径与凋亡相关的交叉递呈，从而诱导强烈的适应性CD4+和CD8+T细胞反应，而当前的结核病疫苗BCG表现出以CD4+T细胞反应为主，CD8+T细胞反应最少的特点。目前的建议的目标是首先，表征在感染SOD减少的结核分枝杆菌后早期在肺内观察到的细胞和细胞因子反应，因为快速的肺间质渗透和经历细胞凋亡的单个核细胞似乎是SOD减少的菌株所独有的过程，在感染强毒力结核杆菌或卡介苗期间没有观察到。这应该定义在体内发生抗原交叉呈递的条件，从而产生可能对各种疫苗有用的信息。第二个目标是通过用突变等位基因取代野生型SOD等位基因来构建H37Rv和BCG的不可逆转的SOD缺失突变，其中一些突变等位基因编码酶效率较低的SOD突变。这应该会产生一种稳定且足够安全的SOD降低的候选疫苗，可以给人接种。第三个目标是确定最大疫苗效力的最佳超氧化物歧化酶产量水平和保护的免疫相关因素。减少由细胞内病原体产生的抑制巨噬细胞凋亡的因子的产生是制造实现MHC I类抗原递呈的新疫苗的一种策略。这不仅对结核病有影响，而且对其他传染病也有影响，在这些疾病中，CD8+T细胞反应是保护性免疫反应的关键组成部分。

DESCRIPTION (provided by applicant): A major hurdle in the development of effective vaccines against pathogens that reside within macrophages, including Mycobacterium tuberculosis, is how to deliver antigens in a manner that stimulates a protective cellular immune response. Recent investigations involving antisense mutants of M. tuberculosis that have diminished production of iron-cofactored superoxide dismutase (SOD) show that they are attenuated, induce strong CD4+ and CD8+ T-cell responses in mice, and exhibit promising activity as a vaccine prototype. These effects appear to be related to an unmasking of the innate immune responses normally inhibited by SOD, which is a prominent extracellular enzyme of M. tuberculosis and other pathogenic mycobacteria. The enhanced innate host immune responses presumably permit apoptosis-associated cross-presentation of microbial antigens via MHC Class I pathways to induce strong adaptive CD4+ and CD8+ T-cell responses, in contrast to the current vaccine for tuberculosis, BCG, which exhibits a predominant CD4+ T-cell response and minimal CD8+ T-cell responses. The goals of the current proposal are first, to characterize the cellular and cytokine responses in the lung observed early after infection with SOD-diminished M. tuberculosis, as rapid pulmonary interstitial infiltration with mononuclear cells undergoing apoptosis appears to be a process unique to the SOD-diminished strains that is not observed during infection with either virulent M. tuberculosis or BCG. This should define the conditions under which antigen cross-presentation occurs in vivo, yielding information that may be useful for a variety of vaccines. The second goal is to construct non-reverting SOD-diminished mutants of H37Rv and BCG by replacing the wild-type SOD allele with mutant alleles, some of which encode enzymatically less efficient mutants of SOD. This should yield a SOD-diminished vaccine candidate that is stable and safe enough for administration to man. The third goal is to determine the optimal level of SOD production for maximal vaccine efficacy and the immune correlates of protection. Diminishing the production of factors produced by intracellular pathogens that inhibit macrophage apoptosis is a strategy for making new vaccines that achieve MHC Class I antigen presentation. This should have implications not only for tuberculosis but also for other infectious diseases in which CD8+ T-cell responses are a critical component of a protective immune response.