Harnessing B cells for TB vaccine development to improve therapy of TB and TB-HIV coinfection

摘要 在存在或不存在人类免疫缺陷病毒（HIV）感染的情况下的当前结核病（TB）控制 不是最理想的：临床使用的唯一结核病疫苗卡介苗（BCG）仅提供有限的 由于毒品的惊人蔓延，儿童期的保护和多种药物化疗面临挑战 阻力一种将化疗与暴露后给予的治疗性疫苗相结合的综合方法 结核分枝杆菌（Mtb）可能是一个前进的方向。结核病疫苗研究主要集中在预防性 预防感染的候选人。需要具有新作用机制的治疗性结核病疫苗 (i)以补充现有的化疗和预防复发后，和（ii）治愈潜伏性结核感染（LTBI） 或防止再激活。T淋巴细胞对于控制结核感染和特异性T细胞应答至关重要 由疫苗引发的免疫原性已被用作免疫原性的关键相关物。相比之下，B细胞研究不足 在结核病研究的所有领域。使用深度免疫表型分析方法，我们在小鼠中的初步数据表明， 结核病感染导致B细胞亚群的急剧变化。我们发现了一个新的B 具有边缘区（MZ）表型的细胞亚群被激活，具有记忆表型并表达 识别人细胞因子A增殖诱导配体、APRIL和B细胞活化因子的受体， BAFF，对B细胞发育和存活至关重要。功能研究表明，小鼠MZ B细胞有助于 到小鼠体内的结核分枝杆菌遏制。令人惊讶的是，这些B细胞表达一组Th 1细胞因子，在T细胞中研究得很好。 细胞，这表明可能在抵御结核病感染的第一道防线中发挥作用。我们发现MZ B细胞 结核病患者和结核病/艾滋病毒合并感染者的血液中的毒素耗尽。我们的假设是MZ B细胞可以被修复 通过抗结核治疗和结核病疫苗的开发。为了测试这个，我们基因改造了 BCG表达刺激BAFF发育和寿命的人细胞因子APRIL和BAFF 受体和APRIL受体表达B细胞，包括MZ B细胞。我们将确定安全性， 免疫原性和预防功效。将在两个新的治疗方案中评价治疗效果。 创新的小鼠模型，使我们能够确定BCG菌株中细胞因子表达的能力， 药物治疗后复发，并减少少杆菌结核病模仿方面的再激活频率， 人类的LTBI我们将测定外周血单个核细胞（PBMC）中MZ B细胞的频率 从患有LTBI和TB的人，跨越HIV状态，包括抗结核和抗逆转录病毒治疗。我们将 用表达卡介菌碱的BCG菌株刺激相同队列的PBMC，以研究免疫学特性。 并原则上证明这些疫苗在结核病、艾滋病毒和艾滋病治疗期间的可行性， 结核病/艾滋病毒合并感染。我们将通过高参数流式细胞术监测T细胞和B细胞的全球景观 以确定结核病感染和疫苗保护的免疫学相关性。我们的提议将决定 B细胞可被分泌亮氨酸的靶向B细胞的BCG疫苗利用，用于TB疫苗开发。

Abstract Current tuberculosis (TB) control in the presence or absence of human immunodeficiency virus (HIV) infection is suboptimal: Bacillus Calmette-Guérin (BCG), the sole TB vaccine in clinical use, provides only limited protection during childhood and multi-drug chemotherapy faces challenges due to the alarming spread of drug resistance. An integrated approach combining chemotherapy with a therapeutic vaccine given after exposure to Mycobacterium tuberculosis (Mtb) could be a way forward. TB vaccine research mostly focused on prophylactic candidates aiming to prevent infection. Therapeutic TB vaccines with novel mechanisms of action are needed (i) to complement existing chemotherapy and prevent relapse thereafter, and (ii) to cure latent TB infection (LTBI) or prevent reactivation. T lymphocytes are critical for the control of TB infection and the specific T cell response elicited by a vaccine has been used as a key correlate of immunogenicity. In contrast, B cells are understudied in all areas of TB research. Using a deep immunophenotyping approach, our preliminary data in mice suggest that TB infection leads to dramatic changes in the landscape of B cell subpopulations. We identified a novel B cell subset with marginal zone (MZ) phenotype that was activated, had a memory phenotype and expressed receptors recognizing the human cytokines A Proliferation-Inducing Ligand, APRIL, and B cell Activating Factor, BAFF, critical for B cell development and survival. Functional studies indicated that murine MZ B cells contributed to Mtb containment in mice. Surprisingly, these B cells expressed a panel of Th1 cytokines, well studied in T cells, suggesting a possible role in the first line of defense against TB infection. We found that MZ B cells were depleted in blood of TB patients and TB/HIV coinfected people. Our hypothesis is that MZ B cells can be restored by antitubercular therapy and harnessed for TB vaccine development. To test this, we genetically engineered BCG to express the human cytokines APRIL and BAFF that stimulate development and longevity of BAFF receptor- and APRIL receptor-expressing B cells, including MZ B cells. We will determine the safety, immunogenicity and prophylactic efficacy in mice. The therapeutic efficacy will be evaluated in two novel innovative mouse models that allow us to determine the capacity of cytokine expression in BCG strains to prevent relapse after drug treatment and to reduce the reactivation frequency of paucibacillary TB mimicking aspect of LTBI in humans. We will determine the frequency of MZ B cells in peripheral blood mononuclear cells (PBMC) from people having LTBI and TB, across HIV status, including antitubercular and antiretroviral therapy. We will stimulate PBMC of the same cohorts with cytokine-expressing BCG strains to study the immunological consequences and to demonstrate, in principle, the feasibility of these vaccines during therapy of TB, HIV and TB/HIV coinfection. We will monitor the global landscapes of T cells and B cells by high parameter flow cytometry to define immunological correlates of TB infection and vaccine protection. Our proposal will determine whether B cells can be harnessed by cytokine-secreting B cell-targeting BCG vaccines for TB vaccine development.