Precision immunotherapies targeting the 9G4 idiotype in lupus erythematosus

项目摘要/摘要 B细胞是自身免疫性疾病系统性红斑狼疮(SLE)的免疫致病因素 以大量针对自身蛋白质和核酸的自身抗体为特征。而B细胞- 定向T细胞疗法在B细胞癌的治疗中具有治疗潜力，并可达到完全 难治性狼疮的疾病缓解，耗尽所有B细胞的治疗与过度的发病率和 感染致死，使其无法在威胁生命的疾病之外使用。有选择性的精准疗法 因此，在保持正常B细胞群的同时，导致SLE的靶向自身反应性B细胞是至关重要的 需要，但针对SLE中过多的自身反应性B细胞会带来实际挑战。自体反应性B 系统性红斑狼疮的细胞室独特的特征是具有B细胞受体(BCR)的扩张性B细胞 使用编码独特型9G4(9G4id B细胞)的可变重链等位基因VH4-34。9G4id B细胞 贡献活动期SLE患者总免疫球蛋白的10-45%，包括针对典型狼疮的抗体 自身抗原。因此，9G4id B细胞是选择性去除自身反应性B细胞的有希望的靶点 泳池，打开了治疗狼疮的机会，而不会增加感染的风险。在这里，我们假设 自体T细胞可以被重新定向，选择性地结合和杀伤在SLE中扩增的9G4id B细胞。为了实现这一目标， 我们将开发针对9G4id的双特异性T细胞结合抗体，旨在将9G4id B细胞与任何 T细胞，从而诱导对靶B细胞的杀伤。在这项提议中，我们将移植单链可变片段 抗9G4id特异性抗体和特性良好的CD3特异性抗体(即OKT3、UCHT1v9) 转化为不同的治疗性双特异性形式(即BITE和scDb)。抗9G4抗体的效价和特异性 将在体外建立选择性结合和耗尽9G4id B细胞的双特异性抗体 利用从患者克隆的表达9G4id自身反应性BCRs的工程化人B细胞系建立模型系统 在系统性红斑狼疮患者中，表达单克隆非9G4id BCRs的人B细胞系，并使用自体B细胞和T细胞 从系统性红斑狼疮患者的外周血中分离。这项工作的最终目标是为 评估这些精确免疫疗法作为SLE的一种新的治疗策略。

PROJECT SUMMARY/ABSTRACT B cells are immunopathogenic drivers of systemic lupus erythematosus (SLE), an autoimmune disease characterized by a large repertoire of autoantibodies targeting self-protein and nucleic acids. While B cell- directed T-cell therapies have curative potential in the treatment of B-cell cancers and can achieve complete disease remission in refractory lupus, therapies that deplete all B cells are associated with excess morbidity and mortality from infection, precluding their use beyond life-threatening disease. Precision therapies that selectively target autoreactive B cells that drive SLE, while preserving normal B cell populations, are therefore critically needed, but targeting the plethora of autoreactive B cells in SLE poses practical challenges. The autoreactive B cell compartment in SLE is uniquely characterized by the expansion B cells bearing B-cell receptors (BCRs) using the variable heavy-chain allele VH4-34, which encodes the idiotype 9G4 (9G4id B cells). 9G4id B cells contribute 10–45% of total IgG in patients with active SLE, including antibodies against canonical lupus autoantigens. 9G4id B cells are therefore promising targets for the selective depletion of the autoreactive B cell pool, opening opportunities to treat lupus without increasing the risk of infection. Here, we hypothesize that autologous T cells can be redirected to selectively bind and kill 9G4id B cells expanded in SLE. To achieve this, we will develop 9G4id-targeted bispecific T cell-engaging antibodies designed to cross-link 9G4id B cells with any T cell, thereby inducing killing of target B cells. In this proposal, we will graft single chain variable fragments of an anti-9G4id-specific antibody and those of well-characterized CD3-specific antibodies (i.e., OKT3, UCHT1v9) into different therapeutic bispecific formats (i.e., BiTE and scDb). The efficacy and specificity of anti-9G4 bispecific antibodies to selectively bind and deplete 9G4id B cells will be established in fully-controlled in vitro model systems using engineered human B cell lines expressing 9G4id autoreactive BCRs cloned from patients with SLE, human B cell lines expressing monoclonal non-9G4id BCRs, and using autologous B cells and T cells isolated from the peripheral blood of patients with SLE. The final goal of this work is to lay the foundation for evaluating these precision immunotherapies as a novel therapeutic strategy in SLE.