Precision immunotherapies targeting the 9G4 idiotype in lupus erythematosus

项目总结/摘要 B细胞是系统性红斑狼疮（SLE）（一种自身免疫性疾病）的免疫病理驱动因素 其特征在于靶向自身蛋白质和核酸的自身抗体的大库。而B细胞- 定向T细胞疗法在治疗B细胞癌症中具有治愈潜力， 在难治性狼疮的疾病缓解中，耗尽所有B细胞的疗法与过度发病率相关， 感染导致的死亡，排除了它们在危及生命的疾病之外的使用。精准治疗， 因此，靶向驱动SLE自身反应性B细胞，同时保留正常的B细胞群， 需要，但针对SLE中过多的自身反应性B细胞提出了实际挑战。自反应性B SLE中的细胞区室以携带B细胞受体（BCR）的扩增B细胞为独特特征 使用可变重链等位基因VH 4 -34，其编码独特型9 G4（9 G4 id B细胞）。9 G4 id B细胞 在活动性SLE患者中占总IgG的10-45%，包括针对典型狼疮的抗体 自身抗原因此，9 G4 id B细胞是选择性耗尽自身反应性B细胞的有希望的靶 池，打开机会，以治疗狼疮，而不增加感染的风险。在这里，我们假设， 自体T细胞可被重定向以选择性地结合并杀死在SLE中扩增的9 G4 id B细胞。为了实现这一点， 我们将开发靶向9 G4 id的双特异性T细胞接合抗体，其设计用于将9 G4 id B细胞与任何 T细胞，从而诱导靶B细胞的杀伤。在这个建议中，我们将移植单链可变区片段， 抗9 G4 id特异性抗体和充分表征的CD 3特异性抗体（即，OKT 3、UCHT 1v9） 分成不同的治疗性双特异性形式（即，BiTE和scDb）。抗9 G4抗体的有效性和特异性 选择性结合和耗尽9 G4 id B细胞的双特异性抗体将在完全受控的体外建立 使用从患者克隆的表达9 G4 id自身反应性BCR的工程化人B细胞系的模型系统 SLE患者，表达单克隆非9 G4 id BCR的人B细胞系，并使用自体B细胞和T细胞 分离自SLE患者的外周血。这项工作的最终目标是奠定基础， 评估这些精确的免疫疗法作为SLE的新治疗策略。

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.