Human Autoantibodies in Anti-GBM Disease

描述(申请人提供)：抗肾小球基底膜(GBM)病是一种由抗GBM抗体介导的自身免疫性疾病。常见的临床表现为快速进展性肾小球肾炎(RPGN)，导致终末期肾病。因此，由于终生需要肾脏替代疗法，这些患者的生活质量显著下降。虽然目前对人类抗GBM疾病抗原(Ag)的结构基础已有大量了解，但Alpha3(IV)NCI胶原(Alpha3(IV))；这种自身免疫性疾病的发病机制尚未完全阐明。虽然已经确定了可能的抗原表位，但对识别这些表位的致病性人类抗GBM抗体的来源、结构和构象知之甚少。本文提出的研究试图确定抗α3(IV)自身抗体是如何通过与GBM结合而引发肾炎的。利用我们实验室建立的人抗GBM病的XenoMouseII(XMII)模型，我建议制备针对抗GBM抗体上两个可能致病相关的表位的人源单抗(MAb)。常见的临床表现为快速进展性肾小球肾炎(RPGN)，导致终末期肾病。因此，由于终生需要肾脏替代疗法，这些患者的生活质量显著下降。虽然目前对人类抗GBM疾病抗原(Ag)的结构基础已有大量了解，但Alpha3(IV)NCI胶原(Alpha3(IV))；这种自身免疫性疾病的发病机制尚未完全阐明。虽然已确定了可能的抗原表位，但对识别这些表位的致病性人抗GBM抗体的来源、结构和构象知之甚少。这里提出的研究试图确定抗α3(IV)自身抗体是如何通过与GBM结合而引发肾炎的。利用我们实验室建立的人类抗GBM病的XenoMouseII(XMII)模型，我建议产生针对Alpha3(IV)上两个可能致病相关的表位的人源性单抗(MAb)(目标1)。这些单抗在体外与Alpha3(IV)结合的特异性和亲和力将被确定(目标2)，并与它们的致病性相关(目标3)。对致病单抗的高变区进行测序将有助于预测Ag结合区的三维结构。随后，这些信息应该使我能够确定高变区的哪些氨基酸残基对于与α3(IV)(目标2)和产生自身抗体的疾病(目标3)的相互作用是必不可少的。这些研究应该有助于深入了解抗GBM疾病的基本病理生理学。此外，这些结果可能有助于设计和评估未来治疗这种毁灭性疾病的有效疗法(例如，小分子)。K08机制将使我能够在基础免疫学和自身免疫性肾小球肾炎的发病机制方面进行指导研究培训。这些研究将在宾夕法尼亚大学迈克尔·P·马代奥博士的实验室进行。培训和学习将极大地促进我在学术环境中成为一名医生/科学家的职业目标。

DESCRIPTION (provided by applicant):Anti glomerular basement membrane (GBM) disease is an autoimmune disease mediated by antibodies against the GBM. The usual clinical picture is rapidly progressive glomerulonephritis (RPGN) resulting in end stage renal disease. These patients consequently suffer a significant reduction in quality of life, due to life-long need for renal replacement therapy. While significant knowledge currently exist about the structural basis of the antigen (Ag) of human anti-GBM disease, alpha3(IV) NCI collagen (alpha3(IV)); the pathogenesis of this autoimmune disease has yet to be fully elucidated. Although putative antigenic epitopes have been identified, little is known about the origin, structure and conformation of pathogenic human anti-GBM antibodies (Ab) that recognize these epitopes.The studies proposed here seek to identify how autoantibodies against alpha3(IV) initiate nephritis through binding to the GBM. Using the XenoMouseII (XMII) model of human anti-GBM disease that has been developed in our laboratory, I propose to generate human monoclonal antibodies (mAb), directed towards 2 putatively pathogenically relevant epitopes on Antibodies against the GBM. The usual clinical picture is rapidly progressive glomerulonephritis (RPGN) resulting in end stage renal disease. These patients consequently suffer a significant reduction in quality of life, due to life-long need for renal replacement therapy. While significant knowledge currently exist about the structural basis of the antigen (Ag) of human anti-GBM disease, alpha3(IV) NCI collagen (alpha3(IV)); the pathogenesis of this autoimmune disease has yet to be fully elucidated. Although putative antigenic epitopes have been identified, little is known about the origin, structure and conformation of pathogenic human anti-GBM antibodies (Ab) that recognize these epitopes. The studies proposed here seek to identify how autoantibodies against alpha3(IV) initiate nephritis through binding to the GBM. Using the XenoMouseII (XMII) model of human anti-GBM disease that has been developed in our laboratory, I propose to generate human monoclonal antibodies (mAb), directed towards 2 putatively pathogenically relevant epitopes on alpha3(IV) (Aim 1). The specificity and affinity with which these mAb bind alpha3(IV) in vitro will be determined (Aim 2), and correlated to their pathogenicity (Aim 3). Sequencing of the hypervariable region of the pathogenic mAb will allow prediction of the 3-dimensional structure of the Ag-binding region. Subsequently, this information should enable me to determine which amino acid residues in the hypervariable region are essential for the interaction with alpha3(IV) (Aim 2) and the disease producing autoAb (Aim 3). These studies should help provide insights into the basic pathophysiology of anti-GBM disease. Additionally, these results may aide in the design and evaluation of effective therapies (e.g., small molecules) for treatment of this devastating disease, in the future.The K08 mechanism will enable me to undertake mentored research training in basic immunology and the pathogenesis of autoimmune glomerulonephritis. These studies will be conducted in Dr. Michael P. Madaio's laboratory at the University of Pennsylvania. The training and studies will greatly facilitate my career goals of working as a physician/scientist in an academic setting.