Anosova Natalie G, Cole Leah E, Li Lu, Zhang Jinrong, Brown Anna M, Mundle Sophia, Zhang Jianxin, Ray Satyajit, Ma Fuqin, Garrone Pierre, Bertraminelli Nicola, Kleanthous Harry, Anderson Stephen F
Sanofi Pasteur Biologics, Cambridge, Massachusetts, USA
Sanofi Pasteur Biologics, Cambridge, Massachusetts, USA.
Clin Vaccine Immunol. 2015 Jul;22(7):711-25. doi: 10.1128/CVI.00763-14. Epub 2015 Apr 29.
Clostridium difficile infection (CDI) is the principal cause of nosocomial diarrhea and pseudomembranous colitis associated with antibiotic therapy. Recent increases in the number of outbreaks attributed to highly virulent antibiotic-resistant strains underscore the importance of identifying efficacious alternatives to antibiotics to control this infection. CDI is mediated by two large exotoxins, toxins A and B. Strong humoral toxin-specific immune responses are associated with recovery and a lack of disease recurrence, whereas insufficient humoral responses are associated with recurrent CDI. Multiple approaches targeting these toxins, including intravenous immunoglobulin, neutralizing polymers, active vaccines, and, most recently, monoclonal antibodies (MAbs), have been explored, with various degrees of success. In this study, we describe the characterization of the first MAbs isolated from healthy human donors using a high-throughput B-cell cloning strategy. The MAbs were selected based on their ability to inhibit the actions of toxins A and B in vitro and because of their in vivo efficacy in a hamster challenge model. A potent 2-MAb cocktail was identified and then further potentiated by the addition of a second anti-toxin B MAb. This 3-MAb combination protected animals against mortality and also reduced the severity and duration of diarrhea associated with challenge with highly virulent strains of C. difficile toxinotypes 0 and III. This highly efficacious cocktail consists of one MAb specific to the receptor binding domain of toxin A and two MAbs specific to nonoverlapping regions of the glucosyltransferase domain of toxin B. This MAb combination offers great potential as a nonantibiotic treatment for the prevention of recurrent CDI.
艰难梭菌感染（CDI）是与抗生素治疗相关的医院获得性腹泻和伪膜性结肠炎的主要原因。近期，由高毒力耐抗生素菌株引起的暴发数量增加，凸显了寻找有效抗生素替代物以控制这种感染的重要性。CDI由两种大型外毒素，即毒素A和毒素B介导。强烈的体液毒素特异性免疫反应与康复及无疾病复发相关，而体液反应不足则与复发性CDI相关。针对这些毒素的多种方法，包括静脉注射免疫球蛋白、中和聚合物、活性疫苗以及最近的单克隆抗体（MAb），都已被探索，且取得了不同程度的成功。在本研究中，我们描述了使用高通量B细胞克隆策略从健康人类供体中分离出的首批单克隆抗体的特性。这些单克隆抗体是基于它们在体外抑制毒素A和毒素B作用的能力以及在仓鼠攻毒模型中的体内疗效而被选择的。一种有效的双抗单克隆抗体鸡尾酒被鉴定出来，然后通过添加第二种抗毒素B单克隆抗体进一步增强其效力。这种三抗单克隆抗体组合可保护动物免于死亡，并减轻与高毒力0型和III型艰难梭菌菌株攻击相关的腹泻严重程度和持续时间。这种高效的鸡尾酒由一种针对毒素A受体结合域的单克隆抗体和两种针对毒素B葡糖基转移酶域非重叠区域的单克隆抗体组成。这种单克隆抗体组合作为预防复发性CDI的非抗生素治疗方法具有巨大潜力。
