Jiang Lianlian, Fantoni Giovanna, Couzens Laura, Gao Jin, Plant Ewan, Ye Zhiping, Eichelberger Maryna C, Wan Hongquan
Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.
Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
J Virol. 2015 Oct 14;90(1):117-28. doi: 10.1128/JVI.01756-15. Print 2016 Jan 1.
Antibodies against the neuraminidase (NA) of influenza virus correlate with resistance against disease, but the effectiveness of antibodies against different NA epitopes has not been compared. In the present study, we evaluated the in vitro and in vivo efficacies of four monoclonal antibodies (MAbs): HF5 and CD6, which are specific to two different epitopes in the NA of 2009 pandemic H1N1 (pH1N1) virus, and 4E9 and 1H5, which are specific to a conserved epitope in the NA of both H1N1 and H5N1 viruses. In the in vitro assays, HF5 and CD6 inhibited virus spread and growth more effectively than 4E9 and 1H5, with HF5 being the most effective inhibitor. When administered prophylactically at 5 mg/kg of body weight, HF5 and CD6 protected ~90 to 100% of DBA/2 mice against lethal wild-type pH1N1 virus challenge; however, at a lower dose (1 mg/kg), HF5 protected ~90% of mice, whereas CD6 protected only 25% of mice. 4E9 and 1H5 were less effective than HF5 and CD6, as indicated by the partial protection achieved even at doses as high as 15 mg/kg. When administered therapeutically, HF5 protected a greater proportion of mice against lethal pH1N1 challenge than CD6. However, HF5 quickly selected pH1N1 virus escape mutants in both prophylactic and therapeutic treatments, while CD6 did not. Our findings confirm the important role of NA-specific antibodies in immunity to influenza virus and provide insight into the properties of NA antibodies that may serve as good candidates for therapeutics against influenza.
Neuraminidase (NA) is one of the major surface proteins of influenza virus, serving as an important target for antivirals and therapeutic antibodies. The impact of NA-specific antibodies on NA activity and virus replication is likely to depend on where the antibody binds. Using in vitro assays and the mouse model, we compared the inhibitory/protective efficacy of four mouse monoclonal antibodies (MAbs) that bind to different sites within the 2009 pandemic H1N1 (pH1N1) virus NA. The ability of each MAb to protect mice against lethal pH1N1 infection corresponded to its ability to inhibit NA activity in vitro; however, the MAb that was the most effective inhibitor of NA activity selected pH1N1 escape variants in vivo. One of the tested MAbs, which binds to a conserved region in the NA of pH1N1 virus, inhibited NA activity but did not result in escape variants, highlighting its suitability for development as a therapeutic agent.
针对流感病毒神经氨酸酶（NA）的抗体与抗病能力相关，但针对不同NA表位的抗体有效性尚未进行比较。在本研究中，我们评估了四种单克隆抗体（MAb）的体外和体内效力：HF5和CD6，它们分别针对2009年大流行H1N1（pH1N1）病毒NA中的两个不同表位；4E9和1H5，它们针对H1N1和H5N1病毒NA中的一个保守表位。在体外试验中，HF5和CD6比4E9和1H5更有效地抑制病毒传播和生长，其中HF5是最有效的抑制剂。当以5mg/kg体重进行预防性给药时，HF5和CD6可保护约90%至100%的DBA/2小鼠免受致死性野生型pH1N1病毒攻击；然而，在较低剂量（1mg/kg）时，HF5可保护约90%的小鼠，而CD6仅保护25%的小鼠。4E9和1H5的效果不如HF5和CD6，即使在高达15mg/kg的剂量下也只能提供部分保护。当进行治疗性给药时，HF5比CD6能保护更多比例的小鼠免受致死性pH1N1攻击。然而，HF5在预防性和治疗性治疗中都能快速筛选出pH1N1病毒逃逸突变体，而CD6则不会。我们的研究结果证实了NA特异性抗体在流感病毒免疫中的重要作用，并深入了解了可能成为抗流感治疗良好候选药物的NA抗体特性。
神经氨酸酶（NA）是流感病毒的主要表面蛋白之一，是抗病毒药物和治疗性抗体的重要靶点。NA特异性抗体对NA活性和病毒复制的影响可能取决于抗体的结合位置。我们使用体外试验和小鼠模型，比较了四种与2009年大流行H1N1（pH1N1）病毒NA内不同位点结合的小鼠单克隆抗体（MAb）的抑制/保护效力。每种MAb保护小鼠免受致死性pH1N1感染的能力与其在体外抑制NA活性的能力相对应；然而，NA活性最有效的抑制剂MAb在体内筛选出了pH1N1逃逸变体。其中一种测试的MAb与pH1N1病毒NA中的一个保守区域结合，可抑制NA活性但不会产生逃逸变体，突出了其作为治疗药物开发的适用性。
