A candidate H1N1 pandemic influenza vaccine elicits protective immunity in mice.

In 2009 a new pandemic disease appeared and spread globally. The recent emergence of the pandemic influenza virus H1N1 first isolated in Mexico and USA raised concerns about vaccine availability. We here report our development of an adenovirus-based influenza H1N1 vaccine tested for immunogenicity and efficacy to confer protection in animal model. We generated two adenovirus(Ad5)-based influenza vaccine candidates encoding the wildtype or a codon-optimized hemagglutinin antigen (HA) from the recently emerged swine influenza isolate A/California/04/2009 (H1N1)pdm. After verification of antigen expression, immunogenicity of the vaccine candidates were tested in a mouse model using dose escalations for subcutaneous immunization. Sera of immunized animals were tested in microneutalization and hemagglutination inhibition assays for the presence of HA-specific antibodies. HA-specific T-cells were measured in IFNγ Elispot assays. The efficiency of the influenza vaccine candidates were evaluated in a challenge model by measuring viral titer in lung and nasal turbinate 3 days after inoculation of a homologous H1N1 virus. A single immunization resulted in robust cellular and humoral immune response. Remarkably, the intensity of the immune response was substantially enhanced with codon-optimized antigen, indicating the benefit of manipulating the genetic code of HA antigens in the context of recombinant influenza vaccine design. These results highlight the value of advanced technologies in vaccine development and deployment in response to infections with pandemic potential. Our study emphasizes the potential of an adenoviral-based influenza vaccine platform with the benefits of speed of manufacture and efficacy of a single dose immunization.

2009年，一种新的大流行性疾病出现并在全球传播。最近在墨西哥和美国首次分离出的甲型H1N1流感大流行病毒的出现，引发了人们对疫苗可获得性的担忧。在此我们报道我们研发的一种基于腺病毒的甲型H1N1流感疫苗，该疫苗在动物模型中进行了免疫原性和功效测试以确定其保护作用。 我们制备了两种基于腺病毒（Ad5）的流感疫苗候选物，它们编码来自最近出现的猪流感分离株A/California/04/2009（H1N1）pdm的野生型或密码子优化的血凝素抗原（HA）。在验证抗原表达之后，在小鼠模型中使用递增剂量进行皮下免疫来测试疫苗候选物的免疫原性。通过微量中和试验和血凝抑制试验检测免疫动物的血清中是否存在HA特异性抗体。通过干扰素γ酶联免疫斑点试验检测HA特异性T细胞。在攻毒模型中，通过在接种同源H1N1病毒3天后测量肺和鼻甲中的病毒滴度来评估流感疫苗候选物的有效性。 单次免疫产生了强烈的细胞免疫和体液免疫反应。值得注意的是，密码子优化的抗原显著增强了免疫反应的强度，这表明在重组流感疫苗设计中对HA抗原的遗传密码进行操作是有益的。这些结果凸显了先进技术在疫苗研发和应用以应对具有大流行潜力的感染方面的价值。我们的研究强调了基于腺病毒的流感疫苗平台的潜力，其具有生产速度快以及单剂量免疫有效的优势。