Immunity to FMDV following combined DNA and inactivated virus antigen.

DNA 和灭活病毒抗原结合后对 FMDV 具有免疫力。

• 批准号: BB/E011403/1
• 负责人: Paul Barnett
• 金额: $ 68.82万
• 依托单位: The Pirbright Institute
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FE011403%2F1
• 关键词: Immunity; FMDV; following; combined; DNA

Despite being clinically protected from FMD vaccinated ruminants replicate virus in the upper respiratory tract and become persistently infected carriers with consequential impact on control measures. However, evidence supports a relationship between vaccine potency, magnitude of response, and incidence of virus replication in the oropharynx. It has been conclusively shown that higher antigen payload vaccines are capable of inhibiting local virus replication, persistence and the carrier state. The effector mechanisms behind this are unclear. Antibody mediated protection is a possibility since increasing the antigen payload promotes a more rapid and greater systemic response. However, the magnitude of this inevitably reaches a ceiling where additional payload shows little beneficial affect, and there are many observations where persistence occurs in the face of high antibody titre. Local antibody may influence persistence, but there is little evidence to support this, even with increased payload, being promoted or even eliciting, such a response. It is therefore extremely likely that other factors play a major role, like cell mediated and innate responses. High potency FMD vaccines are capable of eliciting durable systemic cytokine responses in pigs, such as IL-6, IL-8 and IL-12 , which is indicative of monocytic cell activity. This is an important part of an innate defence that contributes to early protection of the host and absence of persistence. This has led to a similar focus in the ruminant. IFN gamma is a potent inhibitor of FMD virus in persistently infected bovine epithelial cells in-vitro and alpha and beta interferons also inhibit FMDV replication. IFN gamma can be increasingly stimulated systemically in FMD vaccinated sheep, by augmented payload, resulting in no persistence following challenge. Thus, a vaccination regime which consistently enhances a diverse repertoire of cellular and humoral responses, over and above those afforded by traditional FMD vaccines, should have direct beneficial attributes to the inhibition of persistence and the carrier state. This could have major benefit both endemically and in emergency use. The proposal will use DNA vaccine, to examine these hypotheses. An FMD DNA vaccine encoding the 'empty capsid' along with the non-structural proteins 2A, 3C and 3D has been used with an adjuvant plasmid expressing granulocyte macrophage colony stimulating factor (GM-CSF), which induced extremely strong humoral and cellular responses and conferred protection in pigs and sheep. Further optimisation amplified the specific and important neutralising antibody response further, and resulted in cellular immune responses, detected as T cell proliferation. This was more dramatically enhanced when FMD inactivated homologous virus antigen and 3D recombinant protein was used as a final boost and the production of IFN-?, IFN-a, IL-2, 4, 6, 8, and 10 confirmed both innate and specific immune responses are activated. Indeed DNA vaccines are now considered to be an excellent tool for priming an extensive immune repertoire as part of a prime boost strategy and there are many examples where this has been successful in hosts such as cattle, goats and horses. Use of this strategy against bovine herpesvirus-1 led to enhanced and protective cellular and humoral immunity and a significant reduction in virus shedding. Recently, a two dose regime of DNA prime- protein boost or vice versa, 14 day apart, was sufficient in stimulating enhanced immunity against FMDV in cattle. There is therefore potential for shorter intervals between prime and boost and in examining simultaneous vaccination of DNA with the protein antigen for emergency purpose. The ability of DNA vaccination regimes to augment immune responses will be exploited to provide a more comprehensive understanding of those important to protection which can be utilized or better promoted by newer vaccines to prevent persistence and the carrier state.

尽管接种了口蹄疫疫苗的反胃动物在临床上可以免受口蹄疫的侵袭，但它会在上呼吸道复制病毒，并成为持续感染的携带者，从而影响控制措施。然而，有证据支持疫苗效力、应答大小和口咽病毒复制发生率之间的关系。结果表明，较高的抗原有效载荷疫苗能够抑制局部病毒的复制、持久性和携带者状态。这背后的效应机制尚不清楚。抗体介导的保护是可能的，因为增加抗原有效载荷会促进更快和更大的全身反应。然而，这种影响的大小不可避免地达到了一个天花板，在那里，额外的有效载荷几乎没有什么有益的影响，而且有许多观察到，在面对高抗体滴度时会出现持久性。局部抗体可能会影响持久性，但几乎没有证据支持这一点，即使有效载荷增加，被促进，甚至引发这样的反应。因此，极有可能是其他因素发挥了主要作用，如细胞介导的反应和先天反应。高效口蹄疫疫苗能够在猪体内诱导持久的全身性细胞因子反应，如IL-6、IL-8和IL-12，它们是单核细胞活性的标志。这是一种先天防御的重要组成部分，有助于及早保护宿主和缺乏毅力。这导致了反刍动物中类似的焦点。在体外持续感染的牛上皮细胞中，干扰素是口蹄疫病毒的有效抑制剂，α和β干扰素也能抑制口蹄疫病毒的复制。在口蹄疫免疫的绵羊中，通过增加有效载荷，干扰素-γ可以被系统地刺激，导致在挑战后不再持续。因此，在传统口蹄疫疫苗提供的基础上，持续增强各种细胞和体液反应的疫苗接种制度，应该直接有益于抑制持久性和携带者状态。这可能在地方性和紧急情况下都有重大好处。该提案将使用DNA疫苗来检验这些假说。口蹄疫DNA疫苗编码空衣壳以及非结构蛋白2A、3C和3D，与表达粒细胞巨噬细胞集落刺激因子(GM-CSF)的佐剂质粒一起使用，在猪和羊身上诱导了极强的体液和细胞反应，并提供了保护作用。进一步的优化进一步放大了特异性和重要的中和抗体反应，并导致了细胞免疫反应，检测到T细胞的增殖。当口蹄疫灭活的同源病毒抗原和3D重组蛋白作为最终加强剂，并且产生的干扰素-α、干扰素-α、白介素2、4、6、8和10证实先天免疫反应和特异性免疫反应均被激活时，这种增强作用更为显著。事实上，DNA疫苗现在被认为是作为主要促进战略的一部分，启动广泛的免疫曲目的一个很好的工具，而且有许多在牛、山羊和马等宿主身上取得成功的例子。使用这种针对牛疱疹病毒-1的策略可以增强和保护细胞和体液免疫，并显著减少病毒的脱落。最近，间隔14天的两次DNA主蛋白增强或反之亦然，足以刺激牛对口蹄疫病毒的增强免疫力。因此，有可能缩短启动和增强之间的时间间隔，并在紧急情况下检查同时接种DNA和蛋白质抗原的情况。将利用DNA疫苗接种制度增强免疫反应的能力，以更全面地了解那些对保护至关重要的因素，这些因素可以被较新的疫苗利用或更好地促进，以防止持久性和携带者状态。

项目成果

Identification of a novel cell culture adaptation site on the capsid of foot-and-mouth disease virus.

• DOI: 10.1099/jgv.0.000222
• 发表时间: 2015-09
• 期刊: The Journal of general virology
• 作者: Chamberlain K;Fowler VL;Barnett PV;Gold S;Wadsworth J;Knowles NJ;Jackson T
• 通讯作者: Jackson T