Carignan Damien, Thérien Ariane, Rioux Gervais, Paquet Geneviève, Gagné Marie-Ève Laliberté, Bolduc Marilène, Savard Pierre, Leclerc Denis
Department of Microbiology, Infectiology and Immunology, Infectious Disease Research Center, Laval University, 2705 boul. Laurier, Quebec City, PQ, Canada G1V 4G2.
Department of Microbiology, Infectiology and Immunology, Infectious Disease Research Center, Laval University, 2705 boul. Laurier, Quebec City, PQ, Canada G1V 4G2.
Vaccine. 2015 Dec 16;33(51):7245-7253. doi: 10.1016/j.vaccine.2015.10.123. Epub 2015 Nov 6.
The emergence of highly virulent influenza strains and the risks of pandemics as well as the limited efficiency of the current seasonal vaccines are important public health concerns. There is a major need for new influenza vaccines that would be broadly cross-protective. The ectodomain of matrix protein 2 (M2e) is highly conserved amongst different influenza strains and could be used as a broad spectrum antigen. To overcome its low immunogenicity we have fused a short peptide epitope derived from the human consensus sequence of M2e (amino acids 6-14, EVETPIRNE) to the N-terminus of papaya mosaic virus coat protein. The fusion harboring coat proteins were assembled around a single stranded RNA into virus-like particles (PapMV-sM2e). The resulting PapMV-sM2e rod-shaped particle was stable and indistinguishable from regular PapMV particles. A single intramuscular immunization with PapMV-sM2e was sufficient to mount appreciable levels of CD4 dependent M2e specific total IgG and IgG2a antibody in mice sera. PapMV-sM2e proved to be self-adjuvanting since the addition of PapMV as an exogenous adjuvant did not result in significantly improved antibody titers. In addition, we confirmed the adjuvant property of PapMV-sM2e using the trivalent inactivated flu vaccine as antigen and demonstrated that the newly engineered nanoparticles areas efficacious as an adjuvant than the original PapMV nanoparticles. Upon infection with a sub-lethal dose of influenza, PapMV-sM2e vaccinated animals were completely protected from virus induced morbidity and mortality. Mice immunized with decreasing amounts of PapMV-sM2e and challenged with a more stringent dose of influenza virus displayed dose-dependent levels of protection. Seventy percent of the mice immunized once with the highest dose of PapMV-sM2e survived the challenged. The survival of the mice correlated mainly with the levels of anti-M2e IgG2a antibodies obtained before the infection. These results demonstrate that PapMV-sM2e can be an important component of a broadly cross-reactive influenza vaccine.
高致病性流感毒株的出现、大流行的风险以及当前季节性疫苗的有限效力是重要的公共卫生问题。迫切需要新型的具有广泛交叉保护作用的流感疫苗。基质蛋白2（M2e）的胞外域在不同流感毒株中高度保守，可作为广谱抗原。为克服其免疫原性低的问题，我们将一段源自M2e人共有序列（氨基酸6 - 14，EVETPIRNE）的短肽表位融合到木瓜花叶病毒外壳蛋白的N端。携带外壳蛋白的融合体围绕单链RNA组装成病毒样颗粒（PapMV - sM2e）。所得的PapMV - sM2e杆状颗粒稳定，与常规PapMV颗粒无异。用PapMV - sM2e进行单次肌肉注射足以在小鼠血清中产生可观水平的CD4依赖性M2e特异性总IgG和IgG2a抗体。PapMV - sM2e被证明具有自我佐剂作用，因为添加PapMV作为外源性佐剂并未显著提高抗体滴度。此外，我们以三价灭活流感疫苗作为抗原证实了PapMV - sM2e的佐剂特性，并证明新工程化的纳米颗粒作为佐剂比原始PapMV纳米颗粒更有效。在用亚致死剂量的流感病毒感染后，接种PapMV - sM2e的动物完全免受病毒诱导的发病和死亡。用递减剂量的PapMV - sM2e免疫并用更严格剂量的流感病毒攻击的小鼠表现出剂量依赖性的保护水平。用最高剂量的PapMV - sM2e免疫一次的小鼠中有70%在攻击后存活。小鼠的存活主要与感染前获得的抗M2e IgG2a抗体水平相关。这些结果表明PapMV - sM2e可以成为广泛交叉反应性流感疫苗的重要组成部分。
