Bright Rick A, Carter Donald M, Daniluk Shannon, Toapanta Franklin R, Ahmad Attiya, Gavrilov Victor, Massare Mike, Pushko Peter, Mytle Nutan, Rowe Thomas, Smith Gale, Ross Ted M
Novavax, Inc., Rockville, MD 20850, USA.
Vaccine. 2007 May 10;25(19):3871-8. doi: 10.1016/j.vaccine.2007.01.106. Epub 2007 Feb 15.
Influenza virus is a highly infectious respiratory pathogen that results in severe morbidity and mortality. The current licensed trivalent vaccine formulations in the U.S. are made from virus grown in allantoic fluid from infected hen eggs that is then chemically inactivated and split into subunit components. These vaccines elicit antibodies, primarily to the viral hemagglutinin (HA), which are efficacious in healthy adults, but are limited in protecting high risk individuals, such as the elderly and immunocompromised. To address the need for improved influenza vaccines and the limitations of egg-based manufacturing, we have engineered an influenza virus-like particle (VLP) as a new generation of non-egg or non-mammalian cell culture-based candidate vaccine against influenza infection. VLPs, based on the A/Fujian/411/2002 (H3N2) isolate, were purified from the supernatants of Spodoptera frugiperda Sf9 insect cells following infection of baculovirus vectors encoding an expression cassette comprised of only three influenza virus structural proteins, hemagglutinin (HA), neuraminidase (NA), and matrix (M1). Mice or ferrets were vaccinated intramuscularly with VLPs in a dose sparing experiment, based on HA concentration (3 microg-24 ng), and the immune responses were compared to responses elicited in animals vaccinated with recombinant HA (rHA) or inactivated whole influenza virions (WIV). All vaccinated animals had high titer anti-HA antibodies regardless of the vaccine immunogen and animals vaccinated with the highest doses of VLPs (3 microg and 600 ng) also had antibodies against NA. Purified rHA elicited primarily IgG1 antibodies, which is indicative of a T helper (Th) type 2 response, whereas mice vaccinated with the VLPs or WIV were associated with a dominant Th1 immune response (IgG2a and IgG2b). Interestingly, VLPs elicited antibodies that recognized a broader panel of antigenically distinct H3N2 viral isolates compared to rHA or WIV in a hemagglutination-inhibition (HAI) assay.
流感病毒是一种极具传染性的呼吸道病原体，可导致严重的发病和死亡。美国目前获批的三价疫苗制剂是由感染鸡胚尿囊液中培养的病毒制成的，然后进行化学灭活并裂解成亚单位成分。这些疫苗主要诱导针对病毒血凝素（HA）的抗体，对健康成年人有效，但在保护高危人群（如老年人和免疫功能低下者）方面存在局限性。为满足改进流感疫苗的需求并克服基于鸡蛋生产的局限性，我们构建了一种流感病毒样颗粒（VLP），作为新一代基于非鸡蛋或非哺乳动物细胞培养的抗流感感染候选疫苗。基于A/福建/411/2002（H3N2）毒株的VLP，在感染编码仅由三种流感病毒结构蛋白（血凝素（HA）、神经氨酸酶（NA）和基质蛋白（M1））的表达盒的杆状病毒载体后，从草地贪夜蛾Sf9昆虫细胞的上清液中纯化得到。在剂量节省实验中，根据HA浓度（3微克 - 24纳克）对小鼠或雪貂进行肌肉注射VLP，并将免疫反应与用重组HA（rHA）或灭活全流感病毒粒子（WIV）免疫的动物所引发的反应进行比较。无论疫苗免疫原如何，所有接种疫苗的动物都具有高滴度的抗HA抗体，并且接种最高剂量VLP（3微克和600纳克）的动物也具有抗NA抗体。纯化的rHA主要诱导IgG1抗体，这表明是2型辅助性T细胞（Th）反应，而接种VLP或WIV的小鼠则与占主导地位的Th1免疫反应（IgG2a和IgG2b）相关。有趣的是，在血凝抑制（HAI）试验中，与rHA或WIV相比，VLP诱导的抗体能够识别更广泛的抗原性不同的H3N2病毒分离株。
