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EASL 2018 SAT-407 A novel chimpanzee adenoviral vectored HBV vaccine, encoding multiple HBV antigens with a shark invariant chain adjuvant, for use in HBV immunotherapy S.K. Chinnakannan1, T. Cargill1, T. Donnison1, A. Ansari1, M. Maini2, T. Evans3, E. Barnes1. 1Peter Medawar Building, Nuffield Department of Medicine, Oxford, United Kingdom; 2University College of London, Division of Infection and Immunity UCL, London, United Kingdom; 3Vaccitech, Oxford, United Kingdom Email: [email protected]
Background and Aims:
Chronic hepatitis B virus (HBV) infects 257 million people globally. Current therapies suppress HBV but rebound occurs on cessation of therapy; novel therapeutic strategies are urgently required. To develop a potent therapeutic HBV vaccine that will induce T-cells to all major HBV antigens and generate anti-HBs antibodies, using Chimpanzee adenoviral vectors and shark class-II invariant (sIi) chain as a genetic adjuvant.
Method:
We designed two HBV immunogens SIi-HBV-CPmutS and HBV-CPmutS; encoding precore (PreC), core, non-functional polymerase (Pmut), PreS1, PreS2 and surface antigens (Figure 1a). The large envelope protein of HBV (composed of PreS1, PreS2 and surface proteins) was generated separately using furin 2A (F2A) peptide cleavage protein. A 26 amino-acid sequence, derived from shark invariant chain (sIi),was inserted at the 5′ end of the SIi-HBV-CPmutS immunogen. The immunogens were encoded in chimpanzee adenoviral vector (ChAdOx2) and tested in naïve mice given i.m. HBV-specific T-cell responses were assessed using IFN-ϒ ELISpot and intracellular cytokine (ICCS) assays.
Results:
Vaccination generated very high magnitude HBV specific Tcell responses to all HBV antigens (Figure 1b). The mean magnitude of total HBV-specific T-cell responses in inbred BALB/c and outbred CD1 mice were 3858 and 3821 spot forming units [SFU]/106 splenocytes (shown on the left side of Figure 1) and 4514 and 2979 SFU/106 intrahepatic lymphocytes (shown on the right side of Figure 1b) respectively. ICCS showed that HBV specific CD8+ T cells were polyfunctional producing both IFN-ϒ and TNF-α. The inclusion of shark invariant chain (data shown in blue coloured bars in Figure 1b) significantly enhances the T-cell magnitude for both splenocytes (3821 mean total SFU/106 with sIi vs. 386 mean total SFU/106 without sIi, p < 0.0001) and intrahepatic lymphocytes (2979 mean total SFU/106 with sIi vs. 461 mean total SFU/106 without SIi, p = 0.0002). Importantly, T cells to the non-HBV SIi peptides were not generated.
Conclusion:
We have generated a highly potent HBV vaccine that induces T-cells against all major HBV proteins, using chimpanzee adenoviral vector and class-II invariant chain technologies. These pre-clinical studies pave the way for new studies of HBV immunotherapy in humans with chronic HBV infection.
EASL 2018 SAT-407用于HBV免疫治疗的新型黑猩猩腺病毒载体HBV疫苗，编码具有鲨鱼恒定链佐剂的多种HBV抗原。 Chinnakannan1，T.Cargill1，T.Donnison1，A.Sanari1，M.Maini2，T.Evans3，E.Barnes1。英国牛津纳菲尔德医学系1Peter Medawar大楼; 2英国伦敦大学伦敦分校感染与免疫学系; 3Vaccitech，英国牛津邮箱：[email protected]
背景和目标：
慢性乙型肝炎病毒（HBV）感染全球2.57亿人。目前的治疗方法抑制HBV，但在停止治疗时发生反弹;迫切需要新的治疗策略。要开发一种强效的治疗性HBV疫苗，将使用黑猩猩腺病毒载体和鲨鱼II类不变（sIi）链作为遗传佐剂，将T细胞诱导至所有主要HBV抗原并产生抗-HBs抗体。
方法：
我们设计了两种HBV免疫原SIi-HBV-CPmutS和HBV-CPmutS;编码核酸前体（PreC），核心，非功能性聚合酶（Pmut），PreS1，PreS2和表面抗原（图1a）。使用弗林蛋白酶2A（F2A）肽切割蛋白质分别产生HBV的大包膜蛋白（由Pre S1，Pre S2和表面蛋白组成）。在S1i-HBV-CPmutS免疫原的5'末端插入来自鲨鱼不变链（sIi）的26个氨基酸序列。免疫原编码在黑猩猩腺病毒载体（ChAdOx2）中并在给予i.m.的幼稚小鼠中测试。使用IFN-γELISpot和细胞内细胞因子（ICCS）测定来评估HBV特异性T细胞应答。
结果：
疫苗接种对所有HBV抗原产生了非常高的HBV特异性T细胞应答（图1b）。近交BALB / c和远交CD1小鼠的总HBV特异性T细胞应答的平均值分别为3858和3821点形成单位[SFU] / 106脾细胞（显示在图1的左侧）和4514和2979 SFU / 106个肝内淋巴细胞（显示在图1b的右侧）。 ICCS显示HBV特异性CD8 + T细胞是多功能的，产生IFN-Y和TNF-α。包含鲨鱼不变链（图1b中以蓝色条显示的数据）显着增强了两种脾细胞的T细胞强度（3821平均总SFU / 106与sIi与386平均总SFU / 106无sIi，p <0.0001 ）和肝内淋巴细胞（2979平均总SFU / 106，sIi与461平均总SFU / 106无SIi，p = 0.0002）。重要的是，不产生针对非HBV S1i肽的T细胞。
结论：
我们利用黑猩猩腺病毒载体和II类不变链技术，产生了一种高效的乙肝疫苗，可诱导T细胞对抗所有主要的HBV蛋白。这些临床前研究为慢性HBV感染人群进行HBV免疫治疗的新研究铺平了道路。 |
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发表于 2018-4-16 21:54
