酵母疫苗能诱导免疫系统

美国 Ceres制药公司的基因工程酵母能诱导针对疾病的细胞免疫应答 ,这些重组酵母载体代表了抗击传染病和癌症的强有力的疫苗策略。　　采用酵母诱导免疫应答的原因在于其能激活树突状细胞 ,而树突状细胞能刺激介导免疫应答的细胞毒性 T细胞 ( CTL) ,而且基因工程的酵母能表达多种抗原。当树突状细胞与抗原接触后能内在化抗原 ,并且诱导 T细胞攻击它们。 Ceres公司先前报道的研究是以基因工程酿酒酵母表达肿瘤抗原或 1型人类免疫缺陷病毒( HIV- 1 ) gp1 6 0包膜蛋白 ( Hivax) ,结果显示 ,基因工程酵母疫苗能在小鼠中诱导免疫应答。　　…     

副粘病毒融合肽与麻疹病毒核蛋白的CTL表位连结物能掺入ISCOM并可诱导CTL应答

抗原掺入的免疫刺激复合物(ISCOM)可诱导机体产生高水平体液免疫和细胞免疫.本实验将亲水性麻疹病毒(MV)核蛋白(NP)的细胞毒性T淋巴细胞(CTL)表位(NP29)与副粘病毒融合肽(F1)嵌合制成IS-COM,用以诱导CTL的溶细胞效应.首先合成代表WVNP281-290氨基酸序列的NP29和含位于NP29CTL表位羧基端融合蛋白序列的NP29-F1,进而制备IS-COM.用表达MVNP的腺病毒载体RAd 68腹腔注射BALB/c小鼠,5～6天后取脾,分离淋巴细胞.用NP29和NP29-F1体外刺激后,与靶细胞P815共同培育,证实NP29-F1与NP29体外诱导的溶靶细胞效应相同.将乳化于弗氏完全佐剂的NP29免疫BALB/c     

肌肉免疫DC-EBV-LMP2诱导免疫应答的研究

目的探讨肌肉免疫DC-EBV-LMP2诱导的免疫效果。方法从BALB/C小鼠分离骨髓细胞,诱导培养获得小鼠DC,以100 MOI的rAd-LMP2感染获得DC-EBV-LMP2,继续培养48h,诱导DC-EBV-LMP2成熟。用免疫酶法确定LMP2在DC中表达。0,2,4周,以2×105个DC-EBV-LMP2/只免疫BALB/C小鼠,于第5,8周分别LMP2特异性水平和T细胞亚群的变化。结果结果显示,肌肉免疫DC-EBV-LMP2可诱导BALB/C鼠LMP2特异性免疫应答,且第5周强于第8周。CD8+T/CD3+T细胞亚群的比值在第5周高于对照组,而第8周低于对照组。结论 DC-EBV-LMP2肌肉免疫BALB/C鼠可诱导LMP2特异性CTL。     

OK432优化的内皮细胞疫苗抗小鼠乳腺癌作用研究

目的探讨OK432优化的人脐静脉内皮细胞(HUVECs)疫苗对小鼠EAC乳腺癌的生长抑制作用。方法体外培养HUVECs,与佐剂OK432混合,制备HUVECs-OK432疫苗,以小鼠EAC乳腺癌皮下移植瘤模型考查HUVECsOK432疫苗的抗肿瘤效应,并通过ELISA、脾细胞增殖及细胞毒性T淋巴细胞(CTL)杀伤实验检测疫苗免疫后体液及细胞免疫应答水平。结果在预防性免疫中,HUVECsOK432疫苗可以明显抑制EAC乳腺癌生长;HUVECs-OK432疫苗诱导小鼠产生了高滴度的特异性HUVEC抗体;HUVECs-OK432疫苗能有效刺激免疫小鼠脾淋巴细胞的增殖;HUVECs-OK432组小鼠脾细胞诱导产生了明显的靶向HUVEC细胞的CTL杀伤作用。结论 HUVECs-OK432疫苗可以有效诱导机体产生靶向HUVEC的特异性体液及细胞免疫应答,从而有效抑制了小鼠EAC乳腺癌的生长。     

禽流感H5N1灭活疫苗与不同纳米化佐剂联合免疫研究

目的 观察禽流感H5N1灭活疫苗加不同佐剂以及纳米化佐剂免疫小鼠后产生的免疫应答的差异,同时观察免疫对异亚型病毒攻击后的保护情况.   方法 用H5N1灭活疫苗分别联合佐剂氢氧化铝、纳米化氢氧化铝、MF59和纳米化MF59通过腹腔注射方式免疫雌性BALB/c小鼠,同时分别以H5N1灭活疫苗免疫小鼠以及PBS腹腔注射处理小鼠作对照.采用ELISA方法分别对各组小鼠免疫后血清特异性IgG及其亚类IgG1、IgG2a水平进行检测,以PR8病毒鼻腔攻击后观察小鼠体重变化情况和生存率.采用t检验作组间比较.    结果 与PBS处理组相比,无论以何种方式免疫H5N1疫苗,免疫后特异性IgG及其亚类水平均明显升高(t=7.4004,P<0.01),以联合MF59后诱导的特异性抗体水平最高.其中疫苗单独免疫组和联合M59免疫组IgG2a水平升高明显,联合纳米化MF59免疫小鼠后IgG2a水平有所下降,IgG1水平有所升高;联合铝佐剂组以IgG1升高为主.攻毒后各组小鼠体重均出现下降,但疫苗单独免疫小鼠以及疫苗与佐剂联合免疫小鼠于攻毒后期体重恢复接近正常或者正常.PBS处理组小鼠攻毒后全部死亡,佐剂联合免疫组小鼠存活率100%,而疫苗单独免疫小鼠存活率为70%.   结论 H5N1疫苗无论是单独免疫或是联合不同佐剂免疫均可诱导较高水平的特异性抗体产生,有非常好的免疫原性.H5N1灭活疫苗诱导的抗体亚类以IgG2a为主,MF59以及纳米化MF59也以诱导IgG2a亚类为主,但纳米化MF59可诱导更均衡的免疫应答.联合铝佐剂或纳米化铝佐剂免疫小鼠后均可诱导以IgG1亚类为主的抗体应答.联合两种佐剂均可对小鼠产生很好的异亚型保护.     

姬松茸多糖佐剂诱导OVA抗原特异性Th1免疫应答的机制研究

目的： 探讨姬松茸多糖（ABP-AW1）作为佐剂对卵白蛋白（OVA）免疫鼠细胞免疫反应的调节作用。方法： 以OVA为抗原,ABP-AW1为佐剂经皮下两点免疫小鼠,于0,15 d各免疫一次,第28 d,碳粒廓清实验检测Mφ吞噬能力;ELISA法检测血清中免疫球蛋白及其抗体亚类水平,RT-PCR法分析Th1细胞因子IL-2、IFN-γ mRNA表达水平。结果： ABP-AW1可以增强OVA免疫小鼠抗原递呈细胞的吞噬功能;血清中抗体亚类IgG2b明显高于对照组（P<0.05）;脾细胞分泌Th1细胞因子IL-2、IFN-γ mRNA水平也均高于其他各组（P<0.05）。结论： ABP-AW1可作为OVA抗原的细胞免疫佐剂成分,调节OVA抗原Th1型反应的免疫应答。     

用霍乱毒素作佐剂的经皮免疫法

经皮接种 (TCI)是一种新颖的免疫接种策略 ,它通过在皮肤表面外敷抗原和佐剂 ,导致血清和粘膜分泌液中抗原 /佐剂特异性Ig G的产生。作者以具有不同 H- 2主要组织相容性复合体 (MHC)基因的 C5 7BL/ 6、BALB/ c和 C3H品系小鼠为对象 ,以霍乱毒素 (CT)为抗原或作为白喉类毒素 (DT)与鸡蛋溶菌酶 (HEL)的佐剂 ,于小鼠背部和耳部TCI,测定抗体水平和 T细胞增殖应答 ,并且分离 CD4 T细胞。　　为评估 CT作为抗原 TCI诱导免疫应答的情况 ,小鼠于 0周接受初免 ,并于 4和 8周后接受加强免疫。结果显示 ,C5 7BL/ 6组的抗 CT Ig G滴度…     

以链球菌制剂OK432为佐剂的内皮细胞疫苗体内抗小鼠肝癌转移的作用（英文）

目的评估OK432作为佐剂制备的内皮细胞疫苗体内抗肿瘤转移的作用。方法以OK432为佐剂,体外混合人脐静脉内皮细胞(HUVEC),制备HUVEC-OK432疫苗。雄性健康BALB/c小鼠尾静脉注射肝癌细胞5×105建立肝癌肺转移模型,皮下注射HUVEC-OK432疫苗,分别在预防性和治疗性免疫中评价HUVEC-OK432疫苗抗肿瘤转移活性;皮内注射5×104肝癌细胞建立皮内肿瘤血管模型,皮下注射HUVEC-OK432疫苗,评价HUVEC-OK432疫苗抑制肿瘤新生血管的活性;采用ELISA的方法测定小鼠免疫血清中HUVEC抗体水平;采用细胞毒T淋巴细胞(CTL)实验考察HUVEC-OK432疫苗诱导的细胞免疫应答水平。结果肺转移模型结果显示,在预防性和治疗性免疫中,HUVEC-OK432免疫均能有效降低小鼠肺上的肿瘤转移灶数目(P<0.01);皮内肿瘤血管模型的结果显示,HUVEC-OK432免疫能显著降低肿瘤新生血管的数目(116.5±20.6 vs 45.0±8.9,P<0.01);ELISA测定抗体的结果显示,HUVEC-OK432初次免疫后1周小鼠即产生了高滴度的特异性HUVEC抗体,随免疫次数的增加抗体水平不断升高,且该抗体在体外可以显著抑制HUVEC细胞的增殖;CTL实验的结果表明,HUVEC-OK432免疫组淋巴细胞体外有明显的特异性杀伤HUVEC的作用。结论 HUVEC-OK432疫苗免疫可以有效诱导小鼠产生靶向内皮细胞的免疫应答,从而有效抑制小鼠肝癌细胞转移。     

金黄色葡萄球菌锰转运蛋白C的原核表达及小鼠免疫评价

目的在原核系统中表达金黄色葡萄球菌(金葡菌)锰转运蛋白C(manganese transporter C, MntC), 对其免疫原性进行分析, 为筛选金葡菌疫苗候选抗原提供参考。方法合成MntC基因, 克隆至pET-22b(+)载体, 构建重组表达质粒pET-22b-mntc, 转化至E.coli BL21(DE3), 异丙基硫代-β-D-半乳糖苷诱导表达, 镍柱纯化。将纯化产物进行免疫印迹法鉴定, 再采用分子排阻高效液相色谱法进行纯度分析。将铝佐剂吸附重组MntC免疫BALB/c小鼠作为实验组, 将铝佐剂免疫BALB/c小鼠作为对照组。经ELISA检测小鼠血清中特异性IgG抗体水平、中性粒细胞呼吸爆发试验检测小鼠血清特异性抗体功能, 再用细胞因子试剂盒检测小鼠脾淋巴细胞培养上清液中抗原特异性细胞因子水平。免疫后小鼠用致死剂量金葡菌49521菌株攻毒, 观察小鼠存活情况。结果经双酶切及测序鉴定, 重组表达质粒pET-22b-mntc构建正确。重组MntC相对分子质量约为34 000, 以可溶性形式表达, 可与抗His单克隆抗体特异性结合, 纯度大于95%。将铝佐剂吸附MntC免疫小鼠...     

对禽流感H5N1灭活疫苗与不同免疫方式诱导的免疫应答及异亚型保护研究

目的  观察禽流感H5N1灭活疫苗以不同方式免疫后诱导的免疫应答及抗异亚型病毒攻击的保护作用.  方法 将H5N1灭活疫苗分别通过腹腔和滴鼻方式免疫BALB/c小鼠,同时以PBS作为对照;免疫后分别以PR8和H9N2病毒攻击,观察小鼠的体重变化和生存情况.采用ELISA对各组小鼠攻毒后不同时间的血清IgG及其亚类水平进行动态检测;流式细胞仪检测脾淋巴细胞亚群情况.采用t检验对各组数据进行比较.   结果 PR8和H9N2病毒攻击后,各组小鼠体重均下降,但疫苗组小鼠于后期体重恢复正常,存活率分别为100%和70%-80%,而PBS组小鼠则全部死亡.无论以何种方式免疫,疫苗组的特异性IgG及其亚类水平均明显升高,其中以IgG2a水平升高更为明显.攻毒后疫苗组小鼠脾CD4+与CD8+T淋巴细胞比值出现下降(t=6.8017,P<0.01);滴鼻免疫组与腹腔免疫组相比降低更明显(t=3.9701,P<0.05).    结论   H5N1疫苗免疫原性良好,可诱导较高水平的特异性抗体产生,诱导的抗体亚类以IgG2a为主.两种免疫方式均可对小鼠提供很好的异亚型保护,而滴鼻免疫能够诱导更强的CD8+T细胞应答.     

Cytotoxic T-lymphocyte and NK responses in mice treated prenatally with chlordane

It has been reported previously that BALB/c mice, treated in utero with chlordane, showed increased survival to influenza A/PR/8/34 [H1N1] (influenza) virus as young adults. To determine the possible role of cell-mediated immunity (CMI) on this effect, cytotoxic T-lymphocyte (CTL) and natural killer (NK) cell activities were assessed on chlordane-exposed offspring at 100 and 200 days post partum. The CTL response of these offspring showed no significant change from that obtained from their sex- and age-matched control counterparts exposed prenatally to the vehicle. NK responses of chlordane-exposed female offspring were significantly higher at 100 days of age but not at 200 days of age. Although male offspring that were exposed to chlordane prenatally showed no difference in NK cell activity at 100 days of age, NK cell activity was significantly less in chlordane-treated animals than controls at 200 days of age. Thus, prenatal treatment of mice with chlordane had varying effects on the NK cell activity of adult offspring, depending on the sex and age of the animal. It is concluded that the previously reported increase in survival to influenza is due to a resolution of the infection by normal CTL and NK cell activities coupled with a decrease in delayed-type hypersensitivity (DTH)-mediated pathology.     

Preliminary evidence of modulating Th1 cytokine after allergen challenge

We wanted to determine whether a paradigm switch in Th1/Th2 phenotypes in splenic lymphocytes could be induced in BALB/c mice after ultraviolet-B (UVB) irradiation and exposure to pollen. Results showed that UVB irradiation increased IL-1 but decreased IL-12 in vivo, and caused significant cell destruction of macrophages in vitro. We then gave mice cedar pollen intranasally, UVB irradiation (6kJ/cm²), and then splenic lymphocyte functions were examined. Results revealed that: 1) the level of IFN-gamma of splenic lymphocytes from UVB-irradiated mice was significantly decreased, especially in pollen-exposed mice; 2) UVB irradiation did not augment IL-4 levels; 3) IgE levels from UVB-irradiated mice did not increase. UVB irradiation (6kJ/cm²) did not induce Th2 response but suppressed Th1 cytokine, suggesting that Th1 could be more susceptible to UVB irradiation than Th2.     

含前S表位重组HBsAg联合重组HBcAg的免疫原性研究

 目的  研究含前S表位重组HBsAg（SS1S2）与重组HBcAg（C）联合免疫BALB/c小鼠的体液和细胞免疫应答。 方法   用纯化的SS1S2与C分别配制含或不含Al(OH)3佐剂（Al）的疫苗。采用简单随机法将雌性BALB/c小鼠分为5组：阴性对照（NC）、SS1S2、SS1S2+C、SS1S2+Al、SS1S2+C+Al,各组分别于0和21 d进行腹腔免疫,对照组注射磷酸盐缓冲液。初免及加强后1周各取一半小鼠采血,采用ELISA法测定抗-HBs、抗-前S1、抗-前S2和抗-HBc滴度;常规制备脾淋巴细胞,用酶联免疫斑点法测定分泌IFN-γ的T细胞频数。采用t检验对各组结果进行比较。 结果   联合HBcAg的疫苗组均产生了较高水平的抗-HBs、抗-前S1、抗-前S2和抗-HBc。初免后1周,SS1S2+C组的抗-HBs阳转比例（1/5）高于SS1S2组（0/5）、SS1S2+Al+C组（4/5）高于SS1S2+Al组（3/5）;SS1S2+C组的抗-前S1阳转比例（3/5）高于SS1S2组（0/5）;HBcAg对抗-前S2的产生无影响。加强免疫后,各疫苗组的抗体滴度均升高,联合HBcAg的疫苗组各抗体滴度明显高于SS1S2疫苗组。各组疫苗免疫后均可诱导细胞免疫应答,初免后SS1S2+C和SS1S2+Al+C组分泌IFN-γ的T细胞频数显著超过SS1S2和S1S2+Al组（t值分别为2.926、2.974,P值均<0.05）;加强免疫后,各组均有加强效应,SS1S2+C组的T细胞频数明显超过SS1S2组（t=4.604,P=0.010）。 结论   SS1S2联合HBcAg可在BALB/c小鼠中诱导较强的免疫应答,HBcAg可增强SS1S2诱导的体液及细胞免疫应答。     

维生素E对P.y17XL感染BALB/c小鼠早期Th1应答的免疫调节作用

目的探讨维生素E对致死型约氏疟原虫感染BALB/c小鼠Th1免疫应答的调节效应。方法将6～8周、雌性BALB/c小鼠经腹腔接种1×106P.yl7XL寄生的红细胞,并随机分为实验组与感染对照组,实验组于感染前10d口服给予VE预处理。流式细胞术检测感染后第0、3、5天脾Tregs的百分含量;ELISA检测脾细胞培养上清中的IFN-γ、IL-10的水平;Griess反应检测脾细胞培养上清中一氧化氮的含量。结果与正常感染组比较:补充VE组Tregs增殖明显增多;补充VE组IFN-γ和NO分泌减少,而IL-10的分泌水平增加。结论在P.yl7XL感染早期,VE预处理可显著抑制Th1免疫应答效应,从而进一步加剧P.y17XL感染BALB/c的死亡进程。     

Effect of total secondary carotenoids extracts from Chlorococcum sp on Helicobacter pylori-infected BALB/c mice

Helicobacter pylori is a human pathogen associated with type B gastritis, peptic ulcer disease and gastric cancer. A high intake of carotenoids has been suggested to prevent development of gastric malignancies. Microalgae Chlorococcum sp. could accumulate secondary carotenoids under stress conditions. The aim of the present study was to investigate whether dietary cell extract of Chlorococcum sp. could affect the bacterial load of H. pylori infected BALB/c mice and whether it could induce modulation of cytokine production. BALB/c mice were infected with H. pylori three times at 2-day intervals. Two weeks later, they were orally fed with cell extract of Chlorococcum sp. for the following 2 weeks. Animals were killed at the end of the experiments. Stomachs were removed and paraffin sections were stained for histology examination. Splenocytes were obtained and cultured in vitro with H. pylori sonicate to evaluate induction of interferon gamma (IFN-gamma) and interleukin 4 (IL-4) secretion. Mice treated with carotenoids-rich algal meal showed significantly reduced bacterial load and gastric inflammation. These changes were associated with a shift of the T-lymphocytes response from a predominant T helper type 1 (Th1) response dominated by IFN-gamma to a Th1/Th2 response with IFN-gamma and IL-4.     

Cytokine fingerprinting of chemical allergens: species comparisons and statistical analyses

The cellular and molecular mechanisms that result in the induction of chemical respiratory sensitization are unclear, although there is evidence for the development of T helper (Th) 2 type responses and, in some cases, the production of IgE. We have compared cytokine secretion patterns stimulated by topical exposure of BALB/c strain mice or Brown Norway (BN) strain rats to the reference respiratory allergen trimellitic anhydride (TMA), or to the reference contact allergen 2,4-dinitrochlorobenzene (DNCB). Under conditions where TMA and DNCB provoke similar levels of immune activation [increases in lymph node cell (LNC) cellularity and proliferation] divergent cytokine expression patterns are elicited. TMA-activated LNC isolated from BALB/c mice or BN rats elaborated high levels of the Th2-type cytokines interleukin (IL)-10 and IL-13, but relatively little of the Th1-type cytokines IL-12 or interferon γ. For LNC derived from both species there was a requirement for restimulation in vitro with the mitogen concanavalin A for IL-4 production. Generally, DNCB-stimulated LNC displayed the converse type 1 cytokine phenotype. The cytokine secretion profiles of LNC isolated from BN rats were considerably more variable than those observed for LNC from BALB/c mice. Statistically significant differences (P<0.01) between DNCB- and TMA-activated LNC were recorded for all cytokines in BALB/c strain mice. For the BN rat, differences reached statistical significance (P<0.01) only for the expression of IL-4 and IL-13. These data demonstrate that the intrinsic ability of DNCB and TMA to promote preferential Th1- and Th2-type responses, respectively, is species-independent and provide further evidence that chemical respiratory allergens are associated with polarized Th2-type responses. For the prospective assessment of chemical respiratory allergens as a function of induced cytokine secretion profiles, however, these data suggest that the use of the BALB/c strain mouse will provide the more robust method.     

Effect of Low Doses of Low-Let Radiation on the Innate Anti-Tumor Reactions in Radioresistant and Radiosensitive Mice

BALB/c and C57BL/6 mice differ in their Th1/Th2 lymphocyte and M1/M2 macrophage phenotypes, radiosensitivity, and post-irradiation tumor incidence. In this study we evaluated the effects of repeated low-level exposures to X-rays on the development of artificial tumor colonies in the lungs of animals from the two strains and cytotoxic activities of natural killer (NK) cells and macrophages obtained from these mice. After ten daily irradiations of BALB/c or C57BL/6 mice with 0.01, 0.02, and 0.1 Gy X-rays NK cell-enriched splenocytes collected from the animals demonstrated significant and comparable up-regulation of their anti-tumor cytotoxic function. Likewise, peritoneal macrophages collected from the two irradiated strains of mice exhibited the similarly stimulated cytotoxicities against susceptible tumor cells and produced significantly more nitric oxide. These results were accompanied by the significantly reduced numbers of the neoplastic colonies induced in the lungs by intravenous injection of syngeneic tumor cells. The obtained results indicate that ten low-level irradiations with X-rays stimulate the generally similar anti-tumor reactions in BALB/c and C57BL/6 mice.     

Effect of Th2 cytokine antagonist treatments on chemical-induced allergic response in mice

To understand better the cellular and molecular mechanisms of chemical-induced occupational asthma, we examined the effects of the Th2 cytokine antagonists interferon-gamma (IFN-gamma), interleukin (IL)-12 and anti-IL-4 on the balance of the Th1/Th2 response induced by trimellitic anhydride (TMA) and phthalic anhydride (PA). Eight- to ten-week-old BALB/c mice were assigned to be exposed to either TMA or PA plus one of these Th2 cytokine antagonists. Both TMA (25% and 12.5% for sensitization and challenge, respectively) and PA (12.5% and 6.25% for sensitization and challenge, respectively) induced a Th2 response marked by an increasing production of IL-4 and IL-10 in the supernatants of ex vivo spleen cells cultured with concanavalin A and also of serum total IgE. Co-administration of IL-12 and antiIL-4 deviated these PA- or TMA-induced Th2 responses, as judged by an increasing serum total IgG2a production (up to 14-fold), associated with a slight decrease of IL-4 in three out of four experiments and of IL-10 in all four experiments. Co-administration of IFN-gamma, however, had only one weak effect. These findings suggest that the chemical-induced Th2-biased response may be diverted during an induction period by exogenous administration of the Th2 cytokine antagonists, particularly IL-12 and the anti-IL-4 antibody. These results would significantly enhance our understanding of the Th1/Th2 response induced by chemicals.     

Modulation of immune response induced by co-administration of DNA vaccine encoding HBV surface antigen and HCV envelope antigen in BALB/c mice

Plasmid DNA vaccines encoding the hepatitis B virus (HBV) surface and hepatitis C virus (HCV) envelope antigens, respectively, were constructed, and attempt were made to find the possibility of a divalent vaccine against HBV and HCV. The expression of each plasmid in Cos-1 cells was confirmed using immunocytochemistry. To measure the induced immune response by these plasmids in vivo, female BALB/c mice were immunized intramuscularly with 100 microg of either both or just one of the plasmids. Anti-HBV and HCV-specific antibodies and related cytokines were evaluated to investigate the generation of both humoral and cellular immune responses. As a result, specific anti-HBV and anti-HCV serum antibodies from mice immunized with these plasmids were observed using immunoblot. The levels of IL-2 and RANTES showing a Th1 immune response were significantly increased, but there was no change in the level of IL-4 (Th2 immune response) in any of the immunized groups. Compared with each plasmid DNA vaccine, the combined vaccine elicited similar immune responses in both humoral and cell-mediated immunities. These results suggest that the combined DNA vaccine can induce not only comparable immunity experimentally without antigenic interference, but also humoral and Th1 dominant cellular immune responses. Therefore, they could serve as candidates for a simultaneous bivalent vaccine against HBV and HCV infections.