乙型及丙型肝炎DNA疫苗联合重复接种小鼠的免疫应答

目的 :观察由编码 HBs Ag与 HCV- CE2 抗原的两种重组真核细胞表达质粒制备的 DNA疫苗重复联合接种 BAL B/c小鼠后 ,其诱生的特异性免疫应答反应。方法 :应用上述两种 NDA疫苗重复联合免疫小鼠 ,动态观察血中特异性抗体水平、特异性细胞毒性 T淋巴细胞 (CTL )体外杀伤活性 ,并进行 CTL杀伤活性活体诱生实验。结果 :两种 DNA疫苗联合重复免疫小鼠 ,能够诱生机体特异性体液免疫及细胞免疫完全应答。其小鼠荷瘤表达目的抗原的靶细胞后 ,生存率明显高于未免疫鼠 (P <0 .0 5 )。结论 :乙型及丙型肝炎联合 DNA疫苗的重复接种 ,可有效地诱生小鼠机体特异性免疫应答反应。 DNA疫苗诱生的 CTL应答可与体液免疫应答分离存在 ,可能是 DNA疫苗免疫保护的更重要方面。     

HBsAg基因修饰的树突状细胞诱导HBV转基因小鼠的免疫应答

目的探讨HBsAg重组腺病毒Ad—S转染的小鼠树突状细胞（DC）诱导HBV转基因（Tg）小鼠免疫应答的作用特点及其可能的治疗作用。方法Tg小鼠的骨髓细胞体外扩增为DC，转染Ad—S或被HBsAg蛋白冲击后，与pcDNA3．1（＋）-S质粒分别免疫Tg鼠，用流式细胞术、乳酸脱氢酶释放法、酶联免疫分析（ELISA），荧光定量聚合酶链反应（PCR）等分别检测脾脏T细胞内细胞因子和细胞毒性T淋巴细胞（CTL）活性、血清HBsAg，抗-HBs、HBVDNA及丙氨酸转氨酶（ALT）水平；病理和免疫组化分析肝脏组织学及HBsAg和HBcAg表达。结果免疫后1～2周，DC／Ad-S比DC／HBsAg和pcDNA3．1（＋）-S诱导rrc分泌干扰素7（IFN-g）和特异性CTL均显著增强，而DC／HBsAg组CTL较pcDNA3．1（＋）-S组增强（P〈0．05）；DC／HBsAg免疫后1、2、4周CTL迅速减弱，DC／Ad-S在1、2周CTL差异不明显，但至4周时明显减弱。免疫后1～4周，对Tg鼠血清HBsAg、HBVDNA及肝组织HBcAg和HBsAg表达的抑制作用最强为DC／Ad-S免疫，其次为DC／HBsAg，显著强于pcDNA3．1（＋）-S（P〈0．05或P〈0．01）。肝脏组织学、血清抗-HBs和ALT水平各组差异无统计学意义。结论Ad—S转染的DC比HBsAg冲击的DC和DNA疫苗诱导更强的Tcl和CTL应答，能较迅速抑制HBV转基因小鼠血清HBsAg、HBVDNA和肝脏HBcAg和HBsAg表达。     

新型乙型肝炎病毒核心区核酸疫苗的免疫原性研究

目的观察新型乙型肝炎病毒(HBV)核心抗原(HBcAg)核酸疫苗的免疫原性。方法应用新型人体应用载体质粒pSW389l构建HBcAg核酸疫苗(pSW3891／HBc)，对照组和实验组Balb／c小鼠分别以基因枪法免疫对照载体质粒(PSW3891)和HBcAg核酸疫苗，采用酶联免疫吸附试验检测抗HBc，乳酸脱氢酶(LDH)释放测定法检测小鼠HBcAg特异性cTL杀伤活性。结果HBcAg核酸疫苗可在体外293T细胞中高效表达，免疫小鼠后可产生高滴度抗HBc(1：97200)，免疫鼠脾细胞HBc特异性CTL杀伤活性达73．25％。结论新型HBcAg核酸疫苗在Balb／c小鼠实验中表现出良好的体液和细胞免疫原性。     

LDH法检测pcDNA-HPV16L1免疫小鼠CTL活性的研究

目的观察pcDNA—HPV16L1免疫BALB／c小鼠细胞毒性T细胞（CTL）活性变化,建立简便易行的CTL检测体系,为人乳头瘤病毒（HPV）疫苗免疫中CTL作用的研究奠定基础。方法用pcDNA—HPV16L1转染的小鼠黑色素瘤B16细胞作为靶细胞,用pcDNA—HPV16L1免疫BALB／c小鼠（观察组）并以乳酸脱氢酶（LDH）法检测其CTL活性,设空质粒组与空白组作为对照（分别肌注空质粒和葡萄糖）。结果与空质粒组和空白组比较,观察组CTL活性显著增强。结论pcDNA—HPV16L1免疫小鼠的CTL活性增强,LDH法可稳定检测。     

HBsAg真核表达质粒及其诱导的小鼠特异性免疫应答

目的 研究HBsAg真核表达质粒pCI-S和pcDNA3.1-S在真核细胞中的表达和质粒DNA的免疫效果。方法 应用基因重组技术构建HBsAg真核表达质粒pCI-S和pcDNA3.1-S；经酶切和测序鉴定无误后，用阳离子脂质体介导的方法将重组质粒转染HepG2和COS-7细胞，48h后，再ELISA的方法检测重组质粒在细胞中HBsAg的表达，同时同质粒DNA免疫小鼠，用ELISA检测免疫小鼠血清抗-HBs抗体水平；用乳酸脱氢酶释放法检测小鼠肿瘤细胞HBsAg特异性CTL反应。结果 重组质粒pCI-S和pcDNA3.1-S转染的HepG2和COS-7细胞培养上清液和sAg均为阳性。DNA免疫小鼠血清可检测到高滴度的抗-HBs抗体，免疫小鼠脾细胞可检测到校强的HBsAg特异性CTL反应。结论 HBsAg真核表达质粒pCI-S和pcDNA3.1-S可在HepG2和COS-7细胞中高效表达，DNA免疫小鼠成功地诱导出抗-HBs和HBsAg特异性CTL反应。     

胸腺素及干扰素基因表达对乙型肝炎基因疫苗的免疫增强效应

目的观察胸腺素及干扰素基因表达对乙型肝炎基因疫苗pVAX1-S2S的免疫增强效应。方法从乙型肝炎患者血清中扩增S2S基因，构建表达质粒PVAX1—S2S。从成人外周血白细胞总RNA中，逆转录聚合酶链反应扩增干扰素α基因Ⅰ，将其与S2S相连接，构建重组表达质粒PVAX1—I／S2S；将干扰素α基因Ⅰ与人工合成的胸腺素α基因T相连接，构建重组表达质粒pVAX—T／I。将上述表达质粒分组肌肉接种BALB／c小鼠：单独免疫组接种pVAX1-S2S 100μg；联合免疫组1：接种pVAX1—I／S2S 100μg；联合免疫组2：每只小鼠同时接种pVAX1—T／I与pVAX1-S2S各50μg。上述各组于2、4周后分别加强免疫1次。然后动态检测小鼠血清抗-HBS和前S2抗体。结果接种后3、5、8周，小鼠血清抗-HBS阳转率：联合免疫组1分别为12．5％、12．5％、62．5％；联合免疫组2分别为25％、50％、50％，二者总体上均优于pVAX1—S2S单独免疫组。联合免疫组2的前S2抗体水平则高于其它两组。结论胸腺素α1和(或)干扰素α8基因的表达具有分子免疫佐剂的效应，能够增强乙型肝炎基因疫苗的特异性体液免疫诱生效力。     

共表达HIV—1的gag—gp120与IL—2的pGPIL—2诱导小鼠产生细胞毒性T细胞的研究

目的：研究HIV－1CN融合基因与IL－2基因共表达基因质粒pGPIL-2诱导产生细胞毒性T细胞（CTL）。方法：脂质体介导共表达中国流行株HIV－1gag-gp120基因与IL－2基因的基因疫苗质粒pGPIL-2转染BHK－21细胞，以间接免疫荧光法鉴定其表达。取pGPIL-2免疫鼠脾细胞，检测pGPIL-2诱导的细胞毒性T细胞杀伤活性。结果：杀伤实验结果证明，经基因免疫获得的CTL效应细胞，可杀伤HIV－1CN融合基因转染的靶细胞。结果：pGPIL-2可有效地诱导CTL的产生，该研究结果为进一步设计中国流行株HIV-1基因疫苗提供了重要实验依据。     

丙型肝炎病毒包膜基因对核心基因DNA疫苗免疫应答强度的影响

目的 研究丙型肝炎病毒(HCV)包膜基因E1E2对核心基因C DNA疫苗诱生的免疫应答作用。方法 将包含HCV C或CE1E2基因片段插入真核表达载体pcDNA3中,构建重组质粒pHCV-C或pHCV-CE1E2,分别免疫Balb/c小鼠,每间隔2wk加强免疫1次,同时剪尾取血。ELISA法检测免疫小鼠血清中HCV C特异性抗体的水平。以pHCV-C转染并表达HCcAg的BLAB/c小鼠骨髓瘤Sp4/0细胞为靶细胞,采用~(51)Cr释放试验检测特异性CTL的杀伤作用。结果 两个实验组20只小鼠均产生抗HCV C特异性抗体,当效/靶细胞比例为100:1时,CTL的杀伤率均明显高于对照组(p<0.01);而pHCV-CE1E2与pHCV-C组之间,无论是抗HCV C抗体的滴度还是CTL的杀伤率均无显著性差异(p>0.05)。结论 E1E2基因的加入,并没有增加HCV C基因DNA疫苗诱导的抗HCcAg特异性抗体的滴度和CTL的杀伤作用。     

不同剂量HBV疫苗接种产生的细胞毒T淋巴细胞反应

目的研究不同剂量HBV疫苗接种产生的细胞毒T淋巴细胞(cytotoxic T lymphocytes，CTL)反应。方法100只BALB／c小鼠随机分为5组：0．65、1．25、2．5、5组小鼠腹腔分别接种0．65、1．25、2．5、5μg的HBV疫苗，其中一半小鼠2周后加强免疫1次：对照组小鼠同时按种5μg佐剂。分别在初次免疫后4周或加强免疫后2周，分离小鼠牌T淋巴细胞；体外用HBV疫苗特异性CTL表位多肽S28-39-刺激；用特异性多肽S28-39、^51Cr标记的P815细胞作为靶细胞；4小时^51Cr释放实验检测CTL反应。结果开始时随接种剂量增大CTL反应逐步增强，至1．25μg达到最大，以后又逐步减弱；加强免疫显著增强CTL反应。结论不同剂量HBV疫苗接种产生的CTL反应强弱不同，而且加强免疫能够提高CTL反应。     

恶性疟原虫复合抗原DNA疫苗诱导小鼠的细胞免疫及体液免疫应答

目的 观察用恶性疟原虫复合抗原基因HGFSP构建的DNA疫苗pc-HGFSP免疫小鼠诱导的细胞及体液免疫应答。方法 用pc-HGFSP肌注免疫C57BL／6小鼠并加强免疫2次，取小鼠脾淋巴细胞及血清测定；脾淋巴细胞增殖活性（MTT）法，NK细胞活性和CTL活性（LDH）；脾脏CD4^ 及CD8^ T细胞亚群（免疫荧光法）：血清pc-HGFSP批原特异性抗体（ELISA法）及一氧化氮（NO）含量。结果 与pcDNA3对照比较，pc-HGFSP免疫小鼠脾淋巴细胞增殖活性增高24％－37％；NK细胞活性增高38％－90％；CTL活性增高65％－153％；CD8^ T细胞亚群增加。免疫血清产生HGFSP抗原特异性IgG抗体；NO含量也有所增高。结论 恶性疟DNA疫 pc-HGFSP有一定的诱导小鼠细胞免疫和体液免疫应答的作用。     

乙型、丙型肝炎DNA疫苗单次联合接种后小鼠的免疫应答

目的：观察由编码ＨＢｓＡｇ与ＨＣＶ－ＣＥ２抗原的两种重组真核细胞表达质粒制备的ＤＮＡ疫苗联合接种ＢＡＬＢ／ｃ小鼠后,其施生行异性免疫应答的规律和相互影响。方法：应用上述２种ＤＮＡ疫苗单次联合免疫小鼠,动态观察血中特生抗体水平;并完成稳定转染,表达相应抗原的ＳＰ２／０骨髓瘤细胞的建株,采用ＣＴＬ杀伤活性体内诱生实验的方法建立观察ＤＮＡ疫苗免疫保护与治疗泊动物模型。结果：两种ＤＮＡ疫苗单次联合免疫小鼠     

HBV主蛋白、HCV-CE2真核细胞表达质粒在小鼠肌细胞内的共表达

目的:比较真核细胞表达质粒混合与单独接种对各自表达的影响。方法:在小鼠肌组织内单独或混合接种编码HBV主蛋白、HCV-CE2抗原的两种真核细胞表达质粒,取不同时间肌组织进行免疫组化检测,进行比较分析。结果:混合接种后相应蛋白均能够表达,但表达强度及持续时间明显不及单独免疫。结论:两种真核表达质粒可以在小鼠肌细胞内表达,但其程度较弱,可能与相对较弱的体液免疫应答有关。     

乙型肝炎病毒复制调控元件对HBV DNA疫苗诱导的免疫应答

目的研究乙型肝炎病毒（HBV）复制调控元件增强子Ⅰ（ENHⅠ）及前S2（Pre-S2）抗原基因对HBV DNA疫苗诱导的免疫应答的影响。方法采用常规聚合酶链反应（PCR）从HBV adr亚型全基因DNA序列中分别扩增HBsAg、PreS2-HBsAg、HBsAg-ENHI和PreS2-HBsAg-ENHⅠ基因片段，重组到VR1012载体中，构建4种HBV DNA疫苗，转染HepG2细胞并免疫Balb／C小鼠。通过细胞免疫化学、酶联免疫分析（ELISA）、酶联免疫斑点试验（ELISPOT）等方法检测其在HepG2细胞内的表达及小鼠的体液及细胞免疫应答。结果转染的HepG2细胞表达相应的目的蛋白．ENHⅠ及Pre-S2抗原基因均可增强HBV DNA疫苗转染HepG2细胞表达HBsAg；免疫接种小鼠后第2周产生抗-HBs及HBsAg特异性细胞毒T淋巴细胞（CTL），Pre—S2抗原基因可增强HBV DNA疫苗免疫Balb／C小鼠诱导的抗-HBs及HBsAg特异性CTL的产生，ENHⅠ基因对免疫应答无影响。结论ENHI及Pre—s2抗原基因均可增强HBVDNA疫苗转染HepG2细胞表达HBsAg．Pre-S2抗原基因可增强HBVDNA疫苗免疫Balb／C小鼠引起的免疫应答。     

Cloning of HBsAg-encoded genes in different vectors and their expression in eukaryotic cells

AIM: To compare the efficiency of different plasmids as DNA vectors by cloning three HBsAg-encoded genes into two eukaryotic expression vectors, pRc/CMV and pSG5UTPL/Flag, and to express HBsAg S, MS, and LS proteins in SP2/0 cells, and to establish monoclone SP2/0 cell strains that are capable of expressing S or S2S proteins stably.METHODS: Segments of S, preS2-S, preS1-preS2-S genes of Hepatitis B virus were amplified by routine PCR and preS1-S fragment was amplified by Over-Lap Extension PCR. The amplified segments were cleaved with restricted endonuclease Hind Ⅲ/Not I followed by ligation with pRc/CMV, or BamHI/EcoR I followed by ligation with pSG5UTPL/Flag. After the plasmid vectors were cleaved with the correspond enzymes, the amplified segments were inserted into pRc/CMV or pSG5UTPL/Flag plasmid vectors with T4 DNA ligase. KOZAK sequence was added before the initial ATG code of each fragment using specific primer. The inserted segments in the recombinant plasmids were sequenced after subcloning. BALB/c mice myeloma cells(SP2/0 cell line) were transfected with the recombinant plasmids. The expressions of the different recombinants were compared by Western-blot, using a monoclonal anti-HBs antibody as the primary antibody and peroxidase-labeled multi-linker as the secondary. Stable SP2/0-pRc/CMV-S or SP2/0- pRc/CMV-MS clones were established through clone screening with G418.RESULTS: Fragments with anticipated size were harvested after PCR. After recombination and screening, the sequences of the inserted segments in the recombinants were confirmed to be S, preS2S, preS1-preS2S and preS1S encoding genes,determined by sequencing. The results of Western-blot hybridization were positive for the anticipated proteins.Among them, pRc/CMV-S or pRc/CMV-MS demonstrated the highest expressing their respective antigen.CONCLUSION: Eight recombinant plasmids expressing S,M, L or preSiS proteins are obtained. For hepatitis surface antigen expression in eukaryotic cells, the vector pRc/CMV is superior to pSG5UTPL/Flag, and pRc/CMV-S and pRc/CMV-MS are the most efficient in the pRc/CMV clones. SP2/0 cells stably expressing HBsAg are established, and may be used as target cells for evaluating the CTL activity of a DNA vaccine in vitro.     

乙型肝炎病毒基因疫苗诱导小鼠产生免疫应答的效应

目的 :构建编码乙型肝炎病毒 (HBV)表面蛋白S的重组质粒pCR 3 .1 S,将之直接肌肉注射balb/c小鼠 ,观察小鼠HBV特异的免疫应答。方法 :以ELISA法检测小鼠血清 ,3H TdR掺入法测定淋巴细胞增殖 ,51 Cr 4h释放法检测淋巴细胞杀伤功能。结果 :与空载体对照组相比较 ,基因疫苗诱发小鼠产生良好的抗HBs反应及HBV特异的细胞免疫应答 (P <0 .0 5)。结论 :基因疫苗pCR 3 .1 S可诱导balb/c小鼠产生全面的免疫应答     

HBV微环DNA重组质粒的构建及初步药效学实验

目的 构建HBV的治疗性微环质粒并进行体内外实验研究. 方法 采用聚合酶链式反应扩增HBV包膜蛋白preS2.S抗原基因和hIL-2-IFNγ融合基因,将2个基因分别克隆于ZY781载体,得到亲本质粒preS2.S/ZY781和hIL-2-IFNγ/ZY781,测序正确后,用阿拉伯糖诱导生成微环质粒pMCS2.S和pMCIIF. 转染微环质粒于COS-7细胞株,用酶联免疫吸附法定量法检测24、48、72 h时目的蛋白的表达情况.双质粒联合在体电脉冲注射BALB/c小鼠,4周后处死小鼠,检测特异性的体液和细胞免疫应答. 结果 微环质粒pMCS2.S和pMCIIF转染COS-7细胞后,目的蛋白HBsAg、白细胞介素-2、干扰素 γ在不同时间均有表达,在48 h达峰值,分别为(60.3±7.8)、(17.7±1.9)、(10.3±0.9) ng/ml. 微环质粒pMCS2.S能诱导小鼠产生HBsAb的抗体保护,佐剂pMCIIF可显著增强其免疫效果,在低剂量5μg/只就能诱导较强特异性细胞和体液免疫. 结论 成功构建了HBV微环质粒pMCS2.S及其佐剂微环质粒pMCIIF,其有较好的体内外活性.     

Contribution of C3d-P28 repeats to enhancement of immune responses against HBV-preS2／S induced by gene immunization

AIM: To investigate whether P28 derived from C3d can enhance the immune response to HBV-preS2/S induced by directly injection of naked plasmids containing variable repeats of P28 and HBV-preS2/S in fusion form.METHODS: One to four copies of C3d-P28 coding gene,amplified by PCR and modified by restriction endonuclease sdigestion, were subcloned into a eukaryotic expression vector pVAON33 to construct pVAON33-P28, pVAON33-P28.2, pVAON33-P28.3 and pVAON33-P28.4 (pVAON33-P28.[1-4]). HBV-preS2/S coding sequence was then introduced into the pVAON33-P28.[1-4] and identified by both PCR and DNA sequencing. BALB/c mice were primed by intramuscular gene immunization with 100 μg different recombinant plasmids on day 0 and were boosted by subcutaneous inoculation with HBsAg protein (1 μg) 12 wk post-priming. The levels and avidity of specific IgG in sera collected at the indicated times from each group were determined by ELISA and NaSCN-displacement ELISA,respectively.RESULTS: HBsAg specific antibody response was elicited in groups primed with plasmids pVAON33-S2/S-P28.[1-4] and pVAON33-S2/S. However, the response against HBsAg in the groups primed with pVAON33-S2/S-P28.[1-4] was significantly higher than that in pVAON33-S2/S group, the highest level of the specific antibody response was observed in the groups primed with pVAON33-S2/S-P28.4 (P＜0.01).After secondary immunization with specific antigen, the acceleration of antibody levels was significantly higher and faster in the mice primed with DNA expressing preS2/S-P28 fusions than that with DNA expressing preS2/S only (P＜0.05).Interestingly, mice primed with DNA expressing preS2/S-P28.4 fusions maintained the highest levels of anti-HBs antibodies in all animals. The avidity assay showed that the avidity index (AI) collected at 18 wk from mice primed with pVAON33-S2/S-P28.3 and pVAON33-S2/S-P28.4 were significantly higher than that from preS2/S-DNA vaccinated mice (P＜0.01).CONCLUSION: Different repeats of C3d-P28 can enhance both humoral immune response and avidity maturation of specific antibodies induced by gene immunization, in which four copies of C3d-P28 may be necessary to achieve the most modest antibody response.     

Establishment of mice model with human viral hepatitis B

AIM:To establish a mice model of hepatitis B by using HBV-transgenic mice, and to transfer HBV-specific cytotoxic T lymphoo/tes (CTL) induced from syngeneic BALB/c mice immunized by a eukaryotic expression vector containing HBV complete genome DNA.METHODS: HBV DNA was obtained from digested pBR3222HBV and ligated with the vector pcDNA3. Recombinant pcDNA3-HBV was identified by restriction endonuclease assay and transfected into human hepatoma cell line HepG2 with lipofectin. ELISA was used to detect the expression of HBsAg in culture supernatant, and RT-PCR to determine the existence of HBV PreS1 mRNA.BALB/c mice were immunized with pcDNA3-HBV or pcDNA3 by intramuscular injection.ELISA was used to detect the expression of HBsAb in serum. MTT assay was used to measure non-specific or specific proliferation ability and specific killing activity of spleen lymphocytes. Lymphocytes from immunized mice were transferred into HBV-transgenic mice (2.5&#215;10^7 per mouse).Forty-eight hours later,the level of serum protein and transaminase was detected with biochemical method,liver and kidney were sectioned and stained by HE to observe the pathological changes.RESULTS: By enzyme digestion with Eco RI, Xho I and Hind Ⅲ,the recombinant pcDNA3-HBV was verified to contain a single copy of HBV genome,which was inserted in the positive direction.HepG2 cells transfected with the recombinant could stably express PreS1 mRNA and HBsAg.After immunized by pcDNA3-HBV for 4 weeks,HBsAb was detected in the serum of BALB/c mice. The potential of spleen lymphoo/tes for both non-specific and specific proliferation and the specific killing activity against target cells were enhanced. The transgenic mice in model group had no significant changes in the level of serum protein but had an obvious increase of ALT and AST. The liver had obvious pathological changes, while the kidney had no evident damage.CONCLUSION:A eukaryotic expression vector pcDNA3-HBV containing HBV complete genome is constructed successfully. HepG2 cells transfected with the recombinant can express PreS1 mRNA and HBsAg stably.Specific cellular immune response can be induced in mice immunized by pcDNA3-HBV.A mice model of acute hepatitis with HBV has been established.