AIM To develop a safe and effective DNA vaccine for inducing humoral and cellular immunological responses against hepatitis B virus surface antigen (HBsAg).METHODS BALB/c mice were inoculated with NV-HB/s, a recombinant plasmid that had been inserted S gene of hepatitis B virus genome and could express HBsAg in eukaryotes. HBsAg expression was measured by ABC immunohistochemical assay, generation of anti-HBs by ELISA and cytotoxic T lymphocyte (CTL), by MTT method, existence of vaccine DNA by Southern blot hybridization and activation of oncogene C-myc by in situ hybridization.RESULTS With NV-HB/s vaccination by intramuscular injection, anti-HBs was initially positive 2 weeks after inoculation while all mice tested were HBsAg positive in the muscles. The titers and seroconversion rate of anti-HBs were steadily increasing as time went on and were dose-dependent. All the mice inoculated with 100 μg NV-HB/ s were anti-HBs positive one month after inoculation, the titer was 1:1024 or more. The humoral immune response was similar induced by either intramuscular or intradermal injection. CTL activities were much stronger (45.26%) in NV-HB/s DNA immunized mice as compared with those (only 6%) in plasmaderived HBsAg vaccine immunized mice. Two months after inoculation, all muscle samples were positive by Southern-blot hybridization for NV-HB/s DNA detection, but decreased to 25%and all were undetectable by in situ hybridization after 6 months. No oncogene Cmyc activation was found in the muscle of inoculation site.CONCLUSION NV-HB/s could generate humoral and cellular immunological responses against HBsAg that had been safely expressed in situ by NV-HB/s vaccination.

To enhance anti-amyloid-beta (Aβ) antibody generation and induce a Th2 immune response, we constructed a new DNA vaccine p(Aβ3-10 )10-C3d-p28.3 encoding ten repeats of Aβ3-10 and three copies of C3d-p28 as a molecular adjuvant. In this study, we administered this adjuvant intramus-cularly to female C57BL/6J mice at 8-10 weeks of age. Enzyme linked immunosorbent assay was used to detect the titer of serum anti-Aβ antibody, isotypes, and cytokines in splenic T cel s. A 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was used to detect the prolifera-tion rate of splenic T cel s. Brain sections from a 12-month-old APP/PS1 transgenic mouse were used for detecting the binding capacities of anti-Aβ antibodies to Aβ plaques. The p(Aβ3-10)10-C3d-p28.3 vaccine induced high titers of anti-amyloid-βantibodies, which bound to Aβplaques in APP/PS1 transgenic mouse brain tissue, demonstrating that the vaccine is effective against plaques in a mouse model of Alzheimer’s disease. Moreover, the vaccine elicited a pre-dominantly IgG1 humoral response and low levels of interferon-γ in ex vivo cultured splenocytes, indicating that the vaccine could shift the cel ular immune response towards a Th2 phenotype. This indicated that the vaccine did not elicit a detrimental immune response and had a favorable safety profile. Our results indicate that the p(Aβ3-10)10-C3d-p28.3 vaccine is a promising immunothera-peutic option for Aβvaccination in Alzheimer’s disease.

Objective. To evaluate the Plasmodium falciparum CTL epitope vaccines in HLA class I allele specific human cell lines that have high frequency among Chinese population. Methods. Synthesized oligonucleotides encoding for P.f. CTL epitope genes, constructed eukaryotic expression plasmids, transfected the minigenes into HLA class I allele specific human cell lines and identified endogenous expressing of the minigenes by RT-PCR and HLA stabilization assay. Results. Two mini-genes encoding Plasmodium falciparum CTL epitopes were designed and cloned, respectively, into an eukaryotic expressing vector to form TR26 which was restricted to HLA-B51, SH6 which was restricted to HLA-A2.1, and TS, which had the two aforementioned mini-genes fused in tandem. All of these CTL epitope genes were transfected and endogenously expressed in respective cell lines containing appropriate HLA molecules. The obviously increased expressions of HLA class I molecules were detected in the transfected cell lines. It was demonstrated that the two discrete Plasmodium falciparum epitope genes were effectively processed and presented, and the close proximity of the two epitope genes in one chain as in mini-gene TS did not interfere with the processing and presenting of each epitope gene in corresponding cell line. Conclusion. A successful expression and presentation of multiple CTL epitope mini-gene in MHC class I allele specific human cell lines were demonstrated by an in vitro assay, which could be corresponding to the vaccination of CTL vaccines in people with different MHC I molecules. This work also suggested the possibility of constructing a multiple CTL epitope plasmodium falciparum DNA vaccine that could cover most of Chinese population.

乙型肝炎病毒DNA疫苗的研究现状

乙型肝炎(乙肝)病毒(HBV)DNA疫苗是指通过克隆HBV抗原基因,并将其插入真核表达载体构建而成的重组DNA分子.通过皮下、肌肉注射或颗粒轰击技术将重组DNA分子导入体内,使目的基因在体内表达,从而诱导机体产生针对此种抗原的体液免疫和细胞免疫.

表位疫苗:疫苗研制新策略

人类通过接种疫苗已控制了许多重大感染性疾病并且消灭了天花,这是有史以来,人类征服疾病为辉煌的成绩.传统疫苗是将病原体灭活或减毒而制成的,但存在生物危害性和遗传变异致使原疫苗效力丧失等问题.表位疫苗(epitope vaccine)是用抗原表位制备的疫苗,包括合成肽疫苗(synthetic peptide vaccine)、重组表位疫苗(recombinant epitope-based vaccine)及表位核酸疫苗(epitope DNA vaccine,minigenes/epigenes),是目前研制感染性疾病和恶性肿瘤疫苗的方向.

日本血吸虫DNA疫苗的构建

血吸虫病是一种严重危害人类及家畜的寄生虫病,据WHO估计患病人数达2亿,每年死亡人数约20万.血吸虫疫苗虽然种类较多,但由于保护性免疫力较差,至今未能实际应用.DNA疫苗是新近发展起来的一种新型疫苗,由于它自身的特点使其在抗寄生虫感染中意义重大,与其它疫苗相比,DNA疫苗简单方便易于组建多价疫苗[1].

恶性疟BCG多价疫苗及DNA疫苗的实验研制

本项目在恶性疟疫苗候选分子裂殖子表面蛋白-2(MSA2)及环子孢子蛋白(CSP)的分子生物学特征和免疫原性研究的基础上,构建了CSP、MSA2之DNA疫苗,同时率先在国内外构建CSP、MSA2之重组BCG活疫苗,并对疫苗的免疫保护机制、免疫应答及疫苗安全性进行了研究.

DNA疫苗的发展现状及前景

DNA疫苗(DNA vaccine),又称"裸"DNA疫苗(naked DNA vaccine)、基因疫苗(genetic vaccine),是将编码特异性抗原多肽或蛋白的基因构建在表达性DNA质粒中,经一定途径进入机体内,被宿主细胞摄取后转录和翻译表达出目的抗原多肽或蛋白,诱导机体产生针对目的蛋白的特异性的免疫应答从而起到免疫保护作用[1].它既具有亚单位疫苗或灭活疫苗的安全性,同时具有如减毒疫苗或重组疫苗等,可诱导持久而特异的细胞及体液免疫应答的特点,同时还具有广谱、简便、廉价等特点,因此是未来新型疫苗的重点发展方向之一,在病毒性疾病以及肿瘤等的防治中有广阔的应用前景[2].