Interferon γ and antisense transforming growth factor β transgenes synergize to enhance the immunogenicity of a murine mammary carcinoma

Transforming growth factor β (TGFβ) is an immunosuppressive cytokine that contributes to the immunological escape of tumor cells. In a previous study we demonstrated that inhibition of TGFβ production by EMT6 murine mammary tumor cells expressing an antisense TGF-β transgene reduces their tumorigenicity. On the basis of this observation we hypothesized that down-regulation of TGFβ production coupled with interferon γ (IFNγ) stimulation would induce an immune response superior to that generated by either strategy alone. In this study, EMT6 tumor cells expressing antisense TGFβ were transduced with the murine IFNγ gene. Tumor cells expressing either or both transgenes grew more slowly than mock-transduced tumors. Dual-transgene-expressing tumor cells were more immunogenic than tumor cells expressing either transgene alone. Studies in mice depleted of T cell subsets indicated that CD8⁺ T cells are the primary effectors of the antitumor activity observed. These results suggest that down-regulation of immunosuppression combined with cytokine-mediated immune augmentation is a useful strategy to improve antitumor immunity. Received: 6 October 1998 / Accepted: 15 January 1999     

C群奈瑟氏脑膜炎球菌荚膜多糖-TT结合疫苗的制备及其在小鼠体内免疫原性的研究

将C群脑膜炎球菌荚膜多糖以ADH作为间隔剂与TT结合形成GCMP-TT结合疫苗,然后用此结合疫苗免疫NIH小鼠,结果显示使用GCMP免疫小鼠后仅能产生较低水平抗GCMP的IgG抗体,而用GCMP-TT免疫后小鼠血清中产生了较GCMP免疫显著增高抗GCMP的IgG抗体,并且GCMP-TT组第二次和第三次免疫后与初次免疫相比,IgG抗体水平均有显著升高(P<0.01),表明GCMP-TT结合疫苗具有免疫记忆和再次免疫加强应答效应。补体介导的血清抗体体外杀菌试验结果证明,GCMP-TT结合疫苗组免疫小鼠诱导的抗体IgG比GCMP组具有增强的体外杀菌活性。     

昆虫细胞表达的网状内皮组织增殖症病毒囊膜糖蛋白及其免疫性

利用Bac-to-BacBaculovirusExpressionSystems构建了能表达禽网状内皮组织增殖症病毒(REV)囊膜糖蛋白基因(env)的重组杆状病毒。用REV特异性单克隆抗体分别做间接免疫荧光抗体试验(IFA)和免疫转印试验,均可从感染的Sf9昆虫细胞中检出REVenv。重组杆状病毒感染的Sf9细胞裂解后制备成油乳疫苗免疫SPF鸡后,可以诱发维持45d以上的特异性抗REV抗体,并可抵抗REV病毒感染。     

5型肺炎链球菌荚膜多糖结合疫苗的不同糖蛋白比与免疫原性的关系

实验中比较了以不同糖蛋白比结合的5型肺炎链球菌荚膜多糖结合疫苗的免疫原性。以氨还原法制备的不同糖蛋白比的5型多糖结合疫苗分别经腹腔注射NIH小鼠,共免疫3次,间隔2周。末次免疫2周后采血分离血清,以间接ELISA测定血清抗体,t检验统计分析数据。结果显示,生理盐水组(R组)无免疫原性;5型荚膜多糖组(H组)免疫原性低,无免疫加强效应;结合疫苗M组、N组第1、2针有免疫加强效应,第2、3针无免疫加强效应,而F组和Q组的两针次间均有明显的免疫加强效应。说明5型肺炎链球菌荚膜多糖结合疫苗的糖与蛋白比较高时能获得较好的免疫原性。     

6A型肺炎球菌结合物分子大小对小鼠免疫原性的影响

目的 比较不同分子大小的6A型肺炎球菌(serotype 6A Streptococcus Pneumoniae )结合物和佐剂吸附在小鼠体内免疫原性的影响。方法 通过乙酸水解降低6A型荚膜多糖的相对分子质量制备成水解物,水解物经1-氰基-4-二甲胺基吡啶四氟硼酸盐(CDAP)活化并与破伤风类毒素己二酸酰肼衍生物TT AH 结合,制备成结合物。用Sepharose 4 Fast Flow 纯化结合物,并根据化学检测结果将结合物分为 K D 0.0~0.2、 K D 0.2~0.4、 K D 0.4~0.6等3个组分,每个组分分别以磷酸铝佐剂吸附,将吸附前后的各个组分按照每针次每只小鼠0.2 μg分别免疫小鼠,并采用ELISA检测结合物在小鼠体内的抗体水平。结果 3种不同相对分子质量吸附前后的结合物在小鼠体内均能产生较高水平的抗体,各组2、3针之间具有明显的加强效应。在吸附组和未吸附组中,3种不同分子大小的结合物在小鼠体内产生抗体水平无明显差异。各组分佐剂吸附后的结合物血清抗体滴度高于未吸附组,但这种差异无统计学意义( P > 0.05)。结论 结合物的分子大小对小鼠体内抗体水平的产生没有明显影响;磷酸铝佐剂吸附对于不同分子大小的结合物在小鼠体内的免疫原性有一定的增强效应,但这种增强效应差异无统计学意义。     

Genotoxicity and immunogenicity of DNA-advanced glycation end products formed by methylglyoxal and lysine in presence of Cu

The highly reactive electrophile, methylglyoxal (MG), a break down product of carbohydrates, is a major environmental mutagen having potential genotoxic effects. Previous studies have suggested the reaction of MG with free amino groups of proteins forming advanced glycation end products (AGEs). This results in the generation of free radicals which play an important role in pathophysiology of aging and diabetic complications. MG also reacts with free amino group of nucleic acids resulting in the formation of DNA–AGEs. While the formation of nucleoside AGEs has been demonstrated previously, no extensive studies have been performed to assess the genotoxicity and immunogenicity of DNA–AGEs. In this study we report both the genotoxicity and immunogenicity of AGEs formed by MG–Lys–Cu²⁺ system. Genotoxicity of the experimentally generated AGEs was confirmed by comet-assay. Spectroscopical analysis and melting temperature studies suggest structural perturbations in the DNA as a result of modification. This might be due to generation of single-stranded regions and destabilization of hydrogen bonds. Immunogenicity of native and MG–Lys–Cu²⁺-DNA was probed in female rabbits. The modified DNA was highly immunogenic eliciting high titre immunogen specific antibodies, while the unmodified form was almost non-immunogenic. The results show structural perturbations in MG–Lys–Cu²⁺-DNA generating new epitopes that render the molecule immunogenic.     

犬冠状病毒S蛋白主要抗原区基因片断的表达及免疫原性

应用Pichia pastoris酵母表达了犬冠状病毒大熊猫野毒株(CCV DXMV)S蛋白主要抗原区基因片断。用特异性引物扩增出CCV DXMV株S1基因片断,并将其克隆到pGEM-T载体中得到pTS1。用KpnI和Notl双酶切pTS1回收目的基因S1定向克隆到pPICZCαA中,构建出重组质粒pPICZCαAS1。将pPICZCαASl用SacI内切酶线性化后,电转化感受态GS115酵母细胞,用PCR法筛选阳性重组子。用1％的甲醇诱导重组酵母菌,取培养物上清进行重组蛋白的检测。结果重组酵母菌培养物上清用SDS-PAGE电泳可检测到相对分子量为106kDa大小的重组蛋白,Westem-blot证实该重组蛋白可以与CCV多克隆抗体发生特异性血清学反应。凝胶薄层扫描分析表明,3株重组酵母菌在1％甲醇诱导144h后,重组蛋白S1表达量约占培养物上清总蛋白量的6．6-8．6％左右。用重组蛋白S1免疫BALB／C小鼠3次后,小鼠血清CCV中和抗体可达1：8-1：16,表明重组S1蛋白具有一定的免疫原性。     

国产甲型肝炎灭活疫苗用于儿童免疫效果研究

为了探讨国产甲型肝炎灭活疫苗在儿童中应用的免疫效果,选择2～15岁抗-HAV阴性健康易感儿童91名作为接种对象,采用0、6程序接种国产甲型肝炎灭活疫苗250U／剂,观察免疫后的局部反应和全身反应,并于全程免疫后一个月检测抗-HAV阳转率和抗体GMT。结果91例观察对象在初免和加强免疫后均未见即时副反应,只在8～72小时内出现轻微的一过性局部和全身反应。全程免疫后一个月抗-HAV阳转率为100％。抗体GMT为14 407mIU／ml。国产甲肝灭活疫苗在儿童中应用具有良好的安全性和免疫原性,采用0、6个月程序可获得高滴度抗体。     

研究报告Ⅱ型脊灰病毒抗原表位嵌合蛋白的免疫学研究

目的：评价以轮状病毒（RV）重组VP6蛋白为载体插入Ⅱ型脊髓灰质炎病毒（PV2）VP1蛋白上的1个抗原表位构建而成的嵌合蛋白的体外免疫学性质。 方法：采用分子克隆和基因重组技术将PV2抗原表位插入到RV载体蛋白上,在大肠杆菌中表达并用SDS-PAGE确认表达产物,再通过动物免疫、Western blot、免疫荧光和病毒血清抗体中和试验分析嵌合蛋白的免疫学性质。结果：成功构建了以VP6为载体的PV2抗原表位嵌合蛋白6F/PV₂N₁,并且在E.coli系统中高效表达,嵌合蛋白免疫的豚鼠血清抗体对RV和PV2具备较好的中和活性。结论：以RV VP6为载体构建的嵌合蛋白具有较好的免疫原性,免疫豚鼠产生血清抗体可中和RV和PV2在体外细胞上的感染;进一步为研发RV/PV2嵌合疫苗提供了较好的基础。