口蹄疫病毒复合多表位DNA疫苗的设计及构建

目的构建口蹄疫病毒(FMDV)复合多表位基因工程疫苗表达盒OAAT及其DNA疫苗。方法以O型、A型FMDV结构蛋白VP1全基因和Asia1型FMDV两个基因拓扑型的结构蛋白VP1基因上的5个抗原表位基因作为主要免疫原基因,非结构蛋白3ABC上的2个Th2细胞表位基因及结构蛋白VP4上的1个Th2细胞表位基因作为辅助基因,构建表达盒。将构建好的表达盒OAAT克隆到真核表达载体pVAX1 PCMV启动子下游,构建三价口蹄疫核酸疫苗pVAX1-OAAT,并用Western blot和IFA方法检测目的蛋白在HeLa细胞中的表达。结果通过InsightⅡ软件同源建模和DNAStar5.0软件分析表明,所构建的FMDV复合多表位基因工程疫苗表达盒OAAT理论上符合设计要求,且在真核细胞获得了正确表达。结论已成功设计FMDV复合多表位基因工程疫苗表达盒OAAT,并构建了三价口蹄疫核酸疫苗pVAX1-OAAT。     

弓形虫排泄-分泌抗原鼻内免疫小鼠诱导的脾与肠相关淋巴组织细胞免疫效应及动态变化

目的观察弓形虫与Vero细胞共培养提取的排泄-分泌抗原(ESA)鼻内免疫BALB/c小鼠诱导的脾及肠相关淋巴组织(GALT)细胞免疫效应及动态变化。方法84只BALB/c小鼠随机分为实验组和对照组,实验组以ESA(20μg/只)为抗原,对照组用未接种弓形虫的细胞培养上清液(20μl/只),鼻内免疫2次,间隔2周。末次滴鼻后第1、2、3、4、5、6、7周处死小鼠,分离脾、派伊尔结(PP)及小肠上皮内淋巴细胞(IEL)并计数。结果实验组小鼠脾淋巴细胞第3周达高峰,第1、2、3周明显高于对照组;PP淋巴细胞明显增生,第3周达高峰,第1、2、3、4、5周显著高于对照组;IEL第2周增生达高峰,第1～3周显著高于对照组。结论弓形虫ESA鼻内免疫BALB/c小鼠可有效诱导不同黏膜部位及系统特异性的细胞免疫应答,且可持续较长时间。     

基于残余抗原学说的动态记忆风险识别模型

以小概率事件风险识别为研究对象,提出一个基于残余抗原学说的动态记忆风险识别模型DMRIM。DMRIM针对小概率事件风险的无规则等特点,将风险的强度和频度直观地、动态地映射为残余抗原的浓度,以残余抗原刺激免疫记忆、指导抗体进化、控制识别器的生命周期,突破了传统的记忆细胞生命周期,实现了识别器分布自制,提高了小概率事件的辨识能力。仿真实验表明,DMRIM充分体现免疫记忆的动态性,有效地识别小概率事件,其可行性在实际应用中得到了验证。     

人黏蛋白1串联重复区基因真核表达载体的构建及其在动物细胞中的表达

目的构建人黏蛋白1串联重复区(MUC1 VNTR)17重复序列肿瘤抗原真核表达载体,并在COS-7、HeLa和Lewis细胞中表达。方法设计1对分别含SalⅠ和XhoⅠ酶切位点的引物,PCR法合成1重复MUC1 VNTR片段,克隆入pGEM-Teasy载体,依据SalⅠ和XhoⅠ酶切产生相同黏性末端的特性,依次连接,构建17重复MUC1 VNTR(17m),再亚克隆至VR1012真核表达载体,构建真核表达质粒VR1012-17m。分别转染COS-7、HeLa和Lewis细胞,并进行检测。结果酶切鉴定和序列分析证实,构建的重组质粒含17m序列,经转染的COS-7、HeLa和Lewis细胞,RT-PCR检测均有17m mRNA转录,Western blot检测均有17m蛋白的表达,并与MUC1 VNTR单抗产生特异性反应。结论已成功构建17m肿瘤抗原真核表达载体,并在COS-7、HeLa和Lewis细胞中得到表达,可用于MUC1疫苗和肿瘤生物学治疗的进一步研究。     

Endolysosomal‐Escape Nanovaccines through Adjuvant‐Induced Tumor Antigen Assembly for Enhanced Effector CD8+ T Cell Activation

The activation of tumor‐specific effector immune cells is key for successful immunotherapy and vaccination is a powerful strategy to induce such adaptive immune responses. However, the generation of effective anticancer vaccines is challenging. To overcome these challenges, a novel straight‐forward strategy of adjuvant‐induced tumor antigen assembly to generate nanovaccines with superior antigen/adjuvant loading efficiency is developed. To protect nanovaccines in circulation and to introduce additional functionalities, a biocompatible polyphenol coating is installed. The resulting functionalizable nanovaccines are equipped with a pH (low) insertion peptide (pHLIP) to facilitate endolysosomal escape and to promote cytoplasmic localization, with the aim to enhance cross‐presentation of the antigen by dendritic cells to effectively activate CD8⁺ T cell. The results demonstrate that pHLIP‐functionalized model nanovaccine can induce endolysosomal escape and enhance CD8⁺ T cell activation both in vitro and in vivo. Furthermore, based on the adjuvant‐induced antigen assembly, nanovaccines of the clinically relevant tumor‐associated antigen NY‐ESO‐1 are generated and show excellent capacity to elicit NY‐ESO‐1‐specific CD8⁺ T cell activation, demonstrating a high potential of this functionalizable nanovaccine formulation strategy for clinical applications.     

Antigen‐Directed Fabrication of a Multifunctional Nanovaccine with Ultrahigh Antigen Loading Efficiency for Tumor Photothermal‐Immunotherapy

Current antigen‐encapsulated multifunctional nanovaccines for oncotherapy suffer from limited antigen loading efficiency, low yield, tedious manufacture, and systemic toxicity. Here, an antigen‐directed strategy for the fabrication of multifunctional nanovaccine with ultrahigh antigen loading efficiency in a facile way for tumor photothermal‐immunotherapy is shown. As a proof of concept, a model antigen ovalbumin (OVA) is used as a natural carrier to load a representative theranostic agent indocyanine green (ICG). Mixing OVA and ICG in aqueous solution gives the simplest multifunctional nanovaccine so far. The nanovaccine owns antigen loading efficiency of 80.8%, high yield of >90%, intense near‐infrared absorption and fluorescence, excellent reproducibility, good aqueous solubility and stability, and favorable biocompatibility. These merits not only guarantee sensitive labeling/tracking and efficient stimulation of dendritic cells, but also reliable imaging‐guided photothermal‐immunotherapy of tumors and tumor prevention. The proposed strategy provides a facile and robust method for large‐scale and reproducible fabrication of multifunctional nanovaccines with ultrahigh antigen loading efficiency for tumor therapy.     

Vero细胞无血清培养制备弓形虫排泄-分泌抗原适宜条件的筛选

目的筛选Vero细胞无血清培养制备弓形虫排泄-分泌抗原(ESA)的适宜条件。方法采用拉丁方析因设计。第一部分:在血清浓度为0.5%、1.0%、2.0%、4.0%的培养基中,共培养Vero细胞与弓形虫速殖子,分别于培养3、6、12、24h时,改为无血清培养基,继续培养至第7天,收集培养上清液,制备ESA,并检测蛋白含量。第二部分:在含1.0%血清培养基中共培养Vero细胞与弓形虫速殖子,分别于培养12、24、48、72h时,改为无血清培养基,继续培养至第7、9、11、13天,收集培养上清液,制备ESA,并检测蛋白含量。结果Vero细胞与弓形虫速殖子在1.0%血清浓度培养基中培养12或24h时,无血清培养基继续培养7d,制备的ESA蛋白含量显著高于其他血清浓度(0.5%、2.0%、4.0%)及含血清培养时间(3、6h)。Vero细胞与弓形虫速殖子在含1.0%血清培养基中共培养12、24h,无血清培养基继续培养至第13天,制备的ESA蛋白含量显著高于其他培养时间(48、72h)和无血清培养基继续培养时间(7、9、11d)。结论培养基的血清浓度以及含血清和无血清培养时间是影响体外制备ESA的重要因素。Vero细胞与弓形虫速殖子在1.0%血清浓度培养基中培养12h,无血清培养基继续培养13d,为制备ESA的适宜条件。     

CA_(125)时间分辨荧光免疫分析

以CA12 5单克隆抗体固相包被 ,用平衡饱和法与CA12 5、Eu3+标异硫氰酸苄基二乙烯三胺四乙酸 -CA12 5单抗形成三层夹心 ,以 β -二酮体为增强液 ,建立CA12 5的时间分辨荧光免疫分析法。数据采用Logit-Log函数和四参数Logistic函数数据处理程序处理。方法的批内和批间CV分别为 4 .5%和 4 .0 % ,平均回收率 96.7% ,灵敏度 3.3μg L ,可测范围为 16— 2 0 62 μg L。本法与CEA无交叉 ,与AFP有 4 .6%交叉 ,与 β -HCG有 12 .4 %交叉。测定结果与进口IRMA试剂盒相比较 ,相关系数为 0 .999,结果呈高度相关。     

IgA与食物过敏反应

分泌型IgA(SIgA)在消化道内大量存在,阻止着食物抗原进入体内,如果这一机制崩溃,则易引起过敏反应。本文从IgA的观点论述食物过敏反应。     

Quantum bead-based fluorescence-linked immunosorbent assay for ultrasensitive detection of aflatoxin M1 in pasteurized milk,yogurt, and milk powder

Herein, we reported a novel direct competitive fluorescence-linked immunosorbent assay (dcFLISA) for the ultrasensitive detection of aflatoxin M₁ (AFM₁) in pasteurized milk, yogurt, and milk powder using 150-nm quantum dot beads (QB) as the carrier of competing antigen. Large QB were applied to decrease the binding affinity of the competing antigen to antibody and enhance the fluorescent signal intensity. The aflatoxin B₁ molecule was used as the surrogate of AFM₁ to label with BSA on the surface of QB because of its 63% cross reaction to anti-AFM₁ mAb. The binding affinity of the competing antigen to mAb was tuned by changing the labeled molar ratios of aflatoxin B₁ to BSA. Through combining the advantages of QB as the carrier of the competing antigen, including low binding affinity to mAb and highly fluorescent signal output, the proposed dcFLISA exhibited an ultrahigh sensitivity for AFM₁ detection, with a half-maximal inhibitory concentration of 3.15 pg/mL in 0.01 M phosphate-buffered saline solution (pH 7.4), which is substantially lower than that of the traditional horseradish peroxidase-based ELISA. The proposed method also exhibited very low detection limitations of 0.5, 0.6, and 0.72 pg/mL for real pasteurized milk, yogurt, and milk powder, respectively. These values are considerably below the maximum permissible level of the European Commission standard for AFM₁ in dairy products. In summary, the proposed dcFLISA offers a novel strategy with an ultrahigh sensitivity for the routine monitoring of AFM₁ in various dairy products.