PAMAM-Lys,a Novel Vaccine Delivery Vector,Enhances the Protective Effects of the SjC23 DNA Vaccine against Schistosoma japonicum Infection

Background

Schistosomiasis japonica remains a major public-health concern in China. Praziquantel-based chemotherapy effectively reduces both infections and intensity; however, it can not prevent re-infection. Furthermore, there is an increasing concern about praziquantel resistance following long-term repeated use of the drug in endemic areas. Therefore, development of a schistosomiasis vaccine, as a strategy to prevent and control schistosomiasis japonica, has been given high priority. The present study was conducted to develop PAMAM dendrimers as a novel vaccine delivery vector for a schistosomiasis japonica DNA vaccine and evaluate its ability to enhance protective effects against Schistosoma japonicum infection.

Methodology/Principal Findings

Lysine was used to modify 4.0G PAMAM, and the modified product PAMAM-Lys was synthesized. PAMAM-Lys showed both high transfection and low cytotocity for gene delivery in vitro. DNA vaccines combined with PAMAM-Lys produced higher level of protection compare with naked DNA vaccines against S. japonicum infection in a mouse model. Futhermore,antibodies from mice immunized with PAMAM-Lys combined DNA vaccines were significantly higher than those of mice immunized with the naked DNA vaccines. The PAMAM-Lys vector elicited a predominantly IgG2a antibody response and a tremendously increase in the production of IL-2 and IFN-γ.

Conclusion/Significance

Lysine-modified PAMAM-Lys is an excellent vector. PAMAM-Lys may enhance the immunoreactivity of DNA vaccine and increase the protective effect of the SjC23 DNA vaccine against S. japonicum infection.     

Combined TLR7/8 and TLR9 Ligands Potentiate the Activity of a Schistosoma japonicum DNA Vaccine

Background

Toll-like receptor (TLR) ligands have been explored as vaccine adjuvants for tumor and virus immunotherapy, but few TLR ligands affecting schistosoma vaccines have been characterized. Previously, we developed a partially protective DNA vaccine encoding the 26-kDa glutathione S-transferase of Schistosoma japonicum (pVAX1-Sj26GST).

Methodology/Principal Findings

In this study, we evaluated a TLR7/8 ligand (R848) and a TLR9 ligand (CpG oligodeoxynucleotides, or CpG) as adjuvants for pVAX1-Sj26GST and assessed their effects on the immune system and protection against S. japonicum. We show that combining CpG and R848 with pVAX1-Sj26GST immunization significantly increases splenocyte proliferation and IgG and IgG2a levels, decreases CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Treg) frequency in vivo, and enhances protection against S. japonicum. CpG and R848 inhibited Treg-mediated immunosuppression, upregulated the production of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-4, IL-10, IL-2, and IL-6, and decreased Foxp3 expression in vitro, which may contribute to prevent Treg suppression and conversion during vaccination and allow expansion of antigen-specific T cells against pathogens.

Conclusions

Our data shows that selective TLR ligands can increase the protective efficacy of DNA vaccines against schistosomiasis, potentially through combined antagonism of Treg-mediated immunosuppression and conversion.     

A Novel Recombinant BCG Vaccine Encoding Eimeria tenella Rhomboid and Chicken IL-2 Induces Protective Immunity Against Coccidiosis

A novel recombinant Bacille Calmette-Guerin (rBCG) vaccine co-expressed Eimeria tenella rhomboid and cytokine chicken IL-2 (chIL-2) was constructed, and its efficacy against E. tenella challenge was observed. The rhomboid gene of E. tenella and chIL-2 gene were subcloned into integrative expression vector pMV361, producing vaccines rBCG pMV361-rho and pMV361-rho-IL2. Animal experiment via intranasal and subcutaneous route in chickens was carried out to evaluate the immune efficacy of the vaccines. The results indicated that these rBCG vaccines could obviously alleviate cacal lesions and oocyst output. Intranasal immunization with pMV361-rho and pMV361-rho-IL2 elicited better protective immunity against E. tenella than subcutaneous immunization. Splenocytes from chickens immunized with either rBCG pMV361-rho and pMV361-rho-IL2 had increased CD4⁺ and CD8⁺ cell production. Our data indicate recombinant BCG is able to impart partial protection against E. tenella challenge and co-expression of cytokine with antigen was an effective strategy to improve vaccine immunity.     

IL-12对巨细胞病毒DNA疫苗免疫增强作用的研究

白介素12(interleukin 12,IL-12)主要和细胞免疫应答有关,是免疫过程中重要的调节因子。本研究探讨IL-12对编码巨细胞病毒(cytomegalovirus,CMV)即刻早期基因IE1的DNA疫苗的免疫增强作用。将CMVIE1质粒DNA单独或与编码IL-12的质粒DNA共同免疫小鼠,然后用致死量病毒攻击小鼠。通过检测小鼠体内诱导的细胞免疫应答、小鼠的存活率、体重丢失率、器官中的病毒滴度等来评价IL-12对疫苗免疫的佐剂效果。结果显示,与单独疫苗免疫组相比,IE1 DNA联合IL-12 DNA免疫组能够在小鼠体内诱导更高的细胞免疫应答水平,同时能够降低器官中的病毒滴度,显著提高保护率,从而更好地抵抗病毒攻击。实验证明,IL-12能够作为巨细胞病毒IE1 DNA疫苗的佐剂,提高免疫保护效果。     

基于甲病毒复制子载体的猪瘟DNA疫苗的免疫效力评价

此前已构建了基于Semliki Forest病毒（Semliki Forest virus,SFV）复制子载体的表达猪瘟病毒（classical swine fever virus,CSFV）E2基因的新型猪瘟DNA疫苗pFV1CS-E2,通过动物试验证实,该疫苗以600μg/头的剂量免疫3次,免疫猪能抵抗致死剂量猪瘟强毒的攻击。为进一步评价该疫苗在较低的免疫剂量和较少的免疫次数情况下的免疫效力,将DNA疫苗pSFV1CS-E2和空载体pSFV1CS按100μg/头的剂量,接种猪只2次,然后用致死剂量的猪瘟强毒石门株进行攻击。结果表明,pSFV1CS-E2免疫组（n=5）所有免疫猪在加强免疫后均产生了猪瘟特异性中和抗体,攻毒后所有猪只抗体迅速升高,除了短期体温升高外,未出现任何其它临床症状,部分猪出现短期轻微病毒血症,个别猪的部分脏器出现轻微病变;而空载体免疫组（n=3）猪只在攻毒前一直没有检出特异性抗体,攻毒后全都出现典型的猪瘟临床症状和严重的病毒血症,有2头猪分别于攻毒后第10和11d死亡,剖检时可见典型猪瘟病理变化。结果表明,基于甲病毒复制子载体的猪瘟DNA疫苗有望成为具有开发价值的猪瘟标记疫苗。     

基于甲病毒复制子载体的猪瘟DNA疫苗的免疫效力评价

此前已构建了基于SemlikiForest病毒(SemlikiForestvirus,SFV)复制子载体的表达猪瘟病毒(classicalswinefevervirus,CSFV)E2基因的新型猪瘟DNA疫苗pFV1CS-E2,通过动物试验证实,该疫苗以600μg/头的剂量免疫3次,免疫猪能抵抗致死剂量猪瘟强毒的攻击。为进一步评价该疫苗在较低的免疫剂量和较少的免疫次数情况下的免疫效力,将DNA疫苗pSFV1CS-E2和空载体pSFV1CS按100μg/头的剂量,接种猪只2次,然后用致死剂量的猪瘟强毒石门株进行攻击。结果表明,pSFV1CS-E2免疫组(n=5)所有免疫猪在加强免疫后均产生了猪瘟特异性中和抗体,攻毒后所有猪只抗体迅速升高,除了短期体温升高外,未出现任何其它临床症状,部分猪出现短期轻微病毒血症,个别猪的部分脏器出现轻微病变;而空载体免疫组(n=3)猪只在攻毒前一直没有检出特异性抗体,攻毒后全都出现典型的猪瘟临床症状和严重的病毒血症,有2头猪分别于攻毒后第10和11d死亡,剖检时可见典型猪瘟病理变化。结果表明,基于甲病毒复制子载体的猪瘟DNA疫苗有望成为具有开发价值的猪瘟标记疫苗。     

两种血吸虫病DNA疫苗的候选抗原基因研究

目的：以日本血吸虫基因SjFABP和SjGST原核表达产物检测二价DNA疫苗pVIVO2-SjFABP-SjGST在体内诱发的特异性抗体。方法：克隆日本血吸虫抗原基因SjFABP和sjGST,构建重组原核表达载体pET30a-SjFABP、pET30a-SjGST及真核表达载体pVIVO2-SjFABP-SjGST;将pET30a-SjFABP和pET30a-sjGST进行原核表达,并将表达产物用镍亲和柱分离纯化;采用Western印迹对日本血吸虫DNA疫苗pVIVO2-SjFABP-SjGST免疫4周后的BALB／c小鼠血清进行特异性抗体检测。结果：克隆了日本血吸虫抗原基因SjFABP（399bp）和町GST（657bp）,并构建了pET30a-SjFABP、pET30a-SjGST及pVIVO2-SjFABP-SjGST重组质粒;经Western印迹检测,pET30a-SjFABP及pET30a-SjGST原核表达的抗原蛋白均能够与经日本血吸虫二价DNA疫苗pVIVO2-SjFABP-SjGST免疫的小鼠的血清产生特异性免疫反应。结论：日本血吸虫町尉即和町GST基因的原核表达系统成功建立;原核表达的抗原蛋白具有免疫原性;以原核表达产物可检测日本血吸虫DNA疫苗pVIVO2-SiFABP-SiGST在体内诱发的特异性抗体。     

抗日本血吸虫pVAX1/ SjHGPRT·SDISP 多价疫苗对昆明小鼠的保护 作用及其机制探讨

目的:探讨抗日本血吸虫生殖产卵编码基因多价疫苗pVAX1/SjHGPRToSDISP对昆明小鼠的保护作用及其机制。方法:选取昆明小鼠30只,分别使用pVAX1/SjHGPRToSDISP、pVAX1以及生理盐水,每只小鼠100μg或等量经左腿股四头肌注射。处理2周后,采集动物模型血样检测IgG、IL-2,IL-4,IL-10以及INF-γ表达量。处理4周后,以20±1条尾蚴贴腹感染,感染6周后检测减虫率、减卵率。结果:尾蚴攻击动物后6周,pVAX1/SjHGPRToSDISP免疫组的肝脏减虫率为42.2%,子宫与肝脏减卵率分别为68.04%以及72.96%。与对照组比较,差异有显著性。pVAX1/SjHGPRToSDISP免疫组虫体内IgG、IL-4以及INF-γ表达量明显升高,与对照组比较差异有显著性(P<0.05)。结论:pVAX1/SjHGPRToSDISP多价疫苗具有较好的免疫保护作用,且该类作用的机制与IgG、IL-4以及INF-γ的表达升高存在关联。     

抗日本血吸虫pVAX1／SjHGPRT-SDISP多价疫苗对昆明小鼠的保护作用及其机制探讨

目的：探讨抗日本血吸虫生殖产卵编码基因多价疫苗pVAX1／sjHGPRToSDISP对昆明小鼠的保护作用及其机制。方法：选取昆明小鼠30只,分别使用pVAX1／sjHGPRToSDISP、pVAX1以及生理盐水,每只小鼠100ug或等量经左腿股四头肌注射。处理2周后,采集动物模型血样检测IgG、IL-2,IL-4,IL-10以及INF-Y表达量。处理4周后,以20±1条尾蚴贴腹感染,感染6周后检测减虫率、减卵率。结果：尾蚴攻击动物后6周,pVAX1／sjHGPRToSDISP免疫组的肝脏减虫率为42．2％,子宫与肝脏减卵率分别为68．04％以及72．96％。与对照组比较,差异有显著性。pVAX1／sjHGPRToSDISP免疫组虫体内IgG、IL-4以及INF．V表达量明显升高．与对照组比较差异有显著性（P〈0．05）。结论：pVAX1／sjHGPRToSDISP多价疫苗具有较好的免疫保护作用,且该类作用的机制与IgG、IL-4以及INF—v的表达升高存在关联。     

Vaccine potential of hemocyanin from Oncomelania hupensis against Schistosoma japonicum

Hemocyanin, a giant oxygen transport protein which is usually found in many arthropods and mollusks was isolated and purified from Oncomelania hupensis. In this study, we showed that Oncomelania hupensis hemocyanin (OhH) shared carbohydrate epitopes with different developmental stages of Schistosoma japonicum (Cercaria, Schistosomulum, Adult worm and Egg) and exhibited serological cross-reaction with these stages of S. japonicum immune sera, which had a potential for use in diagnostic and therapeutic studies of schistosomasis. OhH was used as a vaccine in combination with Freund's adjuvant to evaluate the induction of immune responses and protection against S. japonicum infection in mice. Mice immunized with OhH induced a Th1 type of immune responses. Strong protection against S. japonicum were observed in adult worm and egg burdens after 42 days post-challenge, which showed a significant worm reduction of 52.5% and egg reduction of 69.2% compared to the control groups, respectively. These results indicated that OhH was a potential candidate to compose an anti-schistosome vaccine.     

抗日本血吸虫pVAX1／SjHGPRT·SDISP多价疫苗的构建方法探讨

目的：探讨抗日本血吸虫生殖产卵编码基因多价疫苗pVAX1／SjHGPRT·SDISP的构建方法并从基因与蛋白水平验证该构建方法是否成功。方法：分别以pcDNA3．0／SjHGPRT、pcDNA3．0／SjSDISP为模板,设计引物扩增SjHGPRT、sjSDISP,采用overlap方法扩增全长SjHGPRT·SDISP。将纯化后的产物sjHGPRT·SDISP以及pVaxl质粒采用KpnI和XbaI双酶切,1％低熔点胶回收目的DNA片段以及酶切后Pvaxl载体片段双胶连。连接产物转化至DH5a细胞。挑选阳性克隆采用双酶切以及测序方法从基因水平鉴定是否构建成功。将构建产物免疫观察动物,采用免疫组化方法从蛋白水平鉴定疫苗pVAX1／SjHGPRT·SDISP是否构建成功。结果：酶切方法以及测序结果均显示重组质粒的插入序列分别与目的基因完全一致,昆明小鼠肌肉组织酶免疫组织化学染色显示免疫组小鼠肌细胞中呈现较强的棕黄色颗粒,而阴性对照组肌细胞呈阴性。结论：真核重组质粒pVAX1／SjHG—PRT·SDISP构建成功,且在昆明鼠肌肉细胞内能够获得良好的表达。     

抗日本血吸虫pVAX1/ SjHGPRT·SDISP 多价疫苗的构建方法探讨

目的:探讨抗日本血吸虫生殖产卵编码基因多价疫苗pVAX1/SjHGPRT.SDISP的构建方法并从基因与蛋白水平验证该构建方法是否成功。方法:分别以pcDNA3.0/SjHGPRT、pcDNA3.0/SjSDISP为模板,设计引物扩增SjHGPRT、SjSDISP,采用overlap方法扩增全长SjHGPRT.SDISP。将纯化后的产物SjHGPRT.SDISP以及pVax1质粒采用Kpn I和Xba I双酶切,1%低熔点胶回收目的 DNA片段以及酶切后Pvax1载体片段双胶连。连接产物转化至DH5α细胞。挑选阳性克隆采用双酶切以及测序方法从基因水平鉴定是否构建成功。将构建产物免疫观察动物,采用免疫组化方法从蛋白水平鉴定疫苗pVAX1/SjHGPRT.SDISP是否构建成功。结果:酶切方法以及测序结果均显示重组质粒的插入序列分别与目的基因完全一致,昆明小鼠肌肉组织酶免疫组织化学染色显示免疫组小鼠肌细胞中呈现较强的棕黄色颗粒,而阴性对照组肌细胞呈阴性。结论:真核重组质粒pVAX1/SjHG-PRT.SDISP构建成功,且在昆明鼠肌肉细胞内能够获得良好的表达。     

噬菌体展示日本血吸虫SSj14单抗的模拟抗原表位及其免疫保护性研究

为获得日本血吸虫保护性单抗SSj14的模拟抗原表位,研究其对日本血吸虫的免疫保护作用。用纯化的SSj14单抗筛选噬菌体随机12肽库,对33个克隆进行ELISA验证,获得30个阳性克隆,DNA序列分析表明这30个克隆分属11个多肽序列,分析比较发现这些多肽具有“H_NQ_X_S_PF_X_X_L_A_T”的相似基序。进而选取3个阳性单克隆及混合阳性噬菌体克隆进行Western_blotting实验,证明都有良好的抗原性。用它们免疫BALBc鼠,并攻击血吸虫尾蚴,观察免疫鼠抗血吸虫感染的保护效果和IL_12的变化,结果表明:筛选获得的噬菌体阳性克隆具有良好的免疫原性,能诱导免疫鼠产生高滴度的抗血吸虫的特异性抗体;和对照组鼠相比,免疫小鼠,分别获得13.84%～52.83%的减虫率,34.17%～65.47%的肝脏减卵率以及28.89%～73.78%的粪便减卵率;三次免疫之后,和对照组相比,免疫小鼠体内IL_12水平均有升高。为发展日本血吸虫疫苗提供了新思路、新途径。     

Characterization of VAMP2 in Schistosoma japonicum and the Evaluation of Protective Efficacy Induced by Recombinant SjVAMP2 in Mice

Background

The outer-tegument membrane covering the schistosome is believed to maintain via the fusion of membranous vesicles. Fusion of biological membranes is a fundamental process in all eukaryotic cells driven by formation of trans-SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complexes through pairing of vesicle associated v-SNAREs (VAMP) with complementary t-SNAREs on target membranes. The purpose of this study was to characterize Schistosoma japonicum vesicle-associated membrane protein 2 (SjVAMP2) and to investigate its potential as a candidate vaccine against schistosomiasis.

Methodology/Principal Findings

The sequence of SjVAMP2 was analyzed, cloned, expressed and characterized. SjVAMP2 is a member of the synaptobrevin superfamily harboring the v-SNARE coiled-coil homology domain. RT–PCR analysis revealed that significantly higher SjVAMP2 levels were observed in 14-, 28- and 42-day-old worms, and SjVAMP2 expression was much higher in 42-day-old female worms than in those male worms. Additionally, the expression of SjVAMP2 was associated with membrane recovery in PZQ-treated worms. Immunostaining assay showed that SjVAMP2 was mainly distributed in the sub-tegument of the worms. Western blotting revealed that rSjVAMP2 showed strong immunogenicity. Purified rSjVAMP2 emulsified with ISA206 adjuvant induced 41.5% and 27.3% reductions in worm burden, and 36.8% and 23.3% reductions in hepatic eggs in two independent trials. Besides, significantly higher rSjVAMP2-specific IgG, IgG1, IgG2a levels were detected in rSjVAMP2-vaccinated mice.

Conclusion

Our study indicated that SjVAMP2 is a potential vaccine candidate against S. japonicum and provided the basis for further investigations into the biological function of SjVAMP2.     

呼吸道合胞病毒重组蛋白候选疫苗的质粒构建、表达及免疫原性和保护性研究

PCR扩增呼吸道合胞病毒（respiratory syncytial virus,RSV）M2 蛋白的CD8＋T细胞表位F/M2:81-95和RSV-G蛋白的B细胞表位片段G:125～225（简称G1）,以一个Linker连接,插入质粒pET-DsbA中构建原核表达重组质粒, 转染E.coli BL21(DE3)后成功表达了融合蛋白DsbA-G1-Linker-F/M2:81-95（简称D-G1LF/M2）,Western-blot结果表明该融合蛋白是RSV特异性的,采用Ni+螯合亲和层析法纯化变性的包涵体溶液,经梯度透析法复性,用该蛋白免疫BALB/c小鼠,结果表明被免疫小鼠肺部及血清中产生了高滴度的抗D-G1LF/M2及抗RSV IgG抗体和中和抗体,同时还诱导产生了RSV特异性的CTL应答;IgG的亚型IgG1/IgG2a的比值为2.66;用RSV攻击免疫后的小鼠,病毒滴定法检测肺部RSV滴度,结果表明D-G1LF/M2对小鼠肺部具有保护作用。     

日本血吸虫DNA疫苗的优化策略

血吸虫病严重危害人类及家畜健康,发展疫苗是防治血吸虫感染的有效措施。传统疫苗的发展因成本高、免疫原性低及安全隐患而受到限制。发展DNA疫苗成为近年的研究重点。为提高DNA疫苗的免疫保护力,候选抗原的筛选、CpG序列的优化、基因佐剂的选用、多价疫苗的构建等被认为是日本血吸虫DNA疫苗的优化策略。     

重组鸡痘病毒和DNA疫苗对口蹄疫病毒的豚鼠免疫保护

将构建的携带FMDV衣壳蛋白P1-2A和蛋白酶3C编码基因的重组鸡痘病毒活载体疫苗vUTAL3CP1以及编码FMDVP1-2A基因和猪IL-18基因的重组DNA疫苗pVIRIL18P1,分别以单独和混合的方式给豚鼠进行2次免疫,然后测定FMDV特异性结合抗体、中和抗体和T淋巴细胞增殖反应,并用250ID50的FMDV进行攻击,观察其保护效果。结果表明这2种基因工程疫苗均能诱导豚鼠产生特异性的体液免疫及细胞免疫应答。其中以vUTAL3CP1两次免疫组的效果最好,其诱导的抗体水平已接近于常规灭活疫苗,而细胞免疫水平则比后者高得多。攻击保护结果表明该组完全保护率可达3/4,而另外两组也具有一定保护效果。上述研究结果为进一步进行大动物免疫攻毒试验,并最终筛选出最佳疫苗和免疫程序奠定了基础。     

重组鸡痘病毒和DNA疫苗对口蹄疫病毒的豚鼠免疫保护

将构建的携带FMDV衣壳蛋白P1-2A和蛋白酶3C编码基因的重组鸡痘病毒活载体疫苗vUTAL3CP1以及编码FMDV P1-2A基因和猪IL-18基因的重组DNA疫苗pVIRIL18P1,分别以单独和混合的方式给豚鼠进行2次免疫,然后测定FMDV特异性结合抗体、中和抗体和T淋巴细胞增殖反应,并用250 ID50的FMDV进行攻击,观察其保护效果.结果表明这2种基因工程疫苗均能诱导豚鼠产生特异性的体液免疫及细胞免疫应答.其中以vUTAL3CP1两次免疫组的效果最好,其诱导的抗体水平已接近于常规灭活疫苗,而细胞免疫水平则比后者高得多.攻击保护结果表明该组完全保护率可达3/4,而另外两组也具有一定保护效果.上述研究结果为进一步进行大动物免疫攻毒试验,并最终筛选出最佳疫苗和免疫程序奠定了基础.     

机械喷射式雾化机对质粒DNA完整性的影响及保护性研究

目的:探索目前临床广泛使用的喷射式雾化机对质粒DNA(pDNA)完整性破坏的影响及保护措施。方法:在研究雾化时间对pDNA完整性影响的实验中,加入5ml pDNA(20μg/ml),分别在开始雾化后收集第1min内;第2min内;第3min内;第4min内;第5min内及第10min内雾化器喷口处的雾化液滴;在研究加样量对裸pDNA完整性影响的实验中,分别取2ml、4ml、6ml、8ml,各雾化4min,收集最后一分钟内雾化液滴。在两种高分子聚合物对pDNA保护性研究的实验中,各取4ml未经高分子聚合物修饰的以及经过聚乙烯亚胺(polyethylenimine, PEI)或阳离子脂质体修饰后的pDNA,分别雾化10min,收集最后一分钟内雾化液滴。使用琼脂糖凝胶电泳分析雾化样本质粒完整性。结果:在雾化时间由1min增至10min后完整性部分所占百分比由(83.5±2.2)%降至(37.1±2.8)%;加样量由2ml 增至8ml 后,pDNA完整性部分所占百分比由(32.1±3.5)%增至(93.6±0.6)%;经过PEI或阳离子脂质体修饰后的pDNA在雾化过程中几乎无破坏现象。结论:喷射式雾化机对pDNA的破坏呈剂量、时间依赖性,PEI与阳离子脂质体对pDNA保护效果良好,为喷射式雾化机在基因雾化治疗中的应用打下一定基础。     

基因工程变链菌防龋疫苗的研制

本文采用我们自己构建的基因工程龋齿疫苗菌株,大罐发酵培养３批、菌体收量平均湿重为２．６７ｇ／Ｌ,表达率为４４．２７％。菌体经超声裂解,硫酸铵和链霉素粗提,再经吸附层检,凝胶过滤和离子交换柱层析等步骤纯化精提ＧＴＦ抗原３批。提纯的ＧＴＦ抗原,平均比活,提纯倍数和收率,分别为５８．３４ｕ／ｍｇ、６．０８倍和１９．２５％。此抗原经ＳＤＳ－ＰＡＧＥ电泳,分子量为５５ＫＤ,纯度达到９６．７％,并对湿度具有较好的稳定性能。且此抗原制备的疫苗免疫家兔具有较好的免疫原性