A recombinant adenovirus expressing CFP10, ESAT6, Ag85A and Ag85B of Mycobacterium tuberculosis elicits strong antigen-specific immune responses in mice

Tuberculosis (TB) is caused by an infection of Mycobacterium tuberculosis (Mtb) and remains an enormous and increasing health burden worldwide. To date, Mycobacterium bovis Bacillus Calmette Guerin (BCG) is the only licensed anti-TB vaccine worldwide, which provides an important but limited protection from the Mtb infection. The development of alternative anti-TB vaccines is therefore urgently needed. Here we report, the generation of Ad5-CEAB, a recombinant adenovirus expressing Mtb antigens of CFP10, ESAT6, Ag85A and Ag85B proteins in a form of mixture. In order to evaluate the immunogenicity of Ad5-CEAB, mice were immunized with Ad5-CEAB by intranasal instillation three times with 2-week intervals. The results demonstrated that Ad5-CEAB elicited a strong antigen-specific immune response, particularly of the Th1 immune responses that were characterized by an increased ratio of IgG2a/IgG1 and secretions of Th1 type cytokines, IFN-γ, TNF-α, IL-2 and IL-12. In addition, the Ad5-CEAB also showed an ability to enhance humoral responses with a dramatically augmented antigen-specific serum IgG. Furthermore, an elevated sIgA were also found in the bronchoalveolar lavage fluid of the immunized mice, suggesting the elicitation of mucosal immune responses. These data indicate that Ad5-CEAB can induce a broad range of antigen-specific immune responses in vivo, which provides a promising and novel route for developing anti-TB vaccines and warrants further investigation.     

重组结核抗原痘苗病毒Ankara株的构建及其免疫原性研究

目的 构建5种不同类型的表达结核杆菌特异抗原的重组痘苗病毒,并研究其特异免疫原性.方法 运用同源重组技术将含结核分泌抗原Ag85A和ESAT-6的基因片段插入痘苗病毒表达质粒p18中.重组质粒导入痘苗病毒Ankara(MVA)后构建重组痘苗病毒,经筛选和Western blot鉴定,得到5个种类的带有结核抗原基因的重组病毒.用构建的5种重组病毒免疫小鼠,MTT法检测免疫后小鼠脾淋巴细胞对特异结核抗原的增殖反应;ELISA检测小鼠脾淋巴细胞培养上清液中IFN-γ的含量;结核菌素纯蛋白衍化物(PPD)皮内试验以检测重组病毒引发的针对结核抗原的特异细胞免疫应答.结果 构建的5种蘑组病毒介导的细胞表达产物经Western blot鉴定确认相对分子质量与结核抗原一致.免疫小鼠两次后,5种重组病毒免疫组脾淋巴细胞体外与Ag85A-ESAT-6融合蛋白共培养后表现出明显的增殖活性(P<0.01),培养上清液中IFN-γ的浓度均较同组细胞经生理盐水刺激明显增高(P<0.05);与空痘苗病毒或生理盐水免疫后小鼠相比,5种重组MVA免疫组脾淋巴细胞与AgB5A.ESAT-6融合蛋白共培养后同样表现出明显的增殖活性(P<0.01),与Ag85A-ESAT-6融合蛋白共培养的细胞上清液中IFN-γ的浓度均升高(P<0.01).与空痘苗病毒或生理盐水免疫后小鼠相比,5种重组MVA免疫组小鼠对PPD都表现出显著的迟发型超敏反应应答(P<0.05).结论 成功构建了5种不同类型的表达结核杆菌抗原的重组痘苗病毒疫苗,其免疫小鼠后可激发针对结核杆菌抗原的特异性细胞免疫.     

Mycobacterium indicus pranii protein MIP_05962 induces Th1 cell mediated immune response in mice

Utility of Mycobacterium indicus pranii (MIP) as a multistage vaccine against mycobacterial infections demands identification of its protective antigens. We explored antigenicity and immunogenicity of a candidate protein MIP_05962 that depicts homology to HSP18 of M. leprae and antigen1 of Mycobacterium tuberculosis. This protein elicited substantial antibody response in immunized mice along with modulation of cellular immune response towards protective Th1 type. Both CD4⁺ and CD8⁺ subsets from immunized mice produced hallmark protective cytokines, IFN-γ, TNF-α and IL-2. This protein also enhanced the CD4⁺ effector memory that could act as first line of defence during infections. These results point to MIP_05962 as a protective antigen that contributes, in conjunction with others, to the protective immunity of this live vaccine candidate.     

A key role for lung‐resident memory lymphocytes in protective immune responses after BCG vaccination

The immune mechanisms that orchestrate protection against tuberculosis as a result of BCG vaccination are not fully understood. We used the immunomodulatory properties of fingolimod (FTY720) treatment to test whether the lung‐resident memory T lymphocytes generated by BCG vaccination were sufficient to maintain immunity against challenge infection with mycobacteria (BCG). Mice were given daily fingolimod treatment, starting either immediately before s.c. BCG vaccination or during subsequent BCG i.n. challenge, to prevent LN effector and memory lymphocytes from entering the periphery either during priming or challenge, respectively. Treatment with fingolimod during vaccination reduced vaccine‐mediated protection against subsequent infection. By contrast, BCG‐vaccinated mice were protected when fingolimod was given during the infectious challenge, suggesting that memory lymphocytes that migrate to the lung following vaccination are sufficient for protection. Notably, the antigen‐reactive IFN‐γ or multicytokine‐producing CD4⁺ T cells present in the lung when fingolimod was given during BCG challenge did not correlate with protection; however, expression of MHC class II on macrophages isolated from the lungs post BCG challenge was increased in the protected mice. We conclude that protection conferred by BCG vaccination is dependent on memory lymphocytes retained in the lung, although IFN‐γ production by this population is not correlated with vaccine‐mediated protection.     

E型沙眼衣原体重组主要外膜蛋白诱导恒河猴的交叉免疫效应

目的 探讨E型重组主要外膜蛋白(rMOMP)对恒河猴诱导产生的衣原体交叉免疫应答效应.方法 恒河猴分3组,每组2只,分别为佐剂蛋白组、佐剂组、对照组.于第0、2、4周双侧肱三头肌注射.末次免疫后两周,ELISA检测恒河猴血清中沙眼衣原体特异性IgG抗体和细胞因子IFN-γ,MTT法检测恒河猴淋巴细胞特异性增殖反应,观察恒河猴的迟发型超敏反应,以及恒河猴的血清抗体中和试验.结果 佐剂蛋白组产生了较强的抗rMOMP反应和高水平细胞因子.淋巴细胞特异性增殖反应、迟发型超敏反应明显强于对照组,抗体中和试验蛋白佐剂组血清能抑制D/E/H/L2型沙眼衣原体生长.结论 沙眼衣原体rMOMP能刺激恒河猴产生有效的交叉免疫.     

Erythropoietin enhances immune responses in mice

Erythropoietin (Epo) is the main erythropoietic hormone. Recombinant human Epo (rHuEpo) is thus used in clinical practice for the treatment of anemia. Accumulating data reveals that Epo exerts pleiotropic activities. We have previously shown an anti-neoplastic activity of Epo in murine multiple myeloma (MM) models, and in MM patients. Our findings that this anti-neoplastic effect operates via CD8+ T lymphocytes led us to hypothesize that Epo possesses a wider range of immunomodulatory functions. Here we demonstrate the effect of Epo on B lymphocyte responses, focusing on three experimental models: (i) tumor-bearing mice, (5T2 MM mouse); (ii) antigen-injected healthy mice; and (iii) antigen-injected transgenic mice (tg6), overexpressing human Epo. In the MM model, despite bone marrow dysfunction, Epo-treated mice retained higher levels of endogenous polyclonal immunoglobulins, compared to their untreated controls. In both Epo-treated wild type and tg6 mice, Epo effect was manifested in the higher levels of splenocyte proliferative response induced in vitro by lipopolysaccharide. Furthermore, these mice had increased in vivo production of anti-dinitrophenyl (DNP) antibodies following immunization with DNP-keyhole limpet hemocyanin. Epo-treated mice showed an enhanced immune response also to the clinically relevant hepatitis B surface antigen. These findings suggest a potential novel use of rHuEpo as an immunomodulator.     

胞壁型rBCG经口服免疫可以诱导BALB/c小鼠产生抗原特异性TH1应答

目的观察胞壁型重组BCG(rBCG)经口服接种后对BALB/c小鼠TH细胞免疫应答的影响。方法以100 ml/L甘油为对照,分别将BCG和以膜蛋白形式表达屋尘螨抗原Der D2的rBCG经口服接种于8周龄BALB/c小鼠,109 CFU/d,连续5 d,用夹心ELISA测定小鼠血清、脾脏T淋巴细胞培养上清(SCS)和肠道相关淋巴细胞培养上清(Gcs)中IL-4、IFN-Υ水平,用双色荧光标记-流式细胞术测定脾脏淋巴细胞(SLC)和肠道相关淋巴细胞(GLC)中TH细胞亚群。结果免疫4周后,ELISA结果表明:BCG和。rBCG两组血清和SCS的IFN-Υ水平较对照组升高,IL-4水平降低;但两组小鼠GCS仅见IFN-Υ水平升高。流式细胞测定结果表明:在CD4 的SLC中,BCG和rBCG免疫小鼠的IL-12Rβ2 细胞比例升高,而CD30 细胞比例降低;在CD4 的GLC中,BCG和rBCG免疫小鼠的IFN-Υ 细胞比例升高;至免疫后8周,上述改变进一步明显,但BCG和rBCG两组之间差异无统计学意义。体外给予抗原刺激后,rBCG组小鼠变化更加显著,而BCG组则无明显改变。但GCS的IL-4水平始终无法测得;同时GLC中IL-5 细胞比例仍持续较低。结论无论rBCG还是BCG通过口服免疫,均可诱导BALB/c小鼠产生TH1优势免疫应答;而胞壁型Der p2-rBCG诱导产生的TH1优势应答具有Der p2抗原特异(记忆)性。     

可表达结核分枝杆菌融合蛋白Ag85A-ESAT-6重组卡介苗免疫保护作用研究

目的以Balb/c小鼠为动物模型,评价重组卡介苗新型结核病疫苗rBCG-Ag85A-ESAT-6(rBC-AE)的免疫保护效应。方法将重组卡介苗rBCG-AE免疫动物10周后,结核分枝杆菌H37Rv尾静脉注射进行感染攻击,分别于感染攻击后3、6和9周,通过观察肺组织大体病变、脾肺组织细菌载荷量计数、肺组织抗酸染色、HE染色结合肺组织病理变化,综合评价该疫苗诱导的免疫保护作用。结果 rBCG-AE组脾肺组织细菌载荷量在各时间点均显著低于阴性对照组(PBST组,P0.01),但明显高于卡介苗(BCG)组(P0.01)。rBCG-AE组肺组织病变在感染攻击后6～9周逐渐改善,但其病理打分在各时间点均明显高于BCG组(P0.01)。各组肺组织大体病变与组织病理打分变化相似。结论重组卡介苗rBCG-AE仅能诱导产生与BCG疫苗相当甚至较低的免疫保护作用。     

rIL-18对肺炎链球菌肺炎小鼠Th1/Th2免疫应答的影响

目的 研究重组白细胞介素18(rIL-18)对肺炎链球菌肺炎小鼠Th1/ Th2免疫应答的影响.方法 鼻腔接种肺炎链球菌建立小鼠肺炎链球菌肺炎模型,将Balb/c小鼠24只随机分为3组,分别为对照组,肺炎组和肺炎rIL-18干预组(n=8 ),RT-PCR法检测各组小鼠肺组织中IFN-γ、IL-4 mRNA 的表达,同时支气管肺泡灌洗液(BALB)进行活菌计数,有核细胞分类计数.结果 ①肺炎rIL-18干预组BA LF中性粒细胞和巨噬细胞计数显著高于肺炎组和对照组(P＜0.001);②肺炎rIL-18 干预组BALF活菌计数显著低于肺炎组(P＜0.001);③肺炎rIL-18干预组肺组织IFN- γ mRNA表达上调而IL-4 mRNA表达下调(P＜0.001).结论 在小鼠肺炎链球菌肺炎早期给予rIL-18可诱导IFN-γ的合成,促进Th1免疫应答,使Th1/ Th2免疫平衡向Th1免疫偏移、促进宿主对肺炎链球菌的防御.     

重组BCG-Sj26GST疫苗诱导小鼠体液免疫应答的动态观察

目的　检测日本血吸虫重组BCG Sj2 6GST疫苗免疫小鼠不同时间后的血清IgG及其亚类和循环抗原 (circulat ingantigen ,CAg)反应。方法　 1× 10 6克隆形成单位 (colony formingunit,CFU)疫苗皮下和静脉注射免疫BALB/c鼠 ,分别于免疫后 0、4、8、10、14和 16周各剖杀 4只 ,收集血清 ,常规ELISA法检测IgG及其亚类和CAg ,同时设PBS皮下注射对照组。结果皮下注射组IgG在免疫后 10周 ,IgG1在免疫后 14～ 16周 ,IgG2a在免疫后 4周和IgG2b在免疫后 16周达最高水平 ,未能测到CAg ;静脉注射组IgG在免疫后 10周 ,IgG1和IgG2a在免疫后 8周以及IgG2b在免疫后 16周达最高水平 ,CAg在免疫后 14周升高。结论　日本血吸虫重组BCG Sj2 6GST疫苗能诱导宿主产生高水平的IgG、IgG2a和IgG2b ,静脉注射的免疫效果优于皮下注射     

A novel fusion protein domain III-capsid from dengue-2, in a highly aggregated form, induces a functional immune response and protection in mice

Based on the immunogenicity of domain III from the Envelope protein of dengue virus as well as the proven protective capacity of the capsid antigen, we have designed a novel domain III-capsid chimeric protein with the goal of obtaining a molecule potentially able to induce both humoral and cell-mediated immunity (CMI). After expression of the recombinant gene in Escherichia coli, the domain III moiety retained its antigenicity as evaluated with anti-dengue sera. In order to explore alternatives for modulating the immunogenicity of the protein, it was mixed with oligodeoxynucleotides in order to obtain particulated aggregates and then immunologically evaluated in mice in comparison with non-aggregated controls. Although the humoral immune response induced by both forms of the protein was equivalent, the aggregated variant resulted in a much stronger CMI as measured by in vitro IFN-γ secretion and protection experiments, mediated by CD4⁺ and CD8⁺ cells. The present work provides additional evidence in support for a crucial role of CMI in protection against dengue virus and describes a novel vaccine candidate against the disease based on a recombinant protein that can stimulate both arms of the acquired immune system.     

结核菌H37Ra在小鼠体内诱导的免疫应答及其保护力

目的:研究结核菌H37Ra免疫小鼠后产生的特异性免疫应答以及保护效果.方法:BALB/c小鼠随机分为H37Ra组、BCG组和生理盐水(NS)组,免疫8周后处死部分小鼠,取脾淋巴细胞经体外培养、PPD刺激后,MTT法检测淋巴细胞的刺激指数,ELISA法检测培养上清液中IFN-γ和IL-4水平.另一部分免疫小鼠经腹腔感染结核分枝杆菌(Mycobacterium tuberculosis,MTB)毒株H37Rv,4周后处死,测定小鼠脏器重量指数.取稀释的小鼠脾脏和肺脏匀浆接种于改良罗氏培养基,培养21天后计数脏器荷菌量.结果:H37Ra和BCG免疫小鼠脾淋巴细胞刺激指数、IFN-γ和IL-4水平均显著高于NS对照组.感染4周后H37Ra和BCG组小鼠脏器重量指数较NS对照组均显著降低.H37Ra组小鼠脾脏和肺脏荷菌量与NS对照组比较分别下降了1.228log10CFU和0.954log10CFU,差异有显著性(P<0.05),与BCG组之间差异均无显著性.结论:H37Ra免疫小鼠后可以诱导产生Th1型免疫应答,能够抵抗毒株H37Rv的攻击,且免疫效果与BCG相当.     

Recombinant BCG coexpressing Ag85B,ESAT-6 and Rv3620c elicits specific Th1 immune responses in C57BL/6 mice

Tuberculosis (TB) remains to be an enormous global health problem. The inconsistent protection efficacy of Bacille Calmette-Guérin (BCG) calls for new vaccines for TB. One choice to improve the efficacy of BCG vaccine is recombinant BCG (rBCG). Experimental evidences have revealed that Ag85B, ESAT-6 and Rv3620c are important immunodominant antigens of Mycobacterium tuberculosis. In this study, we have constructed a novel rBCG expressing fusion protein Ag85B-ESAT6-Rv3620c and evaluated the immunogenicity of this rBCG in C57BL/6 mice. Results show that there is a strong TB-specific CD4⁺ and CD8⁺ T lymphocytes proliferation in mice immunized with this rBCG vaccine. A single dose immunization of rBCG could induce a significantly strong Th1 immune response characterized by an increasing ratio of antigen-specific IgG2b/IgG1 as well as a high expression level of Th1 cytokines such as IFN-γ, TNF-α and IL-2. This conclusion was confirmed by a decreased secretion of Th2 cytokine IL-10. Moreover, this rBCG induced a strong humoral response in mice with an increasing antigen-specific IgG titer. Therefore, we concluded that this rBCG could significantly increase both Th1 type cellular immune response and antigen-specific humoral response compared with BCG. The above observations demonstrated that rBCG::Ag85B-ESAT6-Rv3620c is a potential candidate vaccine against M. tuberculosis for further study.     

Adjuvant effect of zinc oxide on Th2 but not Th1 immune responses in mice

Background and aim: We investigated the effect of zinc oxide (ZnO) on Th1 and Th2 immune responses in mice.

Material and methods: Mice were intraperitoneally administered with ovalbumin (OVA) with or without varying doses of ZnO (day 0). On day 21, anti-OVA IgG, IgG2a, IgG1, and IgE antibodies in sera, OVA-specific proliferative responses of spleen cells, and production of Th1 cytokines including IFN-γ as well as Th2 cytokines such as IL-4 and IL-5 were measured.

Results: The results showed that administration of OVA with ZnO was followed by greater increases in anti-OVA IgG and the antigen-specific splenocyte proliferation compared to that of OVA alone. The production of anti-OVA IgG1 and IgE and secretion of IL-4 and IL-5 were markedly enhanced by ZnO. The enhancing effect of ZnO on these Th2 responses was as strong as aluminium hydroxide (Alum) that was widely used as an adjuvant. In contrast, treatment with OVA plus ZnO failed to affect production of anti-OVA IgG2a as well as IFN-γ. It was also observed that ZnO had a stimulating effect on the secretion of the proinflammatory cytokine IL-17 from a new lineage of effector Th cells.

Conclusion: These results suggest that ZnO appears to have an adjuvant effect on the immune system, especially Th2 but not Th1 immune responses.     

旋毛虫新生幼虫T668重组抗原对小鼠的保护性免疫

目的研究旋毛虫新生幼虫T668重组抗原的免疫原性,制备基因工程疫苗。方法以旋毛虫新生幼虫期特异性基因T668在大肠杆菌中的表达蛋白为抗原免疫小鼠,每间隔10d免疫1次,共免疫3次。末次免疫后10d,每只小鼠攻击感染200条旋毛虫感染性肌幼虫,感染后5周用消化法检查肌幼虫(ML)负荷。结果T668重组抗原免疫组肌幼虫减虫率明显高于佐剂组和对照组。结论T668重组抗原能诱导小鼠产生一定程度的保护性免疫,且可激发特异性体液免疫。     

Dietary nucleotides can up-regulate antigen-specific Th1 immune responses and suppress antigen-specific IgE responses in mice

BACKGROUND: It has been reported that dietary nucleotides enhance T helper cell activities. In this study, we have determined the effects of dietary nucleotides on antigen-specific Th1 and Th2 responses and IgE responses. METHODS: Ovalbumin (OVA)-specific T cell receptor (TCR) transgenic (OVA-TCR Tg) mice, 3 weeks old, were fed a nucleotide-free diet (NT(-) diet) or the NT(-) diet supplemented with dietary nucleotides (NT(+) diet) for 4 weeks. Cytokine production by spleen cells and macrophages obtained from these mice was measured in vitro. BALB/c mice, 3 weeks old, immunized intraperitoneally with OVA adsorbed onto alum, were fed the NT(-) diet or the NT(+) diet for 4 weeks. Serum levels of antigen-specific antibodies in the BALB/c mice were determined by ELISA. RESULTS: The level of production of antigen-specific interferon-gamma by spleen cells was significantly higher in the OVA-TCR Tg mice fed the NT(+) diet than in the control mice. The levels of secretion of bioactive IL-12 by spleen cells and peritoneal macrophages were also significantly increased in the NT(+) diet group. The serum OVA-specific IgE level was significantly decreased in BALB/c mice fed the NT(+) diet compared with those fed the NT(-) diet. CONCLUSION: These results show that dietary nucleotides up-regulate the antigen-specific Th1 immune response through the enhancement of IL-12 production and suppress the antigen-specific IgE response.     

Hepatitis B virus S gene enhances immune responses of a multiple-epitope DNA construct of hepatitis C virus in mice

Hepatitis C virus (HCV) is a major causative agent of acute and chronic hepatitis and mainlytransmitted by blood routes. It is estimated thatthere are 170 million HCV infected individualsworldwide, and so far, interferon γ(IFN γ) com bined with ribavirin treatment is a commonly ac cepted therapeutic strategy. However, only about40% of treated patients develop long term respons es[1]. The hypervariable region 1(HVR1) of theHCV E2 envelope protein is critically …     

Mucosal delivery of antigen‐coated nanoparticles to lungs confers protective immunity against tuberculosis infection in mice

Mucosal boosting of BCG‐immunised individuals with a subunit tuberculosis (TB) vaccine would be highly desirable, considering that the lungs are the principal port of entry for Mycobacterium tuberculosis (MTB) and the site of the primary infection and reactivation. However, the main roadblock for subunit TB vaccine development is the lack of suitable adjuvants that could induce robust local and systemic immune responses. Here, we describe a novel vaccine delivery system that was designed to mimic, in part, the MTB pathogen itself. The surface of yellow carnauba wax nanoparticles was coated with the highly immunogenic Ag85B Ag of MTB and they were directed to the alveolar epithelial surfaces by the incorporation of the heparin‐binding hemagglutinin adhesion (HBHA) protein. Our results showed that the i.n. immunisation of BCG‐primed BALB/c mice with nanoparticles adsorbed with Ag85B‐HBHA (Nano‐AH vaccine) induced robust humoral and cellular immune responses and IFN‐γ production, and multifunctional CD4⁺ T cells expressing IFN‐γ, IL‐2 and TNF‐α. Mice challenged with H37Rv MTB had a significantly reduced bacterial load in their lungs when compared with controls immunised with BCG alone. We therefore conclude that this immunisation approach is an effective means of boosting the BCG‐induced anti‐TB immunity.     

PCV2-ORF2 去信号肽基因的克隆与原核表达及对小鼠免疫效力的评价

 目的 通过基因工程的方法表达猪圆环病毒 2 型的 ORF2 蛋白,并对表达蛋白进行小鼠免疫效力评价,为猪圆环病毒病疫苗的研制提供技术支持。 方法 根据 GenBank 中猪圆环病毒 2 型（PCV-2) ORF2 基因序列,设计了 1 对引物。从疑似断奶仔猪多系统衰竭综合症（PMWS）的死亡仔猪病料中提取基因组 DNA,用 PCR 方法扩增出 ORF2 去信号肽基因,将该基因克隆至原核表达载体 pET32a,获得重组质粒,经 PCR﹑酶切以及序列分析鉴定,表明插入的片段为目的基因,插入的位置、大小和阅读框均正确,成功构建了重组质粒 pet32a-ORF2,阳性重组质粒转化大肠杆菌 Blgold（DE3）,用 IPTG 诱导表达并确定表达的最佳条件,表达产物经纯化后,以每只小鼠 0.2 mg 免疫 5 周龄的雌性小鼠,然后用 ELISA 检测免疫小鼠血清中抗体的产生情况。 结果 纯化的重组蛋白能使小鼠产生了抗猪圆环病毒的特异性抗体,从第 7 d 开始产生抗体,第 28 d 抗体水平达到最高,抗体可维持 7 周以上,并具有良好的安全性。 结论 表达目的蛋白能在小鼠体内产生特异性抗体,为进一步研究猪圆环病毒亚单位疫苗奠定了基础。