Immune Responses against a New HIV-1 p24-gp41/pCAGGS-IL-12 DNA Vaccine in Balb/c Mice

Background: Development of an effective vaccine is highly needed in order to restrict the AIDS pandemic. DNA vaccines initiate both arms of immunity without the potential of causing disease. HIV-1 p24 and gp41 (gag and env) proteins play important roles in viral pathogenesis and are effective candidates for immune induction and vaccine design. Objective: In this study, new DNA vaccine candidates constructed from HIV-1 fused p24-gp41 or gp41 alone were evaluated in Balb/c mice for induction of cellular and humoral immune responses. Methods: Recombinant plasmids, pcDNA3.1/Hygro expression vector containing immunogenic sequences of fused p24-gp41 or gp41alone were produced. Dendrosome used as a system for carrying vectors in laboratory animals, and an IL-12 containing vector (pCAGGS-IL-12) was co-immunized with the p24-gp41 vector as a genetic adjuvant. Induction of effective immune responses against the designed vectors as DNA vaccine candidates in Balb/c mice was evaluated. Levels of total antibodies, IgG isotypes (IgG2a and IgG1); IFN-γ and IL-4 were measured by ELISA. MTT assay was used to evaluate lymphoproliferation. Results: The results confirmed that the immunogenic epitopes of both p24 and gp41 genes are highly effective inducers of immune responses, and administration of fused p24-gp41 alone or along with IL-12 resulted in further enhancement of immune responses. Group 4 that received fused fragments (p24-gp41) along with an IL-12 expressing vector demonstrated a significantly higher Stimulation Index (SI) and IFN-γ production (p<0.0001) with a significant increase in IgG2a/IgG1 ratio, indicating the stimulation of CMI towards Th1. Although gp41 containing vector (group 6) also showed significant increases in both proliferation and IFN-γ production, the responses were persistently lower than that of p24-gp41 containing vectors. Total antibody production was highest in group 6 as expected. Conclusion: Dendrosome proved to be an efficient carrier of recombinant plasmids constructed in this study. Further studies are necessary to evaluate these constructs as HIV vaccine candidates.     

CEA Plasmid as Therapeutic DNA Vaccination against Colorectal Cancer

Background: Human colorectal cancer cells overexpress carcinoembryonic antigen (CEA). CEA is a glycoprotein which has shown to be a promising vaccine target for immunotherapy against colorectal cancer. Objective: To design a DNA vaccine harboring CEA antigen and evaluate its effect on inducing immunity against colorectal cancer cells in tumor bearing mice. Methods: In the first step the coding sequence of the CEA was cloned into the pcDNA3.1 vector. The mice were injected with the vaccine construct and the immune responses were monitored during the experiment period. The specific IgG anti-CEA, IFN-γ, IL-2 and IL-4 were measured by ELISA and levels of IFN-γ was detected by ELISpot assay. The lymphocyte proliferation was assessed using a 5-bromo-2-deoxyuridine (BrdU) cell proliferation assay kit. Results: Immunization of the mice with the CEA plasmid resulted in stimulation of CEA-specific T cell and antibody responses. The serum level of specific IgG antibodies against CEA was increased in immunized mice. Moreover, the injection of CEA plasmid led to the stimulation of T-helper-1 by increase in the secretion of IFN-γ, IL-2 and lymphocyte proliferation response. Conclusion: As the CEA DNA vaccine displayed encouraging antitumor effects, therefore, we suggest that it can be a potential therapeutic modality for colorectal cancer and is worthy of further investigation.     

结核分枝杆菌MPT64抗原DNA疫苗在小鼠体内诱导的免疫应答

目的研究结核分枝杆菌MPT64抗原DNA疫苗在小鼠体内诱导的免疫应答。方法用表达MPT64的真核表达质粒pcDNA-M免疫BALB/c小鼠,ELISA法检测免疫小鼠的特异性抗体滴度和抗体亚类。分离免疫小鼠的脾淋巴细胞,检测淋巴细胞增殖、IFN-γ和IL-12产生水平、流式细胞仪计CD4+细胞和CD8+细胞数、脾淋巴细胞特异性CTL杀伤效应。结果MPT64基因免疫可诱导小鼠高水平的体液免疫应答,免疫小鼠脾淋巴增殖显著,IFN-γ和IL-12含量增加,CD4+细胞和CD8+细胞百分比明显增加,CTL杀伤效应明显。结论MPT64 DNA疫苗可诱导小鼠有效的体液和细胞免疫应答,有可能作为新型TB疫苗的组分。     

Characterization of Immune Responses Induced by Combined Clade-A HIV-1 Recombinant Adenovectors in Mice

Background: Numerous evidences indicate that in some HIV-1 positive patients, the humoral and cellular immune responses are induced against HIV-1 proteins and this is inversely related to the progress of infection. Objective: The aim of this study was the evaluation of the Adenovectors containing HIV genes in induction of immune responses in mice. Methods: The HIV-1 genes including gag p24, rev, nef and exon-1 of tat were amplified from HIV-1 RNA (clade-A). The cDNA of each gene was cloned into a transfer vector. The transfer vector was then co-transformed into E. coli strain BJ5183 together with pAdenovector ΔE1/E3. The recombinant adenoviral construct was transfected into QBI-293A cells. Recombinant viruses were purified and titrated on 293 cell plates. Expression of transgenes was evaluated using western blotting. Then 1012 viral particles were injected into 15 groups of 5 mice and all patterns of combination of these 4 HIV-1 genes were evaluated. After 2 weeks, humoral and cellular immune responses were evaluated using ELISA, cell proliferation and ELISpot (IL-2, IL-4 and IFN-γ) assays, consecutively. Results: It was demonstrated that each gene was expressed. The response targets were mostly toward Th1, though several Th2 responses were also observed. Single injection in our study induced a good cellular response but the humoral responses were not as strong as the cellular ones. Conclusion: Considering and comparing all results and evaluating the various possible interactions revealed that simultaneous injection of tat and gag has enhanced the humoral and cellular responses.     

Immunogenicity of a novel DNA vaccine cassette expressing multiple human immunodeficiency virus (HIV-1) accessory genes

OBJECTIVE: To develop an HIV-1 accessory gene immunogen using a DNA vaccine approach. METHODS: HIV-1 accessory genes vif, vpu and nef were modified to express under the control of a single promoter with cellular proteolytic cleavage sites between the coding sequences (VVN-P). Immune responses induced by these constructs were evaluated in mice. RESULTS: DNA vaccine construct (pVVN-P) expressing Vif, Vpu and Nef was processed and the fusion protein was cleaved appropriately. Vif, Vpu and Nef as a fusion protein with proteolytic cleavage sites (VVN-P) is able to induce a significant level of cellular immune responses. We also observed that accessory genes Vif, Vpu and Nef (VVN-P) induced an effective T helper 1 proliferative response measured by cytokine production. Furthermore, expression cassette pVVN-P was able to induce cytotoxic T lymphocyte (CTL) responses against diverse HIV-1 viruses in infected target cells. CONCLUSION: We conclude that cell-mediated immune responses induced by accessory gene constructs from clade B may have a broader recognition of divergent HIV-1 viruses and should be further examined for both prophylactic and therapeutic vaccination schemes against HIV-1.     

Immunogenicity of a DNA Vaccine Encoding Ag85a-Tb10.4 Antigens from Mycobacterium Tuberculosis

Background: Tuberculosis is a life threatening disease that is partially prevented by BCG vaccine. Development of more effective vaccines is an urgent priority in TB control. Ag85a and Tb10.4 are the members of culture filter protein (CFP) of M. tuberculosis that have high immunogenicity. Objective: To analyze the immunogenicity of Ag85a-Tb10.4 DNA vaccine by enzyme-linked immunosorbent assay (ELISA). Methods: In this study a previously described plasmid DNA vaccine encoding Ag85a-Tb10.4 was used to examine its capability in the stimulation of immune responses in an animal model. Female BALB/c mice were vaccinated with 100 μg of purified recombinant vector intramuscularly 3 times at two-week intervals and the levels of five cytokines including IFN-γ, IL-12, IL-4, IL-10 and TGF-β were measured. Results: The levels of IFN-γ and IL-12 for the mice following immunization with Ag85A-Tb10.4 was significantly greater than that of the BCG and control group (p<0.05). However there was no significant difference in the levels of IL-4, IL-10 and TGF-β between groups. Conclusion: IFN-γ and IL-12 Th1 cytokines increased significantly in mice vaccinated with Ag85a-TB10.4 DNA vaccine in comparison to the control and BCG groups. Our results may serve as groundwork for further research into the prevention and treatment of tuberculosis.     

Vaccine for tuberculosis: up-regulation of IL-15 by Ag85A and not by ESAT-6

IFN-γ is the most commonly measured cytokine released by the cells to define the cellular immune responses induced by the vaccine candidates for tuberculosis. IL-15 acts as a co-stimulator in IFN-γ production by NK cells and may therefore be important in the control of Mycobacterium tuberculosis that requires IFN-γ for clearance. The aim of the study is to determine whether Ag85A can also stimulate the innate immune response through the expression of IL-15, a cytokine that bridges the innate and adaptive immune systems. The expression of IL-15 was up regulated by about 4 fold in PPD+ healthy controls as compared with TB patients. Significantly higher expression of IL-15 mRNA in the Ag85A stimulated cells not only in PPD+ healthy controls but also in TB patients substantiates the use of Ag85A as a vaccine candidate over ESAT-6.     

IL-18 enhances protective effect in mice immunized with a Schistosoma japonicum FABP DNA vaccine

Two recombinant plasmids, pVAX/SjFABP and pVAX/mIL-18 containing Schistosoma japonicum 14 kDa fatty acid binding protein (SjFABP) and murine IL-18, were constructed and evaluated for their ability to induce immune responses and to protect against S. japonicum challenge in mice. Mice were intramuscularly immunized twice at three-weekly intervals, and challenged with S. japonicum cercariae at 4 weeks after the last vaccination. All animals vaccinated with pVAX/SjFABP alone or plus pVAX/mIL-18 developed specific anti-SWAP ELISA antibody and T lymphocyte proliferation. Co-injection of pVAX/mIL-18 significantly increased the production of IFN-γ and IL-2 compared with pVAX/SjFABP alone, indicating that IL-18 enhances the Th1-dominant immune response. The challenge experiment showed that co-injection of plasmid encoding IL-18 significantly enhances protective effect against S. japonicum infection, as demonstrated by worm reduction rates and the hepatic egg reduction rates 45 days post-challenge. These results indicated that IL-18 may become a novel vaccine adjuvant for development of vaccines against schistosomiasis.     

结核分枝杆菌Rpf-DNA疫苗对Mtb感染小鼠免疫保护作用的研究

目的 评价Mtb复苏因子DNA疫苗（resuscitation-promoting factor DNA,Rpf-DNA）对Mtb感染宿主的免疫保护作用。 方法 构建复苏因子D(Rpf D-DNA)和复苏因子E(Rpf E-DNA)质粒疫苗,180只BALB/c小鼠（4周龄）分为6组,每组30只,分别用空质粒、Rpf D-DNA质粒、Rpf E-DNA质粒、BCG、生理盐水免疫,H37Rv标准株气溶胶感染。检测血清复苏因子（Rpf）抗体、IFN-γ;RpfD、E刺激淋巴细胞后进行淋巴细胞增殖、细胞杀伤实验;检测细胞上清IFN-γ、IL-12、IL-2;对肺组织进行病理学检测和细菌负荷（CFU）计数。 结果 （1）疫苗免疫组血清Rpf D、Rpf E抗体水平：Rpf D组0.32±0.1,Rpf E组0.39±0.1,BCG组0.02±0.01,空质粒组0.01±0.0,生理盐水组0.09±0.04,空白对照组0.03±0.01,RpfD组与RpfE组抗体水平与BCG组、空质粒组、生理盐水组、空白对照组比较差异有显著统计学意义,F值分别为Rpf D：45.6,43.2,45.1,45.7;Rpf E：51.6,53.6,51.0,52.2;P值均<0.01。血清IFN-γ：Rpf D组（43.9±24.8）pg/ml,Rpf E组（45.9±21.0）pg/ml,BCG组（21.0±11.0）pg/ml,空质粒组（7.9±4.9）pg/ml,生理盐水组（4.7±2.1）pg/ml,空白对照组（5.8±4.7）pg/ml,Rpf D、Rpf E质粒组与BCG组比较差异有统计学意义（F值分别为Rpf D：10.2;Rpf E：12.4;P值均<0.05）, 与空质粒组、生理盐水组、空白对照组比较差异有显著统计学意义,F值分别为Rpf D：15.6,17.8,17.3;Rpf E：17.5,21.1,20.7;P值均<0.01。（2）淋巴细胞增殖实验CCK-8：Rpf D组176.0±4.2,Rpf E组183.0±4.3,BCG组101.0±1.1,空质粒组100.0±6.8,生理盐水组104.0±8.4,空白对照组116.0±2.2,RpfD、RpfE质粒组与BCG组、空质粒组、生理盐水组、空白对照组比较差异有统计学意义,F值分别为Rpf D：9.5,10.1,10.0,9.0;Rpf E：11.2,12.9,11.7,10.3;P值均<0.05。细胞杀伤实验：Rpf D组32.0±3.2,Rpf E组30.0±4.2,BCG组16.0±5.9,空质粒组3.3±1.5,生理盐水组6.7±0.5,空白对照组7.3±3.5,Rpf D、Rpf E质粒组与BCG组、空质粒组、生理盐水组、空白对照组比较差异有统计学意义,F值分别为Rpf D：8.8,14.5,13.7,11.9;Rpf E：8.1,12.5,11.6,11.1;P值均<0.05。（3）Rpf D、Rpf E蛋白各自刺激淋巴细胞后上清细胞因子检测：IL-2：Rpf D组9.5±2.4,Rpf E组9.2±1.2,BCG组2.4±2.1,空质粒组1.2±0.3,生理盐水组1.8±1.0,空白对照组1.5±0.7,Rpf D、Rpf E质粒组与其他各组比较差异有统计学意义,F值分别为Rpf D：12.5,14.6,13.5,13.9;Rpf E：12.0,13.6,13.1,13.2;P值均<0.05。IFN-γ：Rpf D组22.2±5.7,Rpf E组28.7±14.4,BCG组16.1±10.1,空质粒组9.8±1.6,生理盐水组13.2±2.1,空白对照组15.7±2.9,RpfD、RpfE质粒组与其他各组比较差异有统计学意义,F值分别为Rpf D：7.8,12.6,8.7,8.3;Rpf E：11.3,16.4,14.7,14.2;P值均<0.05。 结论 实验表明复苏因子疫苗能诱导Mtb感染小鼠产生体液免疫和细胞免疫,有希望成为结核病候选疫苗之一。     

树突状细胞DNA多价疫苗抗日本血吸虫感染作用机制的研究

摘 要：目的 探讨树突状细胞（DC）DNA混合多价疫苗抗日本血吸虫感染保护性免疫作用机制。方法 BALB/c小鼠耳廓分别注射Sj26、Sj23和Sj14基因转染DC（A组）、Sj26基因转染DC（B组）、Sj23基因转染DC（C组）、Sj14基因转染DC（D组）、pcDNA3转染DC（E组）、未处理DC（F组）和RPMI-1640（G组）,共免疫3次,间隔2周,末次免疫后第2周,每鼠经皮肤感染40条日本血吸虫尾蚴。ELISA法检测血清特异性IgG抗体、干扰素-γ（IFN-γ）和白细胞介素-4（IL-4）水平,双夹心ELISA法检测脾淋巴细胞经ConA和可溶性虫卵抗原（SEA）刺激后培养上清中IFN-γ和IL-4水平,噻唑蓝（MTT）法检测脾淋巴细胞的增殖。结果 A组小鼠末次免疫后第2周血清特异性IgG抗体水平显著升高（与G组比较,P<0.001）。A组小鼠免疫后血清IFN-γ水平明显升高(P<0.01),而血清IL-4的水平,各组小鼠免疫前、后无明显变化。A组小鼠脾淋巴细胞经ConA和SEA刺激后诱生的IFN-γ水平显著增高,而IL-4水平显著降低(与G组比较,P<0.001)。A组小鼠脾淋巴细胞的刺激指数高于其他各组（与G组比较,P<0.001）。结论 体液免疫和细胞免疫共同参与了DC DNA混合多价疫苗诱导的保护性免疫作用,其中Th1型免疫应答在抗日本血吸虫感染的保护性免疫中起主要作用。 关键词：日本血吸虫;树突状细胞;DNA疫苗;保护性免疫     

Combined Immunization of Mice with DNA, rMVA and rAd5 Expressing HIV-1 Structural Genes from Different Subtypes

The objective of present paper is to study the immunogenicity of combinations of multiple vector vaccines expressing HIV-1 structural genes from different subtypes. Mice were vaccinated with DNA (B'/C) and rMVA (B'/C) vaccines expressing B'/C recombinant subtype gag-pol and env genes, DNA (B') and rAd5 (B') vaccines expressing subtype B' gag gene with different combination schemes. HIV-1 Gag-specific cellular immune responses and P24- specific IgG levels were analyzed by IFN-γ enzyme-linked immunospot assay (ELISPOT) and enzyme-linked immunosorbent assay (ELISA) respectively. ELISPOT results indicated that the Gag-specific cellular immune responses induced by combination of three vaccines were much higher than that induced by combination of two vaccines. Among the groups of mice immunized with two vaccines, the groups with rAd5 booster elicited higher cellular immune responses compared with the groups with rMVA booster. All the test groups of three vaccines in combination could induce similar level of cellular immune responses, which did not correlate with the immunization order. ELISA results showed that p24- specific IgG induced by combination of three vaccines were much higher than that induced by combination of two vaccines. It indicates that the combination scheme of multiple vector vaccines maybe a promising AIDS vaccine strategy.     

An Endogenous Immune Adjuvant Released by Necrotic Cells for Enhancement of DNA Vaccine Potency

Background: Improving vaccine potency in the induction of a strong cell-mediated cytotoxicity can enhance the efficacy of vaccines. Necrotic cells and the supernatant of necrotic tumor cells are attractive adjuvants, on account of their ability to recruit antigen-presenting cells to the site of antigen synthesis as well as its ability to stimulate the maturation of dendritic cells. Objective: To evaluate the utility of supernatant of necrotic tumor cells as a DNA vaccine adjuvant in a murine model. Method: The supernatant of EL4 necrotic cells was co-administered with a DNA vaccine expressing the glycoprotein B of Herpes simplex virus-1 as an antigen model under the control of Cytomegalovirus promoter. C57BL/6 mice were vaccinated three times at two weeks intervals with glycoprotein B DNA vaccine and supernatant of necrotic EL4 cells. Five days after the last immunization, cell cytotoxicity, IFN-γ and IL-4 were evaluated. Results: The obtained data showed that the production of IFN-γ from the splenocytes after antigenic stimulation in the presence of the supernatant of necrotic EL4 cells was significantly higher than the other groups (p<0.002). The flow cytometry results showed a significant increase in the apoptosis/necrosis of EL4 cells in the mice immunized with DNA vaccine and supernatant of necrotic EL4 cells comparing to the other groups (p<0.001). Conclusion: The supernatant of necrotic cells contains adjuvant properties that can be considered as a candidate for tumor vaccination.     

Sjcb2 DNA疫苗在血吸虫感染小鼠中的保护性作用研究

目的 研究Sjcb2 DNA疫苗在日本血吸虫病小鼠模型中的保护性作用和机制,为血吸虫疫苗的研究提供有效的候选抗原分子。方法 构建pcDNA3.1(+)/Sjcb2 核酸疫苗,将6周龄雌性BALB/c小鼠随机分为pcDNA3.1(+)/Sjcb2 核酸疫苗组、pcDNA3.1(+)空质粒组及生理盐水组,每组35只,采用后腿股四头肌注射方法,每次免疫质粒DNA 100 μg,每2周免疫1次,共免疫3次,用日本血吸虫尾蚴攻击感染各组小鼠。PCR及免疫组化法检测Sjcb2基因在小鼠体内的稳定性及表达情况;MTT法检测小鼠脾淋巴细胞特异性增殖反应;ELISA法检测小鼠血清中Sjcb2抗体水平及攻击感染前后脾淋巴细胞培养上清中IFN-γ和IL-4的水平;计数小鼠荷成虫对数和肝脏荷虫卵数。结果 疫苗组小鼠均可在小鼠肌细胞中检测到Sjcb2基因及其抗原的表达;DNA疫苗组T细胞增殖显著增高(P <0.05);ELISA 结果显示疫苗组IFN-γ 水平显著增高(P <0.05),血吸虫尾蚴攻击感染后各组小鼠IL-4水平显著升高(P <0.05)。DNA疫苗组小鼠荷成虫对数及肝脏荷虫卵数与其它组比较显著性减少(P <0.05),其减虫率为36.32％,减卵率为60.61％。结论 Sjcb2 DNA疫苗接种小鼠后能在小鼠肌细胞中稳定存在和表达;Sjcb2可能通过提高IFN-γ 和降低IL-4水平调节Th1细胞亚群产生抗血吸虫感染的保护性作用。     

Short communication: human lymphotropic virus type 1 coinfection modulates the synthesis of cytokines by peripheral blood mononuclear cells from HIV type 1-infected individuals

HIV-1 and HTLV-1 infect CD4(+) T lymphocyte but little is known about the impact of coinfection on patient's immune response. In this study we have evaluated the spontaneous production of interleukin (IL)-2, IL-4, IL-6, and IL-10 and interferon (IFN)-γ by unstimulated peripheral blood mononuclear cell (PBMC) cultures obtained from patients infected by HTLV-1, HIV-1, or both viruses. We have observed that HIV/HTLV-coinfected individuals presented significantly higher production of IL-2 and IFN-γ compared to both HIV single-infected and HTLV single-infected individuals. IL-6 and IL-10 synthesis was similar in all infected groups, but HTLV single-infected individuals presented a lower production of IL-4. These results show that HIV/HTLV-coinfected individuals presented a profile of higher production of Th-1 cytokines, suggesting a predominant stimulus of HTLV-1 in detriment to HIV-1 infection.     

Long-term persistence of HIV-1 vaccine-induced CD4+CD45RA-CD62L-CCR7- memory T-helper cells

OBJECTIVE: To determine in chimpanzees if candidate HIV-1 subunit protein vaccines were capable of eliciting long-lasting T-cell memory responses in the absence of viral infection, and to determine the specific characteristics of these responses. DESIGN: A longitudinal study of cell-mediated immune responses induced in three chimpanzees following immunization with subunit envelope glycoproteins of either HIV-1 or herpes simplex virus (HSV)-2. Following these pre-clinical observations, four human volunteers who had been immunized 7 years previously with the same HIV-1 vaccine candidate donated blood for assessment of immune responses. METHODS: Responses were monitored by protein and peptide based ELISpot assays, lymphocyte proliferation, and intracellular cytokine staining. Humoral responses were assessed by enzyme-linked immunosorbent assay and virus neutralization assays. RESULTS: Although antigen (Ag)-specific CD4 T-cell responses persisted for at least 5 years in chimpanzees, CD8 T-cell responses were discordant and declined within 2 years. Detailed cellular analyses revealed that strong Th1 in addition to Th2 type responses were induced by AS2/gp120 and persisted, whereas CD8 T-cell memory declined in peripheral blood. The specificity of both Th and cytotoxic T-lymphocyte responses revealed that the majority of responses were directed to conserved epitopes. The remarkable persistence of Ag-specific CD4 T-cell memory was characterized as a population of the CD45RA-CD62L-CCR7- "effector phenotype" producing the cytokines IFNgamma, IL-2 and IL-4 upon epitope-specific recognition. Importantly, results in chimpanzees were confirmed in peripheral blood of one of four human volunteers studied more than 7 years after immunization. CONCLUSION: These studies demonstrate that epitope-specific Th1 and Th2 cytokine-dependent Th responses can be induced and maintained for longer than 5 years by immunization with subunit proteins of HIV-1.     

多房棘球绦虫elp基因核酸疫苗诱生免疫应答的实验研究

目的观察多房棘球绦虫elp基因核酸疫苗免疫BALB/c小鼠引起的体液和细胞免疫应答。方法30只BALB/c小鼠随机分成3组:Ⅰ组,肌注空质粒(pcDNA3.1)100μg/鼠;Ⅱ组,肌注多房棘球绦虫elp基因真核表达重组质粒(pcD-ELP)100μg/鼠;NS组,肌注等体积生理盐水。每2周免疫1次,共3次。ELISA方法检测免疫后不同时间产生的特异性IgG1,IgG2a和IgG 2 b水平。双抗体夹心ELISA法检测免疫鼠脾脏单个核细胞(PMNC)在受到特异抗原刺激后,产生IL-4I、L-12和IFN-γ的能力,3H-TdR掺入法检测脾淋巴细胞的增值能力。结果首次免疫后4周,Ⅱ组小鼠血清可检测到特异性IgG1I、gG2a和IgG2b抗体,随免疫时间和免疫次数的增加3种特异性抗体的OD值逐渐增高,实验结束时(首次免疫后7周)3种特异性抗体OD值均最高。Ⅰ组和Ⅱ组小鼠脾PMNC培养上清中IFN-γ浓度分别为50 pg/ml和55 pg/ml,受特异抗原刺激后分别为44 pg/ml和101.5 pg/ml。NS组IFN-γ及各组IL-4和IL-12均未检出。Ⅰ组和Ⅱ组小鼠脾淋巴细胞增殖能力增高,其淋巴细胞CPM值分别为NS组的85倍和123倍,受到特异抗原或刀豆素刺激其淋巴细胞增殖更明显。结论多房棘球绦虫elp基因核酸疫苗可刺激BALB/c小鼠同时产生很强的细胞免疫和体液免疫应答。     

弓形虫SAG1单基因疫苗与SAG1-ROP2复合基因疫苗的免疫效果观察

目的构建弓形虫主要表面抗原SAG1单价基因疫苗及其与棒状体蛋白ROP2的复合基因疫苗,接种BALB/c小鼠,观察疫苗的免疫保护性。方法构建重组质粒pcDNA3.1SAG1及pcDNA3.1SAG1ROP2。将两核酸疫苗分别免疫小鼠,ELISA法检测血清IgG抗体、IFNγ、IL4;流式细胞仪测定T细胞亚群;弓形虫速殖子腹腔攻击感染观察小鼠生存时间。结果获得pcDNA3.1SAG1、pcDNA3.1SAG1ROP2重组质粒;pcDNA3.1SAG1ROP2组小鼠IgG抗体(P<0.05)、IFNγ(P<0.01)及CD8+细胞比例(P<0.05)均高于pcDNA3.1SAG1组;实验组组均未测到IL4;复合基因组感染弓形虫后生存时间较单基因组延长(P<0.01)。结论弓形虫不同生活阶段的抗原基因复合疫苗较单基因疫苗具有更好的免疫保护性。     

Application of SCR priming VLP boosting as a novel vaccination strategy against HIV-1

Human immunodeficiency virus infection is a worldwide health problem and a protective vaccine is desperately needed to control the AIDS pandemics. To address this concern, we previously constructed single-cycle replicable (SCR) HIV-1 virions, which completely maintained the antigenic structures of HIV-1. Herein, to optimize a vaccination strategy, we studied the immunogenicity of produced SCR virions and adjuvant-formulated HIV-1 virus-like particles (VLPs) in homologous and heterologous prime-boosting regimens. Accordingly, BALB/c mice received three doses of immunogens in 3-week intervals and their immune responses were evaluated using ELISA, cytokine and IFN-γ ELISpot assays. These analyses not only indicated the superiority of SCR prime-VLP boosting for strong induction of specific IFN-γ producing cells, but also showed the capability of this strategy over the others for better stimulation of humoral response, which was evidenced with the detection of highest titer of total IgG against HIV ENV glycoprotein. Furthermore, determination of IgG subclasses and IFN-γ/IL4 secretion ratio in cultured splenocytes demonstrated the efficient augmentation of mixed responses with the dominancy of Th1 immunity following SCR/VLP immunization strategy. Our results additionally pointed towards the applicability of Montanide ISA 720 + CpG as a potent Th1-directing adjuvant mixture. Overall, this study suggests SCR prime-VLP boosting as a promising approach in HIV vaccine development.     

卡氏肺孢子菌pVAX-p55-v3 DNA疫苗免疫原性研究

目的用构建的pVAX-p55-v3DNA疫苗免疫SD大鼠,以pVAX-p55-v0作为阳性对照,从细胞及体液免疫水平研究其免疫保护作用机制。方法分别将pVAX-p55-v3、pVAX-p55-v0(阳性对照)DNA疫苗免疫SD大鼠(以pVAX1空载体及PBS作为阴性对照),然后按常规方法建立PC动物模型,于第6周处死大鼠,制作肺印片,计数包囊;取脾,做淋巴细胞增殖试验,测定各组大鼠脾T细胞增殖水平;取血,分离血清,采用ELISA法测定血清中细胞因子IFN-γ、IL-4、IL-2及抗体水平,评价疫苗的免疫水平就其免疫保护作用。结果与pVAX-p55-v0组一样,pVAX-p55-v3免疫组肺印片包囊数较PBS及pVAX1对照组明显减少[(1.75±0.98)个,P<0.05),脾T淋巴细胞显著增殖[(0.1937±0.0156),P<0.05),血清IFN-γ、IL-2水平增高明显[(74.279±2.215)pg/ml,(47.409±3.814)pg/ml,P<0.05),血清IgG显著增高[(1.22±0.09),P<0.05),而免疫下调因子IL-4水平各实验组之间无显著性差异(P>0.05)。结论重组DNA疫苗pVAX-p55-v3可诱导大鼠产生保护性免疫应答。其免疫保护效应与p55-v0DNA疫苗无显著差别。