Immune Responses to Antigens of in vitro Reared Echinococcus granulosus Adult Worms in Balb/c Mice

Background: Cystic echinococcosis (CE), also known as echinococcosis/hydatidosis, is one of the most important parasitic diseases in the world. It enhances both humoral and cellular (Th1 and Th2) responses in infected host. Different antigens of the worm may favor the Th1 or Th2 immune responses in CE patients. Objective: To evaluate the humoral and cellular immune responses of Balb/c mice against the crude and excretory/secretory (E/S) antigens of in vitro reared Echinococcus granulosus adult worms. Methods: A total of 20 Balb/c mice divided into 5 groups of 4 mice each. Three groups of mice (n=4) were immunized with crude, E/S and an immunodominant antigen of in vitro reared Echinococcus granulosus adult worms on day 1 and 28. The fourth and the fifth groups were negative control groups and received PBS plus adjuvant, or nothing, respectively. Two weeks after the second injection, the mice were killed and their blood was collected for determining antibody responses, and their spleens were employed for proliferation assay. Total IgG was measured by indirect ELISA. Spleen cells of immunized mice were cultivated and exposed to different antigens of adult worms including E/S and crude antigens. Levels of IFN-γ, IL-12, IL-4 and IL-10 were measured in the recovered cell culture supernatants by capture ELISA. Results: Total IgG assay showed the highest level of antibody produced in mice immunized with crude antigens. Proliferation assay showed a statistically significant production of cytokines in the mice immunized with crude antigens (p<0.05). The highest levels of IFN-γ, IL-12 and IL-4 were produced in mice immunized with crude antigen of the in vitro reared Echinococcus granulosus adult worms followed by E/S antigens. Immunodomonant antigen induced the lowest levels of cytokines (IL-12, IFN-γ, IL-4 and IL-10) in immunized mice. Conclusion: Significant levels of Th1 related cytokines (IFN-γ and IL-12) were produced in Balb/c mice immunized with crude antigen of the in vitro reared Echinococcus granulosus adult worms.     

vJ38gag/IFNα-2b基因共表达核酸疫苗免疫程序的优化

目的　观察国际流行株HIV - 1gag与IFNα - 2b基因共表达颗粒化抗原疫苗与质粒DNA核酸疫苗免疫程序优化的效果。方法　将质粒 pJ38gag/IFNα- 2b经脂质体介导转染RK细胞 ,并在痘苗病毒中共表达HIV - 1gag与IFNα - 2b基因 ,以间接免疫荧光与斑点酶联免疫法鉴定其表达产物。以表达产物与质粒DNA联合免疫小鼠实验 ,检测淋巴细胞转化率、细胞毒性T细胞杀伤活性、CD+ 4 、CD+ 8细胞计数与体液免疫水平。结果　pJ38gag/IFNα - 2b基因表达的颗粒化抗原疫苗具有良好的免疫原性 ,3vJ38gag/IFNα- 2b +pJ38gag/IFNα- 2b联合免疫效果优于vJ38gag/IFNα - 2b单独免疫。 结论　pJ38gag/IFNα- 2b基因表达的颗粒化抗原疫苗能诱导机体产生细胞免疫与体液免疫。     

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.     

Elicitation of immunity to HIV type 1 Gag is determined by Gag structure

The gag gene of the human immunodeficiency virus type 1 (HIV-1) encodes for viral proteins that self-assemble into viral particles. The primary Gag gene products (capsid, matrix, and nucleocapsid) elicit humoral and cellular immune responses during natural infection, and these proteins are included in many preclinical and clinical HIV/AIDS vaccines. However, the structure (particulate or soluble) of these proteins may influence the immunity elicited during vaccination. In this study, mice were inoculated with four different HIV-1 Gag vaccines to compare the elicitation of immune responses by the same Gag immunogen presented to the immune system in different forms. The immunity elicited by particles produced in vivo by DNA plasmid (pGag) was compared to these same proteins retained intracellularly (pGag(DMyr)). In addition, the elicitation of anti- Gag immunity by Gag(p55) virus-like particles (VLPs) or soluble, nonparticulate Gag(p55) proteins was compared. Enhanced cellular responses, but almost no anti-Gag antibodies, were elicited with intracellularly retained Gag proteins. In contrast, DNA vaccines expressing VLPs elicited both anti-Gag antibodies and cellular responses. Mice vaccinated with purified Gag(p55) VLPs elicited robust humoral and cellular immune responses, which were significantly higher than the immunity elicited by soluble, nonparticulate Gag(p55) protein. Overall, purified particles of Gag effectively elicited the broadest and highest titers of anti-Gag immunity. The structural form of Gag influences the elicited immune responses and should be considered in the design of HIV/AIDS vaccines.     

日本血吸虫重组谷胱甘肽-S-转移酶诱生的保护性免疫应答特征的研究

目的：研究日本血吸虫重组谷胱甘肽－Ｓ－转移酶（ｒｅＳｊｃ２６ＧＳＴ）在不同品系小鼠（ＢＡＬＢ／ｃ小鼠及Ｃ５７ＢＬ／６小鼠）诱生免疫应答的差异。方法：将ｒｅＳｊｃ２６ＧＳＴ（弗氏佐剂）经皮下免疫ＢＡＬＢ／ｃ小鼠及Ｃ５７ＢＬ／６小鼠,收集免疫前和免疫后血清及取小鼠脾脏,分析ｒｅＳｊｃ２６ＧＳＴ免疫小鼠诱生的特异性抗体、脾脏淋巴细胞特异性增殖能力及细胞因子种类等。结果：ｒｅＳｊｃ２６ＧＳＴ免疫Ｃ５７ＢＬ／６小鼠所诱生的抗体总ＩｇＧ及ＩｇＧ亚类均较明显高于免疫ＢＡＬＢ／ｃ小鼠。抗体ＩｇＧ亚类分析显示,ｒｅＳｊｃ２６ＧＳＴ在Ｃ５７ＢＬ／６小鼠诱生较高滴度的ＩｇＧ１和ＩｇＧ２ａ及ＩｇＧ２ｂ（血清按１∶４００稀释,Ａ４９２ｎｍ值分别为＞３．０、１．１２７、＞３．０）,而在ＢＡＬＢ／ｃ小鼠主要诱生较低滴度的ＩｇＧ１和ＩｇＧ２ａ及ＩｇＧ２ｂ（血清按１∶４００稀释,Ａ４９２ｎｍ值分别为１．１８９、０．３９、０．６２５）;ｒｅＳｊｃ２６ＧＳＴ免疫能够诱导小鼠Ｔｈ细胞激活。细胞因子分析显示ｒｅＳｊｃ２６ＧＳＴ免疫Ｃ５７ＢＬ／６小鼠既能诱生较高水平的ＩＬ－２及ＩＦＮ－γ,又能诱生ＩＬ－５。而ｒｅＳｊｃ２６ＧＳＴ免疫ＢＡＬＢ／ｃ小鼠仅     

Induction of strong anti-HIV cellular immunity by a combination of Clostridium perfringens expressing HIV gag and virus like particles

The lower gastrointestinal tract is a major mucosal site of HIV entry and initial infection. Thus, the induction of strong cellular immune responses at this mucosal site will be an important feature of an effective HIV vaccine. We have used a novel prime-boost vaccination approach to induce immune responses at mucosal sites. Orally delivered recombinant Clostridium perfringens expressing HIV-1 gag (Cp-Gag) was evaluated for induction of HIV-1 Gag specific T cell responses in a prime-boost model with intranasal inoculation of HIV-1 virus like particles (VLP). HIV-1 specific cellular immune responses in both the effector (Lamina propria) and inductive sites (Peyer's patches) of the gastrointestinal (GI) tract were significantly higher in mice immunized using Cp-Gag and VLPs in a prime-boost approach compared to mice immunized with either Cp-Gag or VLPs alone. Such cellular immune response was found to be mediated by both CD8(+) and CD4(+) T cells. Such a strong mucosal immune response could be very useful in developing a mucosal vaccine against HIV-1.     

Synergistic effect of combined HIV/HCV immunogens: a combined HIV-1/HCV candidate vaccine induces a higher level of CD8+ T cell-immune responses in HLA-A2.1 mice

Dual infections with HIV-1 and Hepatitis C virus (HCV) may proceed in concert to cause severe disease. HIV positive individuals that become infected with HCV advance more rapidly to AIDS than those that are infected with HIV-1 alone. In this study, HLA-A2.1 mice were immunized with a combination vaccine including HIV and HCV immunogens (polycistronic DNA + proteins) or vaccine containing either HIV or HCV immunogens. Mice immunized with the combined HIV/HCV regimen had similar antibody titers as the group receiving either the HIV-1 or HCV only regimen. Proliferative immune responses showed that mice receiving the combined HIV/HCV vaccine exhibited a three fold higher stimulation index (SI) to gp120 than mice immunized with the vaccine containing HIV alone. To determine whether our vaccine strategy induced Th1 or Th2 immune responses, IFN-gamma and IL-4/IL-5 were measured. The combined HIV/HCV vaccine induced a higher level of Th1 responses to HIV-1 gag protein compared with the other groups, as measured by IFN-gamma production. Interestingly, detection of IFN-gamma by ELISPOT assay demonstrated that the combined HIV/HCV vaccine group had increased numbers of spot forming cells (SFC) to HIV-gp120 peptides when compared to that of the HIV-1 only vaccine group. The combined HIV/HCV vaccine group also showed an increase in SFC to HCV-core peptides in comparison with the group receiving the HCV only vaccine. Intracellular IFN-gamma staining confirmed the ELISPOT results and demonstrated that the combined HIV/HCV group had significantly higher percentages of HIV and HCV-specific CD8+ T cells in comparison to the groups receiving the HIV or HCV vaccines. These results suggest a new approach to maximize vaccine efficacy against HIV and HCV.     

DNA immunization with fusion genes encoding different regions of hepatitis C virus E2 fused to the gene for hepatitis B surface antigen elicits immune responses to both HCV and HBV

AIM：Both Hepatitis B virus(HBV)and Hepatitis C virus (HCV) are major causative agents of transfusion-associated and community-acquired hepatitis wordwide.Development of a HCV vaccine as well as more effective HBV vaccines is and urgent task.DNA immunization provides a promising approach to elicit protective humoral and cellular immune responses against viral infection.The aim of this study is to achieve immune responses against both HCV and HBV by DNA immunization with fusion constructs comprising various HCV E2 gene fragments fused to HBsAg gene of HBV.METHODS:C57BL/6 mice were immunized with plasmid DNA expressing five fragmets of HCV E2 fused to the gene for HBaAg respectively.After one primary and one boosting immunizatios,antibodies against HCV E2 and HBsAg weretested and subtyped in ELISA.Splenic cytokine expression of IFN-γ and IL-10 was analyzed using an RT-PCR assay Post-immune mouse antisera also were tested for their ability to capture HCV viruses in the serum of a hepatitis C patient in vitro.RESULTS:After immunization,antibodies against both HBsAg and HCV E2 were detected in mouse sera,with Ig2a being the dominant immunoglobulin sub-class.Highlevel expression of INF-γwas detected in cultured splenic cells Mouse antisera against three of the five nfusion constructs were able to capture HCV viruses in an in vitro assay.CONCLUSION:The results indicate that these fusion constructs could efficiently elicit humoral and Th1 dominant cellular immune responses against both HBV S and HCV E2 antigens in DNA-immunized mice.They thus could serve as candidates for a bivalent vaccine against HBV and HCV infection.In addition,the capacity of mouse antisera against three of the five fusion constructs to capture HCV viruses in vitro suggested that neutralizing epitopes may be present in other regions of E2 besides the hypervariable region1.     

A candidate DNA vaccine elicits HCV specific humoral and cellular immune responses

AIM: TO investigate the immunogenicity of candidate DNA vaccine against hepatitis C virus (HCV) delivered by two plasmids expressing HCV envelope protein 1 (El) and envelope protein 2 (E2) antigens respectively and to study the effect of CpG adjuvant on this candidate vaccine.METHODS: Recombinant plasmJds expressing HCV EI and E2 antigens respectively were used to simultaneously inoculate mice with or without CpG adjuvant. Antisera were then collected and tJters of antJ-HCV antibodies were analyzed by ELISA. One month after the last injection, animals were sacrificed to prepare single-cell suspension of splenocytes.These cells were subjected to HCV antigen specific proliferaion assays and cytokine secretion assays to evaluate the cellular immune responses of the vaccinated animals.RESULTS: Antibody responses to HCV EI and E2 antigens were detected in vaccinated animals. Animals receiving CpG adjuvant had slightly lower titers of anti-HCV antibodies in the sera, while the splenocytes from these animals showed higher HCV-antigen specific proliferation. Analysis of cytokine secretion from the splenocytes was consistent with the above results. While no antigen-specific IL-4 secretion was detected for all vaccinated animals, HCV antigen-specific INF-γ, secretion was detected for the splenocytes of vaccinated animals. CpG adjuvant enhanced the secretion of INF-γ, but did not change the profile of IL-4 secretion.CONCLUSION: Vaccination of mice with plasmids encoding HCV E1 and E2 antigens induces humoral and cellular immune responses. CpG adjuvant significantly enhances the cellular immune response.     

MIP-1alpha and MIP-1beta differentially mediate mucosal and systemic adaptive immunity

Macrophage inflammatory protein-1alpha (MIP-1alpha) and MIP-1beta are distinct but highly homologous CC chemokines produced by a variety of host cells in response to various external stimuli and share affinity for CCR5. To better elucidate the role of these CC chemokines in adaptive immunity, we have characterized the affects of MIP-1alpha and MIP-1beta on cellular and humoral immune responses. MIP-1alpha stimulated strong antigen (Ag)-specific serum immunoglobulin G (IgG) and IgM responses, while MIP-1beta promoted lower IgG and IgM but higher serum IgA and IgE antibody (Ab) responses. MIP-1alpha elevated Ag-specific IgG1 and IgG2b followed by IgG2a and IgG3 subclass responses, while MIP-1beta only stimulated IgG1 and IgG2b subclasses. Correspondingly, MIP-1beta produced higher titers of Ag-specific mucosal secretory IgA Ab levels when compared with MIP-1alpha. Splenic T cells from MIP-1alpha- or MIP-1beta-treated mice displayed higher Ag-specific Th1 (interferon-gamma [IFN-gamma]) as well as selective Th2 (interleukin-5 [IL-5] and IL-6) cytokine responses than did T cells from control groups. Interestingly, mucosally derived T cells from MIP-1beta-treated mice displayed higher levels of IL-4 and IL-6 compared with MIP-1alpha-treated mice. However, MIP-1alpha effectively enhanced Ag-specific cell-mediated immune responses. In correlation with their selective effects on humoral and cellular immune responses, these chemokines also differentially attract CD4(+) versus CD8(+) T cells and modulate CD40, CD80, and CD86 expressed by B220(+) cells as well as CD28, 4-1BB, and gp39 expression by CD4(+) and CD8(+) T cells in a dose-dependent fashion. Taken together, these studies suggest that these CC chemokines differentially enhance mucosal and serum humoral as well as cellular immune responses.     

Systemic immunological effects of cytokine genes injected into skeletal muscle.

Somatic gene therapy is an interesting approach for the delivery of cytokines for prolonged periods. The present experiments show that direct injections into mouse skeletal muscle of cDNA expression vectors encoding interleukin 2 (IL-2), IL-4, or type beta 1 transforming growth factor (TGF-beta 1) induce biological effects characteristic of these cytokines in vivo. Mice injected intramuscularly with a vector encoding IL-2 had enhanced humoral and cellular immune responses to an exogenous antigen, transferrin, that was delivered at a separate site. These IL-2 effects were abolished by coadministration of a vector directing synthesis of TGF-beta 1. The TGF-beta 1 vector by itself depressed the anti-transferrin antibody response and caused an 8-fold increase in plasma TGF-beta 1 activity. The TGF-beta 1 plasmid injection did not cause muscle infiltration with monocytes or neutrophils and there was no evidence for fibrotic changes. Muscle injection with a cDNA encoding IL-4 selectively increased IgG1 levels but did not alter the cellular immune response to transferrin. In lupus-prone mice (MRL/lpr/lpr), injection with IL-2 expression vectors increased and TGF-beta 1 vectors decreased auto-antibodies to chromatin. These results demonstrate that intramuscular injection of cytokine genes, in the absence of infectious viral vectors, can regulate humoral and cellular immune responses in vivo.     

Therapeutic immunization of HIV-infected chimpanzees using HIV-1 plasmid antigens and interleukin-12 expressing plasmids

OBJECTIVE: To assess HIV-1 DNA vaccination and co-immunization with interleukin (IL)-12 and IL-10 as immunotherapy in the HIV-1 infected chimpanzee model system. METHODS: Four chimpanzees that were infected with HIV-1-IIIB for longer than 4 years and remained symptom free were immunized with HIV-1 plasmid vaccines. Two chimpanzees were immunized with DNA plasmids that encoded env/rev, gag/pol along with a plasmid that encoded both chains of human IL-12. A third animal was immunized with HIV-1 DNA vaccine constructs and co-immunized with an IL-10 expressing plasmid. Finally a control animal received the HIV-1 DNA vaccine constructs alone. RESULTS: There was no evidence of systemic toxicity associated with the administration of the DNA vaccines or the cytokine-expressing plasmids. We observed that the IL-12/HIV-1 DNA vaccinated animals had enhanced proliferative responses to multiple HIV-1 antigens at multiple time points. The animal that was co-immunized with HIV-1 and IL-10 did not have any changes in the proliferative responses. Finally, the control chimpanzee demonstrated moderate increases in the proliferative responses to HIV-1 antigens. The animal that received HIV-1 vaccines alone and the animals co-immunized with IL-12 all had declines in viral load over the course of the study, however, the decrease in viral loads were transient in all animals. CONCLUSION: Immunization of HIV-1 infected chimpanzees with DNA based vaccines containing the env, gag and pol genes can transiently boost the env specific proliferative responses. Co-administration of IL-12 expressing plasmids further leads to transient boosting of the proliferative response to the core protein, p24 as well. However, at these doses the impact on viral load is minimal.     

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.     

结核分枝杆菌EsxV亚单位疫苗黏膜免疫诱导的免疫应答

目的 研究结核分枝杆菌抗原Rv3619c(EsxV)黏膜免疫小鼠诱导的免疫应答水平。方法 PCR法扩增esxV基因克隆入原核表达载体pET28a(+),获得的重组E.coli诱导表达目的蛋白,SDS-PAGE电泳和Western Blot鉴定蛋白的表达,亲和层析法纯化EsxV蛋白。以EsxV和/或联合环二腺苷酸(c-di-AMP)经鼻黏膜免疫BALB/c小鼠,ELISA法检测小鼠特异性抗体水平及亚类,MTS法检测脾细胞增殖,qRT-PCR检测脾和肺脏细胞因子表达水平,ELISA法检测脾细胞因子分泌水平。结果 成功构建EsxV的原核表达载体pET28a(+)-esxV并诱导表达目的蛋白,亲和层析法获得了纯化的重组EsxV蛋白。EsxV经黏膜免疫可诱导显著的体液免疫应答,但诱导的细胞免疫应答水平不高。EsxV与c-di-AMP经黏膜接种可诱导特异性IgG水平增加,EsxV蛋白特异的脾细胞增殖,脾和肺细胞的IFN-γ转录增加。c-di-AMP显著提高EsxV特异的IFN-γ、IL-2、IL-10和IL-17细胞因子分泌,而不诱导炎症因子TNF-α和IL-6表达。结论 EsxV与c-di-AMP佐剂构建的亚单位疫苗可诱导特异性体液和细胞免疫应答,可进一步用于新型结核病亚单位疫苗的研制。     

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.     

Immunization with TCR Vbeta10 peptide reduces the frequency of type-II collagen-specific Th1 type T cells in BUB/BnJ (H-2q) mice

OBJECTIVE: Collagen induced arthritis (CIA) in mice is mediated by synergistic T cell and humoral immune responses specific for type II collagen (CII). We have previously shown that in arthritic joints of BUB mice (TCR Vbetaa, H-2q) the TCR repertoire is enrichedfor Vbeta10 expressing T cells, and that immunization with a Vbeta10 peptide (Vbeta10p) prevents the phenotypic expression of disease. The objective of the present study was to understand how immunization with a synthetic TCR Vbeta peptide affected the development of the pathogenic CII-specific immune response in BUB mice. METHODS: Arthritic and protected animals were tested for Vbeta10p- and CII-specific cytokine production by a highly specific and sensitive ELISA spot assay, andfor CII-specific antibody production by standard ELISA. In adoptive transfer experiments, Vbeta10p-specific LN cells (INF-gamma producing) were injected into naive mice prior to immunization with type-II collagen/CFA. RESULTS: Immune cells from arthritic animals produced IFN-gamma and IL-2, without IL-4 and IL-5 in response to CII and an immunodominant epitope, A2, derivedfrom CII. Serum from these mice contained anti-CII antibodies of both IgGI and IgG2a subtypes. Our results show for thefirst time that immunization with Vbeta10p resulted in Vbeta10p-specific IFN-gamma and IL-2 production that was restricted to the CD4+ T cell subset. Emergence of this Vbeta10p-specific immune response was associated with a dramatic decrease in the frequency of CII and A2-specific, cytokine producing T cells in arthritis protected mice. Protective immunity was cell mediated and could be adoptively transferred. In contrast, the protective immunization had only a marginal effect on the anti-CII antibody response indicating that the CII specific humoral immune response was not significantly affected. CONCLUSION: Immunization with TCR Vbeta10p leads to expansion of a population of Vbeta10p- specific CD4+ Tcells. This anti-TCR Vbeta10p specific type 1 cytokine producing immune response was protective in adoptive transfer studies and appears to inhibit the expansion of the pathogenic anti-CII cellular immunity. Additionally, the anti-TCR Vbeta10p-specific cellular immune response was mediated by CD4+ T cells and these T cells did not produce IL-4 or IL-5. Thus, our results suggest that protection against CIA in mice immunized with synthetic TCR Vbeta10p was achieved by a specific down-regulation of the CII-specific Thl type cellular immune response and not via immune deviation.     

Immunogenicity of a New HIV-1 DNA Construct in a BALB/c Mouse Model

Background: Cell mediated immunity, especially cytotoxic T cell responses against HIV-1 infection, plays a critical role in controlling viral replication and disease progres-sion. DNA vaccine is a novel technology which is known to stimulate strong cellular immune responses. Many DNA vaccines have been tested for HIV infection but there is still no effective vaccine against this infection. Construction of a vaccine consisting of multiple conserved and immunogenic epitopes may increase vaccine efficacy. Objective: In the present study, a DNA vaccine candidate constructed from HIV-1 P24-Nef was evaluated and cellular immune responses were assessed in murine BALB/c model. Methods: HIV-1 P24-Nef gene was cloned in pCDNA3.1 expression vector. Mice were immunized with DNA construct and IL-4 and IFN-γ evaluation was per-formed using ELISPOT. Cytotoxicity response was evaluated with Granzyme B ELIS-POT assay and lymphocyte proliferation was evaluated with LTT assay. Results: Analysis of immune responses showed that, compared to control groups, the candidate vaccine induced production of higher levels of both IL-4 and IFN-γ (p<0.05). Cytotox-icity and lymphocyte proliferation responses of mice vaccinated with the candidate vac-cine were significantly increased compared to control groups (p<0.05). Conclusion: HIV-1 P24-Nef DNA construct displayed strong immunogenicity in a murine model.     

重组质粒pcDNA3．1S2S／Fc在小鼠诱导免疫反应的观察

目的探讨S2S／Fc融合基因疫苗诱导小鼠HBV preS2S特异性体液和细胞免疫应答情况。方法取pcDNA3．1S2S/Fc、pcDNA3．1S2S＋pCMVsFc、pcDNA3．1S2S和空载体对照免疫BALB／c小鼠。在免疫动物2,4和6周后检测血清抗-HBs水平;在初次免疫7周后,测定免疫脾细胞的杀伤活性、增殖活性及细胞因子的分泌水平。结果经pcDNA3．1S2S／Fc免疫小鼠6周抗体滴度升至最高,免疫脾细胞的杀伤活性在效靶比为20：1时最高,免疫脾细胞的增殖活性以及IL-2和IFN-γ的分泌水平均比对照组明显增高。结论S2S／Fc融合基因在小鼠能诱导很强的特异性体液和细胞免疫应答。