OBJECTIVETo eliminate the side effects of aluminum adjuvant and His-tag, we constructed chimeric VLPs displaying the epitope of EV71 (SP70) without His-tagged. Then evaluating whether the VLPs could efficiently evoke not only humoral but also cellular immune responses against EV71 without adjuvant.

METHODSThe fusion protein was constructed by inserting SP70 into the MIR of truncated HBcAg sequence, expressed in E. Coli, and purified through ion exchange chromatography and density gradient centrifugation. Mice were immunized with the VLPs and sera were collected afterwards. The specific antibody titers, IgG subtypes and neutralizing efficacy were detected by ELISA, neutralization assay, and EV71 lethal challenge. IFN-γ and IL-4 secreted by splenocytes were tested by ELISPOT assay.

RESULTSHBc-SP70 proteins can self-assemble into empty VLPs. After immunization with HBc-SP70 VLPs, the detectable anti-EV71 antibodies were effective in neutralizing EV71 and protected newborn mice from EV71 lethal challenge. There was no significant difference for the immune efficacy whether the aluminum adjuvant was added or not. The specific IgG subtypes were mainly IgG1 and IgG2b and splenocytes from the mice immunized produced high levels of IFN-γ and IL-4.

CONCLUSIONThe fusion proteins without His-tagged was expressed and purified as soluble chimeric HBc-SP70 VLPs without renaturation. In the absence of adjuvant, they were efficient to elicit high levels of Th1/Th2 mixed immune response as well as assisted by aluminum adjuvant. Furthermore, the chimeric VLPs have potential to prevent HBV and EV71 infection simultaneously.

Adjuvants, Immunologic ; Animals ; Antibodies, Neutralizing ; Antibodies, Viral ; blood ; Enterovirus A, Human ; genetics ; Enterovirus Infections ; immunology ; virology ; Epitopes ; immunology ; metabolism ; Escherichia coli ; metabolism ; Female ; Immunity, Cellular ; Immunity, Humoral ; Mice ; Recombinant Fusion Proteins ; immunology

To enhance the immunogenicity of DNA and adenoviral vector vaccines expressing HIV-1 subtype B gp160, human interleukin 15 (hIL15) DNA adjuvant (pVR-hIL15) was constructed. BALB/c mice received DNA prime/protein boost immunization with pVR-HIVgp160/Ad5-HIVgp160 alone or combined with pVR-hIL15. Cellular and humoral immune responses were evaluated by IFN-gamma enzyme-linked immunosorbent spot assay and enzyme-linked immunosorbent assay, respectively. Compared with those immunized with vaccines alone, the mice immunized with vaccines combined with pVR-hIL15 had significantly increased specific cellular response and antibody titer (P < 0.05). It suggests that the IL15 DNA adjuvant can enhance the immune responses induced by prime-boost regimen using DNA and adenoviral vector encoding HIV-1 subtype B gp160.
Adenoviridae ; genetics ; Adjuvants, Immunologic ; Animals ; Antibodies, Viral ; immunology ; Antibody Specificity ; Female ; Genetic Vectors ; genetics ; HIV Envelope Protein gp120 ; immunology ; HIV Envelope Protein gp160 ; genetics ; immunology ; HIV Envelope Protein gp41 ; immunology ; Humans ; Immunity, Cellular ; Immunity, Humoral ; Interleukin-15 ; genetics ; Mice ; Mice, Inbred BALB C ; Vaccines, DNA ; genetics ; immunology

OBJECTIVETo construct a Mycobacterium tuberculosis DNA vaccine pVAX1/ESAT-6 plasmid and investigate its immunoreactivity.

METHODSThe ESAT-6 gene fragment amplified from Mycobacterium tuberculosis genome was inserted into pVAX1 vector to construct the recombinant plasmid pVAX1/ESAT-6, which was identified by restriction enzyme digestion and sequencing. The recombinant plasmid was transformed into Hela cells using Sofast® Transfection reagent, and the cellular expressions of ESAT-6 mRNA and protein were analyzed by RT-PCR and immunofluorescence assay, respectively. The recombinant plasmid pVAX1/ESAT-6 was also transfected into mouse by electronic pulse method, and the mouse serum IFN-γ level and anti-ESAT-6 IgG antibody level were detected by ELISA, mouse lymphocyte proliferation assessed with flow cytometry, and IFN-γ-secreting lymphocytes counted using ELISPOT.

RESULTSDouble restriction-enzyme digestion and sequencing showed that the inserted fragment in the recombinant plasmid pVAX1/ESAT-6 was identical to ESAT-6 gene with an inframe insertion. RT-PCR yielded the target band as expected on agarose gel, and immunofluorescence assay of the transfected cells showed specific green fluorescence signals. The mice transfected with the recombinant plasmid showed significantly elevated serum level of anti-ESAT-6 IgG antibody and increased serum IFN-γ level, spleen cell proliferation, and number of IFN-γ-secreting lymphocytes.

CONCLUSIONThe Mycobacterium tuberculosis DNA vaccine pVAX1/ESAT-6 plasmid we constructed can induce high levels of cellular and humoral immunoreactivity in mice.

Animals ; Antibodies, Bacterial ; blood ; Antibody Formation ; Antigens, Bacterial ; immunology ; Bacterial Proteins ; immunology ; Female ; Genetic Vectors ; HeLa Cells ; Humans ; Immunity, Cellular ; Immunity, Humoral ; Immunoglobulin G ; blood ; Interferon-gamma ; blood ; Mice ; Mice, Inbred BALB C ; Mycobacterium tuberculosis ; immunology ; Plasmids ; immunology ; Tuberculosis Vaccines ; genetics ; immunology ; Vaccines, DNA ; genetics ; immunology

To obtain protective human monoclonal antibody from HIV-1 infected person, we adapted a technology for isolating antigen specific monoclonal antibody from human memory B cells through in vitro B cell activation coupled with RT-PCT and expression cloning. Human B cells were purified by negative sorting from PBMCs of HIV-1 infected individuals and memory B cells were further enriched using anti-CD27 microbeads. Two hundred memory B cells per well were cultured in 96-well round-bottom plates Env-specific antibodies in supernatants were with feeder cells in medium containing EBV and CpG. screened by ELISA after 1-2 weeks' culture. Cells from positive wells of Env-specific antibody were harvested and total RNA was isolated. Human VH and Vkappa or Vlambda genes were amplified by RT-PCR and cloned into IgG1 and kappa or lambda expressing vectors. Functional VH and Vkappa or Vlambda were identified by cotransfecting 293T cells with individual heavy chain and light chain clones followed by analysis of culture supernatants by ELISA for Env-specific antibodies. Finally, corresponding mAb was produced by transient transfection of 293T cells with the identified VH and Vkappa/lambda pair and purified by protein A affinity chromatography. Purified monocolonal antibodies were used for HIV-1 specific antibody-dependent cell-mediated cytotoxicity (ADCC) and neutralizing activity assay. Four monocolonal Env-specific antibodies were isolated from one HIV-1 subtype B' infected individual. Two of them showed strong ADCC activity and one showed weak neutralizing activity against HIV-1. Its further studies on their application in therapeutic or prophylactic vaccines against HIV-1 should be grounded.
Antibodies, Monoclonal ; genetics ; immunology ; Antibody Specificity ; Asian Continental Ancestry Group ; B-Lymphocytes ; immunology ; Cloning, Molecular ; HEK293 Cells ; HIV Infections ; blood ; immunology ; HIV-1 ; immunology ; pathogenicity ; Humans ; Immunity, Humoral ; Neutralization Tests ; Polymerase Chain Reaction ; env Gene Products, Human Immunodeficiency Virus ; immunology

Herpes simplex virus type-1 (HSV-1) amplicon vectors are versatile and useful tools for transferring genes into cells that are capable of stimulating a specific immune response to their expressed antigens. In this work, two HSV-1-derived amplicon vectors were generated. One of these expressed the full-length glycoprotein D (gD) of bovine herpesvirus 1 while the second expressed the truncated form of gD (gDtr) which lacked the trans-membrane region. After evaluating gD expression in the infected cells, the ability of both vectors to induce a specific gD immune response was tested in BALB/c mice that were intramuscularly immunized. Specific serum antibody responses were detected in mice inoculated with both vectors, and the response against truncated gD was higher than the response against full-length gD. These results reinforce previous findings that HSV-1 amplicon vectors can potentially deliver antigens to animals and highlight the prospective use of these vectors for treating infectious bovine rhinotracheitis disease.
Animals ; Antibodies, Viral/blood ; Blotting, Western/veterinary ; Cattle ; Female ; Genetic Vectors/*immunology ; Herpesvirus 1, Bovine/genetics/*immunology ; Herpesvirus 1, Human/genetics/*immunology ; Immunity, Humoral/immunology ; Immunization/methods/veterinary ; Infectious Bovine Rhinotracheitis/*immunology/prevention & control/virology ; Mice ; Mice, Inbred BALB C ; Neutralization Tests/veterinary ; Specific Pathogen-Free Organisms ; Viral Proteins/genetics/*immunology ; Viral Vaccines/immunology

BACKGROUNDThe Fc receptor associated pathway might improve the immune responses against hepatitis B virus (HBV) as previously described by us. In addition, the Flt3 ligand (FL) has been reported to potentiate antigen presenting cells in vivo and may act as a potential adjuvant to boost antigen-specific immune responses. In this study, the immune efficacies of a set of fusion proteins of HBsAg and Fc and/or FL were evaluated in HBsAg transgenic mice.

METHODSThe fusion proteins composed of HBsAg and the Fc domain of murine IgG1 (HBsAg-Fc) and/or the Flt3 ligand, and yeast-derived recombinant HBsAg were used as immunogen to immunize HBsAg transgenic mice, respectively. Serum and liver HBsAg levels, serum anti-HBsAg and cytokine profile, and the activities of alanine aminotransferase (ALT)/AST were investigated after immunization.

RESULTSAfter six injections, the most pronounced decrease in serum and liver HBsAg levels was observed in the HBsAg-Fc immunized group. In addition, serum Th1 cytokines and ALT/AST activities were highest in this group, indicating an effective induction of a favorable cellular immune response. Interestingly, the fusion protein containing HBsAg-Fc and the Flt3 ligand stimulated an alternative Th1-type immune response featured with high level productions of tumor necrosis factor α (TNF-α) and monocyte chemoabstractant protein 1 (MCP-1), causing a more severe cytotoxicity in hepatocytes while showed less effective in reducing serum HBsAg level.

CONCLUSIONHBsAg-Fc is effective in eliciting both the humoral and cellular immune responses against HBsAg in HBsAg transgenic mice, which makes it a potential immunogen for the immunotherapy of chronic hepatitis B.

Animals ; Chemokine CCL2 ; metabolism ; Cytokines ; metabolism ; Enzyme-Linked Immunosorbent Assay ; Female ; Hepatitis B Surface Antigens ; genetics ; immunology ; metabolism ; Immunity, Cellular ; immunology ; Immunity, Humoral ; immunology ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Receptors, Fc ; genetics ; immunology ; metabolism ; Recombinant Fusion Proteins ; genetics ; immunology ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism

Exosomes are small membrane vesicles secreted from various types of cells. Tumor-derived exosomes contain MHC class I molecules and tumor-specific antigens, receiving attention as a potential cancer vaccine. For induction of efficient anti-tumor immunity, CD4+ helper T cells are required, which recognize appropriate MHC class II-peptide complexes. In this study, we have established an MHC class II molecule-expressing B16F1 murine melanoma cell line (B16F1-CIITA) by transduction of the CIITA (Class II transactivator) gene. Exosomes from B16-CII cells (CIITA-Exo) contained a high amount of MHC class II as well as a tumor antigen TRP2. When loaded on dendritic cells (DCs), CIITA-Exo induced the increased expression of MHC class II molecules and CD86 than the exosomes from the parental cells (Exo). In vitro assays using co-culture of immunized splenocytes and exosome-loaded DCs demonstrated that CIITA-Exo enhanced the splenocyte proliferation and IL-2 secretion. Consistently, compared to B16-Exo, CIITA-Exo induced the increased mRNA levels of inflammatory cytokines such as TNF-alpha, chemokine receptor CCR7 and the production of Th1-polarizing cytokine IL-12. A tumor preventive model showed that CIITA-Exo significantly inhibited tumor growth in a dose-dependent manner. Ex vivo assays using immunized mice demonstrated that CIITA-Exo induced a higher amount of Th1-polarized immune responses such as Th1-type IgG2a antibodies and IFN-gamma cytokine as well as TRP2-specific CD8+ T cells. A tumor therapeutic model delayed effects of tumor growth by CIITA-Exo. These findings indicate that CIITA-Exo are more efficient as compared to parental Exo to induce anti-tumor immune responses, suggesting a potential role of MHC class II-containing tumor exosomes as an efficient cancer vaccine.
Animals ; Cancer Vaccines/genetics/immunology ; Cell Line, Tumor ; Cell Proliferation ; Dendritic Cells/immunology ; Exosomes/genetics/*metabolism ; Gene Expression Regulation ; Gene Transfer Techniques ; Immunity, Cellular/immunology ; Immunity, Humoral/immunology ; Immunotherapy ; Lymphocyte Activation/immunology ; Melanoma, Experimental/mortality/pathology/*physiopathology ; Mice ; Mice, Inbred C57BL ; Nuclear Proteins/*genetics/*metabolism ; Survival Analysis ; T-Lymphocytes/immunology/metabolism ; Trans-Activators/*genetics/*metabolism ; Transduction, Genetic

Antibodies, Viral ; blood ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; Humans ; Immunity, Cellular ; Immunity, Humoral ; Influenza A Virus, H1N1 Subtype ; immunology ; Influenza, Human ; epidemiology ; immunology ; Pandemics ; Time Factors

PURPOSE: The third variable (V3) loop of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein has been intensively studied for AIDS vaccine development. Bacille Calmette-Guerin (BCG) is widely used to immunize against tuberculosis and has many advantages as a vaccine vehicle, such as low toxicity, adjuvant potential, low cost, and long-lasting immune-inducing capacity. This work was initiated to investigate the immunogenicity of recombinant BCG (rBCG-mV3) designed to express trimeric HIV-1 V3 loop (mV3) in rBCG-mV3-immunized animals. MATERIALS AND METHODS: HIV-1 V3-concatamer was cloned into pMV261, a BCG-expression vector, and then rBCG-mV3 was constructed by introducing the recombinant plasmid (pMV-V3). The recombinant BCG was examined with regard to its expression of V3-concatamer and the genetic stability in vivo and in vitro. The immune responses induced by recombinant BCG were tested in immunized mice and guinea pigs. RESULTS: The rBCG-mV3 expressed detectable amounts of V3-concatamer when induced by single heat-shock. The recombinant BCG was genetically stable and maintained the introduced mV3 gene for several weeks. V3-specific antibodies were clearly detected 6 weeks after inoculation. The antibody titer rapidly increased after immunization up to 10 weeks, and then maintained for over 4 weeks. IgG2a was prevalent in the V3-specific antiserum. The recombinant BCG was also effective in inducing delayed-type hypersensitivity responses in the immunized guinea pigs. rBCG-immunized mice retained substantial amounts of V3-specific T cells in the spleen, even 5 months after the first immunization. CONCLUSION: Recombinant BCG-mV3 is very efficient in inducing humoral and long-lasting cell-mediated immunity against HIV-1 V3 in the immunized animals.
AIDS Vaccines/genetics/*immunology ; Animals ; BCG Vaccine/genetics/*immunology ; Female ; Guinea Pigs ; HIV-1/*immunology ; Humans ; Immunity, Cellular/genetics/*immunology ; Immunity, Humoral/genetics/*immunology ; Mice ; Mice, Inbred BALB C ; env Gene Products, Human Immunodeficiency Virus/genetics/*immunology

PURPOSE: The third variable (V3) loop of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein has been intensively studied for AIDS vaccine development. Bacille Calmette-Guerin (BCG) is widely used to immunize against tuberculosis and has many advantages as a vaccine vehicle, such as low toxicity, adjuvant potential, low cost, and long-lasting immune-inducing capacity. This work was initiated to investigate the immunogenicity of recombinant BCG (rBCG-mV3) designed to express trimeric HIV-1 V3 loop (mV3) in rBCG-mV3-immunized animals. MATERIALS AND METHODS: HIV-1 V3-concatamer was cloned into pMV261, a BCG-expression vector, and then rBCG-mV3 was constructed by introducing the recombinant plasmid (pMV-V3). The recombinant BCG was examined with regard to its expression of V3-concatamer and the genetic stability in vivo and in vitro. The immune responses induced by recombinant BCG were tested in immunized mice and guinea pigs. RESULTS: The rBCG-mV3 expressed detectable amounts of V3-concatamer when induced by single heat-shock. The recombinant BCG was genetically stable and maintained the introduced mV3 gene for several weeks. V3-specific antibodies were clearly detected 6 weeks after inoculation. The antibody titer rapidly increased after immunization up to 10 weeks, and then maintained for over 4 weeks. IgG2a was prevalent in the V3-specific antiserum. The recombinant BCG was also effective in inducing delayed-type hypersensitivity responses in the immunized guinea pigs. rBCG-immunized mice retained substantial amounts of V3-specific T cells in the spleen, even 5 months after the first immunization. CONCLUSION: Recombinant BCG-mV3 is very efficient in inducing humoral and long-lasting cell-mediated immunity against HIV-1 V3 in the immunized animals.
AIDS Vaccines/genetics/*immunology ; Animals ; BCG Vaccine/genetics/*immunology ; Female ; Guinea Pigs ; HIV-1/*immunology ; Humans ; Immunity, Cellular/genetics/*immunology ; Immunity, Humoral/genetics/*immunology ; Mice ; Mice, Inbred BALB C ; env Gene Products, Human Immunodeficiency Virus/genetics/*immunology