DNA vaccine using hemagglutinating virus of Japan-liposome encapsulating combination encoding mycobacterial heat shock protein 65 and interleukin-12 confers protection against Mycobacterium tuberculosis by T cell activation

DNA and RNA vaccines against tuberculosis: a scoping review of human and animal studies

Introduction

To comprehensively identify and provide an overview of in vivo or clinical studies of nucleic acids (NA)-based vaccines against TB we included human or animal studies of NA vaccines for the prevention or treatment of TB and excluded in vitro or in silico research, studies of microorganisms other than M. tuberculosis, reviews, letters, and low-yield reports.

Methods

We searched PubMed, Scopus, Embase, selected Web of Science and ProQuest databases, Google Scholar, eLIBRARY.RU, PROSPERO, OSF Registries, Cochrane CENTRAL, EU Clinical Trials Register, clinicaltrials.gov, and others through WHO International Clinical Trials Registry Platform Search Portal, AVMA and CABI databases, bioRxiv, medRxiv, and others through OSF Preprint Archive Search. We searched the same sources and Google for vaccine names (GX-70) and scanned reviews for references. Data on antigenic composition, delivery systems, adjuvants, and vaccine efficacy were charted and summarized descriptively.

Results

A total of 18,157 records were identified, of which 968 were assessed for eligibility. No clinical studies were identified. 365 reports of 345 animal studies were included in the review. 342 (99.1%) studies involved DNA vaccines, and the remaining three focused on mRNA vaccines. 285 (82.6%) studies used single-antigen vaccines, while 48 (13.9%) used multiple antigens or combinations with adjuvants. Only 12 (3.5%) studies involved multiepitope vaccines. The most frequently used antigens were immunodominant secretory antigens (Ag85A, Ag85B, ESAT6), heat shock proteins, and cell wall proteins. Most studies delivered naked plasmid DNA intramuscularly without additional adjuvants. Only 4 of 17 studies comparing NA vaccines to BCG after M. tuberculosis challenge demonstrated superior protection in terms of bacterial load reduction. Some vaccine variants showed better efficacy compared to BCG.

Systematic review registration

https://osf.io/, identifier F7P9G.

Systemic Levels of Pro-Inflammatory Cytokines and Post-Treatment Modulation in Tuberculous Lymphadenitis

Pro-inflammatory cytokines are potent stimulators of inflammation and immunity and markers of infection severity and bacteriological burden in pulmonary tuberculosis (PTB). Interferons could have both host-protective and detrimental effects on tuberculosis disease. However, their role has not been studied in tuberculous lymphadenitis (TBL). Thus, we evaluated the systemic pro-inflammatory (interleukin (IL)-12, IL-23, interferon (IFN)α, and IFNβ) cytokine levels in TBL, latent tuberculosis (LTBI), and healthy control (HC) individuals. In addition, we also measured the baseline (BL) and post-treatment (PT) systemic levels in TBL individuals. We demonstrate that TBL individuals are characterized by increased pro-inflammatory (IL-12, IL-23, IFNα, IFNβ) cytokines when compared to LTBI and HC individuals. We also show that after anti-tuberculosis treatment (ATT) completion, the systemic levels of pro-inflammatory cytokines were significantly modulated in TBL individuals. A receiver operating characteristic (ROC) analysis revealed IL-23, IFNα, and IFNβ significantly discriminated TBL disease from LTBI and/or HC individuals. Hence, our study demonstrates the altered systemic levels of pro-inflammatory cytokines and their reversal after ATT, suggesting that they are markers of disease pathogenesis/severity and altered immune regulation in TBL disease.

Nanomaterials in tuberculosis DNA vaccine delivery: historical perspective and current landscape

Vaccinations, especially DNA vaccines that promote host immunity, are the most effective interventions for tuberculosis (TB) control. However, the vaccine delivery system exhibits a significant impact on the protective effects of the vaccine. Recently, effective nanomaterial-based delivery systems (including nanoparticles, nanogold, nanoliposomes, virus-like particles, and virus carriers) have been developed for DNA vaccines to control TB. This review highlights the historical development of various nanomaterial-based delivery systems for TB DNA vaccines, along with the emerging technologies. Nanomaterial-based vaccine delivery systems could enhance the efficacy of TB vaccination; therefore, this summary could guide nanomaterial selection for optimal and safe vaccine delivery, facilitating the design and development of highly effective TB vaccines.

IL-12 DNA Displays Efficient Adjuvant Effects Improving Immunogenicity of Ag85A in DNA Prime/MVA Boost Immunizations

Mycobacterium tuberculosis (Mtb) infection is one of the leading causes of death worldwide. The Modified Vaccinia Ankara (MVA) vaccine vector expressing the mycobacterial antigen 85A (MVA85A) was demonstrated to be safe, although it did not improve BCG efficacy, denoting the need to search for improved tuberculosis vaccines. In this work, we investigated the effect of IL-12 DNA -as an adjuvant- on an Ag85A DNA prime/MVA85A boost vaccination regimen. We evaluated the immune response profile elicited in mice and the protection conferred against intratracheal Mtb H37Rv challenge. We observed that the immunization scheme including DNA-A85A+DNA-IL-12/MVA85A induced a strong IFN-γ production to Ag85A in vitro, with a significant expansion of IFN-γ⁺CD4⁺ and IFN-γ⁺CD8⁺ anti-Ag85A lymphocytes. Furthermore, we also detected a significant increase in the proportion of specific CD8⁺CD107⁺ T cells against Ag85A. Additionally, inclusion of IL-12 DNA in the DNA-A85A/MVA85A vaccine scheme induced a marked augment in anti-Ag85A IgG levels. Interestingly, after 30 days of infection with Mtb H37Rv, DNA-A85A+DNA-IL-12/MVA85A vaccinated mice displayed a significant reduction in lung bacterial burden. Together, our findings suggest that IL-12 DNA might be useful as a molecular adjuvant in an Ag85A DNA/MVA prime-boost vaccine against Mtb infection.

Immune responses elicited by the recombinant Erp, HspR, LppX, MmaA4, and OmpA proteins from Mycobacterium tuberculosis in mice

Immunogenic potency of the recombinant Erp, HspR, LppX, MmaA4, and OmpA proteins from Mycobacterium tuberculosis (MTB), formulated with Montanide ISA 720 VG adjuvant, was evaluated in BALB/c mice for the first time in this study. The five vaccine formulations, adjuvant, and BCG vaccine were subcutaneously injected into mice, and the sera were collected at days 0, 15, 30, 41, and 66. The humoral and cellular immune responses against vaccine formulations were determined by measuring serum IgG and serum interferon-gamma (IFN-γ) and interleukin-12 (IL-12) levels, respectively. All formulations significantly increased IgG levels post-vaccination. The highest increase in IFN-γ level was provided by MmaA4 formulation. The Erp, HspR, and LppX formulations were as effective as BCG in enhancement of IFN-γ level. The most efficient vaccine boosting the IL-12 level was HspR formulation, especially at day 66. Erp formulation also increased the IL-12 level more than BCG at days 15 and 30. The IL-12 level boosted by MmaA4 formulation was found to be similar to that by BCG. OmpA formulation was inefficient in enhancement of cellular immune responses. This study showed that MmaA4, HspR, and Erp proteins from MTB are successful in eliciting both humoral and cellular immune responses in mice.

Preclinical study and clinical trial of a novel therapeutic vaccine against multi-drug resistant tuberculosis

[Purpose] Multi-drug resistant (MDR), Mycobacterium tuberculosis (TB) is a big problem in the world. We have developed novel TB therapeutic vaccine (HVJ-E/HSP65 DNA +IL-12 DNA). [Methods and Results] DNA vaccine expressing TB heat shock protein 65 and IL-12 was delivered by the hemagglutinating virus of Japan (HVJ)-envelope. This vaccine provided remarkable protective efficacy and strong therapeutic efficacy against MDR-TB and XDR-TB in murine models. Furthermore, this vaccine provided therapeutic efficacy of prolongation of survival time of TB infected monkeys and augmented the immune responses. Therefore, the preclinical tests were studied for clinical trial. The injection of 100 μg of the vaccine /mouse i.m. three times in two weeks induced significantly strong production of IFN-γ and IL-2. 100 μg and 200 μg DNA vaccine/mouse i.m. augmented the production of these cytokines compared with 25 μg DNA vaccine/mouse i.m.. The ratio of 100 μg pDNA to 1AU HVJ-E enhanced the production of IFN-γ and IL-2. The decrease in the number of M. tuberculosis in liver of mice was observed by the vaccination of 100μg pDNA. By using these conditions, safety pharmacology study and toxicology test is being studied in monkeys administered by GMP level DNA vaccines. By the toxicology test using monkeys, high dose GMP level vaccine/ monkey is administrated. Safety pharmacological study of repeated administration is also being investigated in GLP level. Furthermore, we have planned to do clinical phase I trial. Targets are human patients with MDR-TB. The safety and tolerability of the vaccine will be evaluated. [Conclusion and recommendations] These data indicate that our novel vaccine might be useful against tuberculosis including XDR-TB and MDR-TB for human therapeutic clinical applications.

Adjunctive immunotherapy with α-crystallin based DNA vaccination reduces Tuberculosis chemotherapy period in chronically infected mice

By employing modified Cornell model, we have evaluated the potential of adjunctive immunotherapy with DNA vaccines to shorten the tuberculosis chemotherapy period and reduce disease reactivation. We demonstrate that α-crystallin based DNA vaccine (DNAacr) significantly reduced the chemotherapy period from 12 weeks to 8 weeks when compared with the chemotherapy alone. Immunotherapy with SodA based DNA vaccine (DNAsod) reduced the pulmonary bacilli only as much as DNAvec. Both DNAacr and DNAsod, although significantly delayed the reactivation in comparison to the chemotherapy alone, this delay was associated with the immunostimulatory sequences present in the vector backbone and was not antigen specific. Both DNA vaccines resulted in the production of significantly higher number of T_EM cells than the chemotherapy alone, however, only in the case of DNAsod, this enhancement was significant over the DNAvec treatment. Overall, our findings emphasize the immunotherapeutic potential of DNAacr in shortening the duration of TB chemotherapy.

Novel therapeutic vaccines [(HSP65 + IL-12)DNA-, granulysin- and Ksp37-vaccine] against tuberculosis and synergistic effects in the combination with chemotherapy

PURPOSE

Multi-drug resistant tuberculosis (MDR-TB) and extremely drug resistant (XDR) TB are big problems in the world. We have developed novel TB therapeutic vaccines, HVJ-Envelope/HSP65 + IL-12 DNA vaccine (HSP65-vaccine), granulysin vaccine and killer specific secretory protein of 37kDa (Ksp37) vaccine.

METHODS AND RESULTS

HSP65 vaccine showed strong therapeutic effect against both MDR-TB and XDR-TB in mice. Intradermal immunization of HSP65-vaccine showed stronger therapeutic effect against TB than intramuscular or subcutaneous immunization. Furthermore, the synergistic therapeutic effect was observed when the vaccine was administrated in combination with Isoniazid (INH), which is a first line drug for chemotherapy. The combination of types of vaccines (HSP65- and granulysin- vaccines) also showed synergistic therapeutic effect. In the monkey model, granulysin-vaccine prolonged the survival period after the infection of TB and long-term survival was observed in vaccine-treated group. We examined the potential of two kinds of novel DNA vaccines (Ksp37-vaccine and granulysin-vaccine). Both vaccines augmented in vivo differentiation of CTL against TB. We measured the amount of Ksp37 protein in human serum and revealed that the level of Ksp37 protein of patients with tuberculosis was lower than that of healthy volunteers. Therefore, we established Ksp37 transgenic mice as well as granulysin transgenic mice to elucidate the function of those proteins. Both transgenic mice were resistant to TB infection.

CONCLUSION

These data indicate the potential of combinational therapy; the combination of two DNA vaccines or combination of DNA vaccine with antibiotic drug. Thus, it will provide a novel strategy for the treatment of MDR-TB.

The study of novel DNA vaccines against tuberculosis: induction of pathogen-specific CTL in the mouse and monkey models of tuberculosis

RESULTS

HSP65 + IL-12 DNA vaccine showed higher protective efficacy compared with BCG in both mouse and monkey models of TB. It induced the TB-specific CTL in the mouse model of TB, while little level of activity was observed after the injection of BCG. It also showed strong therapeutic efficacy against MDR-TB. In the monkey model, the vaccine augmented the production of IFN-γ and IL-2 from PBL and the therapeutic effect was correlated with the level of IL-2. We next evaluated the potential of DNA vaccine encoding a granulysin, which is an important defensive molecule expressed by human T cells. We found that granulysin-encoding vaccine induced the differentiation of the CTL in vitro and in vivo. It also showed therapeutic efficacy against TB in the monkey as well as the mouse model. The DNA vaccine encoding a Ksp37 also induced the TB-specific CTL in vitro and in vivo in the mouse model. It augmented the production of IL-2, IFN-γ and IL-6 from T cells and spleen cells. A synergistic effect on the activation of the TB-specific CTL was observed by the combination of Ksp37 DNA vaccine with granulysin DNA vaccine.

PURPOSE AND METHODS

Emergence of the multi-drug resistant (MDR) Mycobacterium tuberculosis (TB) is a big problem in the world. We have developed novel TB vaccines [DNA vaccines encoding HSP65 + IL-12, granulysin or killer-specific secretory protein of 37kDa (Ksp37)] using Hemagglutinating virus of Japan -envelope (HVJ-E). It is suggested that the activity of the TB-specific CTL is one of the most important factor for the resistance to TB and immunity for TB in chronic human TB disease. Therefore, we examined the level of activation of the TB-specific CTL after the administration of these vaccines.

CONCLUSION

These data indicate that our novel vaccines (HSP65 + IL-12 DNA, granulysin and Ksp37) have a capability to activate the TB-specific CTL and will be very strong protective and therapeutic vaccines against TB.

Cytokine therapy of tuberculosis at the crossroads

Drug treatment is the key strategy in TB control. However, the treatment course lasts 6-9 months because the current anti-TB drugs are poorly effective against nondividing (i.e., persistent) bacilli. As a result, completion rates are unsatisfactory, leading to emergence and spread of multidrug-resistant infection. It would, therefore, be very desirable to design a form of complementary treatment that could speed up the recovery process for people afflicted with TB and reduce the relapse rates. With the advancement of our understanding of the immunopathogenesis of TB, it has become increasingly possible to develop novel adjunctive immunotherapies for both drug-susceptible and drug-resistant TB. Notably, cytokines probably offer the most promising prospect of such a therapy being introduced in routine clinical practice. However, in many ways, the cytokine therapy of TB has reached a crossroad, since, although the initial promise failed to live up to expectations, sufficient encouraging evidence exists to warrant further exploration. There are clear arguments in favor as well as against such treatments. This review aims to provide a rationale for cytokine treatment of TB, to describe the current status of several cytokines that have been considered for that purpose and, ultimately, to make a case for the need for further clinical trials.

Immunotherapy for TB

Mycobacterium tuberculosis was one of the first human pathogens to be identified as the cause of a specific disease – TB. TB was also one of the first specific diseases for which immunotherapy was attempted. In more than a century since, multiple different immunotherapies have been attempted, alongside vaccination and antibiotic treatment, with varying degrees of success. Despite this, TB remains a major worldwide health problem that causes nearly 2 million deaths annually and has infected an estimated 2 billion people. A major reason for this is that M. tuberculosis is an ancient human pathogen that has evolved complex strategies for persistence in the human host. It has thus been long understood that, to effectively control TB, we will need to address the ability of the pathogen to establish a persistent, latent infection in most infected individuals. This review discusses what is presently known about the interaction of M. tuberculosis with the immune system, and how this knowledge has been used to design immunotherapeutic strategies.

A Novel Therapeutic and Prophylactic Vaccine against Tuberculosis Using the Cynomolgus Monkey Model and Mouse Model

We have developed a novel tuberculosis (TB) vaccine; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-envelope and -liposome (HSP65 + IL-12/HVJ). This vaccine provided remarkable protective efficacy in mouse model compared to the BCG. This vaccine also provided therapeutic efficacy against multi-drug resistant TB (MDR-TB) and extremely drug resistant TB (XDR-TB) in murine models. Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This novel vaccine provided a higher level of the protective efficacy than BCG based upon the assessment of mortality. The BCG prime and HSP65 + IL-12/HVJ vaccine (boost) by the prime-boost method showed a synergistic prophylactic effect in the monkey. Furthermore, this vaccine exerted therapeutic efficacy (100% survival) and augmentation of immune responses in the TB-infected monkeys.HVJ-Envelope/HSP65 DNA + IL-12 DNA vaccine increased the body weight of TB-infected monkeys, improved the ESR, and augmented the immuneresponses (proliferation of PBL and IL-2 production). The enhancement of IL-2 production from monkeys treated with this vaccine was correlated with the therapeutic efficacy of the vaccine. These data indicate that our novel DNA vaccine might be useful against Mycobacterium tuberculosis including XDR-TB and MDR-TB for human therapeutic clinical trials.

Novel prophylactic vaccine using a prime-boost method and hemagglutinating virus of Japan-envelope against tuberculosis

OBJECTIVE

Mycobacterium tuberculosis infection is a major global threat to human health. The only tuberculosis (TB) vaccine currently available is bacillus Calmette-Guérin (BCG), although it has no efficacy in adults. Therefore, the development of a novel vaccine against TB for adults is desired.

METHOD

A novel TB vaccine expressing mycobacterial heat shock protein 65 (HSP65) and interleukin-12 (IL-12) delivered by the hemagglutinating virus of Japan- (HVJ)- envelope was evaluated against TB infection in mice. Bacterial load reductions and histopathological assessments were used to determine efficacy.

RESULTS

Vaccination by BCG prime with IgHSP65+murine IL-12/HVJ-envelope boost resulted in significant protective efficacy (>10, 000-fold versus BCG alone) against TB infection in the lungs of mice. In addition to bacterial loads, significant protective efficacy was demonstrated by histopathological analysis of the lungs. Furthermore, the vaccine increased the number of T cells secreting IFN-γ.

CONCLUSION

This vaccine showed extremely significant protection against TB in a mouse model, consistent with results from a similar paper on cynomolgus monkeys. The results suggest that further development of the vaccine for eventual testing in clinical trials may be warranted.

Anti-IL-6 receptor antibody causes less promotion of tuberculosis infection than anti-TNF-α antibody in mice

Objective. Our aim was to investigate the effects of IL-6 blockade on the progression of Mycobacterium tuberculosis (TB) and compare them with those of TNF-α blockade in mice. Methods. Mice were intravenously infected with TB and injected with antibodies. Survival was monitored and histological and immunological studies were carried out. Results. All anti-IL-6R Ab-treated mice and 8 of 10 control mice survived until sacrificed 224 days after TB challenge, whereas anti-TNF-α Ab-treated mice all died between 120 and 181 days. Anti-IL-6R Ab-treated mice exhibited no significant differences in TB CFU in organs, including the lungs, and no deterioration in histopathology compared to control mice at 4 weeks. In contrast, anti-TNF-α Ab-treated mice exhibited increased TB CFU and greater progression of histopathological findings in organs than control mice. Spleen cells from anti-TNF-α Ab-treated mice had decreased antigen-specific response in IFN-γ release and proliferation assays. The results in anti-IL-6R Ab-treated mice suggest that spleen cell responses were decreased to a lesser degree. Similar results were obtained in IL-6 knockout (KO) mice, compared with TNF receptor 1 (TNFR1) KO and TNFR1/IL-6 double KO (DKO) mice. Conclusion. IL-6R blockade promotes the progression of TB infection in mice far less than TNF-α blockade.

Immunostimulatory activity of major membrane protein II from Mycobacterium tuberculosis

Previously, we observed that both major membrane protein II of Mycobacterium leprae (MMP-ML) and its fusion with M. bovis BCG (BCG)-derived heat shock protein 70 (HSP70) (Fusion-ML) are immunogenic and that recombinant BCG secreting either of these proteins effectively inhibits the multiplication of M. leprae in mice. Here, we purified M. tuberculosis-derived major membrane protein II (MMP-MTB) and its fusion with HSP70 (Fusion-MTB) in a lipopolysaccharide-free condition and evaluated their immunostimulatory abilities. Both MMP-MTB and Fusion-MTB activated monocyte-derived dendritic cells (DC) in terms of phenotype and interleukin-12 (IL-12) production, but Fusion-MTB more efficiently activated them than MMP-MTB did. The IL-12 production was a consequence of the ligation of those recombinant proteins with Toll-like receptor 2. The M. tuberculosis-derived and M. leprae-derived recombinant proteins activated naïve T cells of both CD4 and CD8 subsets, but M. tuberculosis-derived proteins were superior to M. leprae-derived proteins and fusion proteins were superior to MMP, regardless of the origin of the protein. Memory-type CD4(+) T cells obtained from BCG-vaccinated healthy individuals seem to be primed with MMP-MTB by the vaccination, and both M. tuberculosis-derived recombinant proteins produced perforin-producing CD8(+) T cells from memory-type CD8(+) T cells. Further, infection of DC and macrophages with M. tuberculosis H37Ra and H37Rv induced the expression of MMP on their surface. These results indicate that M. tuberculosis-derived MMP, as a sole protein or as part of a fusion protein, may be useful for developing new vaccinating agents against tuberculosis.

Functional immunogenicity of baculovirus expressing Pfs25, a human malaria transmission-blocking vaccine candidate antigen

We have focused on development of a novel vaccine vector based on "Baculophage", a baculovirus display system for expression of proteins on the surface of the viral envelope, as a non-pathogenic and non-vertebrate insect virus. In the present study, recombinant baculovirus (AcNPV-Pfs25surf) were generated, which displayed Pfs25, a potent Plasmodium falciparum transmission-blocking vaccine candidate. Both intranasal and intramuscular immunizations of mice with AcNPV-Pfs25surf induced high levels of Pfs25-specific antibodies, which strongly reacted with ookinetes of transgenic Plasmodium berghei expressing Pfs25 (TrPfs25Pb). Importantly, sera obtained from immunized rabbits exhibited a significant transmission-blocking effect (>90% reduction in infection intensity) in standard membrane feeding assay using P. falciparum gametocytes. Additionally, active immunization (both intranasal and intramuscular routes) of mice followed by challenge using TrPfs25Pb demonstrated an effective transmission-blocking response, with an 83% (intranasal) and ∼95% (intramuscular) reduction in oocyst intensity, respectively. Thus, the baculovirus-based vaccines offer a promising new alternative to current human vaccine delivery platforms for the development of malaria multi-stage vaccines.

Immunoprophylaxis of tuberculosis: an update of emerging trends

Developing effective prophylactics to combat tuberculosis is currently in an exploratory stage. The HIV pandemic and emergence of multi- and extensively drug-resistant strains of Mycobacterium tuberculosis indicate that the current preventive measures against this ever-evolving pathogen are inadequate. The currently available vaccine BCG in its present form affords variable protection which usually wanes with aging. Various reasons have been cited to explain the discrepancies in the efficacy of BCG, including generic differences in the different BCG vaccine strains used in immunization program throughout the world. The low efficacy of BCG vaccine has promoted the search for novel vaccines for tuberculosis. The search strategies aim at completely replacing the existing vaccine and/or augmenting/improving the current BCG vaccine. Among new vaccine candidates are live attenuated M. tuberculosis vaccines, recombinant BCG, DNA vaccines, subunit vaccine, and fusion protein-based vaccines. More than 200 new vaccine candidates have been developed as a result of research work over the past few years. To date, at least eight vaccine candidates are undergoing clinical evaluation, with a few of them successfully qualifying in the first phase of clinical testing. These recent advances present an optimistic insight whereby a new tuberculosis vaccine might be expected to be available for public use in the next few years.

A Novel Therapeutic and Prophylactic Vaccine (HVJ-Envelope / Hsp65 DNA + IL-12 DNA) against Tuberculosis Using the Cynomolgus Monkey Model

We have developed a novel tuberculosis (TB) vaccine; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-envelope and -liposome (HSP65 + IL-12/HVJ). An IL-12 expression vector (IL-12DNA) encoding single-chain IL-12 proteins comprised of p40 and p35 subunits were constructed. This vaccine provided remarkable protective efficacy in mouse and guinea pig models compared to the BCG vaccine on the basis of C.F.U of number of TB, survival, an induction of the CD8 positive CTL activity and improvement of the histopathological tuberculosis lesions. This vaccine also provided therapeutic efficacy against multi-drug resistant TB (MDR-TB) and extremely drug resistant TB (XDR-TB) (prolongation of survival time and the decrease in the number of TB in the lung) in murine models. Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This novel vaccine provided a higher level of the protective efficacy than BCG based upon the assessment of mortality, the ESR, body weight, chest X-ray findings and immune responses. All monkeys in the control group (saline) died within 8 months, while 50% of monkeys in the HSP65+hIL-12/HVJ group survived more than 14 months post-infection (the termination period of the experiment). Furthermore, the BCG priming and HSP65 + IL-12/HVJ vaccine (booster) by the priming-booster method showed a synergistic effect in the TB-infected cynomolgus monkey (100% survival). In contrast, 33% of monkeys from BCG Tokyo alone group were alive (33% survival). Furthermore, this vaccine exerted therapeutic efficacy (100% survival) and augmentation of immune responses in the TB-infected monkeys. These data indicate that our novel DNA vaccine might be useful against Mycobacterium tuberculosis including XDR-TB and MDR-TB for human therapeutic clinical trials.

Induction of cross-priming of naive CD8+ T lymphocytes by recombinant bacillus Calmette-Guerin that secretes heat shock protein 70-major membrane protein-II fusion protein

Because Mycobacterium bovis bacillus Calmette-Guérin (BCG) unconvincingly activates human naive CD8(+) T cells, a rBCG (BCG-70M) that secretes a fusion protein comprising BCG-derived heat shock protein (HSP)70 and Mycobacterium leprae-derived major membrane protein (MMP)-II, one of the immunodominant Ags of M. leprae, was newly constructed to potentiate the ability of activating naive CD8(+) T cells through dendritic cells (DC). BCG-70M secreted HSP70-MMP-II fusion protein in vitro, which stimulated DC to produce IL-12p70 through TLR2. BCG-70M-infected DC activated not only memory and naive CD8(+) T cells, but also CD4(+) T cells of both types to produce IFN-gamma. The activation of these naive T cells by BCG-70M was dependent on the MHC and CD86 molecules on BCG-70M-infected DC, and was significantly inhibited by pretreatment of DC with chloroquine. Both brefeldin A and lactacystin significantly inhibited the activation of naive CD8(+) T cells by BCG-70M through DC. Thus, the CD8(+) T cell activation may be induced by cross-presentation of Ags through a TAP- and proteosome-dependent cytosolic pathway. When naive CD8(+) T cells were stimulated by BCG-70M-infected DC in the presence of naive CD4(+) T cells, CD62L(low)CD8(+) T cells and perforin-producing CD8(+) T cells were efficiently produced. MMP-II-reactive CD4(+) and CD8(+) memory T cells were efficiently produced in C57BL/6 mice by infection with BCG-70M. These results indicate that BCG-70M activated DC, CD4(+) T cells, and CD8(+) T cells, and the combination of HSP70 and MMP-II may be useful for inducing better T cell activation.

Role of interleukin-12 family cytokines in the cellular response to mycobacterial disease

Interleukin (IL)-12 is a multifunctional cytokine acting as a key regulator of cell-mediated immune responses through the differentiation of naïve CD4+ T cells into type 1 helper T cells (Th1) producing interferon-gamma. As our knowledge of IL-12 family members is rapidly growing, it will be important to specify their involvement in the regulation of mycobacterial infection. This article is a review of the current knowledge regarding the functions of the IL-12 family cytokines in the immune host defense system against mycobacteria. Specifically, this review aims to describe recent scientific evidence concerning the protective role of some members of the IL-12 family cytokines for the control of mycobacterial infection, as well as to summarize knowledge of the potential use of the IL-12 family members as potent adjuvants in the prevention and treatment of mycobacterial infectious diseases. In addition, recent data supporting the importance of the IL-12 family members in mycobacterial diseases in relation to Th17 function are discussed. This examination will help to improve our understanding of the immune response to mycobacterial infection and also improve vaccine design and immunotherapeutic intervention against tuberculosis.

Novel prophylactic and therapeutic vaccine against tuberculosis

We have developed a novel tuberculosis (TB) vaccine; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-envelope and -liposome (HSP65+IL-12/HVJ). This vaccine provided therapeutic efficacy as well as remarkable protective efficacy via CD8(+) T and CD4(+) T cells in murine models compared with the saline controls, on the basis of CFU of number of multi-drug resistant TB (MDR-TB), and survival of extremely drug resistant TB (XDR-TB) challenged mice. Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This vaccine exerted therapeutic efficacy (survival and immune responses) in the TB-infected monkeys. These data indicate that our novel DNA vaccine might be useful against Mycobacterium tuberculosis including XDR-TB and MDR-TB for human therapeutic clinical trials.

An IL-12 DNA vaccine co-expressing Yersinia pestis antigens protects against pneumonic plague

Pneumonic plague remains problematic in endemic areas, and because it can be readily transmitted and has high mortality, the development of efficacious vaccines is warranted. To test whether stimulation of cell-mediated immunity with IL-12 will improve protective immunity against plague, we constructed two IL-12 DNA vaccines using a bicistronic plasmid encoding the protective plague epitopes, capsular (F1) antigen and virulence antigen (V-Ag) as F1-V fusion protein and V-Ag only, respectively. When applied intramuscularly, antibody responses to F1- and V-Ag were detectable beginning at week 6 after 3 weekly doses, and F1-Ag protein boosts were required to induce elevated Ab responses. These Ab responses were supported by mixed Th cell responses, and the IL-12/V-Ag DNA vaccine showed greater cell-mediated immune bias than IL-12/F1-V DNA vaccine. Following pneumonic challenge, both IL-12 DNA vaccines showed similar efficacy despite differences in Th cells simulated. These results show that IL-12 can be used as a molecular adjuvant to enhance protective immunity against pneumonic plague.

[The development of novel vaccines against tuberculosis]

We have developed a novel tuberculosis (TB) vaccine ; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-liposome or-envelope (HSP65+IL-12/HVJ). This vaccine provided remarkable protective efficacy in mouse and guinea pig models compared to the BCG vaccine, on the basis of an induction of the CD8 positive CTL activity against TB antigens and improvement of the histopathological tuberculosis lesions, respectively. The Elispot assay showed that HSP65+IL-12 DNA/ HVJ vaccine induced a greater number of IFN-gamma producing T cells than BCG in the mouse model. Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This novel vaccine provided a higher level of the protective efficacy than BCG based upon the assessment of mortality, the ESR, body weight, chest X-ray findings and immune responses (IFN-gamma, IL-2, IL-6 production , and lymphocyte proliferation of cynomolgus monkey). The combination of HSP65+IL-12/HVJ and BCG by the priming-booster method showed a synergistic effect in the TB-infected cynomolgus monkey (100% survival). In contrast, 33% of monkeys from BCG Tokyo alone group were alive (33% survival). These data indicate that our novel DNA vaccine might be useful against Mycobacterium tuberculosis for human clinical trials.

A nasal interleukin-12 DNA vaccine coexpressing Yersinia pestis F1-V fusion protein confers protection against pneumonic plague

Previous studies have shown that mucosal application of interleukin-12 (IL-12) can stimulate elevated secretory immunoglobulin A (IgA) responses. Since possible exposure to plague is via Yersinia pestis-laden aerosols that results in pneumonic plague, arming both the mucosal and systemic immune systems may offer an added benefit for protective immunity. Two bicistronic plasmids were constructed that encoded the protective plague epitopes, capsular antigen (F1-Ag) and virulence antigen (V-Ag) as a F1-V fusion protein but differed in the amounts of IL-12 produced. When applied nasally, serum IgG and mucosal IgA anti-F1-Ag and anti-V-Ag titers were detectable beginning at week 6 after three weekly doses, and recombinant F1-Ag boosts were required to elevate the F1-Ag-specific antibody (Ab) titers. Following pneumonic challenge, the best efficacy was obtained in mice primed with IL-12(Low)/F1-V vaccine with 80% survival compared to mice immunized with IL-12(Low)/F1, IL-12(Low)/V, or IL-12(Low) vector DNA vaccines. Improved expression of IL-12 resulted in lost efficacy when using the IL-12(High)/F1-V DNA vaccine. Despite differences in the amount of IL-12 produced by the two F1-V DNA vaccines, Ab responses and Th cell responses to F1- and V-Ags were similar. These results show that IL-12 can be used as a molecular adjuvant to enhance protective immunity against pneumonic plague, but in a dose-dependent fashion.

Interleukin-12 and tuberculosis: an old story revisited

Our understanding of the role of interleukin (IL)-12 in controlling tuberculosis has expanded because of increased interest in other members of the IL-12 family of cytokines. Recent data show that IL-12, IL-23 and IL-27 have specific roles in the initiation, expansion and control of the cellular response to tuberculosis. Specifically, IL-12, and to a lesser degree IL-23, generates protective cellular responses and promotes survival, whereas IL-27 moderates the inflammatory response and is required for long-term survival. Paradoxically, IL-27 also limits bacterial control, suggesting that a balance between bacterial killing and tissue damage is required for survival. Understanding the balance between IL-12, IL-23 and IL-27 is crucial to the development of immune intervention in tuberculosis.

Evaluation of a novel vaccine (HVJ-liposome/HSP65 DNA+IL-12 DNA) against tuberculosis using the cynomolgus monkey model of TB

We have developed a novel tuberculosis (TB) vaccine; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-liposome (HSP65+IL-12/HVJ). This vaccine provided remarkable protective efficacy in mouse and guinea pig models compared to the BCG vaccine, on the basis of an induction of the CTL activity and improvement of the histopathological tuberculosis lesions, respectively. Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This novel vaccine provided a higher level of the protective efficacy than BCG based upon the assessment of mortality, the ESR, body weight, chest X-ray findings and immune responses. Furthermore, the combination of HSP65+IL-12/HVJ and BCG by the priming-booster method showed a synergistic effect in the TB-infected cynomolgus monkey (100% survival). These data indicate that our novel DNA vaccine might be useful against Mycobacterium tuberculosis for human clinical trials.

The cell-mediated immune response induced by plasmid encoding bovine herpesvirus 1 glycoprotein B is enhanced by plasmid encoding IL-12 when delivered intramuscularly or by gene gun, but not after intradermal injection

Bovine herpesvirus 1 (BHV-1) causes respiratory and genital infections in cattle. Previously we demonstrated that a DNA vaccine encoding a truncated, secreted form of BHV-1 glycoprotein B (tgB) induces cytotoxic T lymphocyte (CTL) responses in C3H mice. In this study we investigated the potential of interleukin 12 (IL-12) to further enhance the CTL response. C3H mice were immunized with a plasmid encoding tgB or with plasmids encoding tgB and murine IL-12. When the plasmid encoding tgB was delivered intramuscularly or epidermally by a gene gun, co-administration with IL-12 plasmid stimulated the synthesis of more IgG2a, the production of higher levels of IFN-gamma, and more effective killing by CTLs. In contrast, after intradermal delivery no effect of co-administration of IL-12 encoding plasmid was observed. Further investigation suggested that antigen and IL-12 need to be expressed in the draining lymph nodes, where IL-12 can have a direct effect on T cells.

Utilizing IL-12, IL-15 and IL-7 as Mucosal Vaccine Adjuvants

In this paper we review and discuss three of the most exciting and promising cytokines for therapeutic intervention and immunomodulation of immune responses including those on mucosal surfaces. The main properties of IL-12, IL-15 and IL-7 are described and the studies utilizing these cytokines as immunomodulators and vaccine adjuvants discussed.