An mRNA vaccine encoding the SARS-CoV-2 receptor-binding domain protects mice from various Omicron variants

Here, we assessed the efficacy of a lipid nanoparticle-based mRNA vaccine candidate encoding the receptor-binding domain (LNP-mRNA-RBD) in mice. Mice immunized with LNP-mRNA-RBD based on the ancestral strain (ancestral-type LNP-mRNA-RBD) showed similar cellular responses against the ancestral strain and BA.5, but their neutralizing activity against BA.5 was lower than that against the ancestral strain. The ancestral-type LNP-mRNA-RBD protected mice from the ancestral strain or BA.5 challenge; however, its ability to reduce the viral burdens after BA.5 challenge was limited. In contrast, immunization with bivalent LNP-mRNA-RBD consisting of the ancestral-type and BA.4/5-type LNP-mRNA-RBD or monovalent BA.4/5-type LNP-mRNA-RBD elicited robust cellular responses, as well as high and moderate neutralizing titers against BA.5 and XBB.1.5, respectively. Furthermore, the vaccines containing BA.4/5-type LNP-mRNA-RBD remarkably reduced the viral burdens following BA.5 or XBB.1.5 challenge. Overall, our findings suggest that LNP-mRNA-RBD is effective against SARS-CoV-2 infection.

DS-5670a, a novel mRNA-encapsulated lipid nanoparticle vaccine against severe acute respiratory syndrome coronavirus 2: Results from a phase 2 clinical study

BACKGROUND

DS-5670a is a vaccine candidate for coronavirus disease 2019 (COVID-19) harnessing a novel modality composed of messenger ribonucleic acid (mRNA) encoding the receptor-binding domain (RBD) from the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) encapsulated in lipid nanoparticles. Here, we report the safety, immunogenicity, and pharmacokinetic profile of DS-5670a from a phase 2 clinical trial in healthy adults who were immunologically naïve to SARS-CoV-2.

METHODS

The study consisted of an open-label, uncontrolled, dose-escalation part and a double-blind, randomized, uncontrolled, 2-arm, parallel-group part. A total of 80 Japanese participants were assigned to receive intramuscular DS-5670a, containing either 30 or 60 µg of mRNA, as two injections administered 4 weeks apart. Safety was assessed by characterization of treatment-emergent adverse events (TEAEs). Immunogenicity was assessed by neutralization titers against SARS-CoV-2, anti-RBD immunoglobulin (Ig)G levels, and SARS-CoV-2 spike-specific T cell responses. Plasma pharmacokinetic parameters of DS-5670a were also evaluated.

RESULTS

Most solicited TEAEs were mild or moderate with both the 30 and 60 µg mRNA doses. Four participants (10 %) in the 60 µg mRNA group developed severe redness at the injection site, but all cases resolved without treatment. There were no serious TEAEs and no TEAEs leading to discontinuation. Humoral immune responses in both dose groups were greater than those observed in human convalescent serum; the 60 µg mRNA dose produced better responses. Neutralization titers were found to be correlated with anti-RBD IgG levels (specifically IgG1). DS-5670a elicited antigen-specific T helper 1-polarized cellular immune responses.

CONCLUSIONS

The novel mRNA-based vaccine candidate DS-5670a provided favorable immune responses against SARS-CoV-2 with a clinically acceptable safety profile. Confirmatory trials are currently ongoing to evaluate the safety and immunogenicity of DS-5670a as the primary vaccine and to assess the immunogenicity when administered as a heterologous or homologous booster.

TRIAL REGISTRY

https://jrct.niph.go.jp/latest-detail/jRCT2071210086.

Abstract P4-07-04: Detecting early breast cancer by the combination of five serum microRNAs and its possibility of prediction of pathological complete response in neoadjuvant chemotherapy

[Background] It is recently reported that microRNAs (miRNAs) are stably present in serum and potentially useful in the diagnosis and evaluation of treatment of cancer.

[Materials and Methods] Serum samples of breast cancer before treatment (n=1280) between 2008 and 2014 were obtained from National Cancer Center Hospital and controls (n=3348) were obtained from collaborative institutes. Additionally, the serum sample of patients who received neoadjuvant chemotherapy (NAC) and surgery between last chemotherapy administration and surgery were collected. A comprehensive quantitative expression analysis of miRNA was performed using the by DNA chip “3D-Gene® (Toray Industries Inc.)” Clinicopathological data was retrieved from medical records. Pathological complete response (pCR) was defined as the absence of residual invasive and in situ cancer of the resected breast specimen and all sampled regional lymph nodes.

[Results] Serum samples before treatment of breast cancer patients (n=74), non-cancer controls and patients with other cancers were used (n=2007) in a training set. The rest except for samples after NAC were used in a test set. The formula with the combination of five miRNAs (miR-1246, miR-1307-3p, miR-4634, miR-6861-5p, and miR-6875-5p) was found to be able to detect breast cancer (BCmiR set). BCmiR set had a sensitivity of 97.3%, specificity of 82.9% and accuracy of 89.7% in the test cohort. BCmiR set could detect breast cancer in the non-invasive stage (sensitivity of 98.0% for Tis).

In the breast cancer patients, 91 patients received NAC and surgery. Median age of NAC patients was 49 years (range 28-77). Forty-two patients were hormone receptor-positive (HR+) and HER2-negative (HER2-), 24 were HR+ and HER2-positive (HER2+), 11 were hormone receptor-negative (HR-) and HER2+ and 14 were HR- and HER2-. pCR was observed in 19 (20.9%) of NAC patients. pCR in each subtypes were 3 (7.7%) in HR+ and HER2-, 6 (33.3%) in HR+ and HER2+, 4 (57.1%) in HR- and HER2+ and 3 (27.3%) in HR- and HER2-. Serum after NAC were obtained from 19 pCR patients and 71 non-pCR patients. When we applied BCmiR set to the serum samples after NAC, the average diagnostic index (cut-off value=0) in pCR patients was significantly lower than that in non-pCR patients (pCR, -0.30±0.84; non-pCR, 0.31±1.15; p=0.03). In fact, 57.9% of pCR patients were classified into non-breast cancer. However, 40.8% of non-pCR patients were misclassified into non-breast cancer.

[Conclusion] The combination of five miRNAs (BCmiR set) measured from serum can be used to detect breast cancer. BCmiR set has potential to predict pCR in patients who received NAC. The further analysis to predict pCR is underway and further results will be presented in the symposium.

Citation Format: Shimomura A, Shiino S, Kawauchi J, Takizawa S, Sakamoto H, Shimizu C, Takeshita F, Niida S, Kinoshita T, Tamura K, Ochiya T. Detecting early breast cancer by the combination of five serum microRNAs and its possibility of prediction of pathological complete response in neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-07-04.

Age-Specific Profiles of Antibody Responses against Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is one of the most prevalent causative agents of lower respiratory tract infections worldwide, especially in infants around 3 to 4 months old. Infants at such a young age have maternally-transferred passive antibodies against RSV but do not have active immune systems efficient enough for the control of RSV infection. In order to elucidate age-specific profiles of immune responses against RSV protection, antibody responses were examined by using blood samples in both acute and convalescent phases obtained from child patients and adult patients. In addition to the serum neutralization activity, antibody responses to the RSV fusion protein (F protein) were dissected by analyzing levels of total IgG, IgG subclasses, the binding stability, and the levels of antibody for the neutralization epitopes. It was suggested that children's antibody responses against RSV are matured over months and years in at least 5 stages based on 1) levels of the neutralization titer and IgG3 for F protein in the convalescent phase, 2) geometric mean ratios of the neutralization titers and levels of IgG1 and IgG2 for F protein in the convalescent phase compared to those levels in the acute phase, 3) the affinity maturation of IgG for F protein and the cross reactivity of IgG for RSV glycoproteins of groups A and B, 4) levels of neutralization epitope-specific IgG, and 5) augmentation of overall antibody responses due to repetitive RSV infection.

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Children's antibody responses against RSV are matured over months and years in at least 5 stages.

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Age-specific profiles of antibody responses after RSV infection are proposed.

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The profile of IgG3 specific to F protein reflects infants' own antibody response after RSV infection.

In this study, antibody responses to respiratory syncytial virus (RSV) were evaluated by quantitative and qualitative multivariate analyses of acute and convalescent sera from patients infected with RSV. The results suggested that the profiles of antibody responses after RSV infections are delineated by independent factors such as the development of children's immune system and the natural infection with RSV in the presence or absence of maternal antibodies.

Ligand-induced Ordering of the C-terminal Tail Primes STING for Phosphorylation by TBK1

The innate immune protein Stimulator of interferon genes (STING) promotes the induction of interferon beta (IFN-β) production via the phosphorylation of its C-terminal tail (CTT) by TANK-binding kinase 1 (TBK1). Potent ligands of STING are, therefore, promising candidates for novel anti-cancer drugs or vaccine adjuvants. However, the intrinsically flexible CTT poses serious problems in in silico drug discovery. Here, we performed molecular dynamics simulations of the STING fragment containing the CTT in ligand-bound and unbound forms and observed that the binding of a potent ligand cyclic GMP-AMP (cGAMP) induced a local structure in the CTT, reminiscent of the known structure of a TBK1 substrate. The subsequent molecular biological experiments confirmed the observed dynamics of the CTT and identified essential residues for the activation of the IFN-β promoter, leading us to propose a new mechanism of STING activation.

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The binding of the potent ligand cGAMP to STING induces local structural ordering in the flexible C-terminal tail of STING.

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Site-directed mutagenesis studies, designed based on this observation, elucidated residues essential for STING function.

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The local structure formation in the CTT was shown to be essential for the induction of IFN-β production.

Efficient antigen delivery to the draining lymph nodes is a key component in the immunogenic pathway of the intradermal vaccine

BACKGROUND

It has been clinically demonstrated that intradermal (ID) vaccines have a potential to confer a superior immunogenic profile compared to intramuscular (IM) or subcutaneous (SC) vaccines. In terms of distribution of a vaccine antigen depending on the administration routes, at least two independent immunogenic pathways of the vaccines have been proposed: (1) the antigen recognition by the immune cells present at the vaccine-administered site and (2) the antigen recognition by the lymph node (LN)-resident immune cells through the lymphatic flow from the vaccine-administered site after the antigen is directly delivered into the draining LNs.

OBJECTIVE

In order to clarify the key components for the immunogenic pathway of the ID vaccine, the correlation between the kinetics of the antigen distribution to the draining LNs and antibody responses to the antigen were evaluated.

METHODS

We compared the antibody responses in the groups with by surgical removal of the administration site immediately after the ID administration, and by surgical removal of the draining LNs before the ID administration.

RESULTS

The results suggested that the efficient and direct antigen delivery to the draining LNs plays an important role in the antibody responses to the ID vaccine. Indeed, it was confirmed that the direct administration into the draining LNs with the antigen elicited comparable levels of the antibody responses with the ID vaccine. At the cellular level, it was shown that the LN-resident immune cells such as B cells, dendritic cells, and macrophages including medullary macrophages and subcapsular sinus macrophages interacting with the antigens following the ID administration. Finally, we demonstrated by immunofluorescence analysis that the lymphatic vessels are more diffusely distributed in the dermis as compared with the subcutaneous area and muscle.

CONCLUSION

The results of the present study suggested that the skin is an optimal tissue to facilitate the vaccine antigen access to the draining LNs, which is an important immunogenic pathway of the ID vaccine. Further elucidation of regulatory mechanisms underlying such an immunogenic pathway of the ID vaccine would provide us with elements for the development of novel adjuvants and devices to enhance the immunogenicity of the ID vaccines.

Superior immunogenicity profile of the new intradermal influenza vaccine compared to the standard subcutaneous vaccine in subjects 65 years and older: A randomized controlled phase III study

BACKGROUND

Although the elderly are at high risk for influenza, the immunogenicity in the elderly is lower than that in younger adults. We developed the new type of seasonal influenza vaccine with the novel intradermal (ID) injection system. In the previous exploratory phase I/II study of the ID vaccine with a dose of 15 μg HA per strain showed the superior immunogenicity profile to that of the standard subcutaneous (SC) injection vaccine in subjects aged 20 years and older.

METHODS

In this multicenter, randomized, double-blind, active controlled study, 900 adults aged 65 years and older were randomized at an equal ratio to either the ID vaccine group or the licensed standard SC vaccine group. Immunogenicity was assessed using serum hemagglutination inhibition (HAI) titers. The co-primary endpoints were the geometrical mean titers (GMT) and the seroconversion rates (SCR) of HAI titers against 3 vaccine strains on Day 21 (21 days after vaccination). To evaluate the early phase immunogenicity, the GMTs and SCRs on Day 7 were also assessed in the same way as the secondary endpoints.

RESULTS

The superiority of the ID vaccine in the GMTs and SCRs were demonstrated in all 3 vaccine strains both on Day 7 and Day 21. The frequency of any injection-site reactions was higher in the ID vaccine group, while the severity of injection-site reactions and the frequency of systemic AEs were comparable between the ID and the SC vaccine groups.

CONCLUSIONS

A single-dose of the influenza vaccine with the novel ID injection system and a dose of 15 μg HA was suggested as an appropriate regimen for clinical use in influenza prevention and associated disease burden reduction. It was also suggested that the new ID vaccine has the potential to replace the standard influenza vaccine from the view point of immunogenicity and safety.

TRIAL REGISTRATION

JAPIC Clinical Trials Information (JapicCTI-142493).

Role of Extrachromosomal Histone H2B on Recognition of DNA Viruses and Cell Damage

Histones are essential components of chromatin structure, and histone modification plays an important role in various cellular functions including transcription, gene silencing, and immunity. Histones also play distinct roles in extrachromosomal settings. Extrachromosomal histone H2B acts as a cytosolic sensor to detect double-stranded DNA (dsDNA) fragments derived from infectious agents or damaged cells to activate innate and acquired immune responses in various cell types. It also physically interacts with interferon (IFN)-β promoter stimulator 1 (IPS-1), an essential adaptor molecule that activates innate immunity, through COOH-terminal importin 9-related adaptor organizing histone H2B and IPS-1 (CIAO), resulting in a distinct signaling complex that induces dsDNA-induced type I IFN production. Such a molecular platform acts as a cellular sensor to recognize aberrant dsDNA in cases of viral infection and cell damage. This mechanism may also play roles in autoimmunity, transplantation rejection, gene-mediated vaccines, and other therapeutic applications.

Demonstration of innate immune responses in the thyroid gland: potential to sense danger and a possible trigger for autoimmune reactions

BACKGROUND

Autoimmune thyroid disease is an archetypal organ-specific autoimmune disorder that is characterized by the production of thyroid autoantibodies and lymphocytic infiltration into the thyroid. However, the underlying mechanisms by which specific thyroid antibodies are produced are largely unknown. Recent studies have shown that innate immune responses affect both the phenotype and the severity of autoimmune reactions. Moreover, it appears that even non-immune cells, including thyroid cells, have an ability to launch such responses. The aim of this study was to conduct a more detailed analysis of innate immune responses of the thyroid upon stimulation with various "non-self" and "self" factors that might contribute to the initiation of autoimmune reactions.

METHODS

We used rat thyroid FRTL-5 cells, human thyroid cells, and mice to investigate the effects of various pathogen-associated molecular patterns (PAMPs), danger-associated molecular patterns (DAMPs), and iodide on gene expression and function that were related to innate immune responses.

RESULTS

RT-PCR analysis showed that both rat and human thyroid cells expressed mRNAs for Toll-like receptors (TLRs) that sensed PAMPs. Stimulation of thyrocytes with TLR ligands resulted in activation of the interferon-beta (IFN-β) promoter and the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB)-dependent promoter. As a result, pro-inflammatory cytokines, chemokines, and type I interferons were produced. Similar activation was observed when thyroid cells were stimulated with double-stranded DNA, one of the typical DAMPs. In addition to these PAMPs and DAMPs, treatment of thyroid cells with high concentrations of iodide increased mRNA expression of various cytokines.

CONCLUSION

We show that thyroid cells express functional sensors for exogenous and endogenous dangers, and that they are capable of launching innate immune responses without the assistance of immune cells. Such responses may relate to the development of thyroiditis, which in turn may trigger autoimmune reactions.

Recognition of damage-associated molecular patterns related to nucleic acids during inflammation and vaccination

All mammalian cells are equipped with large numbers of sensors for protection from various sorts of invaders, who, in turn, are equipped with molecules containing pathogen-associated molecular patterns (PAMPs). Once these sensors recognize non-self antigens containing PAMPs, various physiological responses including inflammation are induced to eliminate the pathogens. However, the host sometimes suffers from chronic infection or continuous injuries, resulting in production of self-molecules containing damage-associated molecular patterns (DAMPs). DAMPs are also responsible for the elimination of pathogens, but promiscuous recognition of DAMPs through sensors against PAMPs has been reported. Accumulation of DAMPs leads to massive inflammation and continuous production of DAMPs; that is, a vicious circle leading to the development of autoimmune disease. From a vaccinological point of view, the accurate recognition of both PAMPs and DAMPs is important for vaccine immunogenicity, because vaccine adjuvants are composed of several PAMPs and/or DAMPs, which are also associated with severe adverse events after vaccination. Here, we review as the roles of PAMPs and DAMPs upon infection with pathogens or inflammation, and the sensors responsible for recognizing them, as well as their relationship with the development of autoimmune disease or the immunogenicity of vaccines.

Novel strategies to improve DNA vaccine immunogenicity

DNA vaccines can induce both humoral and cellular immune responses in animals. Some DNA vaccines are already licensed for infectious diseases such as West Nile virus encephalitis in horses. When used in humans, however, DNA vaccines suffer from lower immunogenicity profiles. Although the reasons for this are poorly understood, various hypotheses have been proposed. This review aims to provide better understanding of the molecular and immunological mechanisms by which DNA vaccines work and how such knowledge can be used to bring about improvements in their efficacy. Recent studies have provided evidence that the 'adjuvant effect' of plasmid DNA is mediated by its double-stranded structure. This structure activates stimulator of interferon genes/TANK-binding kinase 1 (STING/TBK1)- dependent innate immune signaling pathways in the absence of Toll-like receptors. Indeed, type-I interferons (IFNs), induced in vivo via the STING/TBK1 pathway, were found to be crucial for both direct- and indirect-antigen presentation via distinct cell types (i.e. dendritic cells (DC) and muscle cells, respectively). Importantly, incorporation of TBK1 into a DNA vaccine was found to enhance the antigen-specific humoral immune responses targeting the Plasmodium falciparum serine repeat antigen (SERA), a candidate vaccine antigen expressed in the blood-stages of human malaria parasites. Thus, the results of these studies may offer new ways to develop DNA vaccines, as well as delivering novel vaccine adjuvants against infectious diseases.

Guidelines for the use and interpretation of assays for monitoring autophagy

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.

Application of innate immune molecules for a new class of drugs: infection, inflammation and beyond

The innate immune system plays an important role systemically and locally in infectious and inflammatory diseases. Vaccines, vaccine adjuvants and anti-inflammatory drugs were developed by understanding mechanisms of the innate immune system and causative factors of infection and inflammatory diseases. Pattern-recognition receptors, such as Toll-like receptors, retinoic acid-inducible gene I (RIG-I)-like helicases and nucleotide-binding oligomerization domain(NOD)-like receptors, and their downstream signals have great potential as targets of therapeutics because they are involved in numerous diseases. Furthermore, proteolytic systems such as autophagy and immunoproteasomes play important roles in the innate immune system, making them potential therapeutic targets also. By taking advantage of the immune system, humankind has made a great effort to develop new therapeutic and preventive medicines. Accordingly, we have reported several studies on the development of vaccines and adjuvants based on novel mechanistic strategies. Additionally, we have elucidated the mechanism underlying an interaction between innate immunity and the endocrine system. This review introduces the possible use of innate immune molecules for the development of immunomodulatory drugs and the involvement of the immune system in endocrine metabolic diseases to discuss future applications of innate immune molecules to therapeutics of various inflammatory diseases.

In vivo delivery of interferon-α gene enhances tumor immunity and suppresses immunotolerance in reconstituted lymphopenic hosts

T cells recognize tumor-associated antigens under the condition of lymphopenia-induced homeostatic proliferation (HP); however, HP-driven antitumor responses gradually decay in association with tumor growth. Type I interferon (IFN) has important roles in regulating the innate and adaptive immune system. In this study we examined whether a tumor-specific immune response induced by IFN-α could enhance and sustain HP-induced antitumor immunity. An intratumoral IFN-α gene transfer resulted in marked tumor suppression when administered in the early period of syngeneic hematopoietic stem cell transplantation (synHSCT), and was evident even in distant tumors that were not transduced with the IFN-α vector. The intratumoral delivery of the IFN-α gene promoted the maturation of CD11c(+) cells in the tumors and effectively augmented the antigen-presentation capacity of the cells. An analysis of the cytokine profile showed that the CD11c(+) cells in the treated tumors secreted a large amount of immune-stimulatory cytokines including interleukin (IL)-6. The CD11c(+) cells rescued effector T-cell proliferation from regulatory T-cell-mediated suppression, and IL-6 may have a dominant role in this phenomenon. The intratumoral IFN-α gene transfer creates an environment strongly supporting the enhancement of antitumor immunity in reconstituted lymphopenic recipients through the induction of tumor-specific immunity and suppression of immunotolerance.

Fragments of genomic DNA released by injured cells activate innate immunity and suppress endocrine function in the thyroid

Activation of innate and acquired immune responses, which can be induced by infection, inflammation, or tissue injury, may impact the development of autoimmunity. Although stimulation of cells by double-stranded DNA (dsDNA) has been shown to activate immune responses, the role of self-genomic DNA fragments released in the context of sterile cellular injury is not well understood. Using cultured thyroid cells, we show that cell injury prompts the release of genomic DNA into the cytosol, which is associated with the production of type I interferons, inflammatory cytokines, and chemokines. Molecules necessary for antigen processing and presentation to lymphocytes are also induced in thyroid cells by injury. dsDNA strongly suppressed the expression of sodium/iodide symporter and radioiodine uptake. To identify molecules responsible for sensing cytosolic dsDNA, we directly identified the cellular proteins that bound a dsDNA Sepharose column by mass spectrometry. Our analysis identified histone H2B, which was previously demonstrated to be an essential factor that mediates the activation of innate immunity induced by dsDNA. Knockdown of histone H2B using specific small interfering RNA abolished cell injury-induced innate immune activation and increased sodium/iodide symporter expression. These results indicate that genomic DNA fragments released by cell injury are recognized by extrachromosomal histone H2B, which results in the activation of genes involved in both innate and acquired immune responses in thyroid cells and suppression of thyroid function. These results suggest that sterile thyroid injury, in the absence of infection, may be sufficient to trigger autoimmune reaction and to induce thyroid dysfunction.

NLRP4 negatively regulates autophagic processes through an association with beclin1

Although more than 20 putative members have been assigned to the nucleotide-binding and oligomerization domain-like receptor (NLR) family, their physiological and biological roles, with the exception of the inflammasome, are not fully understood. In this article, we show that NLR members, such as NLRC4, NLRP3, NLRP4, and NLRP10 interact with Beclin1, an important regulator of autophagy, through their neuronal apoptosis inhibitory protein, MHC class II transcription activator, incompatibility locus protein from Podospora anserina, and telomerase-associated protein domain. Among such NLRs, NLRP4 had a strong affinity to the Beclin1 evolutionally conserved domain. Compromising NLRP4 via RNA interference resulted in upregulation of the autophagic process under physiological conditions and upon invasive bacterial infections, leading to enhancement of the autophagic bactericidal process of group A streptococcus. NLRP4 recruited to the subplasma membrane phagosomes containing group A streptococcus and transiently dissociated from Beclin1, suggesting that NLRP4 senses bacterial infection and permits the initiation of Beclin1-mediated autophagic responses. In addition to a role as a negative regulator of the autophagic process, NLRP4 physically associates with the class C vacuolar protein-sorting complex, thereby negatively regulating maturation of the autophagosome and endosome. Collectively, these results provide novel evidence that NLRP4, and possibly other members of the NLR family, plays a crucial role in biogenesis of the autophagosome and its maturation by the association with regulatory molecules, such as Beclin1 and the class C vacuolar protein-sorting complex.

Modulation of intracellular signaling using protein-transduction technology

Protein-transduction technology is one of the most promising therapeutic tools for the control of intracellular events. A number of studies have demonstrated that minimal and efficient protein-transduction domains (PTDs) can act as a peptide vector to transfer bioactive cargo molecules from outside to inside the cell. PTD-mediated transduction has the ability to cross the blood-brain barrier, with transduction taking place in most tissues and cell types in vivo. Thus, recombinant proteins fused to or conjugated with PTDs have the potential to be harnessed as supplementary and/or intervention agents directly modulating cell signaling and/or metabolism, or to be applied to vaccine antigens/adjuvants that are efficiently delivered to the optimal site of action to enhance vaccine immunogenicity. This review introduces the mechanism of action, recent applications, and future perspectives of protein-transduction technology as an alternative therapeutic in the post-genome era.

C/EBP{delta} and STAT-1 are required for TLR8 transcriptional activity

Toll-like receptor 8 (TLR8), which is expressed primarily in myeloid cells, plays a central role in initiating immune responses to viral single-stranded RNA. Despite the great interest in the field of TLR8 research, very little is known in terms of TLR8 biology and its transcriptional regulation. Here, we describe the isolation of the hTLR8 promoter and the characterization of the molecular mechanisms involved in its regulation. Reporter gene analysis and ChIP assays demonstrated that the hTLR8 regulation of the basal transcription is regulated via three C/EBP cis-acting elements that required C/EBPδ and C/EBPβ activity. In addition, we observed that R848 stimulation increases TLR8 transcriptional activity via an enhanced binding of C/EBPδ, and not C/EBPβ, to its responsive sites within the TLR8 promoter. Moreover, we showed that IFN-γ also increased TLR8 transcription activity via the binding of STAT1 transcription factor to IFN-γ activated sequence elements on the TLR8 promoter and enhanced TLR8 functionality. These results shed new light on the mechanisms involved during TLR8-mediated innate immune response.

Expression of Toll-like receptor 9 in renal podocytes in childhood-onset active and inactive lupus nephritis

BACKGROUND

Childhood-onset systemic lupus erythematosus (SLE) is frequently complicated with lupus nephritis (LN), which is characterized by the deposition of DNA-containing immune complex to the glomerulus. Toll-like receptor 9 (TLR9), capable of recognizing the microbially derived CpG oligonucleotide, plays a crucial role in the innate immunity. TLR9 is also assumed to be related to the aetiology of SLE in the recognition of anti-DNA antibody-containing immune complex, but this remains controversial. We conducted a study to elucidate the association between TLR9 and LN in childhood-onset SLE.

METHODS

We compared the expression and localization of TLR9 and the slit membrane-related protein in the biopsied kidney sample by immunostaining in four children with active or inactive LN. We also evaluated their laboratory findings, such as anti-DNA antibody, complement and proteinuria at biopsy, to assess the correlation to the findings of the immunostaining.

RESULTS

TLR9 is not expressed in a normal control kidney. However, TLR9 develops in podocytes only in active LN but disappears in remission. Meanwhile, the slit membrane-related proteins such as nephrin, podocin and synaptopodin in podocytes express clearly and uniformly in remission, but their expression is markedly diminished in active LN, which results in podocyte injury. When TLR9 is expressed in podocytes, all the patients simultaneously showed hypocomplementaemia, high titre of anti-double-stranded DNA (dsDNA) antibody and proteinuria.

CONCLUSION

Injured podocytes in active LN express TLR9. This expression could be associated with proteinuria and increased anti-dsDNA antibody. This is the first report indicating that TLR9 is involved in the aetiology of LN and that it may play some role in podocyte injury.

Mutant mouse p53 transgene elevates the chemical induction of tumors that respond to gene silencing with siRNA

To study the role of mutant p53 in the induction and cure of tumors, we generated transgenic mice carrying mutant p53 (mp53) containing a 9 bp deletion in exon 6 in addition to wild-type p53, expressing both p53 and mp53. The mp53 cDNA was cloned from a radiation-induced mouse tumor and ligated to the chicken beta-actin promoter/CMV-IE enhancer in the expression vector. The presence of mp53 suppressed p21 expression in primary fibroblasts after ionizing irradiation, indicating the dominant-negative activity of mp53 in the mice. These mice developed fibrosarcomas after the subcutaneous injection of 3-methylcholanthrene with an incidence 1.7-fold higher than that of wild-type mice (42% excess). The tumors were then treated via a potent atelocollagen delivery system with small interfering RNA (siRNA), that targeted the promoter/enhancer of the expression vector, resulting in the suppression of tumor growth in 30% of 44 autochthonous tumors, including four cures, and their transplants, the total fraction corresponding to the tumor excess. This suppressive effect involved the induction of apoptosis. These results indicate that mp53 activity causes tumors that can be suppressed by subsequent silencing of mp53 in the presence of wild-type p53 alleles.

Tryptophan aspartate-containing coat protein (CORO1A) suppresses Toll-like receptor signalling in Mycobacterium leprae infection

Mycobacterium leprae is an intracellular pathogen that survives within the phagosome of host macrophages. Several host factors are involved in producing tolerance, while others are responsible for killing the mycobacterium. Tryptophan aspartate-containing coat protein (TACO; also known as CORO1A or coronin-1) inhibits the phagosome maturation that allows intracellular parasitization. In addition, the Toll-like receptor (TLR) activates the innate immune response. Both CORO1A and TLR-2 co-localize on the phagosomal membrane in the dermal lesions of patients with lepromatous leprosy. Therefore, we hypothesized that CORO1A and TLR-2 might interact functionally. This hypothesis was tested by investigating the effect of CORO1A in TLR-2-mediated signalling and, inversely, the effect of TLR-2-mediated signalling on CORO1A expression. We found that CORO1A suppresses TLR-mediated signal activation in human macrophages, and that TLR2-mediated activation of the innate immune response resulted in suppression of CORO1A expression. However, M. leprae infection inhibited the TLR-2-mediated CORO1A suppression and nuclear factor-kappaB activation. These results suggest that the balance between TLR-2-mediated signalling and CORO1A expression will be key in determining the fate of M. leprae following infection.

A signaling polypeptide derived from an innate immune adaptor molecule can be harnessed as a new class of vaccine adjuvant

Modulation of intracellular signaling using cell-permeable polypeptides is a promising technology for future clinical applications. To develop a novel approach to activate innate immune signaling by synthetic polypeptides, we characterized several different polypeptides derived from the caspase recruitment domain (CARD) of IFN-beta promoter stimulator 1, each of which localizes to a different subcellular compartment. Of particular interest was, N'-CARD, which consisted of the nuclear localization signal of histone H2B and the IFN-beta promoter stimulator 1CARD and which localized to the nucleus. This polypeptide led to a strong production of type I IFNs and molecular and genetic analyses showed that nuclear DNA helicase II is critically involved in this response. N'-CARD polypeptide fused to a protein transduction domain (N'-CARD-PTD) readily transmigrated from the outside to the inside of the cell and triggered innate immune signaling. Administration of N'-CARD-PTD polypeptide elicited production of type I IFNs, maturation of bone marrow-derived dendritic cells, and promotion of vaccine immunogenicity by enhancing Ag-specific Th1-type immune responses, thereby protecting mice from lethal influenza infection and from outgrowth of transplanted tumors in vivo. Thus, our results indicate that the N'-CARD-PTD polypeptide belongs to a new class of vaccine adjuvant that directly triggers intracellular signal transduction by a distinct mechanism from those engaged by conventional vaccine adjuvants, such as TLR ligands.

MicroRNAs as biomarkers and therapeutic drugs in human cancer

MicroRNAs (miRNAs) are evolutionarily conserved, endogenous, noncoding small RNAs that act as post-transcriptional gene regulators. Experimental evidence has shown that miRNAs can play roles as oncogenes or tumor suppressor genes, suggesting their contribution to cancer development and progression. Expression profiles of human miRNAs demonstrated that many miRNAs are deregulated in cancers and are differentially expressed in normal tissues and cancers. Therefore, miRNA profiling is used to create signatures for a variety of cancers, indicating that the profile will help further establish molecular diagnosis, prognosis and therapy using miRNAs. This paper introduces the aberrant expression of miRNAs in human cancer, and discusses the potential of these miRNAs as biomarkers and targets/molecules for molecular therapy.

[Molecular mechanisms for intracellular parasitisation and exclusion in macrophage infected with Mycobacterium leprae]

It was previously demonstrated that TLR2 and CORO1A (TACO, Coronin 1, p57) localize phagosome membrane of macrophage. However, the functional relationship between TLR2 and CORO1A was not known. We show here that there is a functional counteraction between TLR2 and CORO1A.

TANK-binding kinase-1 delineates innate and adaptive immune responses to DNA vaccines

Successful vaccines contain not only protective antigen(s) but also an adjuvant component that triggers innate immune activation and is necessary for their optimal immunogenicity. In the case of DNA vaccines, this consists of plasmid DNA; however, the adjuvant element(s) as well as its intra- and inter-cellular innate immune signalling pathway(s) leading to the encoded antigen-specific T- and B-cell responses remain unclear. Here we demonstrate in vivo that TANK-binding kinase 1 (TBK1), a non-canonical IkappaB kinase, mediates the adjuvant effect of DNA vaccines and is essential for its immunogenicity in mice. Plasmid-DNA-activated, TBK1-dependent signalling and the resultant type-I interferon receptor-mediated signalling was required for induction of antigen-specific B and T cells, which occurred even in the absence of innate immune signalling through a well known CpG DNA sensor-Toll-like receptor 9 (TLR9) or Z-DNA binding protein 1 (ZBP1, also known as DAI, which was recently reported as a potential B-form DNA sensor). Moreover, bone-marrow-transfer experiments revealed that TBK1-mediated signalling in haematopoietic cells was critical for the induction of antigen-specific B and CD4(+) T cells, whereas in non-haematopoietic cells TBK1 was required for CD8(+) T-cell induction. These data suggest that TBK1 is a key signalling molecule for DNA-vaccine-induced immunogenicity, by differentially controlling DNA-activated innate immune signalling through haematopoietic and non-haematopoietic cells.

Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes

Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.(2,3) There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.

The non-canonical role of Atg family members as suppressors of innate antiviral immune signaling

Recent research on autophagy clearly demonstrates that the autophagosome-lysosome pathway plays essential roles in elimination of certain pathogens such as group A Streptococcus, Mycobacterium tuberculosis, Listeria monocytogenes, and herpesvirus. (1-4) We have recently found that a key regulator of the autophagic process, the Atg12-Atg5 conjugate, associates with the signaling molecules retinoic acid-inducible gene I (RIG-I) and interferon-beta promoter stimulator 1 (IPS-1), which are essential for recognition of RNA virus infection and which transmit signals to upregulate type I interferons (IFNs). Interestingly, the Atg12-Atg5 conjugate seemed to negatively regulate the type I IFN modulating pathway through direct interaction with caspase recruitment domains (CARDs) presented by RIG-1 and IPS-1.(5) Thus, in contrast to the bactericidal properties of autophagic processes, the autophagy regulator (the Atg12-Atg5 conjugate) appeared to promote RNA virus replication by inhibiting innate anti-virus immune responses. In this addendum, we discuss the non-canonical role of the Atg12-Atg5 conjugate as a suppressor of innate immune responses.

The Atg5 Atg12 conjugate associates with innate antiviral immune responses

Autophagy is an essential process for physiological homeostasis, but its role in viral infection is only beginning to be elucidated. We show here that the Atg5-Atg12 conjugate, a key regulator of the autophagic process, plays an important role in innate antiviral immune responses. Atg5-deficient mouse embryonic fibroblasts (MEFs) were resistant to vesicular stomatitis virus replication, which was largely due to hyperproduction of type I interferons in response to immunostimulatory RNA (isRNA), such as virus-derived, double-stranded, or 5'-phosphorylated RNA. Similar hyperresponse to isRNA was also observed in Atg7-deficient MEFs, in which Atg5-Atg12 conjugation is impaired. Overexpression of Atg5 or Atg12 resulted in Atg5-Atg12 conjugate formation and suppression of isRNA-mediated signaling. Molecular interaction studies indicated that the Atg5-Atg12 conjugate negatively regulates the type I IFN production pathway by direct association with the retinoic acid-inducible gene I (RIG-I) and IFN-beta promoter stimulator 1 (IPS-1) through the caspase recruitment domains (CARDs). Thus, in contrast to its role in promoting the bactericidal process, a component of the autophagic machinery appears to block innate antiviral immune responses, thereby contributing to RNA virus replication in host cells.

Blocking of the TLR5 Activation Domain Hampers Protective Potential of Flagellin DNA Vaccine

Flagellin is a key component of the flagella of many pathogens, including Pseudomonas aeruginosa. Flagellin is an attractive vaccine candidate because it is readily produced and manipulated as a recombinant protein and has intrinsic adjuvant activity mediated through TLR5. Although DNA vaccines encoding native Pseudomonas B-type (FliC) or A-type (FlaA) flagellin are strongly immunogenic, the resultant Ab response interferes with the interaction of homologous flagellin with TLR5. This reduces the ability of the host to clear homologous, but not heterologous, flagellin-expressing P. aeruginosa. To circumvent this problem, a DNA vaccine encoding a mutant FliC R90A flagellin was developed. The mutant Ag encoded by this vaccine was highly immunogenic, but its ability to interact with TLR5 was reduced by >100-fold. Vaccination with this flagellin mutant DNA vaccine induced cross-reactive Abs against both FliC and FlaA, but few Abs capable of interfering with TLR5 activation. The flagellin mutant DNA vaccine provided excellent protection against both FliC- and FlaA-expressing P. aeruginosa. These findings suggest that vaccines against flagellated pathogens should avoid inducing Abs against TLR5 and raise the possibility that flagellated bacteria evade host elimination by facilitating the production of Abs that reduce the host's ability to mount an innate immune response.

Suppression of iodide uptake and thyroid hormone synthesis with stimulation of the type I interferon system by double-stranded ribonucleic acid in cultured human thyroid follicles

Although viral infection is thought to be associated with subacute thyroiditis and probably with autoimmune thyroid disease, possible changes in thyroid function during the prodromal period of infection or subclinical infection remain largely unknown. Recently, it was shown that pathogen-associated molecular patterns stimulate Toll-like receptors (TLR) and activate innate immune responses by producing type I interferons (IFN). Using a human thyroid follicle culture system, in which de novo synthesized thyroid hormones are released into the culture medium under physiological concentrations of human TSH, we studied the effects of polyinosinic-polycytidylic acid [Poly(I:C)], a chemical analog of viral double-stranded RNA (dsRNA), on TSH-induced thyroid function. Thyrocytes expressed ligands for dsRNA (TLR 3, CD14, and retinoic-acid-inducible protein-1) comparable with the TSH receptor. DNA microarray and real-time PCR analyses revealed that dsRNA increased the expression of mRNA for TLR3, IFN-beta, IFN-regulating factors, proinflammatory cytokines, and class I major histocompatibility complex (MHC), whereas genes associated with thyroid hormonogenesis (sodium/iodide symporter, peroxidase, deiodinases) were suppressed. In accordance to these data, Poly(I:C) suppressed TSH-induced 125I uptake and hormone synthesis dose dependently, accompanied by a decrease in the ratio of 125I-T3/125I-T4 released into the culture medium, whereas peptidoglycan, lipopolysaccharides, or unmethylated CpG DNA, ligands for TLR2, TLR4, and TLR9, respectively, had no significant effect. These inhibitory effects of Poly(I:C) were not blocked by a neutralizing antibody against TLR3 and an anti-IFN alpha/beta receptor antibody. These in vitro findings suggest that when thyrocytes are infected with certain viruses, dsRNA formed intracellularly in thyrocytes may be a cause for thyroid dysfunction, leading to development of autoimmune thyroiditis.

Mutant influenza A virus nucleoprotein is preferentially localized in the cytoplasm and its immunization in mice shows higher immunogenicity and cross-reactivity

Many influenza vaccines targeted to hemagglutinin (HA) show efficient immunogenicity for protecting subjects against influenza virus infection. Major antigenic changes to HA molecules can help influenza virus to develop resistance against HA-targeted vaccines. DNA vaccines encoding conserved antigens protect animals against diverse subtypes, but their potency requires further improvement. We generated a DNA-based nucleoprotein (NP)-targeted vaccine using an N-terminal mutant of NP (NPm) that efficiently localized in the cytoplasm, and examined the immune responses in mice immunized with NPm or wild-type (WT) NP DNA vaccine. Importantly, the NPm vaccine showed 1.5-2-fold higher immunogenicity than the WT NP vaccine in mice. Furthermore, NPm vaccination efficiently protected the mice against lethal challenge with influenza viruses and showed cross-reactivity toward heterologous viruses. Therefore, DNA-based vaccination with NPm may contribute to the development of protective immunity against diverse influenza virus through its ability to stimulate cellular immunity.

TLR9 expression and function is abolished by the cervical cancer-associated human papillomavirus type 16

Cervical cancer development is linked to the persistent infection by high-risk mucosal human papillomaviruses (HPVs) types. The E6 and E7 major oncoproteins from this dsDNA virus play a key role in the deregulation of the cell cycle, apoptosis, and adaptive immune surveillance. In this study, we show for the first time that HPV type 16 (HPV16), the most carcinogenic type among the high-risk subgroup, interferes with innate immunity by affecting the expression of TLRs. Infection of human primary keratinocytes with HPV16 E6 and E7 recombinant retroviruses inhibits TLR9 transcription and hence functional loss of TLR9-regulated pathways. Similar findings were achieved in HPV16-positive cancer-derived cell lines and primary cervical cancers, demonstrating that this event occurs also in an in vivo context. Interestingly, E6 and E7 from the low-risk HPV type 6 are unable to down-regulate the TLR9 promoter. In addition, E6 and E7 from the high-risk HPV type 18, which are known to persist less competently in the host than HPV16, have reduced efficiency compared with HPV16 in inhibiting TLR9 transcription. Furthermore, a CpG motif derived from the HPV16 E6 DNA sequence activated TLR9, indicating this virus is able to initiate innate responses via the receptor it later down-regulates. This study reveals a novel mechanism used by HPV16 to suppress the host immune response by deregulating the TLR9 transcript, providing evidence that abolishing innate responses may be a crucial step involved in the carcinogenic events mediated by HPVs.

Muscle creatine kinase/SV40 hybrid promoter for muscle-targeted long-term transgene expression

Gene therapy for congenital protein deficiencies requires lifelong expression of a deficient protein. Current gene therapy approaches preferentially employ the strong cytomegalovirus (CMV) promoter/enhancer or its derivative CAG promoter; however, these promoters provide only temporary transgene expression. To create a promoter that enables long-lasting expression in muscle, hybrid promoters were constructed by coupling the muscle creatine kinase (MCK) enhancer to various strong promoters for enhancement of tissue specificity and improved transcriptional activity. A hybrid promoter containing the MCK enhancer and the simian virus 40 promoter (MCK/SV40 promoter) yielded long-term (>6 months) expression of a human secretory alkaline phosphatase (huSEAP) reporter gene following electrotransfer of the plasmid into mice, whereas expression using a conventional CMV or CAG promoter faded away within a few weeks. To explore the mechanism behind the sustained expression obtained with the MCK/SV40 promoter, mice were immunized with a LacZ expression plasmid driven by MCK/SV40 or a conventional promoter. Minimal cellular and humoral responses to LacZ were observed in MCK/SV40 promoter-treated animals, and mouse SEAP gene expression in vivo was successfully maintained by both the MCK/SV40 and conventional promoters. These results suggest that the lower immunogenicity of the MCK/SV40 promoter contributed to long-lasting gene expression in mice. Therefore, the MCK/SV40 promoter may provide the basis for development of an effective transgene expression cassette for treatment of congenital protein deficiencies in which therapeutic proteins are recognized as foreign by the host immune system.

The degree of apoptosis as an immunostimulant for a DNA vaccine against HIV-1 infection

To regulate the expression of the apoptotic gene, we constructed bicistronic DNA vaccines that encode for HIV env and caspase-3 mutant (casp 3m) that are expressed via the encephalomyocarditis virus internal ribosomal entry site (IRES) or cytomegalovirus (CMV) promoter-dependent translations. While IRES-casp 3m induced weak apoptosis and caused little reduction in antigen expression, CMV-casp 3m elicited strong apoptosis and led to a marked decrease in the antigen expression. Therefore, IRES-casp 3m augmented HIV-specific immune responses, and IRES-casp 3m induced significant protection against the vaccinia-HIV chimeric virus. These results suggest that the appropriate level of apoptosis is important for DNA vaccine development.

Streptozotocin-induced partial beta cell depletion in nude mice without hyperglycaemia induces pancreatic morphogenesis in transplanted embryonic stem cells

AIMS/HYPOTHESIS

It appears that the adult pancreas has limited regenerative ability following beta cell destruction by streptozotocin (STZ). However, it is not clear if this limitation is due to an inability to respond to, rather than an absence of, regenerative stimuli. In this study we aimed to uncouple the regenerative signal from the regenerative response by using an exogenous stem cell source to detect regenerative stimuli produced by the STZ-injured pancreas at physiological blood glucose levels.

METHOD

Adult nude mice received 150 mg/kg STZ and 1x10(6) J1 mouse embryonic stem (ES) cells by i.p. injection. Permanent beta cell depletion of 50% was estimated from the ratio of beta:alpha cells in pancreata from STZ-treated mice compared with control animals after 24 days.

RESULTS

Transplanted ES cells homed to the STZ-injured pancreas and formed tumours. Immunocytochemical analysis of pancreas-associated ES tumours revealed foci containing insulin/PDX-1 double-positive and glucagon-positive/PDX-1-negative cell clusters associated with PDX-1-positive columnar lumenal epithelium and extensive alpha-amylase-positive pancreatic acini comprising approximately 0.1% of ES tumour volume.

CONCLUSIONS/INTERPRETATION

These data indicate that (1) the adult pancreas produces a milieu of regenerative stimuli following beta cell destruction, and (2) this is not dependent on hyperglycaemic conditions; (3) these regenerative stimuli appear to recapitulate the signalling pathways of embryonic development, since both exocrine and endocrine lineages are produced from PDX-1-positive precursor epithelium. This model will be useful for characterising the regenerative mechanisms in the adult pancreas.

Multivalent DNA vaccine protects mice against pulmonary infection caused by Pseudomonas aeruginosa

For efficacious vaccine development against Pseudomonas aeruginosa (P. aeruginosa), the immunogenicity of multivalent DNA vaccine was evaluated. Three different plasmids each targeting a fusion of outer membrane proteins (OprF/OprI), a protein regulating type III secretion system (PcrV), or an appendage (PilA) were prepared and mice were immunized with single (monovalent) or a combination of these plasmids (multivalent) via intramuscular electroporation (imEPT) or gene gun. Immunization with multivalent DNA vaccine via imEPT induced the most potent protection against lethal pneumonia. Although the serum levels of IgG binding to whole bacteria cells were comparable between groups, the strongest immune protection was associated with the serum levels of Th1-dominated multivalent IgG, the bronchoalveolar levels of macrophage inflammatory protein 2 (MIP-2) and IFN-gamma, and the number of neutrophils and macrophages in the bronchoalveolar lavage following intranasal challenge. These results implied the possible clinical application of multivalent DNA vaccine against P. aeruginosa.

Localization of CORO1A in the macrophages containing Mycobacterium leprae

Mycobacteria have acquired an intracellular lifestyle within the macrophage, which is best exemplified by the enlarged infected histiocytes seen in lepromatous leprosy. To survive within the cell, mycobacteria must escape intracellular bactericidal mechanisms. In a study of Mycobacterium bovis Bacille Calmette-Guérin (M. bovis BCG) infection, it was shown that the host protein, CORO1A, also known as tryptophan aspartate-containing coat protein (TACO), accumulates on the phagosomal membrane, resulting in inhibition of phagosome-lysosome fusion, and thus augmenting intracellular survival. In this study, we show that CORO1A strongly localizes on the membrane of phagosomes that contain Mycobacterium leprae (M. leprae), where Toll-like receptor 2 was also visualized by immunostaining. When cultured macrophages were infected with M. leprae, CORO1A recruitment from the plasma membrane to the phagosomal membrane was observed. Moderate to strong CORO1A retention was observed in late lesions that contained foamy histiocytes, in which M. leprae were difficult to detect by acid-fast staining. These results suggest that components accumulating within the phagosome rather than viable bacilli are responsible for the retention of CORO1A, and that there is also a bactericidal mechanism in the macrophage that might counter the effects of CORO1A.

A fused gene of nucleoprotein (NP) and herpes simplex virus genes (VP22) induces highly protective immunity against different subtypes of influenza virus

We evaluated the immunogenicity and protective activity of plasmid DNA vaccines encoding the influenza virus NP gene (pNP) alone or in combination with the herpes simplex virus type 1 protein 22 gene (pVP22). Optimal immune responses were observed in BALB/c mice immunized with the combination of pVP22 plus pNP, as assessed by enzyme-linked immunosorbent assay (ELISA), enzyme-linked immunospot (ELISPOT) and intracellular cytokine staining (ICCS). These mice also showed maximal resistance following challenge with the A/PR/8/34 (H1N1) and A/Udron/72 (H3N2) strains of influenza virus. The susceptibility of immunized mice to virus infection was significantly increased following depletion of either CD4+ or CD8+ T cells. These results indicate that a plasmid DNA vaccine encoding pVP22 plus NP induces a high level of cross-protective immunity against influenza virus subtypes.