Induction of neutralizing antibody in mice by immunization with recombinant 56 kDa protein of Orientia tsutsugamushi

Anti-oriential antibody inhibits Orientia tsutsugamushi attachment to, and penetration of, host cells. However, O. tsutsugamushi antigens that induce the production of a neutralizing antibody have not been identified. The authors immunized mice and rabbits with the recombinant 56 kDa protein of O. tsutsugamushi fused to the maltose binding protein of Escherichia coli (MBP-Bor56) and analysed their effect on O. tsutsugamushi attachment to or penetration of L929 cells. O. tsutsugamushi attachment and penetration were measured by using an indirect immunofluorescent antibody assay (IFA). O. tsutsugamushi growth in L929 cells was determined by [3H]thymidine uptake assay. By IFA, we observed a 96% reduction of attachment or penetration of O. tsutsugamushi treated with rabbit anti-MBP-Bor56 sera. [3H]thymidine uptake showed that mouse anti-MBP-Bor56 sera caused a 91% reduction in O. tsutsugamushi growth, when compared to mouse anti-MBP sera. These results suggest that the 56 kDa protein of O. tsutsugamushi plays an important role in O. tsutsugamushi attachment to or penetration of cells.

Anti-inflammatory effects of 8-hydroxydeoxyguanosine in LPS-induced microglia activation: suppression of STAT3-mediated intercellular adhesion molecule-1 expression

To elucidate the roles of 8-hydroxydeoxyguanosine (oh(8)dG), the nucleoside of 8-hydroxyguanine (oh(8)Gua), we examined the effects of oh(8)dG upon LPS-induced intercellular adhesion molecule-1 (ICAM-1) expression and the underlying mechanisms in brain microglial cells. We found that oh(8)dG reduces LPS-induced reactive oxygen species (ROS) production, STAT3 activation, and ICAM-1 expression. oh(8)dG also suppresses pro-inflammatory cytokines, such as TNF-alpha, IL-6 and IFN-gamma. Overexpression of dominant negative STAT3 completely diminshed STAT3-mediated ICAM-1 transcriptional activity. Chromatin immunoprecipitation studies revealed that oh(8)dG inhibited recruitment of STAT3 to the ICAM-1 promoter, followed by a decrease in ICAM-1 expression. Using mice lacking a functional Toll-like receptor 4 (TLR4), we demonstrated that, while TLR4+/+ microglia were activated by LPS, TLR4-/- microglia exhibited inactivated STAT3 in response to LPS. Evidently, LPS modulates STAT3-dependent ICAM-1 induction through TLR4-mdiated cellular responses. Oh(8)dG apparently plays a role in anti-inflammatory actions via suppression of ICAM-1 gene expression by blockade of the TLR4-STAT3 signal cascade in inflammation-enhanced brain microglia. Therefore, oh(8)dG in the cytosol probably functions as an anti-inflammatory molecule and should be considered as a candidate for development of anti-inflammatory agents.

Role of amphipathic helix of a herpesviral protein in membrane deformation and T cell receptor downregulation

Lipid rafts are membrane microdomains that function as platforms for signal transduction and membrane trafficking. Tyrosine kinase interacting protein (Tip) of T lymphotropic Herpesvirus saimiri (HVS) is targeted to lipid rafts in T cells and downregulates TCR and CD4 surface expression. Here, we report that the membrane-proximal amphipathic helix preceding Tip's transmembrane (TM) domain mediates lipid raft localization and membrane deformation. In turn, this motif directs Tip's lysosomal trafficking and selective TCR downregulation. The amphipathic helix binds to the negatively charged lipids and induces liposome tubulation, the TM domain mediates oligomerization, and cooperation of the membrane-proximal helix with the TM domain is sufficient for localization to lipid rafts and lysosomal compartments, especially the mutivesicular bodies. These findings suggest that the membrane-proximal amphipathic helix and TM domain provide HVS Tip with the unique ability to deform the cellular membranes in lipid rafts and to downregulate TCRs potentially through MVB formation.

GM-CSF-loaded chitosan hydrogel as an immunoadjuvant enhances antigen-specific immune responses with reduced toxicity

BACKGROUND

The application of vaccine adjuvants has been vigorously studied for a diverse range of diseases in order to improve immune responses and reduce toxicity. However, most adjuvants have limited uses in clinical practice due to their toxicity.

METHODS

Therefore, to reduce health risks associated with the use of such adjuvants, we developed an advanced non-toxic adjuvant utilizing biodegradable chitosan hydrogel (CH-HG) containing ovalbumin (OVA) and granulocyte-macrophage colony-stimulating factor (GM-CSF) as a local antigen delivery system.

RESULTS

After subcutaneous injection into mice, OVA/GM-CSF-loaded CH-HG demonstrated improved safety and enhanced OVA-specific antibody production compared to oil-based adjuvants such as Complete Freund's adjuvant (CFA) or Incomplete Freund's adjuvant (IFA). Moreover, CH-HG system-mediated immune responses was characterized by increased number of OVA-specific CD4(+) and CD8(+) INF-γ(+) T cells, leading to enhanced humoral and cellular immunity.

CONCLUSIONS

In this study, the improved safety and enhanced immune response characteristics of our novel adjuvant system suggest the possibility of the extended use of adjuvants in clinical practice with reduced apprehension about toxic side effects.

Global gene expression profile of Orientia tsutsugamushi

Orientia tsutsugamushi, an obligate intracellular bacterium, is the causative agent of Scrub typhus. The control mechanisms for bacterial gene expression are largely unknown. Here, the global gene expression of O. tsutsugamushi within eukaryotic cells was examined using a microarray and proteomic approaches for the first time. These approaches identified 643 genes, corresponding to approximately 30% of the genes encoded in the genome. The majority of expressed genes belonged to several functional categories including protein translation, protein processing/secretion, and replication/repair. We also searched the conserved sequence blocks (CSBs) in the O. tsutsugamushi genome which is unique in that up to 40% of its genome consists of dispersed repeated sequences. Although extensive shuffling of genomic sequences was observed between two different strains, 204 CSBs, covering 48% of the genome, were identified. When combining the data of CSBs and global gene expression, the CSBs correlates well with the location of expressed genes, suggesting the functional conservation between gene expression and genomic location. Finally, we compared the gene expression of the bacteria-infected fibroblasts and macrophages using microarray analysis. Some major changes were the downregulation of genes involved in translation, protein processing and secretion, which correlated with the reduction in bacterial translation rates and growth within macrophages.

Apolipoproteins inhibit the innate immunity activated by necrotic cells or bacterial endotoxin

We suggested earlier that the hydrophobic portions (Hyppos) of molecules, which are normally embedded in the membranes of cells or the core of molecular structures so as to be separated from the aqueous environment, might serve as evolutionarily ancient alarm signals of injury or stress to initiate innate immune responses when they are exposed on the surface. Under normal physiological conditions, the Hyppos released from endogenous or exogenous sources might be handled by 'Hyppo-quenchers'in vivo to maintain the tissue homeostasis and immune modulation. To test this idea, we selected apolipoproteins, which have been known to transport blood lipids and play a role in a number of pathological inflammatory conditions. We examined their role as Hyppo-quenchers in early immune responses and found that apolipoproteins showed significant inhibition of the nuclear factor-kappaB-dependent gene expression in recombinant Chinese hamster ovary (CHO) cells and dendritic cells stimulated by necrotic cells or bacterial endotoxin. In addition, our results indicate that apolipoproteins could dramatically abrogate complement fixation on the surface of necrotic cells. These findings suggest that apolipoproteins, besides having known functions in lipid metabolism, also have a role in preventing the initiation of innate immunity, potentially through neutralizing Hyppos from injured cells or exogenous endotoxin.

Chemokine and cytokine production in susceptible C3H/HeN mice and resistant BALB/c mice during Orientia tsutsugamushi infection

To understand the pathogenesis of scrub typhus, we examined chemokine and cytokine production in susceptible (C3H/HeN) and resistant (BALB/c) mice after infection with O. tsutsugamushi Gilliam. C3H/HeN mice produced high levels of chemokines macrophage inflammatory proteins 1 alpha (MIP-1 alpha ), MIP-2, monocyte chemoattractant protein 1 (MCP-1), and cytokines gamma-interferon (IFN-gamma ), interleukin-12 (IL-12), IL-10, and tumor necrosis factor alpha (TNF-alpha ) in response to O. tsutsugamushi infection, compared to BALB/c mice. Chemokine profiles in infected mice correlated well with the kinetics of inflammatory cell infiltration. Hyperproduction of chemokines and cytokines was observed in another susceptible-infection model (BALB/c-Karp). These results suggest that hyperproduction of chemokines and cytokines are associated with susceptibility during O. tsutsugamushi infection.

Mapping of antigenic determinant regions of the Bor56 protein of Orientia tsutsugamushi

The 56-kDa protein (Bor56) of Orientia tsutsugamushi is an immunoprotective antigen and is the target molecule of neutralizing antibodies. This antigen is recognized by almost all of the serum antibodies produced by patients in the convalescence phase of scrub typhus. We expressed the Bor56 open reading frame in Escherichia coli and generated from it a series of deletion constructs as MalE fusion proteins. Antibody-binding domains were characterized by using patient sera, mouse monoclonal antibodies (MAbs), and Bor56-immunized-mouse sera. None of the antibodies bound to a fusion protein containing the carboxy-terminal 140 amino acids (aa) of the Bor56 protein, suggesting that the carboxy-terminal domain of Bor56 is not exposed on the surface of the molecule. Human immunoglobulin M (IgM) antibodies predominantly bound to antigenic domain I (AD I; amino acids [aa] 19 to 113) and AD III (aa 243 to 328). Human IgG antibodies also showed preferential binding to AD I. The epitope recognized by strain-specific MAb (KI4) or group-specific MAb (KI57) was mapped to AD II (aa 142 to 203). Mouse serum antibodies, elicited by immunization with deletion mutants, consistently bound to AD III. Moreover, the carboxy-terminal 140 aa of the Bor56 protein did not elicit an antibody response in C3H/HeDub mice. A model of the antigenic structure of Bor56 is presented and discussed. These results suggest that antigenic fragments from AD I and AD III are useful in the induction of humoral immunity against O. tsutsugamushi. These antigenic analyses provide an important foundation for further analyses of the neutralizing-antibody responses generated during rickettsial infections. They also provide potential peptide substrates for diagnostic assays and vaccine strategies.

Functional manipulation of dendritic cells by photoswitchable generation of intracellular reactive oxygen species

Reactive oxygen species (ROS) play an important role in cellular signaling as second messengers. However, studying the role of ROS in physiological redox signaling has been hampered by technical difficulties in controlling their generation within cells. Here, we utilize two inert components, a photosensitizer and light, to finely manipulate the generation of intracellular ROS and examine their specific role in activating dendritic cells (DCs). Photoswitchable generation of intracellular ROS rapidly induced cytosolic mobilization of Ca(2+), differential activation of mitogen-activated protein kinases, and nuclear translocation of NF-κB. Moreover, a transient intracellular ROS surge could activate immature DCs to mature and potently enhance migration in vitro and in vivo. Finally, we observed that intracellular ROS-stimulated DCs enhanced antigen specific T-cell responses in vitro and in vivo, which led to delayed tumor growth and prolonged survival of tumor-bearing mice when immunized with a specific tumor antigen. Therefore, a transient intracellular ROS surge alone, if properly manipulated, can cause immature DCs to differentiate into a motile state and mature forms that are sufficient to initiate adaptive T cell responses in vivo.

Modification of dendritic cells with interferon-gamma-inducible protein-10 gene to enhance vaccine potency

BACKGROUND

Dendritic cell (DC)-based vaccines have become a promising modality in cancer immunotherapy. However, their ability to initiate tumor antigen-specific T cell immunity is limited in various negative-feedback mechanisms. The rapid down-regulation of chemokines, such as the interferon inducible protein of 10 kDa (IP-10), which chemoattracts activated antigen-specific CD8+ T cells, would represent negative-feedback regulation. Therefore, we attempted to improve DC vaccine potency by introducing the IP-10 gene retrovirally aiming to replenish the chemoattractive activity of DCs.

METHODS

We introduced IP-10 gene into DC2.4 cells, referred to as DC-IP10, using a retroviral system. Nonsecretable mIP-10-expressing DCs (DC-mIP10) were also prepared to evaluate the effects of secretion in IP-10-mediated modulation of DC biology. Additionally, in vitro and in vivo activation of antigen-specific T lymphocytes and in vivo anti-tumor effects induced by DC-IP10 or DC-mIP10 were determined.

RESULTS

The modification of DC2.4 cells with the IP-10 gene resulted in the secretion of functionally chemoattractive IP-10 and, unexpectedly, a significant up-regulation of surface expression in co-stimulatory molecules, such as CD40 and CD80, compared to that of DCs with vector control (DC-no insert). DC-mIP10 also displayed the partially matured phenotypes but failed to recruit antigen-specific T cells in an in vitro cell culture system. Consistently, DC-IP10 generated more tumor antigen-specific CD8+ T cells and stronger anti-tumor effects in vaccinated mice than did control DCs and DC-mIP10.

CONCLUSIONS

The results obtained provide the groundwork for a future clinical translation of the chemokine-based genetic modification of DCs to increase their vaccine potency.

Cellular invasion of Orientia tsutsugamushi requires initial interaction with cell surface heparan sulfate

Role of transmembrane heparan sulfate proteoglycans on invasion of Orientia tsutsugamushi into host cells was investigated. Pretreatment with heparan sulfate and heparin inhibited the infection of O. tsutsugamushi for L cell, mouse fibroblast, whereas other glycosaminoglycans had little effect. These same treatments were also shown to reduce the infection in a dose-dependent manner, and enzymatic treatment of cells with heparitinase, but not chondroitinase ABC, inhibited the infection. In addition, mutant cell lines of Chinese hamster ovarian cell defective in heparan sulfate synthesis but not chondrotin sulfate synthesis and defective in all glycosaminoglycan synthesis showed marked reduction in susceptibility to infection by O. tsutsugamushi. Also mutant cell lines, which express heparan sulfate proteoglycans at low level, showed intermediate level of infectivity. Finally O. tsutsugamushi bind to(35)S-labelled heparin. Collectively, these findings provide strong evidence that heparan sulfate proteoglycans contribute to the attachment of O. tsutsugamushi to the cells.

Chemokine and cytokine production during Orientia tsutsugamushi infection in mice

Orientia tsutsugamushi, an obligate intracellular bacterium, is the causative agent of scrub typhus which is histopathologically characterized by inflammatory manifestations, indicating that rickettsiae induce mechanisms that amplify the inflammatory response. To understand the pathogenesis of scrub typhus, we examined chemokine and cytokine production after infection with O. tsutsugamushi in mice. The mRNAs that were upregulated included lymphotactin, RANTES (regulated upon activation, normal T-cell expressed and secreted), macrophage inflammatory proteins 1alpha/beta (MIP-1alpha/beta), MIP-2, monocyte chemoattractant protein 1, lymphotoxin beta, tumor necrosis factor alpha, interleukin-6, gamma-interferon, transforming growth factor beta1, and migration inhibition factor. Peak expression of these chemokines and cytokines was observed between 4 and 8 days after infection. Gene induction was followed by the secretion of chemokine and cytokine proteins. Chemokine profile in infected mice was well correlated with kinetics of inflammatory cell infiltration. Thus, O. tsutsugamushi appears to be a strong inducer of chemokines and cytokines which may, by the attraction and activation of phagocytic leukocytes, significantly contribute to inflammation observed in scrub typhus.

Protective anti-tumour immune responses by murine dendritic cells pulsed with recombinant Tat-carcinoembryonic antigen derived from Escherichia coli

Carcinoembryonic antigen (CEA) is over-expressed on various human cancer cells and has been the target of immunotherapies using dendritic cells (DCs) pulsed with CEA-specific RNA or peptides, or transduced by CEA-expressing adenovirus or vaccinia virus. Because activated DCs do not phagocytose soluble protein antigens efficiently and pure immature DCs are not obtained easily ex vivo, an efficacious whole CEA protein-loaded DC vaccine has not been reported. To improve the antigen delivery into DCs, we utilized CEA conjugated to a protein-transduction domain, human immunodeficiency virus transactivating Tat. Furthermore, we purified the truncated non-glycosylated CEA from Escherichia coli to overcome the safety concerns and immunosuppressive functions associated with the native CEA protein. Using confocal microscopy and fluorescence activating cell sorter analysis, we demonstrated that the Tat-CEA protein entered the cytoplasm of DCs efficiently within 10 min of co-culture, compared with the negligible amount of CEA into DCs 30 min later. CEA-specific T cell proliferation and cytotoxic T cell responses were enhanced significantly in mice immunized with Tat-CEA-pulsed DCs [DC (Tat-CEA)] compared with those immunized with CEA-pulsed DCs [DC (CEA)]. T helper type 1 responses were more prominent in the DC (Tat-CEA) immunized mice whose splenocytes secreted more interferon-gamma and less interleukin-4 than those from DC (CEA) immunized mice. In vivo, the DC (Tat-CEA) vaccine delayed tumour growth significantly and prolonged survival of tumour-bearing mice. These results suggest that protective epitopes are well preserved on bacteria-derived recombinant Tat-CEA. This strategy may provide a basic platform for DC-based anti-CEA vaccines that could be utilized in combination with advanced immune-enhancing therapeutics.

Enhancement of DNA vaccine potency by antigen linkage to IFN-γ-inducible protein-10

DNA vaccines have emerged as an attractive approach to generate antigen-specific T-cell immune response. Nevertheless, the potency of DNA vaccines still needs to be improved for cancer immunotherapy. In this study, we explored whether functional linkage of a Th1-polarizing chemokine, IP-10, to a model tumor antigen, human papillomavirus type 16 (HPV-16) E7, enhanced DNA vaccine potency. IP-10 linkage changed the location of E7 from the nucleus to the endoplasmic reticulum and led to the secretion of functionally chemoattractive chimeric IP-10/E7 protein. In addition, this linkage drastically enhanced the endogenous processing of E7 antigen through MHC class I. More importantly, we found that C57BL/6 mice intradermally vaccinated with IP-10/E7 DNA exhibited a dramatic increase in the number of E7-specific CD4(+) Th1 T-cells and CD8(+) T-cells and, consequently, were strongly resistant over the long term to E7-expressing tumors compared to mice vaccinated with wild-type E7 DNA. Thus, because of the increase in tumor antigen-specific T-cell immune responses obtained through both enhanced antigen presentation and chemoattraction, vaccination with DNA encoding IP-10 linked to a tumor antigen holds great promise for treating tumors.

Pattern difference of dissociated hand muscle atrophy in amyotrophic lateral sclerosis and variants

INTRODUCTION

Split hand is considered to be a specific feature of amyotrophic lateral sclerosis (ALS).

METHODS

We evaluated the pattern difference of intrinsic hand muscles of upper limb-onset ALS (UL-ALS), upper limb-onset progressive muscular atrophy (UL-PMA), brachial amyotrophic diplegia (BAD), and Hirayama disease (HD) by measuring objective electrophysiological markers.

RESULTS

The abductor digiti minimi (ADM)/abductor pollicis brevis (APB) compound muscle action potential (CMAP) amplitude ratio was significantly higher in UL-ALS than other variants, but a considerable proportion of UL-ALS cases had an amplitude ratio in the range of other variants. Absent APB CMAP and abnormally high ADM/APB CMAP amplitude ratio (≥4) occurred only with UL-ALS. Conversely, an absent ADM CMAP was identified only in UL-PMA and BAD.

CONCLUSIONS

The absolute ADM/APB CMAP amplitude ratio was not specific for ALS; however, several findings from simple electrophysiological measurements may help predict prognosis in patients with motor neuron diseases and may be early diagnostic markers for ALS.

Homotypic and heterotypic antibody responses to a 56-kilodalton protein of Orientia tsutsugamushi

We analyzed homotypic and heterotypic antibody responses to a type-specific antigen (Tsa), a 56-kDa protein of Orientia tsutsugamushi, by using sera from mice immunized with strains Gilliam, Karp, Kato, and Boryong. We generated a series of deletion constructs of the tsa gene and expressed them as MalE fusion proteins. Variable domain I (VD I) showed strong responses to homotypic antibodies. Antigenic domain II (AD II) from Boryong and Karp showed cross-reactivities to each other. VD III showed no responses to any of the antibodies. Sera from Kato-immunized mice showed only homotypic responses to AD III. On the other hand, sera of the mice immunized with Gilliam, Karp, or Boryong showed homotypic as well as heterotypic responses to this region. VD IV showed the strongest heterotypic antibody responses among the fragments tested. These data suggest that VD I is important in homotypic antibody responses and that AD II, AD III, and VD IV are important in heterotypic antibody responses of the mice to Tsa.

Orientia tsutsugamushi inhibits apoptosis of macrophages by retarding intracellular calcium release

Orientia tsutsugamushi shows both pro- and antiapoptotic activities in infected vertebrate cells. Apoptosis of THP-1 cells induced by beauvericin was inhibited by O. tsutsugamushi infection. Beauvericin-induced calcium redistribution was significantly reduced and retarded in cells infected with O. tsutsugamushi. Antiapoptotic activities of O. tsutsugamushi in infected cells are most probably due to inhibition of the increase in the cytosolic calcium concentration.

Inhibition of Rac and Rac-linked functions by 8-oxo-2'-deoxyguanosine in murine macrophages

Rac is a protein involved in the various functions of macrophages (Mphi), including the production of reactive oxygen species (ROS), phagocytosis, chemotaxis and the secretion of cytokines (such as gamma-INF). This study tested the effects of nucleosides containing 8-oxoguanine(8-hydroxyguanine) such as 8-oxo-2'-guanosine (8-oxoG) or 8-oxo-2'-deoxyguanosine (8-oxodG), on Rac and the above-listed Rac-associated functions of Mphi using mouse peritoneal Mphi (MpMphi). It is reported that 8-oxodG was able to effectively inhibit Rac and the Rac-associated functions of MpMphi. Compared to 8-oxodG, 8-oxoG showed negligible effects. Furthermore, normal nucleosides such as deoxyguanosine (dG), guanosine (G) and adenosine (A) did not exert any effects. These results suggest that 8-oxodG could be used as a potential tool to modulate the functions of Mphi that are intimately related to various pathological processes.

Molecular and serologic survey of Orientia tsutsugamushi infection among field rodents in southern Cholla Province, Korea

Field rodents were collected from six areas in southern Cholla Province, Korea from October to December 1993. Twenty-eight (24%) of the 119 Apodemus agrarius were seropositive (> 1:10) for Orientia tsutsugamushi by the passive hemagglutination assay (PHA). Of the seropositive cases, 11 specimens had antibody titers greater than 1:80. No seropositive specimens were found among the eight Crocidura lasiura collected. On the other hand, the polymerase chain reaction (PCR) amplified about 520 basepairs of a gene encoding the 56-kD protein from the genomic DNA of 12 strains of O. tsutsugamushi tested. This target DNA sequence was amplified from the 11 (8.7%) blood specimens of A. agrarius, and one of the eight C. lasiura also showed evidence of O. tsutsugamushi infection by PCR. Only one of the PCR-positive samples was also PHA-positive. These results suggest that the PCR combined with a serologic assay more accurately detects the degree of infection of rodents with rickettsiae-causing scrub typhus in epidemiologic surveys.

Evaluation of acute and subacute toxicity of sodium taurodeoxycholate in rats

Taurodeoxycholate (TDCA) inhibits various inflammatory responses suggesting potential clinical application. However, the toxicity of TDCA has not been evaluated in detail in vivo. We investigated the acute toxicity and 4-week repeated-dose toxicity of TDCA following intravenous infusion under Good Laboratory Practice regulations. In the sighting study of acute toxicity, one of two rats (one male and one female) treated with 300 mg/kg TDCA died with hepatotoxicity, suggesting that the approximate 50% lethal dose of TDCA is 300 mg/kg. Edema and discoloration were observed at the injection sites of tails when rats were infused with 150 mg/kg or higher amount of TDCA once. In 4-week repeated-dose toxicity study, no treatment-related mortality or systemic changes in hematology and serum biochemistry, organ weights, gross pathology, or histopathology were observed. However, the tail injection site showed redness, discharge, hardening, and crust formation along with histopathological changes such as ulceration, edema, fibrosis, and thrombosis when rats were infused with 20 mg/kg TDCA. Taken together, TDCA induced no systemic toxicity or macroscopic lesions at the injection site at a dose of 10 mg/kg/day, which is 33 times higher than the median effective dose observed in a mouse sepsis model. These findings suggest that TDCA might have a favorable therapeutic index in clinical applications.

Detection and hazard assessment of pathogenic microorganisms in medical wastes

This study was undertaken to investigate the types and concentrations of microbial agents in various medical wastes as well as to characterize their survivals in these wastes at different temperatures for microbial risk assessment. Medical wastes collected from 5 major hospitals in South Korea were classified and stored at three different temperatures (-20, 6, and 30 degrees C). Presence of various microorganisms such as pathogenic viruses and bacteria were investigated by both cultivation and by (RT)-PCR assays. A number of (opportunistic) pathogenic bacteria, including Pseudomonas spp., Lactobacillus spp., Staphylococcus spp., Micrococcus spp., Kocuria spp., Brevibacillus spp., Microbacterium oxydans, and Propionibacterium acnes, were identified from the various medical wastes. In addition, pathogenic viruses such as noroviruses and hepatitis B virus were also detected in one of the human tissue wastes. Commonly identified bacterial and viral pathogens such as Pseudomonas spp., Corynebacterium diphtheriae, Escherichia coli, Staphylococcus spp., and respiratory synctial virus (RSV) were inoculated into either gauzes or diapers, and their survivals were characterized. Viral agents such as RSV showed poor survival in most environmental conditions, and demonstrated that various pathogens could be present in medical wastes but that the associated health risk appeared to be low. However, medical waste should be carefully controlled and monitored to prevent nosocomial infection associated with the exposure to these wastes.

Neuroprotective Effect of Human Adipose Stem Cell-Derived Extract in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating human neurodegenerative disease. The precise pathogenic mechanisms of the disease remain uncertain, and as of yet, there is no effective cure. Human adipose stem cells (hASC) can be easily obtained during operative procedures. hASC have a clinically feasible potential to treat neurodegenerative disorders, since cytosolic extract of hASC contain a number of essential neurotrophic factors. In this study, we investigated effects of hASC extract on the SOD1 G93A mouse model of ALS and in vitro test. Administration of hASC extract improved motor function and prolonged the time until symptom onset, rotarod failure, and death in ALS mice. In the hASC extracts group, choline acetyltransferase immunostaining in the ventral horn of the lumbar spinal cord showed a large number of motor neurons, suggesting normal morphology. The neuroprotective effect of hASC extract in ALS mice was also suggested by western blot analysis of spinal cord extract from ALS mice and in vitro test. hASC extract treatment significantly increased expression of p-Akt, p-CREB, and PGC-1α in SOD1 G93A mouse model and in vitro test. Our results indicated that hASC extract reduced apoptotic cell death and recovered mutant SOD1-induced mitochondrial dysfunction. Moreover, hASC extract reduced mitochondrial membrane potential. In conclusion, we have demonstrated, for the first time, that hASC extract exert a potential therapeutic action in the SOD1 G93A mouse model of ALS and in vitro test. These findings suggest that hASC hold promise as a novel therapeutic strategy for treating ALS.

Down-regulation of gp96 by Orientia tsutsugamushi

gp96 plays a central role in innate as well as acquired immunity, maturation and chemotaxis of dendritic cells, Ab production, and cross-priming, and is a peptide acceptor in endoplasmic reticulum and an accessory to peptide loading of MHC class I molecules. The remarkable conservation of essential immunological properties of gp96 suggests their important roles during the evolution of the immune system. Considering their importance in immunity, immune evasion mechanisms of pathogens by modulating gp96 expression have been speculated. By differential display PCR, we observed that obligate intracellular bacteria, Orientia tsutsugamushi, inhibit gp96 expression of a macrophage cell line, J774A.1. Not only gp96 transcripts but also protein was lower than for null-infected cells. The down-regulation was also consistent in an endothelial cell line, HMEC-1, and in murine peritoneal cells. These data support the idea that gp96 may be one of the target molecules for the immune evasion by intracellular bacteria.

GPCR19 Regulates P2X7R-Mediated NLRP3 Inflammasomal Activation of Microglia by Amyloid β in a Mouse Model of Alzheimer's Disease

Amyloid β (Aβ) and/or ATP activate the NLRP3 inflammasome (N3I) via P2X7R in microglia, which is crucial in neuroinflammation in Alzheimer's disease (AD). Due to polymorphisms, subtypes, and ubiquitous expression of P2X7R, inhibition of P2X7R has not been effective for AD. We first report that taurodeoxycholate (TDCA), a GPCR19 ligand, inhibited the priming phase of N3I activation, suppressed P2X7R expression and P2X7R-mediated Ca++ mobilization and N3I oligomerization, which is essential for production of IL-1β/IL-18 by microglia. Furthermore, TDCA enhanced phagocytosis of Aβ and decreased the number of Aβ plaques in the brains of 5x Familial Alzheimer's disease (5xFAD) mice. TDCA also reduced microgliosis, prevented neuronal loss, and improved memory function in 5xFAD mice. The pleiotropic roles of GPCR19 in P2X7R-mediated N3I activation suggest that targeting GPCR19 might resolve neuroinflammation in AD patients.

The Tat-conjugated N-terminal region of mucin antigen 1 (MUC1) induces protective immunity against MUC1-expressing tumours

Mucin antigen 1 (MUC1) is overexpressed on various human adenocarcinomas and haematological malignancies and has long been used as a target antigen for cancer immunotherapy. Most of the preclinical and clinical studies using MUC1 have used the tandem repeat region of MUC1, which could be presented by only a limited set of major histocompatibility complex haplotypes. Here, we evaluated N-terminal region (2-147 amino acids) of MUC1 (MUC1-N) for dendritic cell (DC)-based cancer immunotherapy. We used Esherichia coli-derived MUC1-N that was fused to the protein transduction domain of human immunodeficiency virus Tat protein for three reasons. First, mature DCs do not phagocytose soluble protein antigens. Secondly, tumour cells express underglycosylated MUC1, which can generate epitopes repertoire that differs from normal cells, which express hyperglycosylated MUC1. Finally, aberrantly glycosylated MUC1 has been known to impair DC function. In our study, Tat-MUC1-N-loaded DCs induced type 1 T cell responses as well as cytotoxic T lymphocytes efficiently. Furthermore, they could break tolerance in the transgenic breast tumour mouse model, where MUC1-positive breast cancers grow spontaneously. Compared with DCs pulsed with unconjugated MUC1-N, DCs loaded with Tat-conjugated MUC1-N could delay tumour growth more effectively in the transgenic tumour model as well as in the tumour injection model. These results suggest that the recombinant N-terminal part of MUC1, which may provide a diverse epitope repertoire, could be utilized as an effective tumour antigen for DC-based cancer immunotherapy.