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Biomedical subjects

Tetsutaro Sata

Publications and source records attributed to Tetsutaro Sata.

At least 55 records · Page 3Linked to original sources
PubMed2005

Protection against influenza virus infection by intranasal administration of hemagglutinin vaccine with chitin microparticles as an adjuvant.

Chitin in the form of microparticles (chitin microparticles, CMP) has been demonstrated to be a potent stimulator of macrophages, promoting T-helper-1 (Th1) activation and cytokine response. In order to examine the mucosal adjuvant effect of CMP co-administered with influenza hemagglutinin (HA) vaccine against influenza infection, CMP were intranasally co-administered with influenza HA vaccine prepared from PR8 (H1N1) virus. Inoculation of the vaccine with CMP induced primary and secondary anti-HA IgA responses in the nasal wash and anti-HA IgG responses in the serum, which were significantly higher than those of nasal vaccination without CMP, and provided a complete protection against a homologous influenza virus challenge in the nasal infection influenza model. In addition, CMP-based immunization using A/Yamagata (H1N1) and A/Guizhou (H3N2) induced PR8 HA-reactive IgA in the nasal washes and specific-IgG in the serum. The immunization with A/Yamagata and CMP resulted in complete protection against a PR8 (H1N1) challenge in A/Yamagata (H1N1)-vaccinated mice, while that with A/Guizhou (H3N2) and CMP exhibited a 100-fold reduction of nasal virus titer, demonstrating the cross-protective effect of CMP and influenza vaccine. It is suggested that CMP provide a safe and effective adjuvant for nasal vaccination with inactivated influenza vaccine.

Adjuvants, Immunologic↗
PubMed2005

Characterization of monoclonal antibodies to Marburg virus nucleoprotein (NP) that can be used for NP-capture enzyme-linked immunosorbent assay.

After the first documented outbreak of Marburg hemorrhagic fever identified in Europe in 1967, several sporadic cases and an outbreak of Marburg hemorrhagic fever have been reported in Africa. In order to establish a diagnostic system for Marburg hemorrhagic fever by the detection of Marburg virus nucleoprotein, monoclonal antibodies to the recombinant nucleoprotein were produced. Two clones of monoclonal antibodies, MAb2A7 and MAb2H6, were efficacious in the antigen-capture enzyme-linked immunosorbent assay (ELISA). At least 40 ng/ml of the recombinant nucleoprotein of Marburg virus was detected by the antigen-capture ELISA format. The epitope of the monoclonal antibody (MAb2A7) was located in the carboxy-terminus of nucleoprotein from amino acid position 634 to 647, while that of the MAb2H6 was located on the extreme region of the carboxy-terminus of the Marburg virus nucleoprotein (amino acid position 643-695). These monoclonal antibodies strongly interacted with the conformational epitopes on the carboxy-terminus of the nucleoprotein. Furthermore, these two monoclonal antibodies were reacted with the authentic Marburg virus antigens by indirect immunofluorescence assay. These data suggest that the Marburg virus nucleoprotein-capture ELISA system using the monoclonal antibodies is a promising technique for rapid diagnosis of Marburg hemorrhagic fever.

Amino Acid Sequence↗
PubMed2005

Herpes simplex virus type 1 mutant HF10 oncolytic viral therapy for bladder cancer.

OBJECTIVES: To investigate the antitumor effects of the oncolytic herpes simplex virus (HSV) type 1 mutant HF10 on human and murine bladder cancer cells (T24 and MBT-2) in vitro and in immunocompetent mouse models. METHODS: In vitro viral oncolytic activity and the replication ability of HF10 were measured in T24 and MBT-2 cells. To evaluate the therapeutic efficacy of HF10, disseminated peritoneal and bladder cancer models using MBT-2 cells were established in C3H/HeJ mice. The therapeutic efficacy was estimated from the survival rates and histopathologic analyses. RESULTS: HF10 replicated well in both T24 and MBT-2 cells, and it induced extensive cell lysis. Treatment with HF10 significantly prolonged the survival periods and increased the survival rates in both models tested. Immunohistochemical studies showed that HSV antigens were detected in the bladders 1 and 3 days after intravesical treatment with HF10 in nonimmunized mice, but only at 1 day after HF10 treatment in preimmunized, HSV-1 antibody-positive mice. A large number of inflammatory cells infiltrated into the bladder mucosa at 3 days after HF10 treatment in the preimmunized mice. CONCLUSIONS: These results suggest that HF10, a novel oncolytic HSV-1 mutant, is a promising agent for the treatment of superficial bladder cancer.

Animals↗
PubMed2005

Temperature-sensitive mutants of enterovirus 71 show attenuation in cynomolgus monkeys.

Enterovirus 71 (EV71) is one of the major causative agents of hand, foot and mouth disease and is sometimes associated with serious neurological disorders. In this study, an attempt was made to identify molecular determinants of EV71 attenuation of neurovirulence in a monkey infection model. An infectious cDNA clone of the virulent strain of EV71 prototype BrCr was constructed; temperature-sensitive (ts) mutations of an attenuated strain of EV71 or of poliovirus (PV) Sabin vaccine strains were then introduced into the infectious clone. In vitro and in vivo phenotypes of the parental and mutant viruses were analysed in cultured cells and in cynomolgus monkeys, respectively. Mutations in 3D polymerase (3D(pol)) and in the 3' non-translated region (NTR), corresponding to ts determinants of Sabin 1, conferred distinct temperature sensitivity to EV71. An EV71 mutant [EV71(S1-3')] carrying mutations in the 5' NTR, 3D(pol) and in the 3' NTR showed attenuated neurovirulence, resulting in limited spread of virus in the central nervous system of monkeys. These results indicate that EV71 and PV1 share common genetic determinants of neurovirulence in monkeys, despite the distinct properties in their original pathogenesis.

3' Untranslated Regions↗
PubMed2005

Interleukin-4 up-regulates T-tropic human immunodeficiency virus type 1 transcription in primary CD4+ CD38+ T-lymphocyte subset.

The capacity of human immunodeficiency virus type 1 (HIV-1) to infect resting cells and to produce progeny particles may contribute significantly to its pathogenicity in vivo. We previously reported that primary culture of resting CD4(+) CD38(+) T-lymphocyte subset had higher production rate of CXCR4-using (X4) HIV-1 than CD4(+) CD38(-) subset. Interleukin (IL)-4 highly contributed to the up-regulation of the X4 virus production in the CD38(+) subset. Here, we show evidences that IL-4 treatment of both resting CD38(+) and CD38(-) subsets allowed the adsorption, entry, and integration of X4 virus at similar rates, while the following viral transcription rate was significantly lower in the CD38(-) than CD38(+) subset. Treatment of the CD38 subsets with IL-4 or phytohemagglutinin revealed no association of X4 virus replication ability in the subsets with classic T-cell activation or proliferation. Interestingly, the activator protein (AP)-1 was significantly activated in the CD38(+) subset after IL-4 treatment, while both nuclear factor (NF)-kappaB and signal transducers and activator of transcription (STAT)-6 were activated in the IL-4-treated CD38(-) and CD38(-) subsets at similar levels. Thus, IL-4-dependent X4 HIV-1 transcription occurs efficiently in the CD38(+) but not CD38(-) subset of CD4(+) population and AP-1 could play a significant role on viral transcription, leading to the up-regulated X4 virus production in the CD38(+) subset.

ADP-ribosyl Cyclase↗
PubMed2005

Hodgkin's lymphoma cells are efficiently engrafted and tumor marker CD30 is expressed with constitutive nuclear factor-kappaB activity in unconditioned NOD/SCID/gammac(null) mice.

As there are very few reproducible animal models without conditioning available for the study of human B-cell-type Hodgkin's lymphoma (HL), we investigated the ability of HL cells to induce tumors using novel NOD/SCID/gammac(null) (NOG) mice. Four human Epstein-Barr virus-negative cell lines (KM-H2 and L428 originated from B cells, L540 and HDLM2 originated from T cells) were inoculated either subcutaneously in the postauricular region or intravenously in the tail of unmanipulated NOG mice. All cell lines successfully engrafted and produced tumors with infiltration of cells in various organs of all mice. Tumor cells had classical histomorphology as well as expression patterns of the tumor marker CD30, which is a cell surface antigen expressed on HL. Tumor progression in mice inoculated with B-cell-type, but not T-cell-type, HL cells correlated with an elevation in serum human interleukin-6 levels. Tumor cells from the mice also retained strong nuclear factor (NF)-kappaB DNA binding activity, and the induced NF-kappaB components were indistinguishable from those cultured in vitro. The reproducible growth behavior and preservation of characteristic features of both B-cell-type and T-cell-type HL in the mice suggest that this new xenotransplant model can provide a unique opportunity to understand and investigate the mechanism of pathogenesis and malignant cell growth, and to develop novel anticancer therapies.

Animals↗
PubMed2005

Amino acid 36 in the human immunodeficiency virus type 1 gp41 ectodomain controls fusogenic activity: implications for the molecular mechanism of viral escape from a fusion inhibitor.

We have previously described a human immunodeficiency virus type 1 (HIV-1) proviral clone, pL2, derived from defective viral particles with higher fusogenicity than the prototypic NL4-3 virus. In this study, we attempted to determine the region that confers the enhanced fusion activity by creating envelope recombinants between pL2 and pNL4-3, as well as point mutants based on pNL4-3. The results indicate that amino acid 36 of gp41 is key for the fusogenic activity and infectivity enhancement and that glycine 36 (36G) of gp41 in pL2 is conserved in nearly all HIV-1 isolates except for pNL4-3. The mutation 36G-->D in a primary-isolate-derived Env decreased syncytium-forming activity and infectivity. The assays for cell-cell fusion and viral binding suggested that the enhanced fusion mediated by the 36D-->G mutation is not due to increased binding efficiency but is directly due to actual enhancement of viral fusion activity. Interestingly, this amino acid position is exactly equivalent to that at which the mutation of HIV-1 isolates that have escaped from a fusion inhibitor, enfuvirtide (T-20), has been frequently observed. The correlation between these previous findings and our findings was suggested by structural analysis. Our finding, therefore, has implications for a molecular basis of the viral escape from this drug.

Amino Acids↗
PubMed2005

An attenuated LC16m8 smallpox vaccine: analysis of full-genome sequence and induction of immune protection.

The potential threat of smallpox bioterrorism has made urgent the development of lower-virulence vaccinia virus vaccines. An attenuated LC16m8 (m8) vaccine was developed in 1975 from the Lister strain used in the World Health Organization smallpox eradication program but was not used against endemic smallpox. Today, no vaccines can be tested with variola virus for efficacy in humans, and the mechanisms of immune protection against the major intracellular mature virion (IMV) and minor extracellular enveloped virion (EEV) populations of poxviruses are poorly understood. Here, we determined the full-genome sequences of the m8, parental LC16mO (mO), and grandparental Lister (LO) strains and analyzed their evolutionary relationships. Sequence data and PCR analysis indicated that m8 was a progeny of LO and that m8 preserved almost all of the open reading frames of vaccinia virus except for the disrupted EEV envelope gene B5R. In accordance with this genomic background, m8 induced 100% protection against a highly pathogenic vaccinia WR virus in mice by a single vaccination, despite the lack of anti-B5R and anti-EEV antibodies. The immunogenicity and priming efficacy with the m8 vaccine consisting mainly of IMV were as high as those with the intact-EEV parental mO and grandparental LO vaccines. Thus, mice vaccinated with 10(7) PFU of m8 produced low levels of anti-B5R antibodies after WR challenge, probably because of quick clearance of B5R-expressing WR EEV by strong immunity induced by the vaccination. These results suggest that priming with m8 IMV provides efficient protection despite undetectable levels of immunity against EEV.

Amino Acid Sequence↗
PubMed2005

Synthetic double-stranded RNA poly(I:C) combined with mucosal vaccine protects against influenza virus infection.

The mucosal adjuvant effect of synthetic double-stranded RNA polyriboinosinic polyribocytidylic acid [poly(I:C)] against influenza virus was examined under intranasal coadministration with inactivated hemagglutinin (HA) vaccine in BALB/c mice and was shown to have a protective effect against both nasal-restricted infection and lethal lung infection. Intranasal administration of vaccine from PR8 (H1N1) with poly(I:C) induced a high anti-HA immunoglobulin A (IgA) response in the nasal wash and IgG antibody response in the serum, while vaccination without poly(I:C) induced little response. Intracerebral injection confirmed the safety of poly(I:C). In addition, we demonstrated that administration of poly(I:C) with either A/Beijing (H1N1) or A/Yamagata (H1N1) vaccine conferred complete protection against PR8 challenge in this mouse nasal infection model, suggesting that poly(I:C) possessed cross-protection ability against variant viruses. To investigate the mechanism of the protective effect of poly(I:C), mRNA levels of Toll-like receptors and cytokines were examined in the nasal-associated lymphoid tissue after vaccination or virus challenge. Intranasal administration of HA vaccine with poly(I:C) up-regulated expression of Toll-like receptor 3 and alpha/beta interferons as well as Th1- and Th2-related cytokines. We propose that poly(I:C) is a new effective intranasal adjuvant for influenza virus vaccine.

Administration, Intranasal↗
PubMed2005

The alpha/beta interferon response controls tissue tropism and pathogenicity of poliovirus.

Poliovirus selectively replicates in neurons in the spinal cord and brainstem, although poliovirus receptor (PVR) expression is observed in both the target and nontarget tissues in humans and transgenic mice expressing human PVR (PVR-transgenic mice). We assessed the role of alpha/beta interferon (IFN) in determining tissue tropism by comparing the pathogenesis of the virulent Mahoney strain in PVR-transgenic mice and PVR-transgenic mice deficient in the alpha/beta IFN receptor gene (PVR-transgenic/Ifnar knockout mice). PVR-transgenic/Ifnar knockout mice showed increased susceptibility to poliovirus. After intravenous inoculation, severe lesions positive for the poliovirus antigen were detected in the liver, spleen, and pancreas in addition to the central nervous system. These results suggest that the alpha/beta IFN system plays an important role in determining tissue tropism by protecting nontarget tissues that are potentially susceptible to infection. We subsequently examined the expression of IFN and IFN-stimulated genes (ISGs) in the PVR-transgenic mice. In the nontarget tissues, ISGs were expressed even in the noninfected state, and the expression level increased soon after poliovirus infection. On the contrary, in the target tissues, ISG expression was low in the noninfected state and sufficient response after poliovirus infection was not observed. The results suggest that the unequal IFN response is one of the important determinants for the differential susceptibility of tissues to poliovirus. We consider that poliovirus replication was observed in the nontarget tissues of PVR-transgenic/Ifnar knockout mice because the IFN response was null in all tissues.

Animals↗
PubMed2005

Immunological detection of severe acute respiratory syndrome coronavirus by monoclonal antibodies.

In order to establish immunological detection methods for severe acute respiratory syndrome coronavirus (SARS-CoV), we established monoclonal antibodies directed against structural components of the virus. B cell hybridomas were generated from mice that were hyper-immunized with inactivated SARS-CoV virion. By screening 2,880 generated hybridomas, we established three hybridoma clones that secreted antibodies specific for nucleocapsid protein (N) and 27 clones that secreted antibodies specific for spike protein (S). Among these, four S-protein specific antibodies had in vitro neutralization activity against SARS-CoV infection. These monoclonal antibodies enabled the immunological detection of SARS-CoV by immunofluorescence staining, Western blot or immunohistology. Furthermore, a combination of monoclonal antibodies with different specificities allowed the establishment of a highly sensitive antigen-capture sandwich ELISA system. These monoclonal antibodies would be a useful tool for rapid and specific diagnosis of SARS and also for possible antibody-based treatment of the disease.

Animals↗
PubMed2005

Full-length sequence of hepatitis B virus belonging to genotype H identified in a Japanese patient with chronic hepatitis.

We have isolated and cloned the full-length nucleotide sequence of the hepatitis B virus (HBV) genome (denoted HBV-IM806-2) recovered from a Japanese patient with chronic hepatitis. This patient had a history of travel to Bangkok, Thailand, and then suffered the onset of acute hepatitis B 3 months after his return to Japan. The HBV-IM806-2 isolate was composed of 3,215 nucleotides and showed the highest similarity to genotype H of HBV. Interestingly, 24 amino acid residues specific for genotype H were identified throughout the full genome sequence. Furthermore, phylogenetic analysis based on the full genome sequence confirmed that IM806-2 belonged to genotype H and was more closely related to the prototype of the Los Angeles strain than to the Nicaragua strain.

Amino Acid Sequence↗
PubMed2005

[Bioterrorism].

Biological terrorism is intentionally to use infectious substances for developing diseases or death in animals or humans, leading to disaster and panic in our community. Bioterrorism-associated diseases are mostly rare or eradicated infectious diseases, and recently, we do not have experience to make a clinical and laboratory diagnosis. In particular, these infectious diseases have incubation periods from infection to development of the disease. The staff working at public health institutions, including legal medicine, must be involved in as a first responder when bioterrorism would happen. The preparedness in general against bioterrorism and the bioterrorism-related diseases, such as anthrax, smallpox, viral hemorrhagic fever, tularemia, and botulinum toxin, important for us are described. Both medical knowledge of bioterrorism and the preparedness with training under simulation should be required in advance.

Animals↗
PubMed2004

Effective antigen-retrieval method for immunohistochemical detection of abnormal isoform of prion proteins in animals.

For immunohistochemistry of the prion diseases, several pretreatment methods to enhance the immunoreactivity of human and animal abnormal proteinase-resistant prion protein (PrP(Sc)) on the tissue sections have been employed. The method of 121 degree C hydrated autoclaving pretreatment or the combination method of 121 degree C hydrated autoclaving with a certain chemical reagent (formic acid or proteinase K, etc) are now widely used. We found that an improved hydrated autoclaving method at 135 degrees C, more effectively enhanced PrP(Sc) immunoreactivity for the antibodies recognizing the linear epitope. In addition, this method was more effective for the long-term fixation samples as compared with other previous methods. However, this modified method could not retrieve PrP(Sc) antigenic epitopes composed of conformational structures or several discontinuous epitopes. We describe the comparative studies between our improved method and other antigen-retrieval procedures reported previously. Based on the differences of reaction among the antibodies, we also discuss the mechanisms of the hydrated autoclaving methods to retrieve PrP(Sc) immunoreactivity.

Animals↗
PubMed2004

Isolation and characterization of a new simian retrovirus type D subtype from monkeys at the Tsukuba Primate Center, Japan.

Exogenous type D simian retroviruses (SRV/D) are prevalent in captive and feral populations of various macaque monkeys. Thus far, five subtypes of SRV/Ds have been reported, three of which (SRV-1, -2 and -3) have been molecularly characterized. Two SRV/D strains (N27 and T150) were isolated from seropositive cynomolgus macaques at the Tsukuba Primate Center (TPC) in Japan, showing clinical signs of SRV/D infection, including anemia and persistent unresponsive diarrhea. Electron microscopy demonstrated that both SRV/D isolates have a virion morphology typical of type D retrovirus. The SRV/D N27 and T150 isolates were essentially the same based on sequence analysis. From homology analysis of the entire gag sequence, the N27 isolate is closely related to the other known SRV/Ds but is distinct from the three molecularly characterized SRV/Ds. Thus, we have tentatively designated the N27 and T150 viruses isolated from TPC cynomolgus macaques as SRV/D-Tsukuba (SRV/D-T).

Amino Acid Sequence↗
PubMed2004

Japanese encephalitis subunit vaccine composed of virus-like envelope antigen particles purified from serum-free medium of a high-producer J12#26 cell clone.

A stable cell clone, J12#26, which continuously secretes large amounts of the envelope (E) antigen of Japanese encephalitis (JE) virus (J. Virol. 77 (2003) 8745) was adapted to serum-free medium. The J12#26 antigen possessed hemagglutinating activity, as well as the viral E and M proteins. More than 10 and 1mg of the antigen quantified with the licensed JE vaccine (JE-VAX) as a standard by E-ELISA and protein determination, respectively, were recovered from 500 ml of serum-free medium by membrane ultrafiltration, Sephacryl S-300 chromatography, sucrose gradient centrifugation and Sephadex G-25 chromatography. SDS-PAGE and Western blot analyses confirmed the high yield and purity of the J12#26 E antigen, which was comprised of small spherical virus-like particles (VLP) of approximately 25 nm in diameter. This antigen induced in mice without adjuvant neutralizing antibody (NT Ab) titers, as high as or higher than the licensed JE vaccine, and complete protection against challenge with wild-type virus. These results suggest that the J12#26 antigen is a promising second-generation JE subunit vaccine.

Animals↗
PubMed2004

A poliomyelitis model through mucosal infection in transgenic mice bearing human poliovirus receptor, TgPVR21.

Transgenic mice bearing the human poliovirus receptor (TgPVR) are less susceptible to oral inoculation, although they are susceptible to parenteral inoculation. We investigated the susceptibility of TgPVR 21 line [Arch. Virol. 130 (1994) 351] to poliovirus through various mucosal routes. Intranasal inoculation of a neurovirulent Mahoney strain (OM1) caused flaccid paralysis with viral replication in the central nervous system at a dose of 10(6) cell culture infectious dose (CCID50), in contrast, no paralysis following oral or intragastric inoculation of the same dose. Intranasal inoculation of a vaccine strain, Sabin 1, at 10(6) CCID50, resulted in no paralysis. Initial replication of poliovirus in the nasal cavity was confirmed by virus isolation and detection of negative-stranded replicative intermediates by RT-PCR and viral antigens using a high-sensitive immunohistochemistry and genome/transcripts by in situ hybridization. Poliovirus-specific IgG antibodies were elevated in the sera of surviving TgPVR21. This model can be used as a mucosal infection model and for differentiation of neurovirulent and attenuated poliovirus strains.

Administration, Intranasal↗