Yasuyuki Gomi

National Institute of Biomedical Innovation, Ibaraki, Osaka-fu, Japan

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Publications (20)72.48 Total impact

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    ABSTRACT: The ORF49 tegument protein of varicella-zoster virus (VZV) is one of the core gene products that is conserved among herpesvirus family members. Although ORF49 is known to be a cell-tropic factor, its detailed functions remain elusive. ORF44 is another core gene product reported to be essential, although its characterization and detailed functional analysis have not been reported. These two core gene products form a complex in other herpesviruses beyond the host species and herpesvirus subfamilies. Here, we show that complex formation between ORF44 and ORF49 is conserved in VZV. We serendipitously found that binding is eliminated by an amino acid substitution at position 129 (phenylalanine 129), and four amino acids in the carboxyl-terminal half of the acidic cluster in ORF49, i.e., aspartate-phenylalanine-aspartate-glutamate from positions 41 to 44 (41DFDE44), were identified as its binding motif. Alanine substitutions in each domain rendered the ORF44F129A mutation lethal for VZV, similar to deletion of the entire ORF44. The phenotype of the ORF49-41AAAA44 mutation was comparable to that of the ORF49-defective virus, including small-plaque formation, impaired growth, and low infectious virus production. These results suggest that the interaction between ORF44 and ORF49 is essential for their role in VZV infection, and that ORF49 is required for the efficient production of infectious progeny virus mediated by the conserved interaction between the two proteins.
    Journal of Virology 10/2013; · 5.08 Impact Factor
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    ABSTRACT: The varicella-zoster virus (VZV) Oka vaccine strain (vOka) is a highly immunogenic and safe live vaccine that has long been used worldwide. vOka is considered a candidate vector for novel polyvalent vaccines, since the large size of the genome makes it suitable for inserting foreign genes. Previously, we generated a recombinant vOka, rvOka-HN, that expresses mumps virus (MuV) hemagglutinin-neuraminidase (HN). rvOka-HN induces the production of neutralizing antibodies against MuV in guinea pigs. MuV also expresses fusion (F) protein in its viral envelope, which is important for inducing neutralizing antibodies. To induce a more robust immune response against MuV than that obtained with rvOka-HN, here we generated an rvOka expressing both HN and F (rvOka-HN-F). However, the co-expression of HN and F caused the infected cells to form syncytia, which reduced the virus titer. To reduce the amount of cell fusion, we generated an rvOka expressing HN and a mutant F, F(S195Y). Almost no syncytia formed in the rvOka-HN-F(S195Y)-infected cells, and the growth of rvOka-HN-F(S195Y) was similar to that of the original vOka clone. Moreover, the replacement of serine 195 with tyrosine had no effect on the immunogenicity of F in mice and guinea pigs. Although an obvious augmentation in neutralizing antibodies was not observed by adding F protein to the vOka-HN, the anti-F antibodies had neutralizing activity. These data suggested that F protein contributes to the induction of immune protection against MuV. Therefore this recombinant virus is a promising candidate vaccine for polyvalent protection against both VZV and MuV.
    Microbiology and Immunology 08/2013; · 1.55 Impact Factor
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    ABSTRACT: SUMMARY The Shozu Herpes Zoster (SHEZ) Study was designed to clarify the incidence of and predictive and immunological factors for herpes zoster in a defined community-based Japanese population. As part of this series, a total of 5683 residents aged ⩾50 years received a varicella-zoster virus (VZV) skin test with VZV antigen, and 48 h later, the erythema and oedema were assessed by measuring the longest diameter. The diameters of both the erythema and oedema decreased with the increasing age of the subject. Sixty-three subjects contracted herpes zoster within a year after receiving the VZV skin test. Analysis of the herpes zoster incidence rate vs. the skin test reaction revealed that the shorter the diameter of erythema or oedema, the greater the likelihood of herpes zoster. These results demonstrated that the VZV skin test is an excellent surrogate marker for predicting the risk of herpes zoster.
    Epidemiology and Infection 12/2012; · 2.87 Impact Factor
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    ABSTRACT: BACKGROUND: Cell-mediated immunity (CMI) has been considered to be related to the development of herpes zoster (HZ). However, there have been no large-scale prospective studies on the relationship between VZV-specific CMI and severity of HZ. OBJECTIVE: We carried out a large-scale prospective cohort study to clarify the relationship between immunological factors for varicella-zoster virus (VZV) and the clinical severity of HZ. METHODS: We carried out a cohort study on VZV immunity in a population living on an island cluster, Shozu County in Japan, and examined the people who developed HZ during a median follow-up period of 2 years, with a focus on the relationship between cell-mediated and humoral immunity and the severity of skin lesions and zoster-associated pain. A total of 12,522 people over the age of 50 were enrolled in this study, and 258 registrants were diagnosed as HZ. CMI was measured by VZV skin test, and humoral immunity was assessed with serological tests (neutralization test, immunoadherence hemagglutination test, and gpELISA test) for VZV-specific antibodies. RESULTS: CMI to VZV assessed by VZV skin test showed a significant inverse relationship to the severity of HZ skin lesions, and also to the severity of acute and subacute pain. Furthermore, weak response to the VZV skin test was associated with a high risk of post-herpetic neuralgia. In contrast, VZV-specific antibody titer was not associated with the severity of skin lesions and zoster-associated pain. CONCLUSION: VZV-specific CMI, but not humoral immunity, may play a key role in controlling the severity of HZ skin lesions and zoster-associated pain.
    Journal of dermatological science 11/2012; · 3.71 Impact Factor
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    ABSTRACT: The antigenicity of seasonal human influenza virus changes continuously; thus, a cross-protective influenza vaccine design needs to be established. Intranasal immunization with an influenza split-virion (SV) vaccine and a mucosal adjuvant induces cross-protection; however, no mucosal adjuvant has been assessed clinically. Formalin-inactivated intact human and avian viruses alone (without adjuvant) induce cross-protection against the highly pathogenic H5N1 avian influenza virus. However, it is unknown whether seasonal human influenza formalin-inactivated whole-virion (WV) vaccine alone induces cross-protection against strains within a subtype or in a different subtype of human influenza virus. Furthermore, there are few reports comparing the cross-protective efficacy of the WV vaccine and SV vaccine-mucosal adjuvant mixtures. Here, we found that the intranasal human influenza WV vaccine alone induced both the innate immune response and acquired immune response, resulting in cross-protection against drift variants within a subtype of human influenza virus. The cross-protective efficacy conferred by the WV vaccine in intranasally immunized mice was almost the same as that conferred by a mixture of SV vaccine and adjuvants. The level of cross-protective efficacy was correlated with the cross-reactive neutralizing antibody titer in the nasal wash and bronchoalveolar fluids. However, neither the SV vaccine with adjuvant nor the WV vaccine induced cross-reactive virus-specific cytotoxic T-lymphocyte activity. These results suggest that the intranasal human WV vaccine injection alone is effective against variants within a virus subtype, mainly through a humoral immune response, and that the cross-protection elicited by the WV vaccine and the SV vaccine plus mucosal adjuvants is similar.
    Clinical and vaccine Immunology: CVI 05/2012; 19(7):979-90. · 2.60 Impact Factor
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    ABSTRACT: Japanese encephalitis is an infectious disease caused by the Japanese encephalitis virus, which is widespread throughout Asia. The worldwide incidence is 50,000 cases per year. There is no specific treatment available, but inactivated mouse brain-derived vaccine was used from the 1950s to prevent infection. However, quality control of mouse brain-derived vaccines is difficult, and therefore a new freeze-dried, cell culture-derived Japanese encephalitis vaccine (inactivated) (JEBIK V; development code: BK-VJE) was developed. In this paper, we report an analysis of neutralizing antibody titers in vaccinated subjects enrolled in clinical study of BK-VJE at various doses, and study of BK-VJE with the mouse brain-derived vaccine as a control. The results show that BK-VJE has superior immunogenicity compared to mouse brain-derived vaccine.
    Vaccine 03/2012; 30(13):2329-35. · 3.77 Impact Factor
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    ABSTRACT: The incidence and risk factors for herpes zoster have been studied in cross-sectional and cohort studies, although most such studies have been conducted in Western countries. Evidence from Asian populations is limited, and no cohort study has been conducted in Asia. We are conducting a 3-year prospective cohort study in Shozu County in Kagawa Prefecture, Japan to determine the incidence and predictive and immunologic factors for herpes zoster among Japanese. The participants are followed for 3 years, and a telephone survey is conducted every 4 weeks. The participants were assigned to 1 of 3 studies. Participants in study A gave information on past history of herpes zoster and completed health questionnaires. Study B participants additionally underwent varicella-zoster virus (VZV) skin testing, and study C participants additionally underwent blood testing. If the participants develop herpes zoster, we evaluate clinical symptoms, measure cell-mediated immunity and humoral immunity using venous blood sampling, photograph skin areas with rash, conduct virus identification testing by polymerase chain reaction (PCR) and virus isolation from crust sampling, and evaluate postherpetic pain. We recruited 12 522 participants aged 50 years or older in Shozu County from December 2009 through November 2010. The participation rate was 65.7% of the target population. The present study is likely to provide valuable data on the incidence and predictive and immunologic factors for herpes zoster in a defined community-based population of Japanese.
    Journal of Epidemiology 03/2012; 22(2):167-74. · 2.11 Impact Factor
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    ABSTRACT: The levels and properties of neutralizing antibodies in nasal wash and serum collected from five healthy adults were examined after intranasal administration of an A/Uruguay/716/2007 (H3N2) split vaccine (45 µg hemagglutinin (HA) per dose; five doses, with an interval of 3 weeks between each dose). Prior to the assays, nasal wash samples were concentrated so that the total amount of antibodies was equivalent to about 1/10 of that found in the natural nasal mucus. Vaccination induced virus-specific neutralizing antibody responses, which increased with the number of vaccine doses given. Neutralizing antibodies were produced more efficiently in the nasal passages than in the serum: A ≥4-fold increase in nasal neutralization titres was observed after the second vaccination in four out of five subjects, whereas a rise in serum neutralization titres was observed only after the fifth vaccination. Nasal and serum neutralizing antibodies were mainly found in the polymeric IgA and monomeric IgG fractions, respectively, after gel filtration. Taken together, these results suggest that intranasal administration of an inactivated split vaccine induces high levels of nasal neutralizing antibodies (primarily polymeric IgA) and low levels of serum neutralizing antibodies (primarily monomeric IgG).
    Journal of Medical Virology 02/2012; 84(2):336-44. · 2.37 Impact Factor
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    ABSTRACT: Affinity column chromatography is a promising method for the purification of flavivirus particles that can supplement or potentially replace diafiltration and sucrose density centrifugation. In this study, the purification of West Nile Virus (WNV) antigens via Cellufine Sulfate column chromatography was examined. Virus-like particles (VLPs) produced by the expression of the prM and E genes were separated from most of the contaminant proteins with 0.2-0.4M NaCl, but still retained their spherical forms and immunogenicity in mice. The column, with a 1 mL bed-volume, concentrated WN-VLPs a minimum of 15 fold from culture supernatants. A heparin analogue, suramin, competitively eluted WN-VLPs, but sulphated polysaccharides, such as heparin, heparin sulfate and dextran sulfate, did not. Furthermore, 2.4 × 10⁹ plaque forming units of WNV and 196 μg of the viral antigens were recovered from 60 mL of infected culture medium at high yields (93% and 96%, respectively). These results indicate that, in addition to conventional methods, Cellufine Sulfate column chromatography is an effective preparation technique for WNV particulate antigens that does not impair the antigen virological characteristics.
    Journal of virological methods 03/2011; 174(1-2):131-5. · 2.13 Impact Factor
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    ABSTRACT: The H1N1 influenza A virus of swine-origin caused pandemics throughout the world in 2009 and the highly pathogenic H5N1 avian influenza virus has also caused epidemics in Southeast Asia in recent years. The threat of influenza A thus remains a serious global health issue and novel drugs that target these viruses are highly desirable. Influenza A possesses an endonuclease within its RNA polymerase which comprises PA, PB1 and PB2 subunits. To identify potential new anti-influenza compounds in our current study, we screened 33 different types of phytochemicals using a PA endonuclease inhibition assay in vitro and an anti-influenza A virus assay. The marchantins are macrocyclic bisbibenzyls found in liverworts, and plagiochin A and perrottetin F are marchantin-related phytochemicals. We found from our screen that marchantin A, B, E, plagiochin A and perrottetin F inhibit influenza PA endonuclease activity in vitro. These compounds have a 3,4-dihydroxyphenethyl group in common, indicating the importance of this moiety for the inhibition of PA endonuclease. Docking simulations of marchantin E with PA endonuclease suggest a putative "fitting and chelating model" as the mechanism underlying PA endonuclease inhibition. The docking amino acids are well conserved between influenza A and B. In a cultured cell system, marchantin E was further found to inhibit the growth of both H3N2 and H1N1 influenza A viruses, and marchantin A, E and perrotein F showed inhibitory properties towards the growth of influenza B. These marchantins also decreased the viral infectivity titer, with marchantin E showing the strongest activity in this assay. We additionally identified a chemical group that is conserved among different anti-influenza chemicals including marchantins, green tea catechins and dihydroxy phenethylphenylphthalimides. Our present results indicate that marchantins are candidate anti-influenza drugs and demonstrate the utility of the PA endonuclease assay in the screening of phytochemicals for anti-influenza characteristics.
    PLoS ONE 01/2011; 6(5):e19825. · 3.53 Impact Factor
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    ABSTRACT: Virus-like particles (VLPs) of flaviviruses generated from the prM and E genes are a promising vaccine candidate. We have established cell clones continuously releasing VLPs of West Nile virus (WNV) in serum-free conditions. Two types of VLPs were distinguished by sedimenting analyses in sucrose density gradients. Fast sedimenting VLPs (F-VLPs) were large (40-50 nm) and composed of the E and processed mature M proteins, whereas slowly sedimenting VLPs (S-VLPs) were small (20-30 nm) particles consisting of the E and immature prM proteins. F-VLPs induced higher neutralizing antibody and anti-WNV IgG titers than S-VLPs. Furthermore, IgG2a was dominant over IgG1 by immunization with F-VLPs as with whole virion-derived antigens. Mice vaccinated with a low dose (3 ng) of F-VLPs showed higher protective efficacy (83% survivals) against WNV infection than S-VLP-immune mice (17% survivals). These results indicate that F-VLPs more closely resemble the virions and take a better immunogenic form than S-VLPs as WNV vaccine candidates.
    Vaccine 09/2010; 28(40):6588-96. · 3.77 Impact Factor
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    ABSTRACT: Using a rapid and reliable system based on Tn7-mediated site-specific transposition, we have successfully constructed a recombinant Oka varicella vaccine (vOka) expressing the mumps virus (MuV) fusion protein (F). The backbone of the vector was our previously reported vOka-BAC (bacterial artificial chromosome) genome. We inserted the transposon Tn7 attachment sequence, LacZalpha-mini-attTn7, into the region between ORF12 and ORF13 to generate a vOka-BAC-Tn genome. The MuV-F expressing cassette was transposed into the vOka-BAC genome at the mini-attTn7 transposition site. MuV-F protein was expressed in recombinant virus, rvOka-F infected cells. In addition, the MuV-F protein was cleaved in the rvOka-F infected cells as in MuV-infected cells. The growth of rvOka-F was similar to that of the original recombinant vOka without the F gene. Thus, we show that Tn7-mediated transposition is an efficient method for introducing a foreign gene expression cassette into the vOka-BAC genome as a live virus vector.
    Virology 06/2010; 402(1):215-21. · 3.35 Impact Factor
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    Emerging Infectious Diseases 10/2009; 15(10):1702-3. · 6.79 Impact Factor
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    ABSTRACT: Cell-mediated immunity (CMI) is critical for the prevention and control of varicella-zoster virus (VZV)-related disease. To assess CMI to VZV, a varicella skin test and interferon-gamma enzyme-linked immunospot (ELISPOT) assay were both performed in healthy volunteers, and the results were compared. A total of 151 subjects were examined: 16 aged 20-29 years, 26 aged 30-39 years, 18 aged 40-49 years, 73 aged 50-59 years, and 18 aged 60-69 years. All were seropositive by a glycoprotein antigen-based enzyme-linked immunosorbent assay (gpELISA). Skin test reactivity was significantly correlated with the ELISPOT count, and both decreased with increasing age, indicating an age-dependent decline in CMI to VZV. In contrast, the antibody titer obtained by the gpELISA did not correlate with skin test reactivity. The results suggest that the skin test and ELISPOT assay are both reliable for assessing CMI to VZV and can easily be applied to screen individuals susceptible to the development of herpes zoster.
    The Journal of Infectious Diseases 10/2008; 198(9):1327-33. · 5.85 Impact Factor
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    ABSTRACT: A live attenuated varicella vaccine, the Oka vaccine strain (vOka), is routinely administered to children in Japan and other countries, including the United States. vOka consists of a mixture of genotypically distinct variants, but little is known about the growth potential of each variants in vivo. We isolated varicella-zoster virus (VZV) DNA sequences from the peripheral blood mononuclear cells (PBMCs) of asymptomatic healthy children immunized with the Oka varicella vaccine. VZV gene 62 DNA fragments were detected in 5 of 166 (3.0%) PBMC samples by nested PCR within 5 weeks of the vaccination. Sequence analysis of VZV DNA from these five PBMC samples indicated that multiple viral clones in the vaccine could infect vaccinees and replicate in vivo. We also provide evidence that a nonsynonymous substitution at position 105356 may affect viral replication in vivo.
    Vaccine 09/2008; 26(44):5627-32. · 3.49 Impact Factor
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    ABSTRACT: We constructed a recombinant varicella-zoster virus (VZV) Oka vaccine strain (vOka) that contained the mumps virus (MuV) hemagglutinin-neuraminidase (HN) gene, inserted into the site of the ORF 13 gene by using the bacterial artificial chromosome (BAC) system in Escherichia coli. Insertion of the HN gene into the VZV genome was confirmed by PCR and Southern blot. The infectious virus reconstituted from the vOka-HN genome (rvOka-HN) had a growth curve similar to the original recombinant vOka without the HN gene. The mumps virus HN protein expressed in rvOka-HN infected cells was expressed diffusely in the cytoplasm, and modification of the protein was similar to that seen in MuV-infected cells. Electron microscopic examination of infected cells revealed that HN was expressed on the plasma membrane of the cells but not in the viral envelope, suggesting that the tropism of rvOka-HN would be unchanged from that of the original vOka strain. Immunization of guinea pigs with rvOka-HN-induced VZV- and HN-specific antibodies. Interestingly, the induced antibodies had a strong neutralizing activity against virus-cell infections of both MuV and VZV. Therefore, the novel varicella vaccine expressing MuV HN protein is suitable as a polyvalent live attenuated vaccine against VZV and MuV infections.
    Vaccine 01/2008; 25(52):8741-55. · 3.49 Impact Factor
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    ABSTRACT: The attenuated Oka vaccine (V-Oka) strain of varicella-zoster virus (VZV) effectively reduces disease produced by primary infection and virus reactivation. V-Oka was developed by propagation of the Oka parental (P-Oka) strain of VZV in guinea pig and human embryo fibroblasts. Complete DNA sequencing of both viruses has revealed 63 sites that differ between P-Oka and V-Oka, 37 of which are located within 21 unique open reading frames (ORFs). Of the ORFs that differ, ORF 62 contains the greatest number (10) of mutated sites. ORF 62 encodes IE 62, the major immediate-early transactivator of virus genes, and is essential for lytic virus replication. To determine whether a disproportionate number of mutations in ORF 62 might account for virus attenuation, we compared the global pattern of V-Oka gene expression to that of P-Oka. Transcription of ORFs 62, 65, 66, and 67 was suppressed, whereas ORF 41 was elevated in V-Oka-infected cells compared to P-Oka-infected cells (P < 0.01; z test). Suppression of ORF 62, 65, and 66 transcription was confirmed by quantitative dot blot and Western blot analyses. Transient-transfection assays to determine whether mutations within V-Oka-derived IE 62 affected its ability to transactivate VZV gene promoters revealed similar IE 62 transactivation of VZV gene 20, 21, 28, 29, 65, and 66 promoters in both P-Oka and V-Oka. Together, our results indicate that mutations in V-Oka IE 62 alone are unlikely to account for vaccine virus attenuation.
    Journal of Virology 03/2006; 80(5):2076-82. · 5.08 Impact Factor
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    ABSTRACT: The complete genome of the varicella-zoster virus (VZV) Oka strain has been cloned as a bacterial artificial chromosome (BAC). Following electroporation into Escherichia coli (E. coli) strain DH10B, the VZV BAC was stably propagated over multiple generations of its host. Human embryonic lung (HEL) cells transfected with VZV BAC DNA recovered from DH10B showed cytopathic effect (CPE), and virus spread to neighbouring cells was observed. BAC vector sequences are flanked by loxP sites and, coinfection of the reconstituted virus, with a recombinant adenovirus expressing Cre recombinase removed the bacterial sequences. The resulting recombinant rV02 grew as well as the parental virus in HEL cells. The recombinant VZV will promote VZV research and increase use of the viral genome as an investigative tool.
    Vaccine 10/2004; 22(29-30):4069-74. · 3.49 Impact Factor
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    ABSTRACT: The DNA sequences of the Oka varicella vaccine virus (V-Oka) and its parental virus (P-Oka) were completed. Comparison of the sequences revealed 42 base substitutions, which led to 20 amino acid conversions and length differences in tandem repeat regions (R1, R3, and R4) and in an origin of DNA replication. Amino acid substitutions existed in open reading frames (ORFs) 6, 9A, 10, 21, 31, 39, 50, 52, 55, 59, 62, and 64. Of these, 15 base substitutions, leading to eight amino acid substitutions, were in the gene 62 region alone. Further DNA sequence analysis showed that these substitutions were specific for V-Oka and were not present in nine clinical isolates. The immediate-early gene 62 product (IE62) of P-Oka had stronger transactivational activity than the mutant IE62 contained in V-Oka in 293 and CV-1 cells. An infectious center assay of a plaque-purified clone (S7-01) from the V-Oka with 8 amino acid substitutions in ORF 62 showed smaller plaque formation and less-efficient virus-spreading activity than did P-Oka in human embryonic lung cells. Another clone (S-13) with only five substitutions in ORF 62 spread slightly faster than S7-01 but not as effectively as P-Oka. Moreover, transient luciferase assay in 293 cells showed that transactivational activities of IE62s of S7-01 and S7-13 were lower than that of P-Oka. Based on these results, it appears that amino acid substitutions in ORF 62 are responsible for virus growth and spreading from infected to uninfected cells. Furthermore, the Oka vaccine virus was completely distinguishable from P-Oka and 54 clinical isolates by seven restriction-enzyme fragment length polymorphisms that detected differences in the DNA sequence.
    Journal of Virology 12/2002; 76(22):11447-59. · 5.08 Impact Factor
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    ABSTRACT: When the nucleotide sequences of the Oka vaccine and its parental varicella-zoster virus (VZV) were compared in 6 open reading frames (ORFs), glycoprotein C (gC) and 5 transactivator genes, mutations were detected only in the immediate-early gene 62. The vaccine virus contained a mixture of different sequences that had variations at 15 nucleotide positions, but only one sequence was found for the Oka parental virus gene 62. The Oka vaccine virus gene 62 could be distinguished from the parental virus gene using a simplified restriction-enzyme fragment length polymorphism analysis, using NaeI and BssHII. This analysis was based on the sequence data obtained in this study. Studies of the regulatory activities of the ORF62 gene product (IE62) in a transient transfection assay indicated that IE62 of the parental virus had a stronger transactivational activity than that of the vaccine virus in activating immediate-early, early, and late gene promoters. These data suggest that IE62 might play an important role in the attenuation of VZV.
    Journal of Medical Virology 09/2000; 61(4):497-503. · 2.37 Impact Factor

Publication Stats

302 Citations
72.48 Total Impact Points

Institutions

  • 2006–2013
    • National Institute of Biomedical Innovation
      • Laboratory of Virology and Vaccinology
      Ibaraki, Osaka-fu, Japan
  • 2012
    • Nara Medical University
      Kashihara, Nara, Japan
    • Osaka University
      • Division of Applied Chemistry
      Suika, Ōsaka, Japan
  • 2004
    • Osaka City University
      Ōsaka, Ōsaka, Japan