Updated on 2024/04/12

写真a

 
Okura Sadayuki
 
Affiliation
Faculty of Medicine, Department of Microbiology and Immunology, Assistant Professor
Title
Assistant Professor
External link

Degree

  • 人間・環境学博士 ( 京都大学 )

Research Interests

  • 抑制因子

  • HIV

  • コウモリ

  • マウス白血病ウイルス

  • レトロウイルス

Research Areas

  • Life Science / Virology

Papers

  • Cytoplasmic and nuclear DROSHA in human villous trophoblasts

    Syunya Noguchi, Sadayuki Ohkura, Yasuyuki Negishi, Shohei Tozawa, Takami Takizawa, Rimpei Morita, Hironori Takahashi, Akihide Ohkuchi, Toshihiro Takizawa

    Journal of Reproductive Immunology   162   104189 - 104189   2024.3

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jri.2023.104189

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  • Localization of DROSHA in the trophoblast cell line BeWo infected with sindbis virus

    Syunya Noguchi, Sadayuki Okura, Yasuyuki Negishi, Rimpei Morita, Akihide Ohkuchi, Hironori Takahashi, Toshihiro Takizawa

    Placenta   141   106 - 106   2023.9

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.placenta.2023.08.046

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  • Characterization of Megabat-favored, CA-dependent Susceptibility to Retrovirus Infection Reviewed International journal

    Sadayuki Ohkura, Masayuki Horie, Masumi Shimizu, So Nakagawa, Haruka Osanai, Yoshitaka Miyagawa, Rimpei Morita

    Journal of Virology   97 ( 3 )   e0180322   2023

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    The isolation of the Koala retrovirus-like virus from Australian megabats and the identification of endogenous retroviruses in the bat genome have raised questions on bat susceptibility to retroviruses in general. To answer this, we studied the susceptibility of 12 cell lines from 11 bat species to four well-studied retroviruses (human and simian immunodeficiency viruses [HIV and SIV] and murine leukemia viruses [B- and N-MLV]). Systematic comparison of retroviral susceptibility among bats revealed that megabat cell lines were overall less susceptible to the four retroviruses than microbat cell lines, particularly to HIV-1 infection, whereas lineage-specific differences were observed for MLV susceptibility. Quantitative PCR of reverse transcription (RT) products, infection in heterokaryon cells, and point mutation analysis of the capsid (CA) revealed that (i) HIV-1 and MLV replication were blocked at the nuclear transport of the pre-integration complexes and before and/or during RT, respectively, and (ii) the observed lineage-specific restriction can be attributed to a dominant cellular factor constrained by specific positions in CA. Investigation of bat homologs of the three previously reported post-entry restriction factors constrained by the same residues in CA, tripartite motif-protein 5α (TRIM5α), myxovirus resistance 2/B (Mx2/MxB), and carboxy terminus-truncated cleavage and polyadenylation factor 6 (CPSF6-358), demonstrated poor anti-HIV-1 activity in megabat cells, whereas megabat TRIM5α restricted MLV infection, suggesting that the major known CA-dependent restriction factors were not dominant in the observed lineage-specific susceptibility to HIV-1 in bat cells. Therefore, HIV-1 susceptibility of megabat cells may be determined in a manner distinct from that of primate cells. IMPORTANCE Recent studies have demonstrated the circulation of gammaretroviruses among megabats in Australia and the bats' resistance to HIV-1 infection; however, the origins of these viruses in megabats and the contribution of bats to retrovirus spread to other mammalian species remains unclear. To determine the intrinsic susceptibility of bat cells to HIV-1 infection, we investigated 12 cell lines isolated from 11 bat species. We report that lineage-specific retrovirus restriction in the bat cell lines can be attributed to CA-dependent factors. However, in the megabat cell lines examined, factors known to bind capsid and block infection in primate cell culture, including homologs of TRIM5α, Mx2/MxB, and CPSF6, failed to exhibit significant anti-HIV-1 activities. These results suggested that the HIV-1 susceptibility of megabat cells occurs in a manner distinct from that of primate cells, where cellular factors, other than major known CA-dependent restriction factors, with lineage-specific functions could recognize retroviral proteins in megabats.

    DOI: 10.1128/jvi.01803-22

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  • Differentiation of Langerhans cells from monocyts and their specific function in inducing IL-22-specific Th cells Reviewed

    Otsuka Y, Watanabe E, Shinya E, Okura S, Saeki H, Geijtenbeek TBH, Takahashi H

    J Immunol   2018

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  • Induction of langerin(+) Langerhans cell-like cells expressing reduced TLR3 from CD34(+) cord blood cells stimulated with GM-CSF, TGF-beta 1, and TNF-alpha Reviewed

    Hideko Azuma, Eri Watanabe, Yohei Otsuka, Yasuyuki Negishi, Sadayuki Ohkura, Eiji Shinya, Hidemi Takahashi

    BIOMEDICAL RESEARCH-TOKYO   37 ( 5 )   271 - 281   2016

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:BIOMEDICAL RESEARCH PRESS LTD  

    Langerhans cells (LCs), a subset of dendritic cells (DCs), reside in body surface presenting antigens from various pathogens and activate immune system after migrating to vicinal lymph nodes. We recently demonstrated that the E-cadherin interaction allowed peripheral blood (PB) CD14(+) cells to differentiate into LC-like cells that closely resemble primary LCs. Here, with a combination of GM-CSF, TGF-beta, and TNF-alpha, we induced LC-like cells from umbilical cord blood (UCB)derived CD34(+) cells and compared them with those induced from PB CD14(+) cells. In contrast to PB CD14(+) cell-derived LC-like cells with an undetectable surface level of toll-like receptor (TLR) 4 and an unresponsiveness feature to bacterial lipopolysaccharide (LPS), CB CD34(+) cells-derived LC like cells expressed a low, but apparent, surface level of TLR4 and a reduced level of intracellular TLR3. Consistent with this result, they responded to bacterial LPS, but poorly to poly(I: C) reflecting viral RNA. These findings suggest that LC-precursors from circulating PB CD14(+) cells seem to be arranged in the outer barrier of skin, while LC-precursors from local undifferentiated UCB-derived CD34(+) cells may be arranged in the inner barrier of mucosal tissues and work together to combat against external pathogens as well as internal malignancies throughout body surface.

    DOI: 10.2220/biomedres.37.271

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  • A Comparison of Murine Leukemia Viruses That Escape from Human and Rhesus Macaque TRIM5 alpha s Reviewed

    Sadayuki Ohkura, Jonathan P. Stoye

    JOURNAL OF VIROLOGY   87 ( 11 )   6455 - 6468   2013.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER SOC MICROBIOLOGY  

    To better understand the binding mechanism of TRIM5 alpha to retrovirus capsid, we had previously selected N-tropic murine leukemia virus (N-MLV) mutants escaping from rhesus macaque TRIM5 alpha (rhTRIM5 alpha) by passaging the virus in rhTRIM5 alpha-expressing cells and selecting for nonrestricted variants. To test the commonality of the findings from the rhTRIM5 alpha study, we have now employed a similar genetic approach using human TRIM5 alpha (huTRIM5 alpha). Consistent with the rhTRIM5 alpha study, the mapped huTRIM5 alpha escape mutations were distributed across the capsid exterior, confirming the extended binding surface between virus and restriction factor. Compared to the results of the previous study, fewer escape mutations were identified, with particular mutants being repeatedly selected. Three out four huTRIM5 alpha escape variants showed resistance to all primate TRIM5 alpha s tested, but two of them sacrificed viral fitness, observations that were not made in the rhTRIM5 alpha study. Moreover, differences in amino acid changes associated with escape from hu-and rhTRIM5 alpha s suggested a charge dependence of the restriction by different TRIM5 alpha s. Taken together, these results suggest that the recognition of the entire capsid surface is a general strategy for TRIM5 alpha to restrict MLV but that significantly different specific interactions are involved in the binding of TRIM5 alpha from different species to the MLV capsid core.

    DOI: 10.1128/JVI.03425-12

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  • Novel escape mutants suggest an extensive TRIM5α binding site spanning the entire outer surface of the murine leukemia virus capsid protein. Reviewed

    Ohkura S, Goldstone DC, Yap MW, Holden-Dye K, Taylor IA, Stoye JP

    PLoS pathogens   7 ( 3 )   e1002011   2011.3

  • Novel Escape Mutants Suggest an Extensive TRIM5 alpha Binding Site Spanning the Entire Outer Surface of the Murine Leukemia Virus Capsid Protein Reviewed

    Sadayuki Ohkura, David C. Goldstone, Melvyn W. Yap, Kate Holden-Dye, Ian A. Taylor, Jonathan P. Stoye

    PLOS PATHOGENS   7 ( 3 )   2011.3

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    After entry into target cells, retroviruses encounter the host restriction factors such as Fv1 and TRIM5 alpha. While it is clear that these factors target retrovirus capsid proteins (CA), recognition remains poorly defined in the absence of structural information. To better understand the binding interaction between TRIM5 alpha and CA, we selected a panel of novel N-tropic murine leukaemia virus (N-MLV) escape mutants by a serial passage of replication competent N-MLV in rhesus macaque TRIM5 alpha (rhTRIM5 alpha)-positive cells using a small percentage of unrestricted cells to allow multiple rounds of virus replication. The newly identified mutations, many of which involve changes in charge, are distributed over the outer 'top' surface of NMLV CA, including the N-terminal beta-hairpin, and map up to 29 A(o) apart. Biological characterisation with a number of restriction factors revealed that only one of the new mutations affects restriction by human TRIM5 alpha, indicating significant differences in the binding interaction between N-MLV and the two TRIM5 alpha s, whereas three of the mutations result in dual sensitivity to Fv1(n) and Fv1(b). Structural studies of two mutants show that no major changes in the overall CA conformation are associated with escape from restriction. We conclude that interactions involving much, if not all, of the surface of CA are vital for TRIM5 alpha binding.

    DOI: 10.1371/journal.ppat.1002011

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  • Restriction of foamy viruses by primate Trim5 alpha Reviewed

    Melvyn W. Yap, Dirk Lindemann, Nicole Stanke, Juliane Reh, Dana Westphal, Helmut Hanenberg, Sadayuki Ohkura, Jonathan P. Stoye

    JOURNAL OF VIROLOGY   82 ( 11 )   5429 - 5439   2008.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER SOC MICROBIOLOGY  

    Foamy viruses (FVs) are unconventional retroviruses with a replication strategy that is significantly different from orthoretroviruses and bears some homology to that of hepadnaviruses. Although some cellular proteins, such as APOBEC3, have been reported to block FVs, no restriction by Trim5 alpha has been described to date. The sensitivity of three FV isolates of human-chimpanzee or prototypic (PFV), macaque (SFVmac), and feline (FFV) origin to a variety of primate Trim5 alpha s was therefore tested. PFV and SFVmac were restricted by Trim5 alpha s from most New World monkeys, but not from other primates, whereas FFV-based vectors were restricted by Trim5 alpha s from the great apes gorilla and orangutan. Trim5 alpha s from Old World monkeys did not restrict any FV isolate tested. Capuchin Trim5 alpha was unique, as it restricted SFVmac and FFV but not PFV. Trim5 alpha specificity for FVs was determined by the B30.2 domain, interestingly involving, in some instances, the same residues of the variable regions previously implicated as major determinants for human immunodeficiency virus type 1 restriction. FVs with chimeric Gags were made to map the viral determinants of sensitivity to restriction. The N-terminal half of the Gag molecule was found to contain the regions that control susceptibility. This region most likely corresponds to the capsid of conventional retroviruses. Due to their unique replication strategy, FVs should provide a valuable new system to examine the mechanism of retroviral restriction by Trim5 alpha.

    DOI: 10.1128/JVI.02462-07

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  • All three variable regions of the TRIM5 alpha B30.2 domain can contribute to the specificity of retrovirus restriction Reviewed

    Sadayuki Ohkura, Melvyn W. Yap, Tom Sheldon, Jonathan P. Stoye

    JOURNAL OF VIROLOGY   80 ( 17 )   8554 - 8565   2006.9

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    Recent studies have revealed the contribution of TRIM alpha to retrovirus restriction in cells from a variety of primate species. TRIM5 alpha consists of a tripartite motif (the RBCC domain) followed by a B30.2 domain. The B30.2 domain is thought to be involved in determination of restriction specificity and contains three variable regions. To investigate the relationship between the phylogeny of primate TRIM5 alpha and retrovirus restriction specificity, a series of chimeric TRIM5 alpha consisting of the human RBCC domain followed by the B30.2 domain from various primates was constructed. These constructs showed restriction profiles largely consistent with the origin of the B30.2 domain. Restriction specificity was further investigated with a variety of TRIM5 alpha s containing mixed or mutated B30.2 domains. This study revealed the importance of all three variable regions for determining restriction specificity. Based on the molecular structures of other PRYSPRY domains solved recently, a model for the molecular structure of the B30.2 domain of TRIM5 alpha was developed. The model revealed that the variable regions of the B30.2 domain are present as loops located on one side of the B30.2 core structure. It is hypothesized that these three loops form a binding surface for virus and that evolutionary changes in any one of the loops can alter restriction specificity.

    DOI: 10.1128/JVI.006880-06

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  • A novel simian immunodeficiency virus from black mangabey (Lophocebus aterrimus) in the Democratic Republic of Congo Reviewed

    T Takemura, M Ekwalanga, B Bikandou, E Ido, Y Yamaguchi-Kabata, S Ohkura, H Harada, J Takehisa, H Ichimura, HJ Parra, M Nende, E Mubwo, M Sepole, M Hayami, T Miura

    JOURNAL OF GENERAL VIROLOGY   86 ( Pt 7 )   1967 - 1971   2005.7

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    In order to understand primate lentivirus; evolution, characterization of additional simian immunodeficiency virus (SIV) strains is essential. Here, an SIV from a black mangabey (Lophocebus aterrimus) originating from the Democratic Republic of Congo was analysed phylogenetically. The monkey had cross-reactive antibodies against human immunodeficiency virus type 1 (HIV-1) and HIV-2. The viral pol region sequence was amplified by nested PCR and sequence analysis confirmed that it was related to known SIV sequences. This is the first report to characterize genetically an SIV from the monkey genus Lophocebus. Phylogenetic analysis of the pol region revealed that this novel SIV, designated SIVbkm, fell into the SIVsyk and SIVgsn virus group, containing viruses isolated from the genus Cercopithecus, and suggests that cross-species transmission has occurred between species of the genera Lophocebus, and Cercopithecus.

    DOI: 10.1099/vir.0.80697-0

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  • Phylogenetic heterogeneity of new HTLV type 1 isolates from southern India in subgroup A Reviewed

    S Ohkura, M Yamashita, T Ishida, PG Babu, Y Koyanagi, N Yamamoto, T Miura, M Hayami

    AIDS RESEARCH AND HUMAN RETROVIRUSES   21 ( 4 )   325 - 330   2005.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:MARY ANN LIEBERT INC  

    Seven isolates of human T cell leukemia virus type 1 (HTLV-1) were taken in southern India and phylogenetically analyzed to gain new insights into the origin and dissemination of HTLV-1 in the subcontinent. The new Indian HTLV-1s were found to be members of subgroup A (Transcontinental subgroup) of the Cosmopolitan group. They formed three different clusters ( South African/Caribbean, Middle Eastern, and East Asian clusters). These results demonstrate that Indian HTLV-1s are genetically heterogeneous and include the most divergent strain of subgroup A. On the basis of these results, we speculate that subgroup A HTLV-1s may have been present for thousands of years in India.

    DOI: 10.1089/aid.2005.21.325

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  • Protective efficacy of nonpathogenic nef-deleted SHIV vaccination combined with recombinant IFN-gamma administration against a pathogenic SHIV challenge in rhesus monkeys Reviewed

    K Kaneyasu, M Kita, S Ohkura, T Yamamoto, K Ibuki, Y Enose, A Sato, M Kodama, T Miura, M Hayami

    MICROBIOLOGY AND IMMUNOLOGY   49 ( 12 )   1083 - 1094   2005

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:CENTER ACADEMIC PUBL JAPAN  

    We previously reported that a nef-deleted SHIV (SHIV-NI) is nonpathogenic and gave macaques protection from challenge infection with pathogenic SHIV-C2/1. To investigate whether IFN-gamma augments the immune response induced by this vaccination, we examined the antiviral and adjuvant effect of recombinant human IFN-gamma (rIFN-gamma) in vaccinated and unvaccinated monkeys. Nine monkeys were vaccinated with nef-deleted nonpathogenic SHIV-NI. Four of them were administered with rIFN-gamma and the other five monkeys were administered with placebo. After the challenge with pathogenic SHIV-C2/1, CD4(+) T-cell counts were maintained similarly in monkeys of both groups, while those of the unvaccinated monkeys decreased dramatically at 2 weeks after challenge. However, the peaks of plasma viral load were reduced to 100-fold in SHIV-NI vaccinated monkeys combined with rIFN-gamma compared with those in SHIV-NI vaccinated monkeys without rIFN-gamma. The peaks of plasma viral load were inversely correlated with the number of SIV Gag-specific IFN-gamma-producing cells. In SHIV-NI-vaccinated monkeys with rIFN-gamma, the number of SIV Gag-specific IFN-gamma-producing cells of PBMCs increased 2-fold compared with those in SHIV-NI-vaccinated monkeys without rIFN-gamma, and the NK activity and MIP-1 alpha production of PBMCs were also enhanced. Thus, vaccination of SHIV-NI in combination with rIFN-gamma was more effective in modulating the antiviral immune system into a Th1 type response than SHIV-NI vaccination alone. These results suggest that IFN-gamma augmented the anti-viral effect by enhancing innate immunity and shifting the immune response to Th1.

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  • The quantity and diversity of infectious viruses in various tissues of SHIV-infected monkeys at the early and AIDS stages Reviewed

    A Miyake, Y Enose, S Ohkura, H Suzuki, T Kuwata, T Shimada, S Kato, O Narayan, M Hayami

    ARCHIVES OF VIROLOGY   149 ( 5 )   943 - 955   2004.5

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:SPRINGER-VERLAG WIEN  

    To detect the major sites of viral replication in immunodeficiency virus-infected individuals, we quantified proviral DNA and infectious viruses using quantitative PCR and a plaque assay, respectively, in various tissues of SHIVKU-2-infected monkeys in the early and AIDS stages of infection. Compared the quantity of infectious virus among PBMC and the lymphoid tissues, the mesenteric lymph node had the largest number of infectious viruses at the AIDS stage more than at the early stage of infection. These results suggested that the gastrointestinal tract was a major site of viral replication. In the brain, proviral DNA was detected at the early and AIDS stage of infection, but infectious viruses were detected at only the AIDS stage. Moreover, we analyzed the nucleotide sequences of the env V3 region in infectious virus clones isolated from each plaque. The viruses in the lymphoid tissues of the monkey that developed AIDS diverged from the inoculated virus and had the same three amino acid substitutions. However, the viruses in the brain were almost identical to the inoculated virus, suggesting that the virus entered the brain early after infection and persisted without replication and genetic diversion until the AIDS stage.

    DOI: 10.1007/s00705-003-0252-0

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  • Linkage of amino acid variation and evolution of human immunodeficiency virus type 1 gp120 envelope glycoprotein (subtype B) with usage of the second receptor Reviewed

    Y Yamaguchi-Kabata, M Yamashita, S Ohkura, M Hayami, T Miura

    JOURNAL OF MOLECULAR EVOLUTION   58 ( 3 )   333 - 340   2004.3

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    To clarify the relationship between the amino acid variations of the gp120 of human immunodeficiency virus type 1 (HIV-1) and the chemokine receptors that are used as the second receptor for HIV, we evaluated amino acid site variation of gp120 between the X4 strains (use CXCR4) and the R5 strains (use CCR5) from 21 sequences of subtype B. Our analysis showed that residues 306 and 322 in the V3 loop and residue 440 in the C4 region were associated with usage of the second receptor. The polymorphism at residue 440 is clearly associated with the usage of the second receptor: The amino acid at position 440 was a basic amino acid in the R5 strains, and a nonbasic and smaller amino acid in the X4 strains, while the V3 loop of the X4 strains was more basic than that of the R5 strains. This suggests that residue 440 in the C4 region, which is close to the V3 loop in the three-dimensional structure, is critical in determining which second receptor is used. Analysis of codon frequency suggests that, in almost all cases, the difference at residue 440 between basic amino acids in the R5 strains and nonbasic amino acids in the X4 strains could be due to a single nucleotide change. These findings predict that the evolutionary changes in amino acid residue 440 may be correlated with evolutionary changes in the V3 loop. One possibility is that a change in electric charge at residue 440 compensates for a change in electric charge in the V3 loop. The amino acid polymorphism at position 440 can be useful to predict the cell tropism of a strain of HIV-1 subtype B.

    DOI: 10.1007/s00239-003-2555-x

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  • Phylogenetic analysis of HTLV-I and STLV - The past movement of HTLV-I-carriers and the origin of PTLV Reviewed

    S Ohkura, T Miura, M Yamashita, K Ibuki, T Takemura, M Hayami

    TWO DECADES OF ADULT T-CELL LEUKEMIA AND HTLV-I RESEARCH   50 ( 50 )   317 - 337   2003

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:JAPAN SCIENTIFIC SOC PRESS  

    Two types of human T-cell leukemia virus (HTLV-1 and -2) and three types of simian T-cell leukemia virus (STLV-1, -2, and -3) have been described to date. Seroepiderniological studies have shown that all types of HTLV and STLV prevail in Africa, whereas no STLV-related retrovirus has been confirmed among New World monkeys. Phylogenetic studies of HTLV-1 revealed that the virus is divided into three distinct genotypes (the Cosmopolitan, Central African, and Australo-Melanesian groups) and that the Cosmopolitan group is further subdivided into five subgroups (Transcontinental, Japanese, West African, North African, and Peruvian Black subgroups). Since these phylogenetic lineages are well linked with geographic origins and the anthropological background of carrier populations, phylogenetic analysis of HTLV-1 allows us to investigate ancient and recent human movements that might have resulted in the unique current distribution of HTLV-1 in the world. Molecular characterization of HTLV-1 and STLV-1 revealed that Central African HTLV-1 is interspersed within lineages of African STLV-1, indicating multiple episodes of interspecies transmission between humans and nonhuman primates in Africa. In contrast, Melanesian HTLV-1 and Asian STLV-1 are much more diverged than African viruses, suggesting that the virus has evolved over a long period in Asia. In this review article, we discuss recent views on the past movement of human populations that carried HTLV-1, and on the origin of HTLV-1/STLV-1. Recent findings of additional STLV-3 infection not only in East Africa, but in Central Africa are also discussed.

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  • High prevalence of simian T-lymphotropic virus type L in wild Ethiopian baboons Reviewed

    T Takemura, M Yamashita, MK Shimada, S Ohkura, T Shotake, M Ikeda, T Miura, M Hayami

    JOURNAL OF VIROLOGY   76 ( 4 )   1642 - 1648   2002.2

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    Simian T-cell leukemia viruses (STLVs) are the simian counterparts of human T-cell leukemia viruses (HTLVs). A novel, divergent type of STLV (STLV-L) from captive baboons was reported in 1994, but its natural prevalence remained unclear. We investigated the prevalence of STLV-L in 519 blood samples from wild-living nonhuman primates in Ethiopia. Seropositive monkeys having cross-reactive antibodies against HTLV were found among 22 out of 40 hamadryas baboons, 8 of 96 anubis baboons, 24 of 50 baboons that are hybrids between hamadryas and anubis baboons, and 41 of 177 grivet monkeys, but not in 156 gelada baboons. A Western blotting assay showed that sera obtained from seropositive hamadryas and hybrid baboons exhibited STLV-L-like reactivity. A PCR assay successfully amplified STLV sequences, which were subsequently sequenced and confirmed as being closely related to STLV-L. Surprisingly, further PCR showed that nearly half of the hamadryas (20 out of 40) and hybrid (19 out of 50) baboons had STLV-L DNA sequences. In contrast, most of the seropositive anubis baboons and grivet monkeys carried typical STLV-1 but not STLV-L. These observations demonstrate that STLV-L naturally prevails among hamadryas and hybrid baboons at significantly high rates. STLV-1 and -2, the close relative of STLV-L, are believed to have jumped across simian-human barriers, which resulted in widespread infection of HTLV-1 and -2. Further studies are required to know if STLV-L is spreading into human populations.

    DOI: 10.1128/JVI.76.4.1642-1648.2002

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  • Natural infection of wild-born mandrills (Mandrillus sphinx) with two different types of simian immunodeficiency virus

    Jun Takehisa, Yosuke Harada, Nicaise Ndembi, Innocent Mboudjeka, Yuko Taniguchi, Charlotte Ngansop, Seraphin Kuate, Leopold Zekeng, Kentaro Ibuki, Toshihide Shimada, Blaise Bikandou, Yumi Yamaguchi-Kabata, Tomoyuki Miura, Mikio Ikeda, Hiroshi Ichimura, Lazare Kaptue, Masanori Hayami

    AIDS Research and Human Retroviruses   17 ( 12 )   1143 - 1154   2001.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Mary Ann Liebert  

    We found a novel primate lentivirus in mandrill (Mandrillus sphinx). To clarify the evolutionary relationships and transmission patterns of human/simian immunodeficiency virus (HIV/SIV), we screened blood samples from 30 wild-born healthy Cameroonian mandrills. Five (16.7%) of them were seropositive for SIV. Three SIV strains were isolated from the five seropositive mandrills by cocultivation of their peripheral blood mononuclear cells (PBMCs) with PBMCs of rhesus macaques, a human T cell line (M8166), and/or a cynomolgus macaque T cell line (HSC-F). One of the newly isolated SIV strains was intravenously inoculated into two rhesus macaques and resulted in chronic infection. In the SIV-infected macaques at 45 weeks after inoculation, we observed a mild decline in the number of peripheral CD4+lymphocytes, lymphadenopathy, and blastic follicular dendritic cells with mild follicular hyperplasia in the peripheral lymph nodes. A phylogenetic analysis based on the pol sequence showed that the newly found SIVs from Cameroonian mandrills did not cluster with SIVmndGB1, which is the former representative strain of SIVmnd. The SIVmnds from Cameroon formed a new, independent lineage that branched before the root of the HIV-1/SIVcpz lineage with 996 of 1000 bootstrap replications. They clustered host specifically, and exhibited about 16.9% diversity at the level of nucleotide sequence among Cameroonian SIVmnd strains. These results indicate that the SIVmnds isolated in Cameroon are a novel type of SIVmnd and have infected Cameroonian mandrills for a long time. We therefore designated the Cameroonian SIVmnd as SIVmnd type 2 and redesignated SIVmndGB1 as SIVmnd type 1. To date, M. sphinx is the only primate species other than humans that is naturally infected with two different types of SIV. © 2001 Mary Ann Liebert, Inc.

    DOI: 10.1089/088922201316912754

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  • Phylogenetic characterization of a new HTLV type 1 from the Ainu in Japan Reviewed

    M Yamashita, T Ishida, S Ohkura, T Miura, M Hayami

    AIDS RESEARCH AND HUMAN RETROVIRUSES   17 ( 8 )   783 - 787   2001.5

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:MARY ANN LIEBERT INC PUBL  

    Human T cell leukemia virus type 1 (HTLV-1) is endemic among three ethnically distinguishable populations in Japan (the Ainu, Ryukyuans, and Wajin), which, together, account for most of the population in Japan. While much is known about the phylogeny of the Ryukyuan and Wajin strains of HTLV-1, only one Ainu strain has been phylogenetically analyzed. We report here a new HTLV-1 strain from the Ainu, The new isolate (U8306), as well as the previously reported isolate, are members of the Cosmopolitan group and further belong to the Transcontinental subgroup. This subgroup also predominates among the Ryukyuans, whereas the Japanese subgroup is the major subgroup among the Wajin, The predominance of subgroup A in the Ainu and Ryukyuans suggests that they share a common origin of HTLV-1.

    DOI: 10.1089/088922201750237068

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  • 低分子化合物,ONO-4007のin vitro抗HIV/SHIV増殖抑制効果

    池川 雅哉, 柴山 史朗, 山下 満左裕, 大倉 定之, 松尾 政芳, 芳賀 久典, 多田 秀明, 田代 啓, 速水 正憲, 本庶 佑

    日本エイズ学会誌   2 ( 4 )   317 - 317   2000.11

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    Language:Japanese   Publisher:(一社)日本エイズ学会  

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  • アカゲザルにおける低分子化合物(ONO-4007)投与によるSHIV増殖抑制効果

    大倉 定之, 山下 満左裕, 池川 雅哉, 伊吹 謙太郎, 柴山 史朗, 築山 貴美, 松尾 政芳, 田丸 敬次郎, 田代 啓, 本庶 佑

    日本エイズ学会誌   2 ( 4 )   452 - 452   2000.11

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  • Identification and phylogenetic characterization of a human T-cell leukaemia virus type I isolate from a native inhabitant (Rapa Nui) of Easter Island Reviewed

    S Ohkura, M Yamashita, L Cartier, DG Tanabe, M Hayami, S Sonoda, K Tajima

    JOURNAL OF GENERAL VIROLOGY   80   1995 - 2001   1999.8

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    Human T-cell leukaemia virus type I (HTLV-I) is endemic in Melanesia, one of the three ethnogeographic regions of the Pacific; in the other two regions, Polynesia and Micronesia, the incidence of the virus is relatively low. In an effort to gain new insights into the prevalence of HTLVI in the Pacific region, we did a seroepidemiological survey on Easter island, which is located on the eastern edge of Polynesia, Of 138 subjects surveyed, including 108 Papa Nui (the native inhabitants of this island), we identified one HTLV-I-seropositive Papa Nui, The new HTLV-I isolate derived from this carrier (E-12) was phylogenetically analysed to ascertain the origin and past dissemination of HTLV-I in the island, The analysis demonstrated that isolate E-12 belongs to subgroup A of the Cosmopolitan group, and that it differs from HTLV-ls found in Melanesia, which are highly divergent variants, In subgroup A, E-12 grouped with South American HTLV-ls including those from Amerindians, This result suggests that this isolate originated in South America rather than in Melanesia.

    DOI: 10.1099/0022-1317-80-8-1995

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  • Molecular epidemiology of human T-cell leukemia virus type I (HTLV-I) in Brazil: The predominant HTLV-Is in South America differ from HTLV-Is of Japan and Africa, as well as those of Japanese immigrants and their relatives in Brazil Reviewed

    M Yamashita, R Veronesi, M Menna-Barreto, WJ Harrington, C Sampio, C Brites, R Badaro, AD Andrade, S Ohkura, T Igarashi, J Takehisa, T Miura, D Chamone, O Bianchini, C Jardim, S Sonoda, M Hayami

    VIROLOGY   261 ( 1 )   59 - 69   1999.8

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    To better understand the origin of human T-cell leukemia virus type I (HTLV-I) in South America, we conducted a phylogenetic study on 27 new HTLV-Is in Brazil. These were obtained from Brazilians of various ethnic origins, such as Japanese immigrants, whites, blacks, and mulattos. We amplified and sequenced proviral DNAs of a part of the long terminal repeats. Phylogenetic trees revealed that all but 6 of the new isolates were not only similar to each other but also similar to HTLV-Is of other South American countries, including those from Amerindians. However, the isolates differed from the HTLV-Is of Africa and Japan. The other six isolates were from Japanese immigrants and were phylogenetically almost identical to HTLV-Is in Japan but different from the majority of South American HTLV-Is, including the other new Brazilian HTLV-Is. These findings indicate that the recent introduction of HTLV-I from Japan is limited to Japanese immigrants. In addition, the results do not support the prevailing hypothesis that HTLV-Is in South America were introduced by blacks who were brought from Africa as slaves. Rather, these results suggest that the majority of HTLV-Is prevailing in South America have spread from Amerindians, some of whom are likely to have possessed this human retrovirus from the beginning of their settlement in South America. (C) 1999 Academic Press.

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  • Phylogenetic relatedness of HTLV type I from Bellona, a Polynesian outlier within the Solomon Islands, to HTLV type I from Japan and far Eastern Asia Reviewed

    S Ohkura, R Yanagihara, M Yamashita, M Hayami

    AIDS RESEARCH AND HUMAN RETROVIRUSES   15 ( 11 )   1041 - 1045   1999.7

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    DOI: 10.1089/088922299310557

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  • HTLV-Is in Argentina are phylogenetically similar to those of other South American countries, but different from HTLV-Is in Africa Reviewed

    M Yamashita, G Picchio, R Veronesi, S Ohkura, P Bare, M Hayami

    JOURNAL OF MEDICAL VIROLOGY   55 ( 2 )   152 - 160   1998.6

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    To understand the origin and past dissemination of human T-cell leukemia/lymphotropic virus type I (HTLV-I) in Latin America, we conducted a phylogenetic study of five new HTLV-I isolates from Argentina. We sequenced partial fragments of long terminal repeats (LTR) of the new HTLV-ls, and then the sequences were subjected to a phylogenetic analysis for comparison with other HTLV-ls of various geographical origins. Our results indicated that all the isolates were members of the Cosmopolitan group. Furthermore, most (four out of five isolates) of the new HTLV-ls belonged to the Transcontinental (A) subgroup, the most widespread subgroup of the four subgroups in the Cosmopolitan group. In this subgroup, they were closely related to HTLV-ls found in other South American countries including those of Amerindians, and were different from those found in Africa. In contrast, the remaining one HTLV-I (ARGMF) did not show any clear similarity to known HTLV-I isolates belonging to the Cosmopolitan group. The close similarity of South American HTLV-ls strongly suggests a common origin of the virus in this continent. Our results do not support the proposed idea of recent introduction of HTLV-I into South America as a consequence of the slave trade from Africa, where phylogenetically different HTLV-ls predominate. (C) 1998 Wiley-Liss, Inc.

    DOI: 10.1002/(SICI)1096-9071(199806)55:2<152::AID-JMV12>3.0.CO;2-K

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  • Prevalence and phylogenetic analysis of HTLV-I isolates in Cameroon, including those of the Baka Pygmy Reviewed

    Mboudjeka, I, L Zekeng, M Yamashita, J Takehisa, E Ido, T Miura, S Ohkura, M Ikeda, L Kaptue, M Hayami

    JAPANESE JOURNAL OF CANCER RESEARCH   88 ( 7 )   619 - 624   1997.7

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    Our previous analysis of an HTLV-I isolate (CMR229) from a Cameroonian Pygmy demonstrated that the isolate is distinct from typical HTLV-Is of the ''Central African group,'' which has a close similarity to HTLV-I-related simian viruses (STLV-I) in Africa. In this study, we analyzed six new HTLV-Is from Cameroon consisting of three isolates from the Pygmy and three from the Bantu to examine further the genetic features of HTLV-I in Cameroon, especially in the Pygmy. A phylogenetic tree based on the long terminal repeats (LTR) region showed that all the new HTLV-Is belong to the Central African group. On the other hand, an env-based analysis of CMR229 confirmed the previous finding derived from LTR-based analysis that CMR229 has a similarity to African STLV-Is, but is distinct from the typical Central African group of HTLV-I. This suggests that multiple interspecies transmissions from non-human primates to humans have occurred in Central Africa, resulting in the presence of two distinct HTLV-I strains in this area. In addition, it seems likely that the Pygmy harbors the heterogeneous HTLV-I strains from which the main HTLV-I population spread into the Bantu.

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Books

  • Gann monograph on cancer research 50, 317-337, 2003

    ( Role: ContributorPHYLOGENETIC ANALYSIS OF HTLV-1 AND STLV : The Past Movement of HTLV-1-Carriers and the Origin of PTLV)

    University of Tokyo Press  2003 

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  • Human Retroviruses: AIDS and HTLV- associated disease

    Ricardo Veronesi( Role: ContributorOrigins of HTLV-Is on South America)

    Atheneum Press,  2000 

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  • Identification and phylogenetic characterization of HTLV-I from a native inhabitant of Easter Island Rapa Nui

    Ohkura, S, Yamashita, M, Cartier, L, Tanabe, D.G, Hayami, M, Sonoda, S, Tajima, K( Role: Contributor)

    Estudios Atacamenos, North Catholic University, Chile  1998 

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Misc.

  • HIV-1 Nef down-regulated CD1a lipid antigen presentation in immature dendritic cells through hemopoietic cell kinase (Hck) and p21-activated kinase 2 (PAK2)

    E. Shinya, M. Shimizu, A. Owaki, S. Okura, H. Takahashi

    EUROPEAN JOURNAL OF IMMUNOLOGY   46   92 - 92   2016.8

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  • nef 欠損弱毒SHIV のワクチン効果に対するrIFN-γ投与の増強効果 Reviewed

    兼安健太郎, 伊吹謙太郎, 大倉定之, 姫野愛, 喜多正和, 山本俊郎, 佐藤彰彦, 三浦智行, 速水正 憲

    第19回日本エイズ 学会、2005 年12 月1 日~3 日、熊本   2005

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  • 計画4-3 T細胞分化過程におけるレトロウイルス感染と分化異常の解析(X.共同利用研究 2.共同利用研究成果)

    速水 正憲, 伊吹 謙太郎, 大倉 定之, 鈴木 元

    霊長類研究所年報   34   127 - 127   2004.9

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  • 5-2 T細胞分化過程におけるレトロウイルス感染と分化異常の解析(VII 共同利用研究 2.研究成果)

    速水 正憲, 伊吹 謙太郎, 大倉 定之, 元原 麻貴子

    霊長類研究所年報   33   92 - 92   2003.8

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  • Basic research for AIDS control. Immunology and pathology for HIV infection. Fiscal year 1999. Establishment of SDF-1 expression system in simian model, and search for new CXCR4 antagonists. Fiscal year 2000. Identification of targeted cells by HIV-1, usi

    田代啓, 大倉定之, 山下満左広, 速水正憲, 柴山史朗, 池川雅哉, 本庶佑, 高橋淳, 堀口聡士

    エイズ制御のための基礎研究 平成10-13年度   160 - 163   2003

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    J-GLOBAL

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  • アカゲザルにおける低分子化合物(ONO-4007)投与によるSHIV増殖抑制効果

    大倉定之, 山下満左裕, 池川雅哉, 伊吹謙太郎, 柴山史朗, 築山貴美, 松尾政芳, 田代啓, 速水正憲

    日本エイズ学会誌   2 ( 4 )   2000

  • 低分子化合物,ONO-4007のin vitro抗HIV/SHIV増殖抑制効果

    池川雅哉, 柴山史朗, 山下満左裕, 大倉定之, 松尾政芳, 芳賀久典, 多田秀明, 田代啓, 本庶佑

    日本エイズ学会誌   2 ( 4 )   2000

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Presentations

  • Characterisation of species-specific, post-entry restriction of retroviruses in bat cell lines

    Sadayuki Ohkura, Masayuki Horie, Masumi Shimizu, Haruka Osanai, Yoshitaka Miyagawa, Rimpei Morita

    2020.12 

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  • Effects of glycolipid antigens on the differentiation of dendritic cells

    Y Negishi, T Ichikawa, E Koike, H Azuma, S Ohkura, T Takeshita, H Takahashi

    The 43rd annual meeting of the Japanese society for immunology  2014.12 

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  • Hemopoietic cel kinase (Hck) augmented the interaction between HIV-1 Nef and p21-activated kinase 2 (PAK2) to down-regulate CD1a-restricted lipid-antigen presentation in dendritic cells

    SHINYA Eiji, SHIMIZU Masumi, OWAKI Atsuko, MATSUMURA Jiro, OKURA Sadayuki, MORI Lucia, DE LIBERO Gennaro, TAKAHASHI Hidemi

    The 44th annual meeting of the Japanese society for immunology  2015.11 

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  • Bat restricts retrovirus infection after the completion of reverse transcription

    Sadayuki Ohkura, Yoshitaka Miyagawa, Rimpei Morita, Hidemi Takahashi

    Sadayuki OkuraThe 67th Annual Meeting of the Japanese Society for Virology  2019.10 

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  • Novel molecular mechanism of bat cells for resisting RNA virus replication

    Sadayuki Ohkura, Yoshitaka Miyagawa, Masumi Shimizu, Rimpei Morita, Hidemi Takahashi

    The 42nd Annual Meeting of the Molecular Biology Society of Japan  2019.12 

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  • Analysis of intracellular localization of retroviral genome in the presence of the intracellular restriction factor, Fv1

    Sadayuki Ohkura, Jonathan P Stoye, Hidemi Takahashi

    The 29th annual meeting of the Japanese society for AIDS  2015.11 

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  • ART中のreservoirであるNKT細胞の制御に関わるγδ T細胞の役割

    松村次郎, 大脇敦子, 清水真澄, 大倉定之, 新谷英滋, 高橋 秀実

    第30回日本エイズ学会  2016.11 

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  • Airway allergy induced by histamine rleased from IgE-sensitized mast cells can be controlled through dendritic cell subset manipulation in a mouse model

    TAKAHASHI Hidemi, MURAKAMI Ryosuku, SHIMIZU Masumi, WAKABAYASHI Ayako, TAKESHITA Hikaru, KOIKE Eri, NEGISHI Yasuyuki, OHKURA Sadayuki, OHKUBO Kimihiro

    2016.12 

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  • Hematopoietic cell kinase (Hck) augmented the interaction between HIV-1 Nef and SERINC5, which might promote HIV-1 infection ny excluding SERINC5 from virion incorporation in immature denderitic cells

    Eiji SHINYA, Atsuko OWAKI, Jiro MATSUMURA, Sadayuki OKURA, Yohei OTSUKA, Shun TAKAKU, Hidemi TAKAHASHI

    2017.12 

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  • Recognition of retrovirus capsid by a intracellular restriction factor, TRIM5α; comparison to the recognition by another restriction factor, Fv1

    Sadayuki Okura, Jonathan P Stoye, Hidemi Takahashi

    The 28th annual meeting of the Japanese society for AIDS  2014.12 

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  • Recognition of murine leukaemia virus (MLV) capsid by TRIM5; existence of molecular patterns to recognise multiple retroviruses? Invited

    Sadayuki Okura

    2010.12 

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  • Restriction Factor Recognition of Retroviral Capsid International conference

    S. Ohkura, J. Stoye

    24th Workshop on Retroviral Pathogenesis  2012.10 

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  • Retrovirus recognition by capsid targeting restriction factors Invited

    Sadayuki Okura

    2013.1 

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  • Recognition of the entire surface of capsid protein is a shared feature of FV1- and Trim5α-mediated restriction of murine leukaemia virus International conference

    Sadayuki Okura, Jonathan P Stoye

    Frontiers of Retrovirology  2013.9 

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  • Recognition of murine leukaemia virus (MLV) by the mouse restriction factor Fv1

    Sadayuki Okura, Jonathan P Stoye, Hidemi Takahashi

    The 62th annual meeting of the Japanese society for virology  2014.11 

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  • Recognition of murine leukaemia virus (MLV) capsid by TRIM5α; existence of molecular patterns to recognise multiple retroviruses? Invited

    Sadayuki Okura

    2010.12 

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  • Novel escape mutants suggest an extensive TRIM5α binding site spanning the entire outer surface of the murine leukaemia virus capsid protein International conference

    Sadayuki Okura, David C Goldstone, Melvyn W Yap, Kate Holden-Dye, Ian Taylor, Jonathan Stoye

    XV International Congress of Virology, IUMS 2011 Congress  2011.9 

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  • Mechanism of TRIM5/Fv1 recognition of retroviral capsid; what pattern do they recognise? Invited

    Sadayuki Okura

    2012.8 

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  • Retrovirus recognition by capsid targeting restriction factors

    Sadayuki Okura

    2012.8 

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  • Further characterization of an MLV escape mutant from rhesus macaque TRIM5α International conference

    Sada Okura, Melvyn W. Yap, nd Jonathan, P. Stoye

    The 2009 meeting on RETROVIRUSES  2009.5 

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  • Recognition of murine leukaemia virus (MLV) capsid by TRIM5α; existence of molecular patterns to recognise multiple retroviruses? Invited

    Sadayuki Okura

    2010.12 

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  • Quantification and genetic analysis of infectious viruses at development AIDS stage in monkeys infected with a chimeric simian/human immunodeficiency virus International conference

    Miyake, A, Enose, Y, Ohkura, S, Kato, S, Hayami, M

    13th Joint Meeting of AIDS Panel, Japan-US Cooperative Medical Science Program  2001.3 

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  • Administration of a Novel Entry-block Compound to Rhesus Monkeys Infected with Simian/human Immunodeficiency Virus Including HIV-1 env gene International conference

    Ohkura, S, Yamashita, M, Ikegawa, M, Ibuki, K, Shibayama, S, Shimada, T, Matsuo, M, Tashiro, K, Honjo, T, Hayami, M

    20th Annual Symposium on Nonhuman Primate Models for AIDS  2002.9 

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  • Specificity Determinants of HIV-1 Restriction by TRIM5α International conference

    Sada Okura, Melvyn W. Yap, Tom Sheldon, d Jonathan, P. Stoye

    The 2006 meeting on RETROVIRUSES  2006.5 

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  • Identification of MLV escape mutants naturally selected by TRIM5α International conference

    Sada Okura, Melvyn W. Yap, nd Jonathan, P. Stoye

    The 2008 meeting on RETROVIRUSES  2008.5 

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  • Phylogenetic analysis of HTLV-I isolate in the South Pacific Ocean International conference

    Ohkura, S, Tajima, K, Sonoda, S, Cartier, L, Yamashita, M, Hayami, M

    Ninth international conference on human retrovirology: HTLV and related viruses  1999 

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  • Histopathology of the lymphoid tissues in monkeys infected with live attenuated SHIV revealed partial protection after pathogenic SHIV89.6p challenge International conference

    Shimada, T, Ui, M, Ibuki, K, Ohkura, S, Kuwata, T, Igarashi, T, Hayami, M

    1st International Conference on Vaccine Development and Immunotherapy in HIV  2000.6 

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Research Projects

  • コウモリ細胞ライブラリ由来の宿主因子によるHIV-1キャプシド標的抑制分子の作出

    Grant number:23K06503  2023.4 - 2026.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    大倉 定之, 石野 孔祐

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

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  • Elucidation of the novel function of trophoblast DROSHA as a novel therapeutic strategy for preventing congenital viral infection

    Grant number:20K09611  2020.4 - 2024.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

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  • Examination of innate immune responses in the local mucosal surfaces in the acute phase of HIV-1 infection using a humanized mice model

    Grant number:15K06811  2015.4 - 2019.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Ohkura Sadayuki, Negishi Yasuyuki, Maruyama Motoyo, Shimizu Masumi

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    Grant amount:\5070000 ( Direct Cost: \3900000 、 Indirect Cost:\1170000 )

    In this study, we established a humanized mouse model where innate immune cells are efficiently reconstituted in order to unveil the viral dynamics and the locally induced innate immunity at very early time points after human immunodeficiency virus type 1 (HIV-1) inoculation.
    We observed the successful reconstitution of human innate immune cells including Langerhans cells in the skin epithelia of the newly established humanized mice by injection of cocultured human haematopoitic and messenchymal stem cells. After intrarectal inoculation, the challenge virus resided at the anal side of the rectum, and some virus particles were found inside rectal villi as early as three hours after inoculation, suggesting much earlier incorporation of virus particles into the rectum tissue than previously thought. We are currently analyzing systematically the immune cells surrounding the infected cells to clarify the innate immune response to HIV-1 infection at the vey early phase of infection.

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  • ヒトT細胞白血病ウイルスの遺伝子系統解析による起源と進化の解明

    Grant number:00J02978  2000 - 2001

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    大倉 定之

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    Grant amount:\2000000 ( Direct Cost: \2000000 )

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