Biomedical subjects

M Hayami

Publications and source records attributed to M Hayami.

At least 19 recordsLinked to original sources

PubMed2005

Comparison of susceptibility to SIVmac239 infection between CD4(+) and CD4(+)8(+) T cells.

CD4-bearing T cells are the primary targets for human immunodeficiency virus type 1(HIV-1)/simian immunodeficiency virus (SIV) infection. However, it is unclear whether the susceptibility of CD4-bearing T cells including CD4 single positive and CD4/8 double positive T cells to HIV/SIV infection is the same or not. In this study, we compared the susceptibility to SIV infection between CD4(+) and CD4(+)8(+) T cells, using Herpesvirus saimiri (HVS)-transformed CD4(+) and CD4(+)8(+) T cells established from peripheral blood mononuclear cells (PBMC) of rhesus macaques. Although there was little difference between the two CD4-bearing T cell population in the expression level of CD4 molecules and chemokine receptors such as CXCR4 and CCR5, SIV replicated more efficiently in CD4(+)8(+) T cells than in CD4(+) T cells. Moreover, we found that reverse transcription initiated more efficiently in CD4(+)8(+) T cells than in CD4(+) T cells and that the cell lysates from CD4(+) T cells impaired the RT activity more strongly than that from CD4(+)8(+) T cells. These findings suggest that intracellular environment in CD4(+) 8(+) T cells is better for reverse transcription and that the infection of those CD4(+)8(+) T cells might play critical and different roles in HIV-1/SIV infection and dissemination.

Animals↗

PubMed2005

Analysis of evolutionary conservation in CD1d molecules among primates.

The hereditary conservation in the genetically encoded CD1D sequences of various primates was analyzed. Genomic CD1D sequences of 17 rhesus macaques with distinct origins, eight Indian and nine Chinese, were examined and differences of only one or two nucleotides were detected and the consensus sequence of rhesus CD1D was determined. CD1D consensus sequences of three African green monkeys (AGMs) and the rhesus monkeys were then compared to study the evolutionary differences among interspecies. The CD1D consensus sequence determined from AGMs apparently differed by seven nucleotides from the rhesus consensus sequence, and nucleotide difference induced only three amino acid changes within Exon3, corresponding to the alpha2 domain of CD1d having a hydrophobic ligand-binding pocket. Such changes in the alpha2 domain may alter the characteristics of the SIV-derived glycolipid/lipid antigens presented by each CD1d molecule to innate natural killer T cells. In addition, the CD1D genomic sequences of three chimpanzees (chimps) were determined. To our surprise, although Exon2 and Exon3 reflecting antigen-binding alpha1 and alpha2 domains in chimps' CD1D were identical to that in humans except one amino acid, three amino acids within Exon4, reflecting alpha3 domain, were distinct from humans, and one of them was identical to those in rhesus and AGM CD1D. On the basis of the findings, the evolutionary relationship of the CD1d molecules among the various primates and their HIV-1/SIV susceptibility will be discussed.

Amino Acid Sequence↗

PubMed2004

Protective effects of nef-deleted SHIV or that having IFN-gamma against disease induced with a pathogenic virus early after vaccination.

To clarify the involvement of primitive non-specific immune responses in the protective effects of a live, attenuated virus, each two rhesus macaques were intravenously immunized with an attenuated chimeric simian and human immunodeficiency virus (SHIV) in which the nef gene was deleted (SHIV-NI) or a SHIV having human IFN-gamma inserted into the deleted nef region (SHIV IFN-gamma). These immunized monkeys were intravenously challenged with a heterologous pathogenic SHIV (SHIV-C2/1) at four weeks post immunization (wpi). After vaccination, one of each SHIV-NI- or SHIV IFN-gamma-immunized monkeys showed a low level of SIV Gag-specific lymphocyte proliferative response but did not have neutralizing antibodies to both the parental and challenge viruses. After the challenge, the plasma viral RNA loads of the challenge virus were suppressed in all the immunized monkeys and the severe CD4+ T cell loss observed in the unimmunized monkeys was not found. Thus, both SHIV IFN-gamma and SHIV-NI infections could prevent from disease progression by a pathogenic virus early after immunization, suggesting that primitive non-specific immune response elicited by attenuated virus infection, in addition to highly acquired virus-specific immunity, contributes to the protective effect against a pathogenic virus.

AIDS Vaccines↗

PubMed2003

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

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 SHIV(KU-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.

Amino Acid Sequence↗

PubMed2003

Augmentation of antigen-specific cytokine responses in the early phase of vaccination with a live-attenuated simian/human immunodeficiency chimeric virus expressing IFN-gamma.

A nef-deleted SHIV-NM-3rN (SHIV-NI) was previously shown to be nonpathogenic and to induce protective immunity. In the present study, a SHIV-NI expressing human interferon-gamma (SHIV-IFN-gamma) was constructed and the effect of co-expression of IFN-gamma on virus replication and immunopotentiation was investigated in macaques that were vaccinated with both viruses, by comparing cytokine responses during the first 4 weeks after vaccination. Peripheral blood mononuclear cells (PBMC) isolated from vaccinated macaques were stimulated with inactivated viral particles for 24 h, and the production of IL-2, IL-4, IL-6, IL-10, IL-12, TNF-alpha and IFN-gamma was determined by ELISA and flow cytometry. All of the vaccinated macaques showed increases in cytokine production. However, the production of IFN-gamma (Th1-type cytokine) was more rapidly induced by SHIV-IFN-gamma vaccination, and IFN-gamma-producing cells appeared to be still increasing at 4 weeks after vaccination, although the difference of virus replication during the time was not significant in contrast to in vitro replication in cultured PBMC. These results suggest that co-expression of IFN-gamma with SHIV can modulate the antiviral immune responses into the Th1 type response, which would probably provide more protective immunity.

Animals↗

PubMed2003

Optical coherence tomography of adult-onset vitelliform dystrophy.

PURPOSE: To report the cross-sectional structure of the retina and choroid in eyes with adult-onset vitelliform macular dystrophy as obtained by optical coherence tomography (OCT). METHODS: Seven patients with adult-onset vitelliform macular dystrophy and one patient with Best disease were examined by fundoscopy, fluorescein and indocyanine green angiography and OCT. Three patients underwent also electro-oculography. RESULTS: 1. Seven cases with adult-onset vitelliform macular dystrophy showed a well-circumscribed elevation of a highly reflective band, corresponding to the retinal pigment epithelium 2. In these 7 patients, the space below this band was inhomogeneous and moderately reflective. 3. Four cases out of 7 had a well defined posterior boundary. 4. The patient with Best disease disclosed a different aspect on OCT, although the contour of the lesion was similar to the others. CONCLUSION: Optical coherence tomography disclosed the structure of the vitelliform lesion in vivo and could be helpful for its pathological interpretation.

Adult↗

PubMed2002

Infection of macaques with chimeric simian and human immunodeficiency viruses containing Env from subtype F.

Chimeric simian and human immunodeficiency viruses (SHIVs) are useful for investigating the pathogenicity of human immunodeficiency virus (HIV-1) and to develop an anti-HIV-1 vaccine. We attempted to construct SHIVs containing Env from various subtypes, because almost all SHIVs which have been reported so far have Env from HIV-1 that belongs to subtype B. Two infectious SHIVs containing Env from two strains of HIV-1, CMR304 and CMR306, which belong to subtype F and A, respectively, were newly obtained. These SHIVs essentially showed a coreceptor usage and a neutralization pattern that were similar to those of the parental HIV-1s. In macaque PBMC, SHIVcmr304 replicated with kinetics similar to that of prototypic SHIV-NM-3rN with HIV-1 NL432 Env, but SHIVcmr306 replicated poorly. Inoculation of four rhesus macaques with SHIVcmr304 resulted in an increase of plasma viral load in all the macaques, though viral RNA copies were 100-fold lower than that in the infection with NM-3rN. This SHIV containing Env from HIV-1 subtype F will be a valuable source for the analysis of HIV-1 subtype F and the evaluation of vaccine candidates as a genetically divergent challenge virus.

Animals↗

PubMed2002

Characterization of simian and human immunodeficiency chimeric viruses re-isolated from vaccinated macaque monkeys after challenge infection.

Monkeys that have been vaccinated with nef-deleted SHIVs were either fully or partially protected against challenge with acute pathogenic SHIV-89.6 P. Viruses isolated from these vaccinated monkeys were all found to be the 89.6 P challenge virus using PCR amplification and restriction enzyme analysis of the env region of the viruses. Analysis of the 3'-end of the env region and 5'-half of the nef region using a heteroduplex mobility assay revealed that the parental 89.6 P and re-isolated viruses from unvaccinated 89.6 P-infected monkeys had quite an abundant and similar heterogeneous quasispecies population. In contrast, the viruses isolated from the vaccinated monkeys had different and fewer quasispecies indicating a selective immune pressure in the vaccinated monkeys. The in vitro replication of the viruses isolated from the vaccinated monkeys in human and macaque peripheral blood mononucular cells (PBMCs) as well as in established cell lines such as M8166 and HSC-F cells, were slow and delayed when compared to the parental 89.6 P and re-isolated viruses from unvaccinated 89.6 P-infected monkeys. Further comparison revealed that in HSC-F cells the viruses from vaccinated monkeys again showed delayed and weak CD4(+) cell down-modulation as well as having little or no effect on cell growth or cell viability on HSC-F cells and monkey PBMC. Thus we noticed that these re-isolated 89.6 P viruses from the vaccinated monkeys had changed or had been selected for low pathogenic viruses in the monkeys. This suggests that though the vaccination did not completely prevent the replication of the challenge virus in the monkeys it did contain the challenge virus by suppressing the pathogenic variants. This further enhances the prospects of this nef-deleted SHIV as the bases for effective anti-HIV vaccine candidates.

AIDS Vaccines↗

PubMed2001

Apoptosis induced by in vitro infection with simian-human immunodeficiency chimeric virus in macaque and human peripheral blood mononuclear cells.

We investigated apoptosis induced by in vitro infection with the chimeric virus of simian immunodeficiency virus and human immunodeficiency virus (SHIV). Macaque and human peripheral blood mononuclear cells (PBMCs) were infected with pathogenic SHIV-89.6p (89.6p) or nonpathogenic SHIV-NM-3rN (NM-3rN). In macaque PBMCs, the extent of virus production and apoptosis induction in CD4(+) cells was much greater in 89.6p infection than in NM-3rN infection. The result was consistent with our previous study of in vivo SHIV infection. In human PBMCs, 89.6p replicated and induced apoptosis more extensively than did NM-3rN, when the cells were infected with the same infectious doses of the viruses. However, in cells infected with a high dose of NM-3rN, the levels of virus production and apoptosis induction were comparable to those in 89.6p infection. There was no significant difference in the extent of apoptosis induction between 89.6p and NM-3rN infection when growth curves of the two viruses matched. Thus, apoptosis induction by SHIV might depend quantitatively on the amount of virus production rather than on the strains of the virus. Moreover, the correlation between the extent of apoptosis induction and virus pathogenicity in macaque PBMCs has also been found in SHIV-infected macaques. This suggests that the profiles of SHIV infection in vitro reflect the in vivo phenomena. Therefore, the in vitro evaluation of apoptosis induction by SHIV could be useful as a safety test for the development of live-attenuated vaccines.

Animals↗

PubMed2001

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

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.

Animals↗

PubMed2001

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

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.

Cloning, Molecular↗

PubMed2001

Characterization of less pathogenic infectious molecular clones derived from acute-pathogenic SHIV-89.6p stock virus.

For a better understanding of the acute pathogenicity of SHIV-89.6P stock virus, which induces prominent CD4 cell loss within a month after inoculation in monkeys, we have constructed four infectious molecular clones (cl 18, cl 64, cl 69, and cl 71). Cl 64, cl 69, and cl 71, like the parental virus, showed a high in vitro replication ability and a pathogenic-like effect (CD4 downmodulation) in a monkey CD4(+) cell line, whereas cl 18 showed a lower replication ability and could not downmodulate CD4. Cl 64, which has characteristics similar to those of the parental virus in vitro, was inoculated into four rhesus monkeys. All monkeys showed a plasma viral load similar to that of the parental virus with a peak at 2 weeks after inoculation. However, the viral load gradually decreased and the virus failed to cause an AIDS-like disease in infected monkeys, but it induced a strong antiviral antibody response. These results demonstrate the polyclonal nature of the parental SHIV-89.6P virus stock and demonstrate that cl 64, aside from its high replicability, may differ qualitatively from the parental virus.

Acquired Immunodeficiency Syndrome↗

PubMed2001

Construction of SIV/HIV-1 chimeric viruses having the IL-5 gene and determination of their ability to replicate and produce IL-5.

During the progression of AIDS, there is a shift in abundance of immune cells from Th1-producing cells to Th2-producing cells. To determine whether this change might have an effect on HIV-1 replication in vivo, we constructed simian/human immunodeficiency chimeric viruses having the human IL-5 gene (a Th2-type cytokine) and examined the effect of the inserted gene on viral replication, IL-5 production and viral stability in vitro. The DNA of human IL-5 was inserted into vpr-deleted and nef-deleted infectious SHIVs. The obtained replication-competent viruses were used to infect human T-cell lines and monkey peripheral blood mononuclear cells. As a result, at the time of peak NI-IL5 virus production, IL-5 was produced with a significantly higher titer than 3sj-IL5. The functionality of the produced IL-5 was confirmed by IL-5-dependent cells. The replication of both SHIVs having IL-5 appeared to be faster than that of the parental viruses without the IL-5 gene. These results show that co-expression of IL-5 stimulates SHIV replication in vitro. Thus, it is expected that expression of IL-5 will also have an effect on viral replication and pathogenicity in vivo.

Acquired Immunodeficiency Syndrome↗

PubMed2001

A single amino acid change at Leu-188 in the reverse transcriptase of HIV-2 and SIV renders them sensitive to non-nucleoside reverse transcriptase inhibitors.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are selective for human immunodeficiency virus type 1 (HIV-1) and generally not effective on HIV-2 or simian immunodeficiency virus (SIV). Only SIVagm was found to be sensitive to NNRTIs. When the amino acid differences in RT between SIVmac and SIVagm were compared with the known amino acid substitutions of NNRTI-resistance variants of HIV-1, we came to consider that the amino acid residue Leu-188 of HIV-2 and SIVmac might be related to their resistance to NNRTIs. To test this hypothesis, we substituted Leu-188 to Cys or Tyr in HIV-2 and SIVmac, and examined sensitivity of the mutant molecular clones to NNRTIs. The L188Y mutant of HIV-2 became completely sensitive to delavirdine and efavirenz, while that of SIVmac was also significantly sensitive to these NNRTIs. We further isolated NNRTI-resistant variants from these mutant viruses and determined amino acid substitutions in RT. The roles of the observed substitutions in NNRTI-resistance were further confirmed by site-directed mutagenesis. Our study reveals the crucial role of L188 in the natural resistance of HIV-2 and SIVmac to NNRTIs. Furthermore, the observed substitutions in RT of HIV-2 and SIVmac support the common mechanism of action of NNRTIs against HIV-1, HIV-2 and SIV.

Alkynes↗

PubMed2001

Using SHIVs to develop an anti-HIV-1 live-attenuated vaccine.

The use of chimeric simian and human immunodeficiency viruses (SHIVs) that encode HIV-1 Env and are infectious to macaques has made it possible to analyze the pathogenicity of HIV-1 in vivo, and to evaluate the efficacy of candidate vaccines in macaques. In addition, we believe that gene-deleted SHIVs could potentially be used as anti-HIV-1 live-attenuated vaccines. Gene-deleted SHIVs replicate transiently, are non-pathogenic and induce strong protection against challenge infection. The most important advantage of gene-deleted SHIVs is that their efficacy and safety can be evaluated in macaques before they are used in humans.

AIDS Vaccines↗

PubMed2001

Cytokine kinetics in the plasma of monkeys infected with pathogenic and nonpathogenic simian and human immunodeficiency chimeric viruses at an early stage of infection.

To evaluate the pattern of cytokines as a result of pathogenic and nonpathogenic SHIV infections in monkeys, we analyzed the cytokines interleukin (IL)-2, IL-4, IL-10, IL-12, and interferon (IFN)-gamma in the plasma of 8 monkeys infected with either pathogenic 89.6P or nonpathogenic NM-3rN chimeric viruses. The cytokine kinetics in the 89.6P-infected monkeys was characterized by increases of IL-2, IL-10, and to some extent IFN-gamma and a decrease of IL-12. Although that of NM-3rN-infected monkeys was characterized by an increase of IFN-gamma, and a transient decrease of IL-12. IL-4 was not detected in any of the monkeys. The results, therefore, showed a mixture of Th-1 and Th-2 cytokine profiles implying these cytokines are not clear enough to use as an index of the pathogenicity of the viruses at an early stage of infection.

Animals↗

PubMed2000

DNA vaccination of macaques by a full genome HIV-1 plasmid which produces noninfectious virus particles.

In this study, we tried a DNA vaccination regime in rhesus macaques using a full genome HIV-1 plasmid. The HIV-1 genome is under the control of its original LTR promoter, but has a mutated zinc finger motif gene in the nucleocapsid region. Due to the lack of genomic RNA packaging, the plasmid produces only noninfectious viral particles. We repeatedly injected four macaque monkeys intramuscularly with the naked DNA over a period of 40 weeks. To evaluate the humoral and cell-mediated immunity provided by this DNA vaccination, no other booster or other recombinant viral vectors were used. Immunological responses against HIV-1 were elicited in all of the vaccinated monkeys: stable anti-HIV-1 Env antibodies were raised in two monkeys and CTL activities were induced in the other monkeys. The macaques were intravenously challenged at 54 weeks with 100 TCID(50) of SHIV-NM-3rN, which possesses an envelope gene homologous to the one in the vaccinated plasmid. In all of the vaccinated macaques, the peak plasma viral loads induced by the challenge virus were two to three orders of magnitude lower than those of the naive controls. These results suggest that a DNA vaccination regime with a full genome plasmid alone is potentially efficacious and provides a new possibility for the development of an AIDS vaccine.

AIDS Vaccines↗

PubMed2000

Development of novel simian immunodeficiency virus vectors carrying a dual gene expression system.

The development of highly efficient and safe gene transfer methods suitable for clinical use is required for human gene therapies. We have developed a novel lentiviral vector system, based on the nonpathogenic simian immunodeficiency virus from African green monkeys (SIVagm), that carries a unique dual gene expression system. This system utilizes the lentivirus Rev responsive element (RRE). Self-inactivating vectors were also developed by deleting a U3 region in the 3' long terminal repeat (3' LTR) of the virus. When pseudotyped with a vesicular stomatitis virus envelope glycoprotein G (VSV-G), the SIVagm-based vectors could transduce both growth-arrested human cells and terminally differentiated neuronal cell lines. Using these vectors, two reporter genes could be expressed simultaneously at equal levels, and expression levels of both genes could be altered by modifying the length of the RRE sequence. These SIVagm-based vectors might offer safety advantages over other lentivirus-based vectors. Furthermore, the novel dual gene expression system described here could increase the usefulness and value of both viral and nonviral vectors in gene therapy.

Base Sequence↗