Acquired Immunodeficiency Syndrome: Suzuki H

Kuwata T, Kodama M, Sato A, Suzuki H, Miyazaki Y, Miura T, Hayami M. · Laboratory of Primate Model, Experimental Research Center for Infectious Disease, Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan. · AIDS Res Hum Retroviruses. · Pubmed #17411370 No free full text.

Abstract: Monocytes are known as an alternative target for HIV/SIV infection, but the contribution of monocytes to viral spread in a host is unclear. In this study, CD14 monocytes were monitored in 6 macaques until six weeks postinfection (wpi) with SIVmac239 to evaluate their contribution to viral load. The monocyte count in blood significantly increased with peak viremia at 2 wpi and the expression level of CD14 on monocytes significantly decreased at 1-2 wpi, though the number of CD4(+) T cells was stable in these macaques. The number of CD14 monocytes and the expression level of CD14 on monocytes at 2 wpi were also significantly related to the extent of viremia in plasma. An increased number of monocytes at 2 wpi was associated with a lower postacute viral load, suggesting that monocytes have a role in suppressing the virus. The lower expression level of CD14 in monocytes at 2 wpi was associated with a higher viral load and greater degree of infection of monocytes. This correlation suggests that monocytes with a low level of CD14 may be more susceptible to SIV and may enhance viral replication. The analysis of monocytes in persistently infected macaques revealed that the expression level of CD14 was also significantly low during persistent infection compared with naïve macaques, though the monocyte count was within the normal range. Monocytes may suppress viruses, perhaps by their immune function, during acute infection. However, infection of monocytes may increase the viral load and spread viruses in a host.

Ishimatsu M, Suzuki H, Akiyama H, Miura T, Hayami M, Ido E. · Laboratory for Viral Replication, Center for Emerging Virus Research, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaracho, Kyoto 606-8507, Japan. · Microbes Infect. · Pubmed #17350308 No free full text.

Abstract: We generated a novel SHIV (termed SHIV-pr) that possesses the HIV-1-derived protease (PR) gene in the corresponding position in the SIVmac genome. SHIV-pr is replication-competent in human and monkey CD4(+) T lymphoid cell lines as well as rhesus macaque PBMCs. The viral growth of SHIV-pr was completely blocked in the presence of a peptide-analog PR inhibitor at the tissue culture level. When SHIV-pr was intravenously inoculated into two rhesus macaques, it resulted in a weak but long-lasting persistent infection in one monkey, whereas the infection of another was only temporary. To enhance the viral growth competence by adaptation, we then passaged the virus in vivo from a monkey up to the fourth generation. The initial peak values of plasma viral loads as well as the setpoint values increased generation by generation and reached those of a parental virus SIVmac. When a medication using the content of Kaletra capsule (a mixture of two PR inhibitors, lopinavir and ritonavir) was orally given to three SHIV-pr-infected monkeys for 4 weeks, plasma viral loads dropped to near or below the detection limit and quickly rebounded after the cessation of medication. The results suggest that SHIV-pr can be used to evaluate PR inhibitors using monkeys.

Motohara M, Ibuki K, Miyake A, Fukazawa Y, Inaba K, Suzuki H, Masuda K, Minato N, Kawamoto H, Nakasone T, Honda M, Hayami M, Miura T. · Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research, Kyoto University, 53 Shogoinkawara-Machi, Sakyo-Ku, Kyoto 606-8507, Japan. · Microbes Infect. · Pubmed #16702011 No free full text.

Abstract: One of the mechanisms by which HIV infection induces the depletion of CD4+ T cells has been suggested to be impairment of T-cell development in the thymus, although there is no direct evidence that this occurs. To examine this possibility, we compared T-cell maturation in the intrathymic progenitors between macaques infected with an acute pathogenic chimeric simian-human immunodeficiency virus (SHIV), which causes profound and irreversible CD4+ T-cell depletion, and macaques infected with a less pathogenic SHIV, which causes only a transient CD4+ T-cell decline. Within 27 days post-inoculation (dpi), the two virus infections caused similar increases in plasma viral loads and similar decreases in CD4+ T-cell counts. However, in the thymus, the acute pathogenic SHIV resulted in increased thymic involution, atrophy and the depletion of immature T cells including CD4(+)CD8(+) double-positive (DP) cells, whereas the less pathogenic SHIV did not have these effects. Ex vivo differentiation of CD3(-)CD4(-)CD8(-) triple-negative (TN) intrathymic progenitors to DP cells was assessed by a monkey-mouse xenogenic fetal thymus organ culture system. Differentiation was impaired in the TN intrathymic progenitors of the acute pathogenic SHIV-infected monkeys, while differentiation was not impaired in the TN intrathymic progenitors of the less pathogenic SHIV-infected monkeys. These differences suggest that dysfunction of thymic maturation makes an important contribution to the irreversible depletion of circulating CD4+ T cells in vivo.

Miyake A, Ibuki K, Enose Y, Suzuki H, Horiuchi R, Motohara M, Saito N, Nakasone T, Honda M, Watanabe T, Miura T, Hayami M. · Institute for Virus Research, Laboratory of Primate Model, Experimental Research Center for Infectious Disease, Kyoto University, Sakyo-ku, Japan. · J Gen Virol. · Pubmed #16603534 links to  free full text

Abstract: A better understanding of virological events during the early phase of human immunodeficiency virus 1 (HIV-1) infection is important for development of effective antiviral vaccines. In this study, by using quantitative PCR and an infectious plaque assay, virus distribution and replication were examined in various internal organs of rhesus macaques for almost 1 month after intrarectal inoculation of a pathogenic simian immunodeficiency virus/HIV chimeric virus (SHIV-C2/1-KS661c). At 3 days post-inoculation (p.i.), proviral DNA was detected in the rectum, thymus and axillary lymph node. In lymphoid tissues, infectious virus was first detected at 6 days p.i. and a high level of proviral DNA and infectious virus were both detected at 13 days p.i. By 27 days p.i., levels of infectious virus decreased dramatically, although proviral DNA load remained unaltered. In the intestinal tract, levels of infectious virus detected were much lower than in lymphoid tissues, whereas proviral DNA was detected at the same level as in lymphoid tissues throughout the infection. In the thymus and jejunum, CD4CD8 double-positive T cells were depleted earlier than CD4 single-positive cells. These results show that the virus spread quickly to systemic tissues after mucosal transmission. Thereafter, infectious virus was actively produced in the lymphoid tissues, but levels decreased significantly after the peak of viraemia. In contrast, in the intestinal tract, infectious virus was produced at low levels from the beginning of infection. Moreover, virus pathogenesis differed in CD4 single-positive and CD4CD8 double-positive T cells.

Shimizu Y, Miyazaki Y, Ibuki K, Suzuki H, Kaneyasu K, Goto Y, Hayami M, Miura T, Haga T. · Department of Veterinary Microbiology, University of Miyazaki, Miyazaki 889-2192, Japan. · Virology. · Pubmed #16169034 No free full text.

Abstract: TNF-alpha has been implicated in the pathogenesis of, and the immune response against, HIV-1 infection. To clarify the roles of TNF-alpha against HIV-1-related virus infection in an SHIV-macaque model, we genetically engineered an SHIV to express the TNF-alpha gene (SHIV-TNF) and characterized the virus's properties in vivo. After the acute viremic stage, the plasma viral loads declined earlier in the SHIV-TNF-inoculated monkeys than in the parental SHIV (SHIV-NI)-inoculated monkeys. SHIV-TNF induced cell death in the lymph nodes without depletion of circulating CD4(+) T cells. SHIV-TNF provided some immunity in monkeys by increasing the production of the chemokine RANTES and by inducing an antigen-specific proliferation of lymphocytes. The monkeys immunized with SHIV-TNF were partly protected against a pathogenic SHIV (SHIV-C2/1) challenge. These findings suggest that TNF-alpha contributes to the induction of an effective immune response against HIV-1 rather than to the progression of disease at the early stage of infection.

Miyake A, Ibuki K, Suzuki H, Horiuchi R, Saito N, Motohara M, Hayami M, Miura T. · Institute for Virus Research, Kyoto University, Kyoto, Japan. · J Med Primatol. · Pubmed #16128924 No free full text.

Abstract: Children infected with human immunodeficiency virus type 1 often have higher viral loads and progress to acquired immunodeficiency syndrome more rapidly than adults. In our previous study of simian-human immunodeficiency virus (SHIV)-infected adult monkeys, immature CD4CD8 double-positive T cells in the thymus and jejunum decreased faster than mature CD4 single-positive T cells. Here, we examined the effect of virus replication on immature T cells from the same SHIV-inoculated newborn monkeys having more immature T cells than adults. The infectious viruses were more abundantly detected in the thymus than in other tissues at both 13 and 26 days post-infection (dpi). However, mature CD4(+) T cells in the thymus declined after 13 dpi and immature CD3(-) CD4 single-positive T cells remained at 26 dpi. These results suggested that many immature CD4(+) T cells in the thymus of newborns support the production of infectious viruses even after the depletion of mature CD4(+) T cells.

Suzuki H, Motohara M, Miyake A, Ibuki K, Fukazawa Y, Inaba K, Masuda K, Minato N, Kawamoto H, Hayami M, Miura T. · Laboratory of Primate Model, Institute for Virus Research, Kyoto University, Japan. · Microbiol Immunol. · Pubmed #16034211 links to  free full text

Abstract: We intrarectally infected newborn macaques with a pathogenic simian/human immunodeficiency virus (SHIV) that induced rapid and profound CD4 (+) T cell depletion, and examined the early effects of this SHIV on the thymus. After intrarectal infection, viral loads were much higher in the thymus than in other lymphoid tissues in newborns. In contrast, no clear difference was seen in the viral loads of different tissues in adults. Histological and immunohistochemical observations showed severe thymic involution. Depletion of CD4 (+) thymocytes began in the medulla at 2 weeks post infection and spread over the whole thymus. After in vivo infection, the CD2 (+) subpopulation, which represents a relatively later stage of T cell progenitors, was selectively reduced and development of thymocytes from CD3 (-) CD4 (-) CD8 (-) cells to CD4 (+) CD8 (+) cells was impaired. These results suggest that profound and irreversible loss of CD4 (+) cells that are observed in the peripheral blood of SHIV-infected monkeys are due to destruction of the thymus and impaired thymopoiesis as a result of SHIV infection in the thymus.

Enose Y, Kita M, Yamamoto T, Suzuki H, Miyake A, Horiuchi R, Ibuki K, Kaneyasu K, Kuwata T, Takahashi E, Sakai K, Shinohara K, Miura T, Hayami M. · Institute for Virus Research, Kyoto University, Kyoto, Japan. · Arch Virol. · Pubmed #15593414 No free full text.

Abstract: 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.

Miyake A, Enose Y, Ohkura S, Suzuki H, Kuwata T, Shimada T, Kato S, Narayan O, Hayami M. · Institute for Virus Research, Kyoto University, Kyoto, Japan. · Arch Virol. · Pubmed #15098109 No free full text.

Abstract: 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.

Iida T, Kuwata T, Ui M, Suzuki H, Miura T, Ibuki K, Takahashi H, Yamamoto T, Imanishi J, Hayami M, Kita M. · Department of Microbiology, Kyoto Prefectural University of Medicine, Kyoto, Japan. · Arch Virol. · Pubmed #15045561 No free full text.

Abstract: 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.

Yoshimura K, Ido E, Akiyama H, Kimura T, Aoki M, Suzuki H, Mitsuya H, Hayami M, Matsushita S. · Division of Clinical Retrovirology and Infectious Diseases, Center for AIDS Research, Kumamoto University, 2-2-1 Honjo, Kumamoto, 860-0811, Japan. · J Virol Methods. · Pubmed #12951220 No free full text.

Abstract: The objective of this study was to assess the impact of highly active antiretroviral therapy (HAART) by an oral route on the peripheral blood CD8 subset in the monkeys infected persistently with a pathogenic strain, SHIV(89.6P). Two rhesus macaques were inoculated intravenously with SHIV(89.6P), then treated with the combination of AZT, 3TC and Lopinavir/Ritonavir (LPV/RTV) as recommended in humans by the oral route with confectionery continued for 28 days. In one of two chronically infected macaques, MM260, the viral load was maintained in the range of 10(4)-10(5) copies/ml before HAART. The plasma viral load and proviral DNA decreased dramatically during the treatment, and cessation of this therapy the viral load rebounded to the pre-treatment level but the proviral DNA rebound was delayed. The other monkey, MM242, had low viral loads (1.2x10(3)-<5x10(2) copies/ml) both before and after HAART. CD4(+) and CD8(+) T cell counts and proviral DNA level were not significantly changed after the treatment. The percentages of CD8(+)CD45RA(-)Ki67(+)cells increased during (MM260) or after (MM242) HAART and the subset was maintained at a high percentage until 18 weeks post HAART in MM242. These findings suggest that this primate model might serve an important role in testing the virological and immunological efficacy of novel therapeutic strategies combined with HAART.

Shimada T, Suzuki H, Motohara M, Kuwata T, Ibuki K, Ui M, Iida T, Fukumoto M, Miura T, Hayami M. · Department of Pathology, Kyoto City Hospital, 604-8845, Kyoto, Japan. · Virology. · Pubmed #12642106 No free full text.

Abstract: To clarify the early pathological events in simian and human immunodeficiency chimeric virus (SHIV)-infected lymphoid organs, we examined rhesus macaques infected with an acute pathogenic SHIV (SHIV89.6P) or a nonpathogenic SHIV (NM-3rN) by sequential biopsies and serial necropsies. In the SHIV89.6P-infected monkeys, acute thymic involution as shown by increased cortical tingible-body macrophages and by neutrophilic infiltrates without follicular aggregation in the medulla began within 14 days postinoculation (dpi). Cells that were strongly positive for the virus were identified in the thymic medulla. SHIV89.6P-infected lymph nodes showed severe paracortical lymphadenitis with scattered virus-positive cells at 14 dpi and they developed paracortical depletion without the obvious follicular involution. In contrast, NM-3rN-infected monkeys showed no signs of thymic dysinvolution and the lymph nodes exhibited only follicular hyperplasia. NM-3rN-infected monkeys showed much fewer virus-positive cells in these lymphoid tissues than did SHIV89.6P-infected monkeys during the same period. These differences clearly reflect the difference in the virulence of these SHIVs.

Kwofie TB, Miura T, Ibuki K, Enose Y, Suzuki H, Ui M, Kuwata T, Hayami M. · Laboratory of Viral Pathogenesis, Research Center for AIDS, Institute for Virus Research, Kyoto University, Japan. · Arch Virol. · Pubmed #12111421 No free full text.

Abstract: 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.