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Biomedical subjects

Kazuhiro Matsuo

Publications and source records attributed to Kazuhiro Matsuo.

At least 19 recordsLinked to original sources
PubMed2006

A single-nucleotide synonymous mutation in the gag gene controlling human immunodeficiency virus type 1 virion production.

Viral factors as well as host ones play major roles in the disease progression of human immunodeficiency virus type 1 (HIV-1) infection. We have examined cytotoxic T-lymphocyte activity and HIV-1 DNA PCR results of 312 high-risk seronegative drug users in northern Thailand and identified four seronegative cases positive for both assays. Furthermore, we have identified a synonymous mutation in nucleotide position 75 of the gag p17 gene (A426G) of HIV-1 that belongs to the CRF01_AE virus circulating in Thailand. The replication-competent HIV-1 clone containing the A426G mutation demonstrated a dramatic reduction of virion production and perturbation of viral morphogenesis without affecting viral protein synthesis in cells.

DNA, Viral↗
PubMed2006

Induction of positive cellular and humoral immune responses by a prime-boost vaccine encoded with simian immunodeficiency virus gag/pol.

It is believed likely that immune responses are responsible for controlling viral load and infection. In this study, when macaques were primed with plasmid DNA encoding SIV gag and pol genes (SIVgag/pol DNA) and then boosted with replication-deficient vaccinia virus DIs recombinant expressing the same genes (rDIsSIVgag/pol), this prime-boost regimen generated higher levels of Gag-specific CD4+ and CD8+ T cell responses than did either SIVgag/pol DNA or rDIsSIVgag/pol alone. When the macaques were i.v. challenged with pathogenic simian/HIV, the prime-boost group maintained high CD4+ T cell counts and reduced plasma viral loads up to 30 wk after viral challenge, whereas the rDIsSIVgag/pol group showed only a partial attenuation of the viral infection, and the group immunized with SIVgag/pol DNA alone showed none at all. The protection levels were better correlated with the levels of virus-specific T cell responses than the levels of neutralization Ab responses. These results demonstrate that a vaccine regimen that primes with DNA and then boosts with a replication-defective vaccinia virus DIs generates anti-SIV immunity, suggesting that it will be a promising vaccine regimen for HIV-1 vaccine development.

Animals↗
PubMed2006

Intradermal and oral immunization with recombinant Mycobacterium bovis BCG expressing the simian immunodeficiency virus Gag protein induces long-lasting, antigen-specific immune responses in guinea pigs.

To develop a new recombinant BCG (rBCG) vaccine, we constructed rBCG that expresses the full-length Gag protein of simian immunodeficiency virus (rBCG-SIVGag) at a level of 0.5 ng/mg after 3 weeks of bacterial cell culture. Intradermal (i.d.) inoculation of guinea pigs with 0.1 mg of rBCG-SIVGag resulted in the induction of delayed-type hypersensitivity (DTH) responses to both purified protein derivative (PPD) of tuberculin and SIV Gag p27 protein; responses that were maintained for the duration of the 50-week study. In contrast, guinea pigs orally vaccinated with 160 mg of the same antigen exhibited a long-lasting DTH response to the SIV Gag p27 protein, but mounted no response to PPD. Proliferative responses to SIV Gag p27 and PPD antigens were detected in both i.d. and orally immunized animals; however, the levels of PPD-specific responses were significantly higher in guinea pigs immunized by the i.d. than the oral route. A significant increase in the level of PPD- and SIV Gag p27-specific IFNgamma mRNA expression was also detected in both immunization groups receiving rBCG-SIVGag. In addition, both i.d. and oral immunization with rBCG-SIVGag induced PPD- and SIV Gag p27-specific serum IgG responses. Insertion of the SIV gag gene into BCG did not appear to change the ability of rBCG-immunized animals to elicit PPD-specific immune responses. These results indicate that rBCG-SIVGag has the ability to effectively induce long-lasting, cell-mediated and humoral immunity against both viral and bacterial antigens in guinea pigs, suggesting that rBCG-Gag has the potential to elicit immunities specific not only for tuberculosis but also for HIV at human doses.

Administration, Oral↗
PubMed2006

Recombinant vaccinia DIs expressing simian immunodeficiency virus gag and pol in mammalian cells induces efficient cellular immunity as a safe immunodeficiency virus vaccine candidate.

A highly attenuated vaccinia virus substrain of Dairen-I (DIs) shows promise as a candidate vector for eliciting positive immunity against immune deficiency virus. DIs was randomly obtained by serial 1-day egg passages of a chorioarantoic membrane-adapted Dairen strain (DIE), resulting in substantial genomic deletion, including various genes regulating the virus-host-range. To investigate the impact of that deletion and of the subsequent insertion of a foreign gene into that region of DIs on the ability of the DIs recombinant to induce antigen-specific immunity, we generated a recombinant vaccinia DIs expressing fulllength gag and pol genes of simian immunodeficiency virus (SIV) (rDIsSIV gag/pol) and studied the biological and immunological characteristics of the recombinant natural mutant. The rDIsSIV gag/pol developed a tiny plaque on the chick embryo fibroblast (CEF). Viral particles of rDIsSIV gag/pol as well as SIV Gag-like particles were electromicroscopically detected in the cytoplasm. Interestingly, the recombinant DIs strain grows well in CEF cells but not in mammalian cells. While rDIsSIV gag/pol produces SIV proteins in mammalian HeLa and CV-1 cells, recombinant modified vaccinia Ankara strain (MVA) expressing SIV gag and pol genes (MVA/SIV239 gag/pol) clearly replicates in HeLa and CV-1 cell lines under synchronized growth conditions and produces the SIV protein in all cell lines. Moreover, intradermal administration of rDIsSIV gag/pol or of MVA/SIV239 gag/pol elicited similar levels of IFN-gamma spot-forming cells specific for SIV Gag. If the non-productive infection characteristically induced by recombinant DIs is sufficient to trigger immune induction, as we believe it is, then a human immunodeficiency virus vaccine employing the DIs recombinant would have the twin advantages of being both effective and safe.

Animals↗
PubMed2005

Ag85B of mycobacteria elicits effective CTL responses through activation of robust Th1 immunity as a novel adjuvant in DNA vaccine.

CD4+ T cells play a crucial role in CTL generation in a DNA vaccination strategy. Several studies have demonstrated the requirement of CD4+ T cells for the induction of a sufficient immune response by coadministrating DNAs. In the present study we investigated the effectiveness of Ag85B of mycobacteria, which is known to be one of the immunogenic proteins for Th1 development, as an adjuvant of a DNA vaccine. HIV gp120 DNA vaccine mixed with Ag85B DNA as an adjuvant induced HIV gp120-specific Th1 responses, as shown by delayed-type hypersensitivity, cytokine secretion, and increasing HIV-specific CTL responses. Moreover, these responses were enhanced in mice primed with Mycobacterium bovis bacillus Calmette-Guérin before immunization of HIV DNA vaccine mixed with Ag85B DNA. Furthermore, these immunized mice showed substantial reduction of HIV gp120-expressing recombinant vaccinia virus titers compared with the titers in other experimental mice after recombinant vaccinia virus challenge. Because most humans have been sensitized by spontaneous infection or by vaccination with mycobacteria, these findings indicate that Ag85B is a promising adjuvant for enhancing CTL responses in a DNA vaccination strategy.

Acyltransferases↗
PubMed2005

The effect of fosfomycin on nedaplatin-induced nephrotoxicity in rats.

The effect of coadministration of fosfomycin (FOM) on nedaplatin-induced nephrotoxicity in rats was investigated for 6 days. FOM decreased nedaplatin-induced nephrotoxicity, as shown by reduced blood urea nitrogen (BUN), serum creatinine levels, and urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG). Further, there were fewer histopathological signs of nephrotoxicity in the groups treated with the combination of nedaplatin and FOM as compared with the nedaplatin-alone group. The concentration of nedaplatin was significantly lower in the renal cortex of rats treated with the combination of nedaplatin and FOM as compared with those treated with nedaplatin alone (p < 0.05). In conclusion, the concomitant administration of FOM and nedaplatin may help to achieve a chemotherapeutic strategy that reduces the nephrotoxic effects of nedaplatin.

Acetylglucosaminidase↗
PubMed2005

Replication-defective HIV isolated from seronegative individuals at high risk for HIV infection.

We have identified a mutant human immunodeficiency virus type 1 (HIV-1) CRF01_AE that contains a single nucleotide mutation in gag gene from 4 HIV-1 seronegative drug users in Thailand. We found A to G mutation at the nucleotide position 75 of gag p17 gene (A75G) not changing the amino acid sequence. The mutant HIV-1 molecular clones were examined for their replication capability. Although the mutation dramatically reduced the level of virion production, it did not affect the amounts of viral protein synthesis within the transfected cells. In addition, this mutation did not affect the levels of Gag polyproteins. Furthermore, electron microscopic examinations have revealed a dramatic reduction of the virion production and perturbation of viral morphogenesis at the cytoplasmic membrane. These results indicate that the A75G mutation is attributable to the long-term sero-negativity of individuals at high risk of HIV-1 infection and suggest a novel mechanism that regulates HIV production.

Gene Products, gag↗
PubMed2005

Mycobacterial codon optimization enhances antigen expression and virus-specific immune responses in recombinant Mycobacterium bovis bacille Calmette-Guérin expressing human immunodeficiency virus type 1 Gag.

Although its potential for vaccine development is already known, the introduction of recombinant human immunodeficiency virus (HIV) genes to Mycobacterium bovis bacille Calmette-Guérin (BCG) has thus far elicited only limited responses. In order to improve the expression levels, we optimized the codon usage of the HIV type 1 (HIV-1) p24 antigen gene of gag (p24 gag) and established a codon-optimized recombinant BCG (rBCG)-p24 Gag which expressed a 40-fold-higher level of p24 Gag than did that of nonoptimized rBCG-p24 Gag. Inoculation of mice with the codon-optimized rBCG-p24 Gag elicited effective immunity, as evidenced by virus-specific lymphocyte proliferation, gamma interferon ELISPOT cell induction, and antibody production. In contrast, inoculation of animals with the nonoptimized rBCG-p24 Gag induced only low levels of immune responses. Furthermore, a dose as small as 0.01 mg of the codon-optimized rBCG per animal proved capable of eliciting immune responses, suggesting that even low doses of a codon-optimized rBCG-based vaccine could effectively elicit HIV-1-specific immune responses.

AIDS Vaccines↗
PubMed2005

Priming-boosting vaccination with recombinant Mycobacterium bovis bacillus Calmette-Guérin and a nonreplicating vaccinia virus recombinant leads to long-lasting and effective immunity.

Virus-specific T-cell responses can limit immunodeficiency virus type 1 (HIV-1) transmission and prevent disease progression and so could serve as the basis for an affordable, safe, and effective vaccine in humans. To assess their potential for a vaccine, we used Mycobacterium bovis bacillus Calmette-Guérin (BCG)-Tokyo and a replication-deficient vaccinia virus strain (DIs) as vectors to express full-length gag from simian immunodeficiency viruses (SIVs) (rBCG-SIVgag and rDIsSIVgag). Cynomolgus macaques were vaccinated with either rBCG-SIVgag dermally as a single modality or in combination with rDIsSIVgag intravenously. When cynomologus macaques were primed with rBCG-SIVgag and then boosted with rDIsSIVgag, high levels of gamma interferon (IFN-gamma) spot-forming cells specific for SIV Gag were induced. This combination regimen elicited effective protective immunity against mucosal challenge with pathogenic simian-human immunodeficiency virus for the 1 year the macaques were under observation. Antigen-specific intracellular IFN-gamma activity was similarly induced in each of the macaques with the priming-boosting regimen. Other groups receiving the opposite combination or the single-modality vaccines were not effectively protected. These results suggest that a recombinant M. bovis BCG-based vector may have potential as an HIV/AIDS vaccine when administered in combination with a replication-deficient vaccinia virus DIs vector in a priming-boosting strategy.

Animals↗
PubMed2005

Vaccination of rhesus macaques with recombinant Mycobacterium bovis bacillus Calmette-Guérin Env V3 elicits neutralizing antibody-mediated protection against simian-human immunodeficiency virus with a homologous but not a heterologous V3 motif.

Although the correlates of vaccine-induced protection against human immunodeficiency virus type 1 (HIV-1) are not fully known, it is presumed that neutralizing antibodies (NAb) play a role in controlling virus infection. In this study, we examined immune responses elicited in rhesus macaques following vaccination with recombinant Mycobacterium bovis bacillus Calmette-Guérin expressing an HIV-1 Env V3 antigen (rBCG Env V3). We also determined the effect of vaccination on protection against challenge with either a simian-human immunodeficiency virus (SHIV-MN) or a highly pathogenic SHIV strain (SHIV-89.6PD). Immunization with rBCG Env V3 elicited significant levels of NAb for the 24 weeks tested that were predominantly HIV-1 type specific. Sera from the immunized macaques neutralized primary HIV-1 isolates in vitro, including HIV-1BZ167/X4, HIV-1SF2/X4, HIV-1CI2/X4, and, to a lesser extent, HIV-1MNp/X4, all of which contain a V3 sequence homologous to that of rBCG Env V3. In contrast, neutralization was not observed against HIV-1SF33/X4, which has a heterologous V3 sequence, nor was it found against primary HIV-1 R5 isolates from either clade A or B. Furthermore, the viral load in the vaccinated macaques was significantly reduced following low-dose challenge with SHIV-MN, and early plasma viremia was markedly decreased after high-dose SHIV-MN challenge. In contrast, replication of pathogenic SHIV-89.6PD was not affected by vaccination in any of the macaques. Thus, we have shown that immunization with an rBCG Env V3 vaccine elicits a strong, type-specific V3 NAb response in rhesus macaques. While this response was not sufficient to provide protection against a pathogenic SHIV challenge, it was able to significantly reduce the viral load in macaques following challenge with a nonpathogenic SHIV. These observations suggest that rBCG vectors have the potential to deliver an appropriate virus immunogen for desirable immune elicitations.

AIDS Vaccines↗
PubMed2005

The role of the Tat gene in the pathogenesis of HIV infection.

The human immunodeficiency virus Tat regulatory protein is essential for virus replication and for the efficient transcription of HIV-1 provirus, and in the pathogenesis of AIDS. The role of the tat gene was investigated in 300 samples. It was found that 71.7% were subtype CRF_01AE, 9.3% were subtype B, while 11.7 and 7.3% of them were cross-reactive and non-typeable, respectively. Moreover the results from peptide ELISA also showed that a low CD4 cell count was related to a low anti-Tat antibody (p < 0.05), which may be due to the progression of HIV-1, which can be found predominantly in AIDS patients. The results of nested PCR showed that the second Tat exon might also play a role in T-cell activation. Reverse transcription polymerase chain reaction (RT-PCR) was used to measure HIV-1 mRNA expression in PBMC. RT-PCR negative results were found mostly in the asymptomatic HIV-seropositive group (88%). HIV-1 mRNA expression was found to correlate with current immunologic status. The differences in Tat protein sequences from DNA sequencing between the patients who had anti-Tat antibody positive and anti-Tat antibody negative, were not significant (p > 0.05). These results suggested that the Tat amino acid sequences were conserved among each group of samples and did not change significantly compared with the consensus sequence in previous studies. Several factors make Tat an attractive target for vaccine design.

Adult↗
PubMed2005

Specific immune response and pathological findings in BALB/c mice inoculated with recombinant BCG expressing HIV-1 antigen.

Recombinant BCGs (rBCGs) containing extrachromosomal plasmids with different HIV-1 insert sequences: nef, env (V3J1 and E9Q), gag p17 or whole gag p55 were evaluated for their immunogenicity, safety and persistent infection in BALB/c mice. Animal injected with, rBCG-plJKV3J1, rBCG-pSO gag p17 or rBCG-pSO gag p55 could elicit lymphocyte proliferation as tested by specific HIV-1 peptides or protein antigen. Inoculation with various concentration of rBCG-pSO gag p55 generated satisfactory specific lymphocyte proliferation in dose escalation trials. The rBCG-pSO gag p55 recovered from spleen tissues at different time interval post-inoculation could express the HIV protein as determined by ELISA p24 antigen detection kit. This result indicated that the extrachromosomal plasmid was stable and capable to express Gag protein. It was also demonstrated that rBCGs did not cause serious pathological change in the inoculated animals. The present study suggested the role of BCG as a potential vehicle for using in HIV vaccine development.

Animals↗
PubMed2004

Determination of HIV type 1 CRF01_AE gag p17 and env-V3 consensus sequences for HIV/AIDS vaccine design.

A molecular epidemiological study of the gag p17 and env-V3 regions on HIV-infected drug users and blood donors was carried out in northern Thailand from 1998 through 2002 to determine the predominant subtype and consensus sequence (CS) for circulating HIV-1 strains. CRF01_AE was concluded to be a predominant strain and the nucleotide CSs in gag p17 and env-V3 showed only 1.26% and no difference from CS in the Los Alamos database, respectively. Our env-V3 CS was identical to the previously published CSs, suggesting that the CS was very conserved from 1990 through 2002 in Thailand. Gag p17 and env-V3 nucleotide sequences of seroconvertors in our subjects were quite similar to the CS and conserved for at least 9 and 6 years postinfection, respectively. These results suggest that the CS approach to the HIV-1 antigen design could overcome HIV diversity and help us develop an effective HIV/AIDS vaccine.

AIDS Vaccines↗
PubMed2004

A consecutive priming-boosting vaccination of mice with simian immunodeficiency virus (SIV) gag/pol DNA and recombinant vaccinia virus strain DIs elicits effective anti-SIV immunity.

To evaluate immunity induced by a novel DNA prime-boost regimen, we constructed a DNA plasmid encoding the gag and pol genes from simian immunodeficiency virus (SIV) (SIVgag/pol DNA), in addition to a replication-deficient vaccinia virus strain DIs recombinant expressing SIV gag and pol genes (rDIsSIVgag/pol). In mice, priming with SIVgag/pol DNA, followed by rDIsSIVgag/pol induced an SIV-specific lymphoproliferative response that was mediated by a CD4+-T-lymphocyte subset. Immunization with either vaccine alone was insufficient to induce high levels of proliferation or Th1 responses in the animals. The prime-boost regimen also induced SIV Gag-specific cellular responses based on gamma interferon secretion, as well as cytotoxic-T-lymphocyte responses. Thus, the regimen of DNA priming and recombinant DIs boosting induced Th1-type cell-mediated immunity, which was associated with resistance to viral challenge with wild-type vaccinia virus expressing SIVgag/pol, suggesting that this new regimen may hold promise as a safe and effective vaccine against human immunodeficiency virus type 1.

AIDS Vaccines↗
PubMed2003

Immunization with recombinant Calmette-Guerin bacillus (BCG)-hepatitis C virus (HCV) elicits HCV-specific cytotoxic T lymphocytes in mice.

Since virus-specific cytotoxic T lymphocytes (CTLs) play a critical role in preventing the spread of hepatitis C virus (HCV), an effective HCV vaccine should be capable of eliciting HCV-specific CTLs. In the present study, we assessed the capability of a novel recombinant vaccine using an attenuated tuberculosis bacillus, Calmette-Guerin bacillus (BCG), as a vaccine vehicle to elicit HCV-specific CTLs. BCG was engineered to express the CTL epitope of HCV-non-structure protein 5a (NS5a) as a chimeric protein with alpha antigen of mycobacteria. Immunization with this recombinant BCG elicited major histocompatibility complex class I-restricted CD8(+) HCV-NS5a-specific CTLs in mice. Immunized mice showed a substantial reduction in the vaccinia virus titer compared with control mice when the immunized mice were challenged with a recombinant vaccinia virus expressing HCV-NS5a genes. These findings provide evidences for the possibility of BCG as a vaccine vector and its continued exploration as a vehicle for eliciting HCV-specific immunity.

Animals↗
PubMed2003

Intravenous inoculation of replication-deficient recombinant vaccinia virus DIs expressing simian immunodeficiency virus gag controls highly pathogenic simian-human immunodeficiency virus in monkeys.

To be effective, a vaccine against human immunodeficiency virus type 1 (HIV-1) must induce virus-specific T-cell responses and it must be safe for use in humans. To address these issues, we developed a recombinant vaccinia virus DIs vaccine (rDIsSIVGag), which is nonreplicative in mammalian cells and expresses the full-length gag gene of simian immunodeficiency virus (SIV). Intravenous inoculation of 10(6) PFU of rDIsSIVGag in cynomologus macaques induced significant levels of gamma interferon (IFN-gamma) spot-forming cells (SFC) specific for SIV Gag. Antigen-specific lymphocyte proliferative responses were also induced and were temporally associated with the peak of IFN-gamma SFC activity in each macaque. In contrast, macaques immunized with a vector control (rDIsLacZ) showed no significant induction of antigen-specific immune responses. After challenge with a highly pathogenic simian-human immunodeficiency virus (SHIV), CD4(+) T lymphocytes were maintained in the peripheral blood and lymphoid tissues of the immunized macaques. The viral set point in plasma was also reduced in these animals, which may be related to the enhancement of virus-specific intracellular IFN-gamma(+) CD8(+) cell numbers and increased antibody titers after SHIV challenge. These results demonstrate that recombinant DIs has potential for use as an HIV/AIDS vaccine.

AIDS Vaccines↗
PubMed2002

Combined intrarectal/intradermal inoculation of recombinant Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces enhanced immune responses against the inserted HIV-1 V3 antigen.

The development of a successful recombinant Mycobacterium bovis bacillus Calmette-Guérin (rBCG) vector-based vaccine for human immunodeficiency virus type 1 (HIV-1) requires the induction of high levels of HIV-1-specific immunity while at the same time maintaining immunity to tuberculosis. To examine a combined vaccination strategy for enhancement of immune responses specific for HIV-1, guinea pigs were inoculated with either a single or combination intradermal (i.d.), intrarectal (i.r.) and intranasal (i.n.) administration of rBCG-pSOV3J1 which secretes a chimeric protein of HIV-1 V3J1 peptide and alpha-antigen. Significant level of delayed-type hypersensitivity to both V3J1 peptide and tuberculin was induced in guinea pigs inoculated with human doses of rBCG-pSOV3J1 by a combination of intrarectal and intradermal routes. Guinea pigs inoculated by combined routes also had significantly higher titers of HIV-1-specific serum IgG and IgA compared with those animals immunized only intrarectally, which led to the enhanced neutralization activity against HIV-1(MN). In addition, the induction of high levels of IFNgamma and interleukin-2 (IL-2) mRNA in PBMC, splenocytes, and intraepithelial lymphocytes from the immunized animals was detected until at least 110 weeks post-inoculation. These results suggest that enhanced immune responses specific for HIV-1 are efficiently induced by combined intrarectal and intradermal immunization with rBCG-HIV, and antigen-specific Th1-type memory cells are maintained for more than 2 years in the immunized animals. Thus, inoculation with rBCG-HIV by combined routes represents an effective vaccination strategy to elicit high levels of HIV-1-specific immune responses.

AIDS Vaccines↗