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Biomedical subjects

M Hayami

Publications and source records attributed to M Hayami.

At least 145 records · Page 8Linked to original sources
PubMed1990

Multiple antigenic epitopes expressed on gag proteins, p26 and p15, of a human immunodeficiency virus (HIV) type 2 as defined with a library of monoclonal antibodies.

Thirty-two hybridoma clones producing monoclonal antibody (MAb) against HIV-2[GH-1] were established from mice immunized with NP-40-disrupted purified whole virus of a Ghanaian isolate of human immunodeficiency virus type 2 (HIV-2), strain HIV-2[GH-1]. Of these 32 MAbs, 20 reacted with p26 and the other MAbs recognized p15 of the HIV-2[GH-1] isolate. From the results of serological characterization by these MAbs, p26 and p15 were identified as capsid proteins and matrix protein, respectively, of HIV-2[GH-1] gag products. In addition to two gag proteins, a 55-kD protein corresponding to the primary translational product of gag gene and 39-kD protein corresponding to an intermediate product of cleavage of p55 were recognized by these MAbs in the lysate of HIV-2[GH-1]-infected cells. Moreover, these MAbs were used to analyze the number of antigenic epitopes on p26 and p15 of HIV-2[GH-1] isolate. The results of cross-reactivity with different HIV-1, HIV-2, and simian immunodeficiency virus (SIV) isolates and competitive binding assay suggest that there are at least four and five antigenic epitopes in p26 and p15, respectively, of the HIV-2[GH-1] isolate. The biological activity of MAbs was studied by performing syncytium inhibition assay and infection inhibition assays. However, our MAbs could not inhibit syncytium formation and infection by cell-free virus.

Animals↗
PubMed1990

Heterogeneity of antigen molecules recognized by anti-tax1 monoclonal antibody Lt-4 in cell lines bearing human T cell leukemia virus type I and related retroviruses.

Using a monoclonal antibody, Lt-4, directed against human T cell leukemia virus type I (HTLV-I) trans-activator (tax1) antigen, we examined the expression of tax1 and related antigens in a variety of T cell lines bearing HTLV-I and related retroviruses, simian T cell leukemia virus type I (STLV-I) and HTLV-II, by immunofluorescence and immunoblot assays. Lt-4 reacted with all HTLV-I-bearing cell lines tested and five out of eight simian cell lines bearing STLV-I, but not with an HTLV-II-bearing cell line. Lt-4 detected 40 kd tax1 antigen molecules in most HTLV-I-bearing cell lines except one cell line that expressed 39 kd tax1 antigen. In the STLV-I-bearing T cell lines, tax1-related antigen molecules detected by Lt-4 were heterogeneous, having molecular weights in the range of 36-41 kd.

Animals↗
PubMed1990

Antibody to HTLV-I in indigenous inhabitants of the Andes and Amazon regions in Colombia.

To explore the HTLV-I-carrying groups among the indigenous inhabitants in South America, a sero-epidemiological study on HTLV-I focusing on hinterland villages isolated from others in the Andes and Amazon regions was conducted. Five (2.9%) out of 171 subjects showed positive for HTLV-I antibody in the gelatin particle agglutination (PA) test. Two out of 5 positives with high antibody titer (greater than or equal to x 1024) in the PA test also showed a positive immunofluorescence (IF) test and anti-HTLV-I-specific protein products, p19, p24, p28, gp46, and p53 in sera by the Western blotting (WB) test. One of three negatives in the IF test showed positive antibodies to p19 and p24 by the WB test. Finally, two were confirmed as HTLV-I carriers and one was suspected of being a carrier. All three are Paez Indians from the central Andes; 53- and 34-year-old women and a 35-year-old man. The results show that HTLV-I carriers exist among isolated indigenous people in South America.

Adult↗
PubMed1990

Construction and characterization of an infectious DNA clone and of mutants of simian immunodeficiency virus isolated from the African green monkey.

We constructed a full-length molecular clone of simian immunodeficiency virus from an African green monkey. Upon transfection, this clone directed the production of virus particles cytopathic and infectious to human CD4+ leukemia cell lines. Mutations were introduced by recombinant DNA techniques into eight open reading frames of simian immunodeficiency virus from the African green monkey thus far identified. The phenotypes of mutant viruses, i.e., infectivity, cytopathogenicity, transactivation of gene expression controlled by a long terminal repeat, and viral RNA and protein syntheses, were examined by transfection and infection experiments. Three structural (gag, pol, and env) and two regulatory (tat and rev) gene mutants were not infectious, whereas vif, vpx, and nef were dispensable for infectivity and mutant viruses were highly cytopathic. In transient transfection assays, a rev mutant produced mainly small mRNA species and no detectable virus protein and particles. The transactivation potential of a tat mutant was about 10-fold less than that of wild-type DNA, generating small amounts of virus.

Animals↗
PubMed1990

Generation and characterization of infectious chimeric clones between human immunodeficiency virus type 1 and simian immunodeficiency virus from an African green monkey.

A series of chimeric clones of human immunodeficiency virus type 1 and simian immunodeficiency virus isolated from an African green monkey was constructed in vitro. In transient transfection experiments, all clones produced virion-associated reverse transcriptase, gag proteins, and env proteins. Eight out of 10 chimeric viruses clearly grew in the human CD4+ cell line C8166. Susceptibility of other CD4+ cell lines, MT-4, A3.01, and Molt4 clone 8, to infection with these viruses was also demonstrated.

Animals↗
PubMed1990

Mutational analysis of the human immunodeficiency virus type 2 (HIV-2) genome in relation to HIV-1 and simian immunodeficiency virus SIV (AGM).

We constructed an infectious molecular clone of the human immunodeficiency virus type 2 (HIV-2) and generated nine frameshift mutants corresponding to nine open reading frames identified so far. Three structural (gag, pol, env) and two regulative (tat, rev) gene mutants were not infectious, whereas vif, vpx, vpr, and nef genes were dispensable for infectivity. All of the mutants except env and rev were cytopathic in CD4+ human leukemia cells. In transfection assays, the expression of HIV-2 long terminal repeat was activated by infectious clones of HIV-1, HIV-2, and simian immunodeficiency virus from African green monkey but not by the tat mutants. However, an HIV-2 tat mutant could produce small amounts of virus proteins and particles in contrast to a rev mutant, which directed no detectable synthesis of virus proteins and virions.

Blotting, Northern↗
PubMed1990

Complementation of the rev gene mutation among human and simian lentiviruses.

The functional exchangeability of the rev gene was assessed in transient transfection experiments by using in vitro-constructed rev and gag mutants of the following three primate lentiviruses: human immunodeficiency virus type 1 (HIV-1), HIV-2, and simian immunodeficiency virus from the African green monkey (SIV AGM). Cotransfection into SW480 cells of the rev and gag mutants derived from the DNA of each infectious virus resulted in the generation of progeny particles as determined by reverse transcriptase assay. rev gene mutants of HIV-2 and SIV AGM were also complemented by all gag mutants derived from the three viruses. In contrast, no evidence of complementation was obtained following cotransfection of the HIV-1 rev mutant and the gag mutant of HIV-2 or SIV AGM.

Amino Acid Sequence↗
PubMed1990

Mutational analysis of simian immunodeficiency virus from African green monkeys and human immunodeficiency virus type 2.

We constructed ten mutants of simian immunodeficiency virus isolated from African green monkey (SIVAGM), and nine mutants of human immunodeficiency virus type 2 (HIV-2) in vitro. Their infectivity, cytopathogenicity, transactivation potential, virus RNA, and protein synthesis were examined by transfection and infection experiments. Mutations in three structural (gag, pol, env) and two regulator (tat, rev) genes abolished the infectivity of both viruses, but vpx, vpr (HIV-2), and nef were dispensable and mutant viruses were indistinguishable phenotypically from wild type virus. A vif mutant of HIV-2 showed poor infectivity in cell-free condition, whereas SIVAGM mutants grew equally well with wild type virus. In transient transfection assays, rev mutants derived from both viruses produced mainly small mRNA species and no detectable virus proteins and particles. Transactivation potential of tat mutants originated from both viruses was about three- to ten-fold less than that of respective wild type DNAs, generating small amounts of virus.

Animals↗
PubMed1989

Sequence of a novel simian immunodeficiency virus from a wild-caught African mandrill.

Since the isolation of an HIV-2-related virus from captive macaques (SIVMAC), the origin of human immunodeficiency viruses, a much debated subject, has been attributed to monkeys. The sequence of SIVAGM, which is derived from a naturally infected African green monkey, shows equal relatedness to HIV-1 and HIV-2, suggesting that the derivation of these viruses from SIVAGM is unlikely. Recent sequence analysis of SIV from a captive sooty mangabey (SIVMAC), however, shows its close relatedness to HIV-2 and SIVMAC, indicating a possible origin of HIV-2 and SIVMAC from SIVSM (refs 4, 7, 9). We report here the sequence of a novel simian lentivirus, SIVMND, isolated from a wild-caught mandrill in Africa. It is distinct from the three other main groups, HIV-1, HIV-2/SIVMAC/SIVSM and SIVAGM, and therefore represents a fourth main group of primate lentiviruses. Phylogenetic analysis indicates that these four main virus groups might have diverged from a common ancestor at about the same time, long before the spread of AIDS in humans.

Animals↗
PubMed1989

Molecular cloning of a feline leukemia provirus integrated adjacent to the c-myc gene in a feline T-cell leukemia cell line and the unique structure of its long terminal repeat.

This paper reports the molecular cloning of a rearranged c-myc region from the FT-1 cell line, which was derived from a spontaneous feline T-cell leukemia carrying the feline leukemia virus (FeLV). An abnormal c-myc EcoRI fragment of about 18 kilobases, detected by Southern blotting, was molecularly cloned from the DNA of the FT-1 cell line. The c-myc rearrangement in FT-1 was due to direct integration of the FeLV provirus genome immediately upstream of the c-myc gene in the opposite transcriptional orientation. Nucleotide sequencing showed that the LTR of this provirus had three copies of an enhancer-like sequence, unlike the sequences of FeLVs reported previously, which have only a single copy of this enhancer-like sequence.

Base Sequence↗
PubMed1989

Genomic divergence of HIV-2 from Ghana.

Genetic variability in human immunodeficiency virus type 1 (HIV-1) has been studied extensively, but the total nucleotide sequence of the HIV-2 genome has been reported only in two strains. For phylogenetic analyses of HIV, the genetic variability of HIV-2 should be investigated. This paper reports the complete nucleotide sequence of an HIV-2 isolate from Ghana, HIV-2[GH-1]. This virus showed approximately 85% homology in overall nucleotide sequence with HIV-2ROD. The amino acid sequence of the gag and pol proteins of HIV-2[GH-1] showed 90% homology with those of HIV-2ROD, but its env gene and central regions were highly variable (more than 20% divergence in amino acids), indicating the presence of extensive genetic heterogeneity in HIV-2. However, the sequences with specific functions were relatively well conserved in these HIV-2 isolates.

Amino Acid Sequence↗
PubMed1989

Presence of antibody to human herpesvirus 6 in monkeys.

A serological survey of monkeys was conducted to determine the prevalence of antibody to human herpesvirus 6 (HHV-6). Two-hundred and fifteen sera from 10 species of monkeys were examined by an immunofluorescent antibody (IF) assay. The antibody was found in monkeys from eight of the 10 species examined, but was not detected in silvered lutongs or cotton-top tamarins. The prevalence of antibody was highest in squirrel monkeys. Sera with high antibody titres were examined further by Western blot analysis and the neutralizing antibody test and the antibody levels were compared with that from a patient with exanthem subitum. On Western blotting, monkey and human sera that were antibody-positive to HHV-6 antigen gave similar reactions with antigen components of almost the same Mr. Furthermore, sera that were antibody-positive by the IF test were also positive by the neutralizing antibody test and their titres in the two tests were comparable. These results suggest the existence of HHV-6 or an HHV-6-related virus in monkeys.

Animals↗
PubMed1989

Experimental infection of rhesus monkeys with SIV isolated from African green monkeys.

To establish an animal model for AIDS, 6 juvenile rhesus monkeys were infected intravenously with cell-free SIVagmTYO-1, 5, or 7. One animal was infected with SIV of known pathogenicity isolated from a sooty mangabey (SIVsmm). The 2 animals infected with TYO-1, 1 of 2 infected with TYO-7 and the 1 infected with SIVsmm seroconverted within 4-8 weeks after infection and infectious virus could be recovered 8-10 or 44 weeks after infection. Three of the 4 seroconverted monkeys developed a persistent lymphadenopathy 12 weeks after infection. Rhesus monkeys infected with SIVagm could serve as a model to study HIV infection and for vaccine trials.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Genetic analysis and infection of SIVAGM and SIVMND.

Recently, the authors determined the partial sequence of simian immunodeficiency virus (SIV) from the mandrill (SIVMND) and found SIVMND to be a new member of the HIV/SIV group, equidistant from other members, including SIVAGM. Experimentally, the African green monkey and cynomolgus monkey could be infected with SIVAGM and the cottontop tamarin with SIVMND. However, no clinical sign of an AIDS-like disease was observed in these monkeys.

Animals↗