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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The free-ranging population of rhesus monkeys (Macaca mulatta) on Cayo Santiago was sero-surveyed for human measles, simian virus 40, B virus (Herpes simiae), rhesus cytomegalovirus, human and simian retroviruses and encephalomyocarditis virus to determine the prevalence of these viruses in the colony. The results of this study indicate that the colony is free of SV40, HTLVIII (HIV-1), STLVIII (SIV) and SRV1; has a low prevalence of measles and EMCV; and high prevalence rates for B virus, CMV and HTLVI.
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PMID:Serological survey for viral diseases in the Cayo Santiago rhesus macaque population. 257 Nov 76

To investigate the function of vpx, a gene in HIV-2 and SIV, but not in HIV-1, three site-directed mutants (pMX) were constructed from a functional proviral HIV-2 plasmid clone (pSE). Transfection of COS-1 cells with all three mutants as well as pSE gave rise to equivalent amounts of virus. Each virus could be passaged in H9 and CEM lymphoid cell lines, peripheral blood lymphocytes, and monocytes with equal efficiency and demonstrated similar cytopathic effects. Hybridization data with DAN from the infected cells demonstrated the presence of similar levels of viral sequences and the mutations in each of the MX-infected cell lines. Immunoprecipitation analysis demonstrated a 16-kDa VPX protein in cells infected with SE virus, as well as in the virus particles, but not in cells infected with MX viruses or the particles themselves. However, equivalent levels of gag and env proteins were demonstrated in all infected cells and virion preparations. These data suggest that VPX is dispensable for virus replication and cytopathicity.
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PMID:Analysis of the function of viral protein X (VPX) of HIV-2. 259 32

Two categories of obstacles impede the development of an AIDS vaccine. Virological obstacles are due to lentiviruses, to which HIV and SIV belong, having developed strategies to escape the immune responses of infected hosts and establish persistent infection. These strategies are based on two mechanisms: latency corresponding to restriction of viral gene expression that renders the virus antigenically invisible, and variability, the consequences of which are antigenic shift and permanent adaptation to selective pressures. Immunological obstacles are linked to a central unanswered question: is the global effect of the immune response against HIV beneficial or deleterious to the host and, if beneficial, is it able to resist the virally induced immunosuppression? These obstacles are difficult to overcome theoretically and empirical trials are necessary; live attenuated or recombinant vaccines, inactivated vaccines, subunit vaccines, anti-idiotypes, and synthetic and chimeric vaccines are currently being tested in animals or in humans. At present, promising results have been obtained with inactivated virus vaccines with the use of macaque monkeys infected by SIV as a model.
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PMID:AIDS vaccines: concepts and first trials. 269 45

Institute for Virus Research, Kyoto University, and Noguchi Memorial Research Institute in Ghana jointly isolated HIV-2 from a Ghanaian AIDS patient. Ghanaian HIV-2[GH-1] was similar in genomic organization to, but different in Restriction Enzyme Maps from the first isolated case, French LAV-2 (HIV-2ROD). This fact is significant in suggesting multiplicity of HIV-2 virus. HIV-2[GH-1] was different from LAV-2 in its antigenicity of envProtein. Sero-reactive patterns of 125 Ghanaians including 57 AIDS/ARC patients were analyzed using HIV-1, HIV-2, and SIVAGM as antigen. 4 groups were recognized. Group I was HIV-1 only positive; Group II, HIV-2-only positive; Group III, mixed HIV-1 and HIV-2 positive; Group IV reacted to gag protein of HIV-1, HIV-2 and SIVAGM but not to envProtein of any. 24 Ghanians were HIV-1 positive; 38 were HIV-2 positive. 19 out of 20 HIV-2-only positive patients were AIDS/ARC patients. Symptoms and route of infection from HIV-1 and HIV-2 AIDS seem to be similar but HIV-2 is weaker pathologically and in communicability. HIV positive patients were mostly found in the big city such as Accra among young women, especially prostitutes who were migratory "workers" in neighboring countries along the Ivory Coast. Sero-reactive patterns of Ghanaians with SIV as antigen had been known for some time to be different from those of Kenyans in the east coast and those of Gabonese. While KEnyan's antibody was high for HIV-1 and lower for SIVAGM, Ghanian's was higher for SIVAGM than HIV-1. Gabonese's was in between. With discovery of LAV-2 (HIV-2ROD) and Ghanian hybridization with its DNA probe Ghanaian's was found to have among other things VPX and VPR in common with HIV-2ROD.
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PMID:[Isolation of HIV-2 from AIDS patient in Ghana and analysis of sero-reactive patterns of Ghanaian sera]. 272 59

Nucleotide sequence comparison between HIV-1, HIV-2 and SIV has revealed the presence of an open reading frame (ORF) in the central region of the genomes of HIV-2 and SIV that has no counterpart in HIV-1. This new ORF, called vpx, is highly conserved between HIV-2ROD and SIVmac. Using anti-peptide sera to the predicted protein and site-directed mutagenesis, we show that mutations in the vpx ORF eliminate the synthesis of a 16 kd protein in HIV-2 infected cells, confirming that this protein is the product of this gene. Full-length clones of HIV-2 containing these mutations are infectious in two permanent T lymphocytic cell lines and two monocytic cell lines. In contrast, we show that loss of VPX function results in a severe defect in the productive infection of human peripheral blood lymphocytes both in the amount of reverse transcriptase activity produced and in core protein expression. These findings suggest that the VPX protein plays an important role in the in vivo life cycle of the HIV-2/SIV viruses.
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PMID:VPX mutants of HIV-2 are infectious in established cell lines but display a severe defect in peripheral blood lymphocytes. 274 77

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.
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PMID:Sequence of a novel simian immunodeficiency virus from a wild-caught African mandrill. 279 81

An important point of regulation in the reproductive growth and latency of the human and simian immunodeficiency viruses (HIV and SIV, respectively) is provided by virally encoded trans-activators (tat), proteins capable of dramatically increasing viral gene expression. The mechanism of this autostimulatory pathway has remained unclear, however, with substantial effects having been reported at the level of either mRNA accumulation, translational efficiency, or both. Our previous findings indicated that trans-activation results primarily from induction of RNA levels but could not distinguish between the roles of transcriptional rate, RNA stabilization, and RNA transport in this event. In addition, the boundaries of tat-responding elements, which would be valuable in elucidating the mode of tat action, are not precisely known. In this study, HIV-1 and HIV-2 long terminal repeat-directed expression was characterized by using an in vitro nuclear transcription assay to clarify this mechanism, and a detailed mutational analysis was undertaken to localize precisely the sequences participating in this process. Two key findings were revealed: an increased transcription rate was the primary event in tat-mediated activation of HIV-1 and HIV-2, and trans-activation was impaired by mutations in two regions, the TATA box and sequences between +19 to +42, a region lacking enhancer activity. These results implicate a discrete 3' regulatory element in the transcriptional activation of the HIVs.
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PMID:A discrete element 3' of human immunodeficiency virus 1 (HIV-1) and HIV-2 mRNA initiation sites mediates transcriptional activation by an HIV trans activator. 284 83

The genomic organization of HIV-1 and the family of HIV-2 and SIV viruses is similar. However, there is an open reading frame, orf-x, that is present in HIV-2 and SIV, but not in HIV-1. The extent of protein sequence conservation in orf-x between HIV-2ROD and SIVMAC suggests that this open reading frame encodes a gene that may be important for infectivity or replication. Here, we show that the orf-x products of SIVMAC and HIV-2SBL-6669 are virion-associated and that the introduction of a premature stop codon into orf-x, did not abrogate virus infectivity and replication in vitro. Antibody reactivity to the orf-x product was detected in 35 of 42 HIV-2 positive serum samples and 11 of 52 SIV seropositive monkeys. No such antibodies were detected in HIV-1 positive donors, blood donors seronegative for both HIV-2 and HIV-1, or SIV seronegative monkeys. This suggests that orf-x is dispensable for in vitro replication of SIVMAC and that the orf-x gene product of HIV-2 or its antibody can be used to distinguish HIV-2 from HIV-1 infection.
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PMID:A naturally immunogenic virion-associated protein specific for HIV-2 and SIV. 284 94

Human immunodeficiency virus 1 (HIV-1) is the aetiological agent of AIDS. The virus establishes lytic, latent and non-cytopathic productive infection in cells in culture. The complexity of virus-host cell interaction is reflected in the complex organization of the viral genome. In addition to the genes that encode the virion capsid and envelope proteins and the enzymes required for proviral synthesis and integration common to all retroviruses, HIV-1 is known to encode at least four additional proteins that regulate virus replication, the tat, art, sor and 3' orf proteins, as well as a protein of unknown function from the open reading frame called R. Close examination of the nucleic acid sequences of the genomes of multiple HIV isolates raised the possibility that the virus encodes a previously undetected additional protein. Here we report that HIV-1 encodes a ninth protein and that antibodies to this protein are detected in the sera of people infected with HIV-1. This protein distinguishes HIV-1 isolates from the other human and simian immunodeficiency viruses (HIV-2 and SIV) that do not have the capacity to encode a similar protein.
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PMID:Identification of a protein encoded by the vpu gene of HIV-1. 304 30

The HIV-2 genome contains an open reading frame (designated X-orf) that does not have a counterpart in HIV-1. To establish whether X-orf is a gene, we studied its expression in HIV-2-infected individuals and in infected cells in vitro. An HIV-2 proviral DNA fragment containing the X-orf was expressed in E. coli, and the recombinant protein was used in an immunoblot assay. The X-orf protein was recognized specifically by the sera of HIV-2-infected people but not by the sera of SIV-infected monkeys or HIV-1-infected humans. A rabbit antiserum raised against the recombinant X-orf protein recognized a 16 kD protein in HIV-2-infected cells. The native X-orf protein was not glycosylated or phosphorylated, was localized in the cytoplasm of HIV-2-infected cells, and appeared to be associated with mature virions.
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PMID:The human immunodeficiency virus type 2 (HIV-2) contains a novel gene encoding a 16 kD protein associated with mature virions. 306 15


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