UMLS:C0019693 - FACTA Search

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Query: UMLS:C0019693 (HIV)
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Beside the risk of infection via HIV-1-contaminated blood, ophthalmologists are especially interested in the possibility of HIV-1 infection via tears. Therefore we tried to isolate HIV-1 from tears of 50 HIV-1-infected persons in different stages of disease by reverse transcriptase (RT) and by p24-antigen (p24-AG) in the cultures. Simultaneously we tried to isolate HIV-1 in the supernatant from peripheral blood lymphocytes (PBL), which was successful in 32 of the 50 examined specimens. HIV-1 could not be isolated from the tears of these persons. In addition, polymerasechain-reaction (PCR) was performed to detect proviral sequences (gag, pol, env) of HIV-1 in tears and blood of ten HIV-1-infected patients. While in all the examined patients gag, pol and env could be detected in the blood samples, only one tear sample was found positive for gag and pol DNA fragments. These results indicate that tears of HIV-1-positive contain extremely low quantities of tissue culture infectious doses (TCID) of HIV-1 in contrast to PBL. HIV-1 infection via tears therefore appears to be unlikely.
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PMID:Infrequent detection of HIV-1 components in tears compared to blood of HIV-1-infected persons. 138 31

The proteolytic cleavage sites of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein precursor gp160 and the fusion protein of respiratory syncytial virus (RSV) show a sequence homology. To study this homology two synthetic peptides corresponding to HIV-1-env-gp160-aa 507-518 (KAKRRVVQREKR) and RSV-F2-aa 130-136 (SKKRKRR) were synthesized. Human serum samples from HIV-positive or RSV-positive collections recognized the appropriate peptide in 90.6 or 37.2% respectively. No cross-reactivity towards the nonhomologous peptide could be monitored in both serum collections. In contrast, antipeptide antibodies raised against both peptides demonstrate a high degree of cross-reactivity. These data indicate that the high specificity of the virus-induced antibodies may be a result of strong conformational restrictions at the proteolytic cleavage site of both proteins. Moreover, these observations are important for diagnostic purposes. Synthetic peptides are a valuable tool for HIV antibody screening. Our data provide information concerning the specificity of antigen-antibody interaction on a highly immunogenic HIV-1 epitope.
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PMID:Epitopes at the proteolytic cleavage sites of HIV-1-gp120 and RSV-F protein share a sequence homology: comparative studies with virus-induced and antipeptide antibodies. 138 56

In vivo priming of CTL requires the association with MHC class I molecules of peptides derived from the processing of endogenously produced proteins. Immunization with exogenous proteins or peptides rarely induces MHC class I-restricted CTL unless they are associated with lipidic compounds. The capacity to induce CTL was compared in synthetic peptides and simple lipopeptides containing the Immunodominant MHC class I H-2Dd-restricted T-cell epitope of HIV-1 gp160. In contrast with free peptides in saline, lipopeptides induced strong primary CTL responses in vivo. These CTL were able to lyse cells infected with a recombinant vaccinia virus expressing the HIV-1 env gene. Priming of CTL was also successful when using 16-amino acid lipopeptides as 34-amino acid lipopeptides, suggesting that several epitopes might be included in a single construct. In vivo priming of CTL also requires CD4+ T cell help. We therefore searched for Th cell activation after priming with lipopeptides. Our results show that, as with CTL induction, Th cell activation with lipopeptides did not require mixing with adjuvant. In addition, lipopeptides were also efficient at stimulating antibody-mediated responses. Our results show that a single lipopeptidic construct can induce a total immune response, which is of importance in vaccine development.
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PMID:Immunization of mice with lipopeptides bypasses the prerequisite for adjuvant. Immune response of BALB/c mice to human immunodeficiency virus envelope glycoprotein. 138 24

Previous studies of the genetic and biologic characteristics of human immunodeficiency virus type 1 (HIV-1) have by necessity used tissue culture-derived virus. We recently reported the molecular cloning of four full-length HIV-1 genomes directly from uncultured human brain tissue (Y. Li, J. C. Kappes, J. A. Conway, R. W. Price, G. M. Shaw, and B. H. Hahn, J. Virol. 65:3973-3985, 1991). In this report, we describe the biologic properties of these four clones and the complete nucleotide sequences and genome organization of two of them. Clones HIV-1YU-2 and HIV-1YU-10 were 9,174 and 9,176 nucleotides in length, differed by 0.26% in nucleotide sequence, and except for a frameshift mutation in the pol gene in HIV-1YU-10, contained open reading frames corresponding to 5'-gag-pol-vif-vpr-tat-rev-vpu-env-nef-3' flanked by long terminal repeats. HIV-1YU-2 was fully replication competent, while HIV-1YU-10 and two other clones, HIV-1YU-21 and HIV-1YU-32, were defective. All three defective clones, however, when transfected into Cos-1 cells in any pairwise combination, yielded virions that were replication competent and transmissible by cell-free passage. The cellular host range of HIV-1YU-2 was strictly limited to primary T lymphocytes and monocyte-macrophages, a property conferred by its external envelope glycoprotein. Phylogenetic analyses of HIV-1YU-2 gene sequences revealed this virus to be a member of the North American/European HIV-1 subgroup, with specific similarity to other monocyte-tropic viruses in its V3 envelope amino acid sequence. These results indicate that HIV-1 infection of brain is characterized by the persistence of mixtures of fully competent, minimally defective, and more substantially altered viral forms and that complementation among them is readily attainable. In addition, the limited degree of genotypic heterogeneity observed among HIV-1YU and other brain-derived viruses and their preferential tropism for monocyte-macrophages suggest that viral replication within the central nervous system may differ from that within the peripheral lymphoid compartment in significant and clinically important ways. The availability of genetically and biologically well characterized HIV-1 clones from uncultured human tissue should facilitate future studies of virus-cell interactions relevant to viral pathogenesis and drug and vaccine development.
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PMID:Complete nucleotide sequence, genome organization, and biological properties of human immunodeficiency virus type 1 in vivo: evidence for limited defectiveness and complementation. 140 5

Several mono-, di-, tetra-, penta- and nonaribozymes were developed. These multitarget-ribozymes were targeted to cleave HIV-1 env RNA at up to nine different conserved sites. Each multitarget-ribozyme consisted of a chain of up to nine hammerhead motifs, each flanked by a different targeting sequence. The multitarget-ribozymes were functional in vitro and gave rise to multiple, specific partial and/or complete RNA digestion products. Per RNA copy, multitarget-ribozymes were more efficient than monoribozymes or ribozymes targeting a subset of the same sites. In contrast to monoribozymes, a 400nt nonaribozyme, targeted to cleave at nine different sites within a 1.3kb HIV-1 env RNA substrate, was active and showed the same specificity of cleavage when it was part of a large 3.3kb transcript. We conclude that multitarget-ribozymes retain the specificity of monoribozymes, but they are more efficient per ribozyme RNA copy and they remain active when they are part of a large transcript. A tetra-, penta- or nonaribozyme under control of the SV40 late promoter, the beta-actin gene promoter or the HIV-1 LTR, respectively, were cotransfected with the infectious HIV-1 DNA clone pNL4-3 into permissive HeLa T4 cells. Each cotransfection resulted in a specific inhibition of HIV-1 replication as determined by syncytia formation and p24 antigen release. In addition, coexpression of the nonaribozyme with an HIV-1 env RNA transcript resulted in the specific dramatic reduction of the env transcript. We conclude that the multitarget-ribozymes are also functional intracellularly. A nucleotide sequence comparison of the target sites indicates that the multitarget-ribozymes could potentially be effective against all thirty HIV-1 isolates presently sequenced. Their use may help to slow the selection of viral escape mutants and thereby prolong their effectiveness. We anticipate that multitarget-ribozymes will also be more effective in the successful targeting of less variable cellular RNAs.
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PMID:Multitarget-ribozyme directed to cleave at up to nine highly conserved HIV-1 env RNA regions inhibits HIV-1 replication--potential effectiveness against most presently sequenced HIV-1 isolates. 140 60

Clinicians drew blood samples from 3019 people living in Denmark to determine whether HIV-2 had reached that country. The groups tested included drug users from Copenhagen, healthy HIV-1 positive and negative homosexual men from Copenhagen, patients at a clinic for sexually transmitted diseases (STDs), healthy Africans, Danes who had sexual intercourse with an African, Danish blood donors who went to Africa more than 2 years before they gave a blood sample, and people who had inconclusive HIV-1 Western Blot (WB) patterns. Laboratory personnel used an in-house HIV-1 ELISA and an in-house HIV-2 ELISA to test all samples and an in-house HIV-2 test. 4 (.13%) samples tested positive for HIV-2. 3 of the serum samples were from men from the Ivory Coast, Guinea Bissau and Senegal. The 4th sample belonged to the wife of one of these men. She was positive only for HIV-2 while the 3 men also tested positive for HIV-1. The serum of 2 of the 3 people who tested ELISA HIV-1 reactive had inconclusive HIV-1 WB patterns who tested ELISA HIV-1 reactive had inconclusive HIV-1 WB patterns which made the researchers suspect HIV-2 infection. The woman's serum reacted to the core and env proteins in both the HIV-1 Wb and HIV-2 WB, the HIV-1 ELISA was negative. RIPA and immunofluorescence tests confirmed HIV-2 infection. Her case demonstrates the need to do both HIV-1 and HIV-2 ELISA tests. None of the 650 blood donors who had been in Africa within the last 10 years tested positive for HIV-2. These findings indicated that HIV-2 was not prevalent in Denmark and was limited to West Africa. Health workers whose patients have ties with West Africa and have an inconclusive HIV-1 WB pattern should request testing for HIV-2. The researchers suggested that serological surveillance for HIV-2 should be done at regular intervals.
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PMID:HIV-2 infection in Denmark. 141 6

Bacteriophage T7 RNA polymerase and a derivative containing a nuclear localization signal were transiently expressed in CV-1 cells and were shown to localize to the cytoplasm and nucleus, respectively. A vector was constructed containing T7 promoter and transcription terminator sequences flanking a picornaviral 5' untranslated sequence for cap-independent translation and a polyA signal. Expression of the HIV-1 envelope glycoproteins in this vector system gave high levels of specific transcripts and translation products, independent of the subcellular localization of T7 RNA polymerase. The synthesis of HIV glycoproteins was also completely independent of the coexpression of the HIV rev protein, which is normally required for the expression of HIV structural proteins. In addition, a polyA signal was not required, whereas the presence of the picornaviral 5' untranslated region was necessary for efficient expression. Different possibilities to account for these findings are discussed. The HIV glycoproteins synthesized in this system were normally processed and assembled; they could induce syncytium formation and complement an env-deletion mutant of HIV-1.
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PMID:Expression of biologically active HIV glycoproteins using a T7 RNA polymerase-based eucaryotic vector system. 141 40

A group of 58 heterosexual female partners (FP) of human immunodeficiency virus type 1 (HIV-1)-seropositive hemophiliacs was studied by conventional diagnostic methods such as enzyme-linked immunosorbent assay (ELISA) and Western blot analysis to examine whether any had acquired HIV-1 infection through sexual transmission. A subset of 29 FP were asked to answer a detailed questionnaire concerning their health, use of "safer sex" techniques, and other risk factors for HIV-1 infection. They also had additional blood drawn for CD4 cell analysis, viral cultures, nef, gag, and env immunoblots, and polymerase chain reaction (PCR) analysis to assess the occurrence of "silent" HIV-1 infection in a high-risk seronegative population. Among the 58 FP, three were found to be HIV-1-seropositive on first testing, with no new seroconversions occurring with subsequent testing in the remaining 55. Two seropositive FP had the additional testing and were found to have positive viral cultures, as well as positive PCR results. All of the seronegative FP (n = 24) who had additional testing were negative in viral culture, had negative immunoblots, and had no HIV-1 nucleic acid sequences detected by PCR. Thus, in this population, silent HIV-1 infection appears to be a rare occurrence and antibody testing seems to correlate with the more sensitive techniques of PCR and viral cultures.
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PMID:Silent human immunodeficiency virus type 1 infection: a rare occurrence in a high-risk heterosexual population. 142 11

We studied a single round of replication of Simian immunodeficiency virus (SIV) through the use of a replication defective vector that expresses the hygromycin resistance gene. It was possible to pseudotype SIV particles by complementation with the env gene from a murine amphotropic retrovirus. Moreover, SIV RNA was packaged and propagated by core particles of the heterologous lentivirus, HIV-1. These results indicate that coinfection of cells with SIV and other retroviruses could lead to infection of new cell types in nature.
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PMID:Simian immunodeficiency virus vectors: replication and pseudotyping. 143 69

A 41-kDa unprocessed human immunodeficiency virus 2 (HIV-2) gag precursor protein that has a deletion of a portion of the viral protease assembles as virus-like particles by budding through the cytoplasmic membrane of recombinant baculovirus-infected insect cells. We have constructed six different combinations of chimeric genes by coupling the truncated HIV-2 gag gene to the neutralizing domain (V3) or the neutralizing and the CD4 binding domains (V3+CD4BD) of gp120 env gene sequences from HIV-1 or HIV-2. The env gene sequences were inserted either into the middle of the gag gene or at the 3' terminus of the gag gene. Virus-like particles were formed by chimeric gene products only when the env gene sequences were linked to the 3' terminus of the gag gene. Insertion of env gene sequence in the middle of the gag gene resulted in high-level chimeric gene expression but without the formation of virus-like particles. Three different chimeric genes [gag gene with HIV-1 V3 (1V3), gag gene with HIV-2 V3 (2V3), and gag gene with HIV-2 V3+CD4BD (2V3+CD4BD)] formed virus-like particles that were secreted into the cell culture medium. In contrast, the HIV-1 V3+CD4BD/HIV-2 gag construct did not form virus-like particles. The chimeric gag-env particles had spherical morphology and the size was slightly larger than that of the gag particles, but the chimeric particles were similar to the mature HIV particles. Western blot analysis showed that the gag-env chimeric proteins were recognized by antibodies in HIV-positive human serum and rabbit anti-gp120 serum. Rabbit anti-gag 1V3 and anti-gag 2V3 sera reacted with authentic gp120 of HIV-1 and HIV-2, respectively, and neutralized homologous HIV infectivity. Our results show that precursor gag protein has potential as a carrier for the presentation of foreign epitopes in good immunological context. The gag protein is highly immunogenic and has the ability to carry large foreign inserts; as such, it offers an attractive approach for HIV vaccine development.
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PMID:Chimeric gag-V3 virus-like particles of human immunodeficiency virus induce virus-neutralizing antibodies. 143 41

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