Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We found that naive (CD45RA+) CD4 T cells have a lower capacity of adhesion to Epstein-Barr virus (EBV) immortalized B cells than memory (CD45RO+) CD4 T cells, as judged by conjugate formation. This would appear to be due to differences in the expression of adhesion molecules [lymphocyte function-associated antigen (LFA)-1, CD2]. However, kinetic studies showed that the degree of adhesion of naive T cells to B cells was stable over 60 min while that of memory T cells, like that of unseparated CD4 T cells, was characterized by a rapid formation and rapid dissociation of conjugates. This could be explained by a difference in the sensitivity of naive and memory CD4 T cells to down-regulation of antigen-independent adhesion by CD4-MHC class II interaction. Indeed, memory T cells also adhered stably to MHC class II(-) B cells. The adhesion of memory T cells, but not naive T cells, to MHC class II(+) B cells was sensitive to inhibition by OKT4a an anti-CD4 antibody, human immunodeficiency (HIV) gp160 (env) protein and a 12-mer peptide encompassing the 35-46 sequence of the HLA, DR beta 1 domain and previously shown to inhibit activation of HLA class II-restricted CD4 T cell responses. Since MHC class II expression did not influence the degree of conjugate formation by naive or memory CD4 T cells with B cells, CD4-MHC class II interaction does not appear to be involved in binding itself, but may down-regulate the adhesion of memory but not naive CD4 T cells.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Antigen-independent adhesion of CD45RA (naive) and CD45RO (memory) CD4 T cells to B cells. 135 61

The objective of the present study was to compare the data of in situ hybridization (ISH), RNA polymerase chain reaction (PCR/RNA) and p24 core antigen (p24 Ag) enzyme immunoassay (EIA) for the detection of HIV-1 expression in peripheral blood mononuclear cells (PBMCs) and in plasma of infected patients at various CDC stages. PBMCs of 24 patients mostly of CDC stage II were obtained from heparinized blood samples, cytocentrifuged and hybridized with a (35S) labelled single-stranded RNA probe specific for gag-pol of LAVBru HIV-1 allowing the detection of genomic and/or messenger RNA. The corresponding plasma samples were used for the determination of p24 Ag by EIA and detection of HIV-1 genomic RNA by RT-PCR using specific primers in the LTR, gag and env regions. Whereas p24 was detected in only six out of 24 patients, both ISH and PCR/RNA enabled the detection of viral RNAs in more than 60% of the patients; cumulation of positive results of ISH and RT-PCR showed that 100% of patients at stage IV and 83% of patients at stages II/III have molecular signs of HIV expression therefore indicating that transcription of the provirus is a highly frequent event, even in the early stages of the disease, and, pleading for undertaking a very early antiviral chemotherapy.
 ...
PMID:Analysis of HIV-1 expression in vivo with in situ hybridization and the polymerase chain reaction. 135 48

The antibody recognition of the major neutralization epitopes of human immunodeficiency virus type 1 (HIV-1) in 829 HIV-1-seropositive subjects from North America (106), Europe (241), Africa (342), and Asia (100) was investigated. Peptides derived from diverse published V3 loop sequences were used as antigen, and serum reactivity was detected by sensitive ELISAs. Antibody binding to peptides derived from the V3 loop sequence of HIV-1 isolates varies considerably depending on the geographic origin of the antibody and is associated with neutralization titer against homologous isolates. Serotype reactivity to peptides may be a simple and rapid approach to investigation of HIV-1 env diversity worldwide and may assist the choice of immunogen for development of future AIDS vaccines.
 ...
PMID:Geographic diversity of human immunodeficiency virus type 1: serologic reactivity to env epitopes and relationship to neutralization. 137 May 25

The in vitro suppressive effect of gp120 and gp120/anti-gp120 antibody is well known but not yet proven to operate in vivo. We report findings consistent with the presence of gp120/anti-gp120 antibody complexes on CD4+ lymphocytes from HIV-infected patients with advanced disease. PBMC from most AIDS patients showed selective masking of the CD4 epitope associated with the gp120 binding site; immunoprecipitation of PBMC with anti-CD4 mAb disclosed high amounts of IgG bound to CD4 receptors. Antibodies against HIV env proteins, but not other HIV products or CD4 Ag, were detected in purified CD4+ cell culture supernatants; in vitro culture was associated with normalization of both CD4 expression in PBMC and the lymphocyte proliferative response to anti-CD3. gp120 presence could not be directly demonstrated, but findings strongly suggested that CD4+ lymphocytes from most HIV-infected patients with advanced disease were covered with gp120/anti-gp120 antibody complexes, which are responsible for down-regulation of surface CD4 expression as well as functional lymphocyte impairment; this event may represent an important mechanism in the pathogenesis of HIV-associated immunodeficiency.
 ...
PMID:CD4 epitope masking by gp120/anti-gp120 antibody complexes. A potential mechanism for CD4+ cell function down-regulation in AIDS patients. 137 95

Polymerase chain reaction (PCR) has been used to amplify the large fragments from viral genomic DNA of SIV from wild caught, asymptomatic Erythrocebus monkeys from Western Africa (Senegal) and also from HIV-2 infected cell lines. By using consensus primer sequences from highly conserved stretches of gag, pol and env genes, two halves of the viral genome of HIV-2 and SIV (isolated from west African Erythrocebus monkeys) have amplified by PCR. One half spans 5200 bp from within the U3 region of the 5' long terminal repeat (LTR) into pol gene and an overlapping fragment spans 3700 bp from the pol gene into U5 region of 3' LTR. Also fragments ranging from 1-2.3 kb from gag pol and env genes have been successfully amplified. Our data demonstrate that primers used to amplify large segments from viral DNA yield better results if they are derived from a consensus sequence of a highly conserved stretch of the viral genome.
 ...
PMID:PCR amplification of large genomic fragments from human and simian immunodeficiency virus infected cell lines. 137 1

Cellular immunogenicity of env gp160, nef p27, and gag p55 proteins of human immunodeficiency virus type 1 (HIV-1) was studied in mice immunized with vaccinia virus recombinants. Proliferative responses of spleen cells were comparable against env gp160, nef p27, and gag p25 recombinant proteins. No specific activity was observed against gag p18 protein. Env, nef, and gag-specific T-cell lines were generated by repeated stimulation of immune spleen cells with recombinant HIV-1 proteins. They were CD4 positive, proliferative, and also cytotoxic against HIV-transfected target cells. Specificity of the T-cell response against nef and gag protein was analyzed with synthetic peptides. Peptides nef 15, nef 16, and gag AM-30 were, respectively, reactive in nef- and gag-specific proliferative and cytolytic assays. The three peptides described have a relatively conserved amino acid sequence among HIV isolates and appear broadly immunoreactive among species.
 ...
PMID:HIV-1 env, nef, and gag-specific T-cell immunity in mice: conserved epitopes in nef p27 and gag p25 proteins. 137 36

Immunization of mice and rats with purified external glycoprotein gp120 from two divergent human immunodeficiency virus type 1 (HIV-1) isolates resulted in the development of seven hybridomas secreting monoclonal antibodies able to recognize regions of gp120 which are common among divergent strains of HIV-1. These monoclonal antibodies cross-reacted with env glycoproteins from one African (Rutz), one Haitian (RF), and three North American viral isolates, namely IIIB, MN, and 451 by either immunoblot or radioimmunoprecipitation assays. All recognized denatured gp120 in immunoblots with the exception of one which required a conformationally intact glycoprotein for reactivity. The gp120 epitopes identified by these antibodies were mapped by screening of an env gene library in the lambda gt11 expression system. Three out of four epitopes were found to reside in the amino-terminal half of gp120 (Cys9 to Cys35, Thr44 to Glu72 and Val108 to Met130), the other was located in the middle region (Thr221 to Ser255). By virtue of their extent of cross-reactivity these reagents might provide a unique resource for the detection of new viral isolates related to HIV-1.
 ...
PMID:Delineation of immunoreactive, conserved regions in the external glycoprotein of the human immunodeficiency virus type 1. 138 Feb 59

The development of AIDS-related lymphomas (ARL) has been on the rise in recent years. During an analysis of ARL from AIDS patients, one individual developed atypical syncytial variants of high-grade Burkitt's-type B-cell lymphomas, which prompted further study. However, the search for a HIV-1 retrovirus, which we hypothesized was infecting these cells, led to the subsequent discovery of a type D retrovirus in two early-passage lymphoma cell lines derived from this patient. Nucleotide and amino acid sequence analysis, as well as immunologic reactivity, indicated that the virus was closely related to Mason-Pfizer monkey virus (MPMV) or simian retrovirus type 1 (SRV-1). MPMV and SRV-1 are immunosuppressive type D retroviruses that cause an AIDS-like syndrome in rhesus macaques. Amplification of DNA from the patient's diagnostic bone marrow biopsy specimen by the polymerase chain reaction generated MPMV-specific fragments indicative of infection by a retrovirus similar to MPMV. Additionally, the patient's serum contained antibodies that recognized type D retroviral env proteins (gp20 and gp70) and gag proteins (p27 and p14) as assayed by immunoblot and radioimmunoprecipitation techniques. Although there have been reports of human cell lines infected with type D retroviruses and of type D reactive human sera, this is the first report of a type D retrovirus infection in a human confirmed by virus isolation, serum immunoreactivity, and viral DNA identification in tumor tissue.
 ...
PMID:Studies on a type D retrovirus isolated from an AIDS patient lymphoma. 138 Dec 7

Previous studies have disagreed about the presence of O-linked carbohydrate epitopes on gp 120 of HIV, although antibodies against short-chain O-linked glycans neutralize HIV infection and block syncytium formation in vitro. To settle this question, we analysed the O-linked glycans of gp 120 by chemical methods using purified HIV-1 gp 120 from cells infected with recombinant vaccinia virus solely expressing gp 160 or gp 120. Alkaline borohydride degradation of recombinant gp 120 released monosaccharides and also slightly larger structures (di/trisaccharides) by a beta-elimination, confirming the presence of simple O-linked oligosaccharides. The functional activity as neutralisation epitopes of the O-linked oligosaccharides expressed on recombinant gp 120 was preserved, since fusion between uninfected CD4+ cells and cells infected with recombinant vaccinia was blocked by monoclonal antibodies to the O-linked oligosaccharides of gp 120. Although the mechanism for HIV induction of O-linked oligosaccharide neoantigens is unknown, these results indicate that the O-linked neutralization epitopes are inherent to the glycoprotein itself, and that the unusual appearance of simple O-linked oligosaccharides on gp 120 is independent of any interaction between the host cell and retroviral genes other than env.
 ...
PMID:An O-linked carbohydrate neutralization epitope of HIV-1 gp 120 is expressed by HIV-1 env gene recombinant vaccinia virus. 138 7

In a search for synthetic peptide antigens fit to detect anti-HIV antibodies, a set of algorithms were used to predict the probable antigenic determinants of gag, pol, env and nef proteins of HIV-1 and HIV-2. Over forty peptides were synthesized by the solid-phase method. The reactivity of the peptide antigens was evaluated in ELISA on panels of HIV-1/2-positive sera. Application of the synthetic peptides for the early HIV diagnostics was examined.
 ...
PMID:[Study of the antigenic structure of human immunodeficiency virus using synthetic peptides]. 138 9


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>