Search results for "gp120"
showing 10 items of 14 documents
Stable changes in CD4+ T lymphocyte miRNA expression after exposure to HIV-1
2012
Abstract MicroRNAs (miRNAs) inhibit HIV-1 expression by either modulating host innate immunity or by directly interfering with viral mRNAs. We evaluated the expression of 377 miRNAs in CD4+ T cells from HIV-1 élite long-term nonprogressors (éLTNPs), naive patients, and multiply exposed uninfected (MEU) patients, and we observed that the éLTNP patients clustered with naive patients, whereas all MEU subjects grouped together. The discriminatory power of miRNAs showed that 21 miRNAs significantly differentiated éLTNP from MEU patients and 23 miRNAs distinguished naive from MEU patients, whereas only 1 miRNA (miR-155) discriminated éLTNP from naive patients. We proposed that miRNA expression ma…
CD4-mediated regulatory T-cell activation inhibits the development of disease in a humanized mouse model of allergic airway disease
2012
Background Based on their potency to control allergic diseases, regulatory T (Treg) cells represent a promising target for novel strategies to interfere with allergic airway inflammation. We have previously demonstrated that stimulation of the CD4 molecule on human Treg cells activates their suppressive activity in vitro and in vivo . Objective We sought to determine the effect of CD4-mediated Treg-cell activation on pulmonary inflammation in a humanized mouse model of allergic airway inflammation. Methods PBMCs obtained from donors allergic to birch pollen or from healthy donors were injected into NOD-severe combined immunodeficiency γc −/− mice, followed by allergen airway challenges and …
Exposure to gp120 of HIV-1 induces an increased release of arachidonic acid in rat primary neuronal cell culture followed by NMDA receptor-mediated n…
1995
After incubation of highly enriched neurons from rat cerebral cortex with the HIV-1 coat protein gp120 for 18 h, cells showed fragmentation of DNA at internucleosomal linkers followed by NMDA receptor-mediated neurotoxicity. We report that in response to exposure to gp120 cells react with an increased release of arachidonic acid (AA) via activation of phospholipase A2. This process was not inhibited by NMDA receptor antagonists. To investigate the role of AA on the sensitivity of the NMDA receptor towards its agonist, low concentrations of NMDA were co-administered with AA. This condition enhanced the NMDA-mediated cytotoxicity. Administration of mepacrine reduced cytotoxicity caused by gp1…
T cells can present antigens such as HIV gp120 targeted to their own surface molecules
1988
To trigger class II-restricted T cells, antigen presenting cells have to capture antigens, process them and display their fragments in association with class II molecules. In most species, activated T cells express class II molecules; however, no evidence has been found that these cells can present soluble antigens. This failure may be due to the inefficient capture, processing or display of antigens in a stimulatory form by T-cells. The capture of a soluble antigen, which is achieved by nonspecific mechanisms in macrophages and dendritic cells, can be up to 10(3) times more efficient in the presence of surface receptors, such as surface immunoglobulin on B cells that specifically bind anti…
Polyclonal antibodies to mannan from yeast also recognize the carbohydrate structure of gp120 of the AIDS virus: an approach to raise neutralizing an…
1990
This study initiates a new method of developing an antigen which might be useful in the prevention of HIV-1 infection. Using a mannan preparation from Saccharomyces cerevisiae neutralizing antiserum was raised in rabbits which prevents HIV-1 infection in vitro up to a titre of 1:128. The corresponding antibody preparation neutralized the in vitro infectivity down to a concentration of 5 micrograms/ml. Analytical studies suggest that the antibodies are directed against the mannose residues of the HIV-1 glycoprotein (gp) 120 and its precursor gp 160.
Inhibition of human immunodeficiency virus-1 infection by human conglutinin-like protein: in vitro studies.
1992
The lectin-like protein analogous to bovine conglutinin was purified from human serum. The carbohydrate-binding ability of conglutinin-like protein was inhibited by D-mannose, N-acetylglucosamine and L-fucose as well as by mannan-containing oligosaccharides. By applying a lectin-based ELISA system it was demonstrated that conglutinin-like protein binds to human immunodeficiency virus-1 (HIV-1) glycoprotein 120 (gp120) via its carbohydrate binding site. In vitro experiments with T-lymphoblastoid CEM cells revealed that conglutinin-like protein abolishes infection by HIV-1; a 50% cytoprotective concentration of 23.9 micrograms/ml was measured. These findings demonstrate that human conglutinin…
Frequency-dependent selection in human immunodeficiency virus type 1.
2001
Genetic variation is the main evolutionary strategy adopted by RNA viruses and retroviruses. Evolution operates through competition between different individuals in the same environment, resulting in the imposition of the fittest variant. The process of competition could be affected by various factors, including the frequency of the different competing individuals. In order to investigate this aspect, individual virus populations derived from a human immunodeficiency virus type 1 isolate were studied at different competing proportions. The dynamics of variant imposition in each competition experiment permitted the detection of frequency-dependent selection (FDS); i.e. the imposition of vari…
Human conglutinin-like protein inhibits infection by the human immunodeficiency virus-1 in vitro.
1992
In summary the lectin-like protein analogous to bovine conglutinin was purified from human serum. Using a lectin-based ELISA system, it was demonstrated that conglutinin-like protein binds to human immunodeficiency virus-1 (HIV1) glycoprotein 120 (gp 120) via its carbohydrate binding site. In vitro experiments with T-lymphoblastoid CEM cells revealed that conglutinin-like protein abolishes infection by HIV1; a 50 % cytoprotective concentration of 23.9 μg/ml was measured.
Protection from graft-versus-host disease by HIV-1 envelope protein gp120-mediated activation of human CD4+CD25+ regulatory T cells.
2009
AbstractNaturally occurring CD4+CD25+ regulatory T cells (Tregs) represent a unique T-cell lineage that is endowed with the ability to actively suppress immune responses. Therefore, approaches to modulate Treg function in vivo could provide ways to enhance or reduce immune responses and lead to novel therapies. Here we show that the CD4 binding human immunodeficiency virus-1 envelope glycoprotein gp120 is a useful and potent tool for functional activation of human Tregs in vitro and in vivo. Gp120 activates human Tregs by binding and signaling through CD4. Upon stimulation with gp120, human Tregs accumulate cyclic adenosine monophosphate (cAMP) in their cytosol. Inhibition of endogeneous cA…
Trimeric HIV Env provides epitope occlusion mediated by hypervariable loops
2014
AbstractHypervariable loops of HIV-1 Env protein gp120 are speculated to play roles in the conformational transition of Env to the receptor binding-induced metastable state. Structural analysis of full-length Env-based immunogens, containing the entire V2 loop, displayed tighter association between gp120 subunits, resulting in a smaller trimeric diameter than constructs lacking V2. A prominent basal quaternary location of V2 and V3′ that challenges previous reports would facilitate gp41-independent gp120-gp120 interactions and suggests a quaternary mechanism of epitope occlusion facilitated by hypervariable loops. Deletion of V2 resulted in dramatic exposure of basal, membrane-proximal gp41…