Search results for "Envelope"
showing 10 items of 336 documents
Non-redundant and redundant roles of cytomegalovirus gH/gL complexes in host organ entry and intra-tissue spread
2015
Herpesviruses form different gH/gL virion envelope glycoprotein complexes that serve as entry complexes for mediating viral cell-type tropism in vitro; their roles in vivo, however, remained speculative and can be addressed experimentally only in animal models. For murine cytomegalovirus two alternative gH/gL complexes, gH/gL/gO and gH/gL/MCK-2, have been identified. A limitation of studies on viral tropism in vivo has been the difficulty in distinguishing between infection initiation by viral entry into first-hit target cells and subsequent cell-to-cell spread within tissues. As a new strategy to dissect these two events, we used a gO-transcomplemented ΔgO mutant for providing the gH/gL/gO…
Immune evasion proteins gpUS2 and gpUS11 of human cytomegalovirus incompletely protect infected cells from CD8 T cell recognition
2009
AbstractHuman cytomegalovirus (HCMV) encodes four glycoproteins, termed gpUS2, gpUS3, gpUS6 and gpUS11 that interfere with MHC class I biosynthesis and antigen presentation. Despite gpUS2–11 expression, however, HCMV infection is efficiently controlled by cytolytic CD8 T lymphocytes (CTL). To address the role of gpUS2 and gpUS11 in antigen presentation during viral infection, HCMV mutants were generated that expressed either gpUS2 or gpUS11 alone without coexpression of the three other proteins. Fibroblasts infected with these viruses showed reduced HLA-A2 and HLA-B7 surface expression. Surprisingly, however, CTL directed against the tegument protein pp65 and the regulatory IE1 protein stil…
Stalemating a clever opportunist: lessons from murine cytomegalovirus.
2003
Abstract Cytomegaloviruses and their specific hosts have come to an arrangement that avoids disease but allows the viruses to persist in the individual host and to spread in the host species. Recent work has uncovered some of the molecular details of this evolutionary “contract for mutual survival.” Cytomegaloviruses encode proteins, referred to as “immunoevasins,” which are specifically committed to subvert the immune defense of the host for evading virus elimination. In reply, the hosts have evolved countermeasures to overcome the viral immunoevasins and present antigenic peptides to an extent that is sufficient for confining virus replication to below a harmful level. Accordingly, cytome…
Macrophages Escape Inhibition of Major Histocompatibility Complex Class I-Dependent Antigen Presentation by Cytomegalovirus
2000
ABSTRACTThe mouse cytomegalovirus (MCMV)m152- andm06-encoded glycoproteins gp40 and gp48, respectively, independently downregulate major histocompatibility complex (MHC) class I surface expression during the course of productive MCMV infection in fibroblasts. As a result, presentation of an immediate-early protein pp89-derived nonapeptide toH-2Ld-restricted CD8+cytotoxic T cells is completely prevented in fibroblasts. Here we demonstrate that MCMV-infected primary bone marrow macrophages and the macrophage cell line J774 constitutively present pp89 peptides during permissive MCMV infection to cytotoxic T lymphocytes (CTL). In contrast to fibroblasts, expression of them152andm06genes in macr…
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…
Integrazione di celle solari di terza generazione nel vetromattone per la realizzazione di pannelli traslucidi fotovoltaici. Analisi prestazione e st…
2013
L’articolo illustra i primi risultati ottenuti nell’ambito dell’analisi prestazionale del vetromattone fotovoltaico, un prodotto edilizio innovativo derivato dall’integrazione di celle fotovoltaiche di terza generazione (DSSC) nel vetromattone, ideato per la realizzazione di involucri traslucidi energeticamente effi cienti ed “attivi”, in grado di ridurre i consumi energetici degli edifi ci e di produrre, al contempo, energia verde. L’analisi è stata condotta su quattro differenti ipotesi di integrazione. Attraverso simulazioni numeriche si è effettuata una valutazione dell’energia assorbita dagli strati attivi oltre che delle prestazioni ottiche complessive del dispositivo. Lo studio anali…
Reducing Electric and Thermal Energy Needs in Buildings by Using Innovative Envelope Materials
2018
The life style of building occupants is continuously arising towards conditions that are more comfortable involving, on turn, the growing of the electric energy consumptions for climatization purposes. This calls for the improvement of the efficiencies of equipment along with environmental performance of building materials. Laboratory analyses of samples of mixed materials, utilizing tomato stems harvested in Sicily and Cataluna, have been conducted Thermal conductance and mechanical properties have been detected for different rates of bio-component and inert materials. First results of the thermal properties seem to situate such bio-composites among the insulating building materials, for a…
The Be/X-ray binary LS 992/RX J0812.4-3114: Physical parameters and long-term variability
2000
We present the first long-term optical and infrared study of the optical counterpart to the source RX J0812.4-3114, an X-ray pulsar with a Be type companion. During the period covered by the observations the profile of some Balmer lines changed from absorption to emission and back again to absorption. Contemporaneously, the infrared magnitudes varied by more than 0.8 mag. This long-term variability is interpreted as the formation and subsequent dissipation of the Be star's disc. The building up of the disc ended up in an active X-ray state characterised by regular outbursts occurring at 80 day intervals. The overall duration of the formation/dissipation of the disc is found to be < 4.3 year…
Strongly decelerated expansion of SN 1979C
2002
We observed SN1979C in M100 on 4 June 1999, about twenty years after explosion, with a very sensitive four-antenna VLBI array at the wavelength of 18cm. The distance to M100 and the expansion velocities are such that the supernova cannot be fully resolved by our Earth-wide array. Model-dependent sizes for the source have been determined and compared with previous results. We conclude that the supernova shock was initially in free expansion for 6 +/- 2 yrs and then experienced a very strong deceleration. The onset of deceleration took place a few years before the abrupt trend change in the integrated radio flux density curves. We estimate the shocked swept-up mass to be about 1.6 solar masse…