Antibodies play a crucial role in the humoral immune response against health threats, such as viral infections. Although the theoretical number of human immunoglobulins is well over a trillion, the total number of unique antibody protein sequences accessible in databases is much lower than the number found in a single individual. Training AI (Artificial Intelligence) models, for example to assist in developing serodiagnoses or antibody-based therapies, requires building datasets according to strict criteria to include as many standardized antibody sequences as possible.
View Article and Find Full Text PDFEquine hepacivirus (EqHV) is the closest known genetic homologue of hepatitis C virus. An effective prophylactic vaccine is currently not available for either of these hepaciviruses. The equine as potential surrogate model for hepacivirus vaccine studies was investigated, while equine host responses following vaccination with EqHV E2 recombinant protein and subsequent EqHV inoculation were elucidated.
View Article and Find Full Text PDF(1) Background: Equine hepacivirus (EqHV), also referred to as non-primate hepacivirus (NPHV), infects horses-and dogs in some instances-and is closely related to hepatitis C virus (HCV) that has infected up to 3% of the world's human population, causing an epidemic of liver cirrhosis and cancer. EqHV also chronically infects the liver of horses, but does not appear to cause serious liver damages. Previous studies have been looking to identify route(s) of EqHV transmission to and between horses.
View Article and Find Full Text PDFLike hepatitis C virus (HCV) in humans, the newly identified equine hepacivirus (NPHV) displays a predominating liver tropism that may evolve into chronic infections. The genomes of the two viruses share several organizational and functional features and are phylogenetically closest amongst the Hepacivirus genus. A limited amount of data is available regarding the spread of hepacivirus infections in horses.
View Article and Find Full Text PDFAim: To determine if calnexin (CANX), RAB1 and alpha-tubulin were involved in the production of hepatitis C virus (HCV) particles by baby hamster kidney-West Nile virus (BHK-WNV) cells.
Methods: Using a siRNA-based approach complemented with immuno-fluorescence confocal microscope and Western blot studies, we examined the roles of CANX, RAB1 and alpha-tubulin in the production of HCV particles by permissive BHK-WNV cells expressing HCV structural proteins or the full-length genome of HCV genotype 1a. Immuno-fluorescence studies in producer cells were performed with monoclonal antibodies against HCV structural proteins, as well as immunoglobulin from the serum of a patient recently cured from an HCV infection of same genotype.
Unlabelled: The development of human cultured hepatitis C virus (HCV) replication-permissive hepatocarcinoma cell lines has provided important new virological tools to study the mechanisms of HCV infection; however, this experimental model remains distantly related to physiological and pathological conditions. Here, we report the development of a new ex vivo model using human adult liver slices culture, demonstrating, for the first time, the ability of primary isolates to undergo de novo viral replication with the production of high-titer infectious virus as well as Japanese fulminant hepatitis type 1, H77/C3, and Con1/C3. This experimental model was employed to demonstrate HCV neutralization or HCV inhibition, in a dose-dependent manner, either by cluster of differentiation 81 or envelope protein 2-specific antibodies or convalescent serum from a recovered HCV patient or by antiviral drugs.
View Article and Find Full Text PDFStudying the immunological processes taking place during the initial steps of acute hepatitis C virus (HCV) infection has been a challenge in patients. Shin et al. have recently reported that delayed induction, not impaired recruitment of specific CD8(+) T cells, causes the late onset of acute hepatitis C in chimpanzees (Gastroenterology, 2011).
View Article and Find Full Text PDFThis article addresses issues of liability when a single-payor in a national health care system makes a decision based on a utilization review program that injures the patient as a result. In Part I, the history of Managed Care Organizations (MCOs) is discussed to establish an understanding of the current health care landscape. Part II explains MCOs' use of utilization review to contain costs and analyzes the manner in which courts have addressed the issue of MCO liability for patient injuries sustained from denial ofcoverage.
View Article and Find Full Text PDFCD4(+) and CD8(+) T cells, the main effectors of adaptive cellular immune responses, differentiate from immature, non-functional CD4(+)CD8(+) double-positive T (DPT) cells in the thymus. Increased proportions of circulating DPT lymphocytes have been observed during acute viral infections; in chronic viral diseases, the role and repartition of extra-thymic DPT cells remain largely uncharacterized. We performed a phenotypic analysis of DPT cells in blood and liver from patients chronically infected by hepatitis C (HCV) or B (HBV) viruses.
View Article and Find Full Text PDFNumerous constraints significantly hamper the experimental study of hepatitis C virus (HCV). Robust replication in cell culture occurs with only a few strains, and is invariably accompanied by adaptive mutations that impair in vivo infectivity/replication. This problem complicates the production and study of authentic HCV, including the most prevalent and clinically important genotype 1 (subtypes 1a and 1b).
View Article and Find Full Text PDFThymic leukemia (TL) is a MHC class Ib molecule that interacts with CD8alphaalpha homodimers. CD8alphaalpha is abundantly expressed by intraepithelial T lymphocytes (IELs) located in close proximity to TL-expressing intestinal epithelial cells. In this study, we show that CD8alphaalpha(+) IELs "snatch" TL from the plasma membrane of TL-expressing cells and express TL in its proper orientation on their own cell surface.
View Article and Find Full Text PDFThe lectins DC-SIGN and DC-SIGNR can augment viral infection; however, the range of pathogens interacting with these attachment factors is incompletely defined. Here we show that DC-SIGN and DC-SIGNR enhance infection mediated by the glycoprotein (GP) of Marburg virus (MARV) and the S protein of severe acute respiratory syndrome coronavirus and might promote viral dissemination. SIGNR1, a murine DC-SIGN homologue, also enhanced infection driven by MARV and Ebola virus GP and could be targeted to assess the role of attachment factors in filovirus infection in vivo.
View Article and Find Full Text PDFWe used a baculovirus-based system to prepare structural proteins of hepatitis C virus (HCV) genotype 1a. Binding of this preparation to cultured human hepatic cells was both dose dependent and saturable. This binding was decreased by calcium depletion and was partially prevented by ligands of the asialoglycoprotein receptor (ASGP-R), thyroglobulin, asialothyroglobulin, and antibody against a peptide in the carbohydrate recognition domain of ASGP-R but not preimmune antibody.
View Article and Find Full Text PDFHepatitis C virus-like particles (HCV-LPs) containing the structural proteins of HCV H77 strain (1a genotype) was used as a model for HCV virion to study virus-cell interaction. HCV-LPs showed a buoyant density of 1.17 to 1.
View Article and Find Full Text PDFCell Mol Biol (Noisy-le-grand)
March 2002
In response to many stresses and pathologic states, including different models of nervous system injury, cells synthesize a variety of proteins, most notably the inducible 72 kDa heat shock protein 70 (Hsp70), which plays important roles in maintaining cellular integrity and viability. We report here that cultured astrocytes from rat diencephalon express high levels of Hsp70 upon exposure to elevated temperatures, and are less vulnerable to a subsequent oxidative stress. Complex oxidative stress was induced by exposure of astrocytes to an aqueous extract of tobacco smoke.
View Article and Find Full Text PDFEnhanced activation of Akt occurs in Cowden's disease, an inherited syndrome of follicular thyroid, breast, colon, and skin tumors, via inactivation of its regulatory protein, PTEN. Whereas PTEN inactivation is uncommon in sporadic thyroid cancer, activation of growth factor pathways that signal through Akt is frequently identified. We hypothesized that Akt overactivation could be a common finding in sporadic thyroid cancer and might be important in thyroid cancer biology.
View Article and Find Full Text PDFThe regulation of the thyroid gland by TSH is mediated by a heterotrimeric G protein-coupled receptor. Nonthyroid effects of TSH have been reported, and expression of its receptor has been described in adipocytes and lymphocytes. We have previously reported the existence of specific and saturable binding sites of TSH and specific TSH effects in primary cultured rat brain astroglial cells.
View Article and Find Full Text PDFIn astrocytes, cytokines stimulate the release of secretory phospholipase A(2) (sPLA(2)) activity and group II(A) sPLA(2) expression. This paper reports that two sPLA(2) isoforms, group II(A) and group V, are in fact expressed by astrocytes. Our studies showed that tumor necrosis factor alpha (TNFalpha) enhanced the mRNA of both isoforms, but the time courses of enhancement differed; group V was induced much faster than group II(A).
View Article and Find Full Text PDFIn this report we summarize evidence to support a model for the development of Graves' disease. The model suggests that Graves' disease is initiated by an insult to the thyrocyte in an individual with a normal immune system. The insult, infectious or otherwise, causes double strand DNA or RNA to enter the cytoplasm of the cell.
View Article and Find Full Text PDFReactive oxygen species modulate major cellular functions by mechanisms which are still poorly understood. Recently, H2O2 has been reported to stimulate the activity of the mitogen-activated protein kinases (MAPKs) ERK and JNK, and the expression of the proto-oncogenes c-fos and c-jun. As their expression is enhanced by H2O2 in astrocytes, we studied whether these MAPKs were stimulated by H2O2 in primary cultured astrocytes.
View Article and Find Full Text PDFIn human thyroid glands the TSH receptor undergoes a cleavage reaction which yields to an extracellular alpha subunit and a membrane spanning beta subunit linked together by disulfide bridges. A similar reaction is observed in transfected L cells although some uncleaved monomers persist in these cells. We have recently shown that the alpha subunit of the TSH receptor undergoes partial shedding in human thyroid cells and heterologous cells permanently transfected with an expression vector encoding the receptor.
View Article and Find Full Text PDFIn the thyroid, thyrotropin (TSH) stimulates both growth and function, and stimulates the production of cAMP which reproduces most of the effects of TSH. Here, we report evidence that TSH stimulates the mitogen-activated protein (MAP) kinase cascade through a cAMP-independent pathway, in human thyroid. TSH stimulated MAP kinase activity (4-9-fold the basal level) measured in the cytosolic fractions of primary cultured thyroid follicles.
View Article and Find Full Text PDFEur J Biochem
February 1995
We have recently reported the expression of the thyrotropin (TSH) receptor and the stimulation by TSH of type-II iodothyronine 5'-deiodinase in astrocytes. In these cells, TSH stimulated arachidonate release, but neither cAMP production, nor phosphatidylinositolbisphosphate hydrolysis, as described in the human thyroid gland. Here we report, in contrast to a recent observation made in dog thyroid cells, that TSH stimulates mitogen-activated protein kinase (MAP kinase) in astrocytes.
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