Animals ; Antigens, CD ; metabolism ; Hepacivirus ; pathogenicity ; physiology ; Humans ; Receptors, LDL ; physiology ; Receptors, Virus ; physiology ; Tetraspanin 28

Carcinoma, Hepatocellular ; virology ; Hepatitis B virus ; genetics ; pathogenicity ; Humans ; Liver Neoplasms ; virology ; Receptors, Virus ; metabolism ; Virus Integration

OBJECTIVETo screen the molecules binding dengue II virus expressed in Aedes albopictus C6/36 cells and characterize their biological functions.

METHODSAedes albopictus C6/36 cells were infected with dengue II virus, and the virus were collected and purified. The total and membrane proteins of C6/36 cells were extracted and analyzed using 12% SDS-polyacrylamide gel (PAGE). After electrophoresis, the proteins were transferred to a nitrocellulose membrane, and virus overlay protein-binding assay (VOPBA) was carried out using an anti-dengue virus 1-4 monoclonal antibody.

RESULTSTwo specific bands of 67 000 and 30 000 occurred after VOPBA of the proteins from the cells incubated with the virus, while the negative control group did not show these specific bands.

CONCLUSIONTwo putative dengue virus receptor molecules of 67 000 and 30000 have been obtained from C6/36 cells using VOPBA, and their functional identification is in progress.

Aedes ; cytology ; virology ; Animals ; Cells, Cultured ; Dengue Virus ; isolation & purification ; Membrane Proteins ; Receptors, Virus ; isolation & purification ; metabolism ; Virus Attachment

Melamine in combination with cyanuric acid has been considered to be more toxic than either melamine or cyanuric acid alone. The objective of this study was designed to evaluate the combined genotoxicity and cytotoxicity of melamine (M) and cyanuric acid (C) at three mass ratios (1:1, 1:2, 2:1). MC (1:1), MC (1:2), and MC (2:1) were evaluated for their potential genotoxic risk, at gene level by Ames test, and at chromosomal level by micronucleus test. In order to evaluate cytotoxicity in HEK-293 cells, the MTT assay was included. Western blot was also employed to investigate the renal injury molecule-1 (Kim-1) expression in HEK-293 cells exposed to MC. Neither genotoxicity at gene level nor at chromosomal level was observed for MC (1:1), MC (1:2), and MC (2:1). Based on MTT assay, three ratios of MC at 82.5 and 165 µg/mL slightly inhibited viability of HEK-293 cells (P<0.05). MC (1:1) at 41.25 and 82.50 µg/mL could elevate the Kim-1 expression in HEK-293 cells.
Cell Survival ; drug effects ; HEK293 Cells ; Hepatitis A Virus Cellular Receptor 1 ; Humans ; Membrane Glycoproteins ; metabolism ; Receptors, Virus ; metabolism ; Triazines ; pharmacology

The innate immune system is essential for the initial detection of invading viruses and subsequent activation of adaptive immunity. Three types pattern recognition receptors (PRRs) in innate immune cells play a pivotal role in the first line of host defense system. PRRs include Toll-like receptors (TLRs), RIG-I-like receptors(RLRs) and nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs). PRRs recognize pathogen-associated molecular patterns(PAMPs) or danger-associated molecular patterns (DAMPs) to initiate and regulate innate and adaptive immune responses. Three types PRRs have their own features in ligand recognition and cellular location. Activated PRRs deliver signals to adaptor molecules (MyD88, TRIF, IRAK, IPS-1), which act as important messengers to activate downstream kinases (IKK complex, MAPKs, TBK1, RIP-1) and transcription factors (NF-kappaB, AP-1, IRF3), which produce effected molecules including cytokines, chemokines, inflammatory enzymes, and type I interferons. This review focuses on discussing PRRs signaling pathways and achievements in this field in order to provide beneficial strategies for human life and immune diseases prevention.
Animals ; Humans ; Immunity, Innate ; Receptors, Pattern Recognition ; genetics ; immunology ; metabolism ; Signal Transduction ; Virus Diseases ; immunology ; metabolism ; virology ; Virus Physiological Phenomena

To determine the functions of N-carbohydrate chains in human parainfluenza virus type 3 hemagglutinin-neuraminidase(HN) protein, a PCR-based site-directed mutagenesis method was used to obtain N-glycan mutants. Protein electrophoresis rate, cell surface expression,receptor binding activity, neuraminidase activity and cell fusion promotion activity were determined. The HN proteins of single mutants (G1, G2, and G4) and multiple mutants (G12, G14, G24 and G124) migrated faster than the wild-type (wt) HN protein on polyacrylamide gels, while G3-mutated protein and wt HN protein migrated at the same position. There was no statistic difference in cell surface expression and neuraminidase activity between wt and each mutant HN protein (P>0.05), but receptor binding activity and cell fusion promotion activity of each mutant protein was reduced to significant extent (P<0.05). G1, G2 and G4 mutants exhibited re duced receptor binding activity, which was 83.94%, 76.45% and 55.32% of the wt level, respectively. G1, G2 and G4-mutated proteins also showed reductions in fusion promotion activity, which was 80.84%, 77.83% and 64.16%, respectively. Multiple mutants with G12-, G14-, G24- and G124- substitutions could further reduce receptor binding activities, 33.07%, 20.67%, 19.96% and 15.11% of the wt HN level, respectively. G12, G14, G24 and G124 mutants exhibited levels of fusion promotion activity that were only 46.360, 12.04%, 13.43% and 4.05% of the wt amount, respectively. As N-glycans of hPIV3 HN protein play an important role in receptor binding activity and cell fusion promotion activity of HN protein. We propose that the loss of N-glycans change the conformation or orientation of globular domain that is responsible for receptor binding and lower receptor binding activity and cell fusion promotion activi ty.
Glycosylation ; HN Protein ; chemistry ; genetics ; metabolism ; Humans ; Mutation ; Parainfluenza Virus 3, Human ; chemistry ; enzymology ; genetics ; physiology ; Protein Binding ; Receptors, Virus ; metabolism ; Respirovirus Infections ; metabolism ; virology ; Virus Internalization

Rotaviruses, which are recognized as one of the major etiological agents among infants and young children with diarrhea, consist of three concentric layers of protein capsid with the enclosed double-stranded RNA genome. Rotaviruses infect host cells mainly by identifying the specific receptors on cell surfaces and binding to them. Therefore, receptors are important factors for viruses infecting cells. So far, there have been many receptors found to be involved in rotavirus infection, including sialic acid, integrin, Toll-like receptor, and blood group antigen. This article provides an overview of receptors involved in rotavirus infection.
Animals ; Humans ; Receptors, Virus ; genetics ; metabolism ; Rotavirus ; genetics ; physiology ; Rotavirus Infections ; genetics ; metabolism ; virology

Animals ; Enterovirus A, Human ; metabolism ; Humans ; Lysosome-Associated Membrane Glycoproteins ; metabolism ; Receptors, Scavenger ; metabolism ; Virion ; metabolism ; Virus Attachment

Measles virus is an enveloped virus with a non-segmented negative-sense RNA genome. Two envelope glycoproteins on the viral surface, namely hemagglutinin (H) and membrane fusion protein (F), are responsible for the virus entry into susceptible host cells. The specific interaction between H and its cellular receptors is a key step in successful virus infection, determining the infectivity and tissue tropism of the measles virus. Thus far, three H receptors have been identified, including the complement regulatory molecule CD46, the signaling lymphocyte activation molecule (SLAM) and the cell adhesion molecule Nectin-4. Here, we reviewed our molecular understanding on the recognition mechanism of these receptors by the viral H protein, aiming to promote future studies on antiviral drug design and measles virus-based oncolytic therapy.
Animals ; Antigens, CD ; metabolism ; Cell Adhesion Molecules ; metabolism ; Hemagglutinins, Viral ; metabolism ; Humans ; Measles virus ; pathogenicity ; physiology ; Membrane Cofactor Protein ; metabolism ; Membrane Fusion ; Membrane Fusion Proteins ; metabolism ; Receptors, Cell Surface ; metabolism ; Receptors, Virus ; metabolism ; Signaling Lymphocytic Activation Molecule Family Member 1

Ebolavirus can cause hemorrhagic fever in humans with a mortality rate of 50%-90%. Currently, no approved vaccines and antiviral therapies are available. Human TIM1 is considered as an attachment factor for EBOV, enhancing viral infection through interaction with PS located on the viral envelope. However, reasons underlying the preferable usage of hTIM-1, but not other PS binding receptors by filovirus, remain unknown. We firstly demonstrated a direct interaction between hTIM-1 and EBOV GP in vitro and determined the crystal structures of the Ig V domains of hTIM-1 and hTIM-4. The binding region in hTIM-1 to EBOV GP was mapped by chimeras and mutation assays, which were designed based on structural analysis. Pseudovirion infection assays performed using hTIM-1 and its homologs as well as point mutants verified the location of the GP binding site and the importance of EBOV GP-hTIM-1 interaction in EBOV cellular entry.
Ebolavirus ; metabolism ; Flow Cytometry ; Glycoproteins ; metabolism ; Hepatitis A Virus Cellular Receptor 1 ; Hepatitis A Virus Cellular Receptor 2 ; Humans ; Membrane Glycoproteins ; metabolism ; Membrane Proteins ; metabolism ; Protein Binding ; Receptors, Virus ; metabolism ; Surface Plasmon Resonance ; Viral Envelope Proteins ; metabolism ; Viral Proteins ; metabolism