scholarly journals Characterization of Low- and Very-Low-Density Hepatitis C Virus RNA-Containing Particles

2002 ◽  
Vol 76 (14) ◽  
pp. 6919-6928 ◽  
Author(s):  
P. André ◽  
F. Komurian-Pradel ◽  
S. Deforges ◽  
M. Perret ◽  
J. L. Berland ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Apolipoprotein B ◽  
Core Protein ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Hcv Rna ◽  
Low Density ◽  
Density Fractions

ABSTRACT The presence of hepatitis C virus (HCV) RNA-containing particles in the low-density fractions of plasma has been associated with high infectivity. However, the nature of circulating HCV particles and their association with immunoglobulins or lipoproteins as well as the characterization of cell entry have all been subject to conflicting reports. For a better analysis of HCV RNA-containing particles, we quantified HCV RNA in the low-density fractions of plasma corresponding to the very-low-density lipoprotein (VLDL), intermediate-density lipoprotein, and low-density lipoprotein (LDL) fractions from untreated chronically HCV-infected patients. HCV RNA was always found in at least one of these fractions and represented 8 to 95% of the total plasma HCV RNA. Surprisingly, immunoglobulins G and M were also found in the low-density fractions and could be used to purify the HCV RNA-containing particles (lipo-viro-particles [LVP]). Purified LVP were rich in triglycerides; contained at least apolipoprotein B, HCV RNA, and core protein; and appeared as large spherical particles with a diameter of more than 100 nm and with internal structures. Delipidation of these particles resulted in capsid-like structures recognized by anti-HCV core protein antibody. Purified LVP efficiently bind and enter hepatocyte cell lines, while serum or whole-density fractions do not. Binding of these particles was competed out by VLDL and LDL from noninfected donors and was blocked by anti-apolipoprotein B and E antibodies, whereas upregulation of the LDL receptor increased their internalization. These results suggest that the infectivity of LVP is mediated by endogenous proteins rather than by viral components providing a mechanism of escape from the humoral immune response.

scholarly journals Association between Hepatitis C Virus and Very-Low-Density Lipoprotein (VLDL)/LDL Analyzed in Iodixanol Density Gradients

2006 ◽  
Vol 80 (5) ◽  
pp. 2418-2428 ◽  
Author(s):  
Søren U. Nielsen ◽  
Margaret F. Bassendine ◽  
Alastair D. Burt ◽  
Caroline Martin ◽  
Wanna Pumeechockchai ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Deoxycholic Acid ◽  
Polyclonal Antibodies ◽  
Gradient Centrifugation ◽  
Low Density Lipoprotein ◽  
Sedimentation Coefficient ◽  
Density Lipoprotein ◽  
Hcv Rna ◽  
Low Density

ABSTRACT Hepatitis C virus (HCV) RNA circulates in the blood of persistently infected patients in lipoviroparticles (LVPs), which are heterogeneous in density and associated with host lipoproteins and antibodies. The variability and lability of these virus-host complexes on fractionation has hindered our understanding of the structure of LVP and determination of the physicochemical properties of the HCV virion. In this study, HCV from an antibody-negative immunodeficient patient was analyzed using three fractionation techniques, NaBr gradients, isotonic iodixanol, and sucrose gradient centrifugation. Iodixanol gradients were shown to best preserve host lipoprotein-virus complexes, and all HCV RNA was found at densities below 1.13 g/ml, with the majority at low density, ≤1.08 g/ml. Immunoprecipitation with polyclonal antibodies against human ApoB and ApoE precipitated 91.8% and 95.0% of HCV with low density, respectively, suggesting that host lipoprotein is closely associated with HCV in a particle resembling VLDL. Immunoprecipitation with antibodies against glycoprotein E2 precipitated 25% of HCV with low density, providing evidence for the presence of E2 in LVPs. Treatment of serum with 0.5% deoxycholic acid in the absence of salt produced HCV with a density of 1.12 g/ml and a sedimentation coefficient of 215S. The diameters of these particles were calculated as 54 nm. Treatment of serum with 0.18% NP-40 produced HCV with a density of 1.18 g/ml, a sedimentation coefficient of 180S, and a diameter of 42 nm. Immunoprecipitation analysis showed that ApoB remained associated with HCV after treatment of serum with deoxycholic acid or NP-40, whereas ApoE was removed from HCV with these detergents.

scholarly journals Characterization of the inhibition of hepatitis C virus entry byIn vitro-generated and patient-derived oxidized low-density lipoprotein

Hepatology ◽  
2013 ◽  
Vol 57 (5) ◽  
pp. 1716-1724 ◽  
Author(s):  
Sandra Westhaus ◽  
Dorothea Bankwitz ◽  
Stefanie Ernst ◽  
Katrin Rohrmann ◽  
Ilka Wappler ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Entry ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Oxidized Low Density Lipoprotein

scholarly journals Infectivity of Hepatitis C Virus Is Influenced by Association with Apolipoprotein E Isoforms

2010 ◽  
Vol 84 (22) ◽  
pp. 12048-12057 ◽  
Author(s):  
Takayuki Hishiki ◽  
Yuko Shimizu ◽  
Reiri Tobita ◽  
Kazuo Sugiyama ◽  
Kazuya Ogawa ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Apolipoprotein E ◽  
Culture Medium ◽  
Low Density Lipoprotein ◽  
Ectopic Expression ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
Virus Production ◽  
Low Density

ABSTRACT Hepatitis C virus (HCV) is a causative agent of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV in circulating blood associates with lipoproteins such as very low density lipoprotein (VLDL) and low-density lipoprotein (LDL). Although these associations suggest that lipoproteins are important for HCV infectivity, the roles of lipoproteins in HCV production and infectivity are not fully understood. To clarify the roles of lipoprotein in the HCV life cycle, we analyzed the effect of apolipoprotein E (ApoE), a component of lipoprotein, on virus production and infectivity. The production of infectious HCV was significantly reduced by the knockdown of ApoE. When an ApoE mutant that fails to be secreted into the culture medium was used, the amount of infectious HCV in the culture medium was dramatically reduced; the infectious HCV accumulated inside these cells, suggesting that infectious HCV must associate with ApoE prior to virus release. We performed rescue experiments in which ApoE isoforms were ectopically expressed in cells depleted of endogenous ApoE. The ectopic expression of the ApoE2 isoform, which has low affinity for the LDL receptor (LDLR), resulted in poor recovery of infectious HCV, whereas the expression of other isoforms, ApoE3 and ApoE4, rescued the production of infectious virus, raising it to an almost normal level. Furthermore, we found that the infectivity of HCV required both the LDLR and scavenger receptor class B, member I (SR-BI), ligands for ApoE. These findings indicate that ApoE is an essential apolipoprotein for HCV infectivity.

scholarly journals Characterization of apolipoprotein B from human serum low density lipoprotein in n-dodecyl octaethyleneglycol monoether: an electron microscope study.

1980 ◽  
Vol 87 (3) ◽  
pp. 555-561 ◽  
Author(s):  
G Zampighi ◽  
J A Reynolds ◽  
R M Watt
Keyword(s):  
Apolipoprotein B ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Serum Lipoprotein ◽  
Low Density ◽  
Apo B ◽  
Shaped Particle ◽  
Orderly Fashion ◽  
High Degree

We have studied the structure of the totally delipidated polypeptide (apolipoprotein B [apo B]) present in low-density serum lipoprotein in detergent (n-dodecyl octaethyleneglycol monoether) solution by electron microscopy. The protein-detergent complex appears as a rod-shaped particle, 75-80 nm long and 4.5-5.5 nm wide. The volume of this particle is consistent with the previously published composition reported by Watt and Reynolds (1980, Biochemistry 19:1593-1598) of two copies of apo B and five to six equivalent micelles of detergent. The asymmetric particle possesses a high degree of flexibility and a strong tendency to self-associate in an orderly fashion. The extent of this association is pH dependent.

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