Frequency of Anti-HBc & HBV DNA detection in blood donors of Kerman province, Iran

Hepatitis B is a serious global infection disease and a major cause of mortality and morbidity worldwide. However, data on Occult Hepatitis B in Iran are scare. The current study assessed the frequency of Anti-HBc and HBV DNA in serum sample of healthy blood donors negative for HBsAg stratified by sex and age; and also investigated the relationship between detection of HBV-DNA and anti-HBc positivity. Since anti-HBc screening is not performed in Iranian Blood Bank, we assessed whether anti-HBc could be adopted as a screening assay for the donated blood. The study included a total of 1525 blood samples of blood donors negative for hepatitis B virus surface antigen ( 87% male with a mean age &plusmn; SD: of 31&plusmn;8yr; and 13% female with a mean age &plusmn; SD of 30&plusmn;6yr). Eight percent (121 out of 1525) of the blood samples with negative HBs-Ag were positive for Anti-HBc and were all from males. HBV-DNA was detected in 36 out of 121 anti-HBc+ specimens (29.7%). The study found a positive relation between anti-HBc positivity and detection of HBV-DNA in serum samples of HBs-Ag negative blood donors. Findings from this study suggest that, introducing anti HBc screening in Iran maybe very practical in order to limit the transmission risk of Occult Hepatitis B virus through blood transfusion.<br /

Human Immunodeficiency Virus Impairs Reverse Cholesterol Transport from Macrophages

Several steps of HIV-1 replication critically depend on cholesterol. HIV infection is associated with profound changes in lipid and lipoprotein metabolism and an increased risk of coronary artery disease. Whereas numerous studies have investigated the role of anti-HIV drugs in lipodystrophy and dyslipidemia, the effects of HIV infection on cellular cholesterol metabolism remain uncharacterized. Here, we demonstrate that HIV-1 impairs ATP-binding cassette transporter A1 (ABCA1)-dependent cholesterol efflux from human macrophages, a condition previously shown to be highly atherogenic. In HIV-1–infected cells, this effect was mediated by Nef. Transfection of murine macrophages with Nef impaired cholesterol efflux from these cells. At least two mechanisms were found to be responsible for this phenomenon: first, HIV infection and transfection with Nef induced post-transcriptional down-regulation of ABCA1; and second, Nef caused redistribution of ABCA1 to the plasma membrane and inhibited internalization of apolipoprotein A-I. Binding of Nef to ABCA1 was required for down-regulation and redistribution of ABCA1. HIV-infected and Nef-transfected macrophages accumulated substantial amounts of lipids, thus resembling foam cells. The contribution of HIV-infected macrophages to the pathogenesis of atherosclerosis was supported by the presence of HIV-positive foam cells in atherosclerotic plaques of HIV-infected patients. Stimulation of cholesterol efflux from macrophages significantly reduced infectivity of the virions produced by these cells, and this effect correlated with a decreased amount of virion-associated cholesterol, suggesting that impairment of cholesterol efflux is essential to ensure proper cholesterol content in nascent HIV particles. These results reveal a previously unrecognized dysregulation of intracellular lipid metabolism in HIV-infected macrophages and identify Nef and ABCA1 as the key players responsible for this effect. Our findings have implications for pathogenesis of both HIV disease and atherosclerosis, because they reveal the role of cholesterol efflux impairment in HIV infectivity and suggest a possible mechanism by which HIV infection of macrophages may contribute to increased risk of atherosclerosis in HIV-infected patients

Stimulation of the Liver X Receptor Pathway Inhibits HIV-1 Replication via Induction of ATP-Binding Cassette Transporter A1

Cholesterol plays an important role in the HIV life cycle, and infectivity of cholesterol-depleted HIV virions is significantly impaired. Recently, we demonstrated that HIV-1, via its protein Nef, inhibits the activity of the major cellular cholesterol transporter ATP binding cassette transporter A1 (ABCA1), suggesting that the virus may use this mechanism to get access to cellular cholesterol. In this study, we investigated the effect on HIV infection of a synthetic liver X receptor (LXR) ligand, N-(2,2,2-trifluoro-ethyl)-N-[4-(2,2,2-trifluoro-1-hydroxy-1-trifluoromethyl-ethyl)-phenyl]-benzenesulfonamide (TO-901317), which is a potent stimulator of ABCA1 expression. We demonstrate that TO-901317 restores cholesterol efflux from HIV-infected T lymphocytes and macrophages. TO-901317 potently suppressed HIV-1 replication in both cell types and inhibited HIV-1 replication in ex vivo cultured lymphoid tissue and in RAG-hu mice infected in vivo. This anti-HIV activity was dependent on ABCA1, because the effect of the drug was significantly reduced in ABCA1-defective T cells from a patient with Tangier disease, and RNA interference-mediated inhibition of ABCA1 expression eliminated the effect of TO-901317 on HIV-1 replication. TO-901317-mediated inhibition of HIV replication was due to reduced virus production and reduced infectivity of produced virions. The infectivity defect was in part due to reduced fusion activity of the virions, which was directly linked to reduced viral cholesterol. These results describe a novel approach to inhibiting HIV infection by stimulating ABCA1 expression

Circulating Nef Induces Dyslipidemia in Simian Immunodeficiency Virus–Infected Macaques by Suppressing Cholesterol Efflux

HIV infection and subsequent antiretroviral therapy have been associated with an increased incidence of dyslipidemia and cardiovascular disease and has been shown to suppress cholesterol efflux from virus-infected macrophages by inducing Nef-dependent downregulation of ABCA1. The SIV/macaque model was used to examine consequences and mechanisms involved. SIV infection drove a significant remodeling of high-density lipoprotein profiles suggesting systemic inhibition of the ABCA1-dependent reverse cholesterol transport pathway. The ABCA1 cholesterol transporter was significantly down regulated in the livers of the SIV-infected macaques and the viral protein Nef could be detected in the liver as well as in plasma of infected animals. Extracellular myristoylated HIV Nef inhibited cholesterol efflux from macrophages and hepatocytes. Moreover, sera from SIV-infected macaques also suppressed cholesterol efflux in a Nef-dependent fashion. These results indicate that SIV infection is a significant contributor to primary dyslipidemia, likely through the ability of Nef to suppress ABCA1-dependent reverse cholesterol transport

The Effect of Nef on ABCA1 Localization

<div><p>(A–D) On day 5 after infection with VSV-G-pseudotyped Nef-expressing (B and D) or ΔNef (A and C) HIV-1 SF2, cells were co-stained with anti-p24 mouse monoclonal and anti-ABCA1 rabbit polyclonal antibodies, followed by FITC-conjugated anti-mouse (A and B) and Cy5-conjugated anti-rabbit IgG (C and D). Arrows point to cells with re-localized ABCA1. The scale bars represent 20 μm.</p> <p>(E–G) Distribution of ABCA1 revealed by staining with monoclonal anti-ABCA1 antibody and FITC-conjugated anti-mouse IgG in RAW 264.7 cells transfected with empty vector (E), WT Nef derived from SF2 HIV-1 (<i>Nef.wt,</i> panel [F]), or SF2 Nef carrying a G2A mutation (<i>Nef.G2A</i>, [G]). Insets in (E and F) show cross-section of the image reconstituted from serial sectioning. Scale bars represent 20 μm.</p> <p>(H) [¹²⁵-I]apoA-I binding (left panel) and internalization (right panel) in RAW 264.7 macrophages transfected with HIV-1 SF2-derived Nef. An asterisk (*) indicates <i>p</i> < 0.01.</p></div