scholarly journals New Insights into the Structure of Kappa/Beta-Carrageenan: A Novel Potential Inhibitor of HIV-1

2021 ◽  
Vol 22 (23) ◽  
pp. 12905
Author(s):  
Irina Yermak ◽  
Stanislav Anastyuk ◽  
Anna Kravchenko ◽  
William Helbert ◽  
Valery Glazunov ◽  
...  
Keyword(s):  
T Lymphocyte ◽  
Hybrid Structure ◽  
Red Alga ◽  
Jurkat Cells ◽  
Negative Ion ◽  
Transduction Efficiency ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Tichocarpus Crinitus ◽  
Enzymatic Depolymerization

New insights into the structure of the hybrid κ/β-carrageenan (κ/β-CRG) of the red alga Tichocarpus crinitus have been obtained. Carrageenan oligosaccharides were prepared through the chemical and enzymatic depolymerization of κ/β-CRG with κ-carrageenase and its the enzyme-resistant fraction. The composition and distribution of the repetition units of κ/β- CRG were investigated by using the negative ion tandem MALDI-TOFMS and ESIMS method, which made it possible to prove and characterize the hybrid structure of this polysaccharide. An analysis revealed the blockwise distribution of the long β-blocks along the polysaccharide chain, with the inclusion of κ/β, μ/ν-blocks and some ι-blocks. Furthermore, the desulfated κ/β-CRG was shown to contain of –G–D– repeating units up to 3.5 kDa. Previous studies have demonstrated that CRGs suppress the replication of several viruses. Here, we established that κ/β-CRG and its oligosaccharides significantly inhibit the transduction efficiency of replication-defective lentiviral particles pseudotyped with the envelope proteins of three different viruses. We found that the polysaccharide and its oligosaccharides strongly reduced the transduction efficiency of lentiviral particles pseudotyped with GP160—the envelope protein of the human immunodeficiency virus HIV-1—when added to T-lymphocyte Jurkat cells. The CRG oligosaccharides displayed significantly higher antiviral activity.

scholarly journals Discordant Outcomes following Failure of Antiretroviral Therapy Are Associated with Substantial Differences in Human Immunodeficiency Virus-Specific Cellular Immunity

2003 ◽  
Vol 77 (10) ◽  
pp. 6041-6049 ◽  
Author(s):  
David A. Price ◽  
George Scullard ◽  
Annette Oxenius ◽  
Ruth Braganza ◽  
Simon A. Beddows ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiretroviral Therapy ◽  
T Lymphocyte ◽  
Virologic Failure ◽  
Multiple Drug Resistance ◽  
Testable Hypothesis ◽  
Plasma Virus ◽  
Immunodeficiency Virus ◽  
Lymphocyte Responses ◽  
Hiv 1

ABSTRACT Many individuals chronically infected with human immunodeficiency virus type 1 (HIV-1) experience a recrudescence of plasma virus during continuous combination antiretroviral therapy (ART) due either to the emergence of drug-resistant viruses or to poor compliance. In most cases, virologic failure on ART is associated with a coincident decline in CD4+ T lymphocyte levels. However, a proportion of discordant individuals retain a stable or even increasing CD4+ T lymphocyte count despite virological failure. In order to address the nature of these different outcomes, we evaluated virologic and immunologic variables in a prospective, single-blinded, nonrandomized cohort of 53 subjects with chronic HIV-1 infection who had been treated with continuous ART and monitored intensively over a period of 19 months. In all individuals with detectable viremia on ART, multiple drug resistance mutations with similar impacts on viral growth kinetics were detected in the pol gene of circulating plasma virus. Further, C2V3 env gene analysis demonstrated sequences indicative of CCR5 coreceptor usage in the majority of those with detectable plasma viremia. In contrast to this homogeneous virologic pattern, comprehensive screening with a range of antigens derived from HIV-1 revealed substantial immunologic differences. Discordant subjects with stable CD4+ T lymphocyte counts in the presence of recrudescent virus demonstrated potent virus-specific CD4+ and CD8+ T lymphocyte responses. In contrast, subjects with virologic failure associated with declining CD4+ T lymphocyte counts had substantially weaker HIV-specific CD4+ T lymphocyte responses and exhibited a trend towards weaker HIV-specific CD8+ T lymphocyte responses. Importantly the CD4+ response was sustained over periods as long as 11 months, confirming the stability of the phenomenon. These correlative data lead to the testable hypothesis that the consequences of viral recrudescence during continuous ART are modulated by the HIV-specific cellular immune response.

An in vitro transcription analysis of early responses of the human immunodeficiency virus type 1 long terminal repeat to different transcriptional activators

1991 ◽  
Vol 11 (4) ◽  
pp. 1883-1893
Author(s):  
Y C Li ◽  
J Ross ◽  
J A Scheppler ◽  
B R Franza
Keyword(s):  
Human Immunodeficiency Virus ◽  
Protein Synthesis ◽  
Early Time ◽  
In Vitro Transcription ◽  
Jurkat Cells ◽  
Time Points ◽  
Immunodeficiency Virus ◽  
Hiv 1

In this report we introduce a simple, fast, and reliable method to prepare whole cell or nuclear extracts from small numbers of cells. These extracts were used to study transcriptional activation of the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) in vitro. Our results revealed that the time courses of activation of extracts derived from cells stimulated with the mitogenic lectin phytohemagglutinin (PHA) or with the tumor promoter phorbol 12-myristate 13-acetate (PMA) are different. PMA induces a rapid onset of increased in vitro transcription from the HIV-1 LTR, while PHA causes a slow and sustained response. The biochemical relevance of protein synthesis inhibition by cycloheximide treatment of cells was investigated. In these studies, PMA induction of a change in in vitro transcriptional activity is not dependent on protein synthesis. Cycloheximide alone is insufficient to induce activation. Oligonucleotide-mediated site-directed mutagenesis demonstrated that mutation of the TATA box in the LTR ablated initiation of both basal-level transcription and activation by extracts from cells stimulated with PMA. Surprisingly, mutation of both kappa B sites in the LTR reduced but did not eliminate the in vitro response to extracts prepared at early time points after PHA or PMA stimulation of Jurkat cells. The reduction was greater in extracts derived from cells treated with PMA. Deletion analysis of the HIV-1 LTR revealed at least one region (-464 to -252) capable of suppressing in vitro transcription in extracts from Jurkat cells stimulated by PMA. This result is consistent with early studies of the HIV-1 LTR in transient transfection assays. We therefore have been able to observe distinct regulatory events at early time points after cells are exposed to agents known to induce transcription of both the HIV-1 LTR reporter gene constructs and the HIV-1 provirus itself.

scholarly journals Upregulation of c-Fos in Activated T Lymphoid and Monocytic Cells by Human Immunodeficiency Virus-1 Tat Protein

Blood ◽  
1997 ◽  
Vol 89 (5) ◽  
pp. 1654-1664 ◽  
Author(s):  
Davide Gibellini ◽  
Antonella Caputo ◽  
Silvano Capitani ◽  
Michele La Placa ◽  
Giorgio Zauli
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Lines ◽  
Promoter Activity ◽  
Jurkat Cells ◽  
U937 Cells ◽  
Tat Protein ◽  
Fos Protein ◽  
Significant Difference ◽  
Immunodeficiency Virus ◽  
Hiv 1

Abstract The regulatory Tat protein of the human immunodeficiency virus type-1 (HIV-1) is essential for viral replication and also shows pleiotropic activities on various cell functions. To get further insights into the molecular mechanisms underlying the biological activity of Tat, we investigated the effect of endogenous and exogenous Tat protein on c-fos gene expression in T lymphoblastoid (Jurkat) and monocytic (U937) cell lines, as well as in primary peripheral blood mononuclear cells (PBMC). Transient cotransfection of tat cDNA in sense orientation (tat/S), together with a plasmid containing the c-fos promoter (FC3, from −711 to +42) in front of the bacterial chloramphenicol acetyltransferase (CAT) gene significantly enhanced CAT activity in Jurkat cells activated by the addition of 15% fetal calf serum (FCS) or 5 μg/mL phytohemagglutinin plus 10−7 mol/L phorbol myristate acetate (PMA) and U937 cells activated by 15% FCS or 10−7 mol/L PMA. This effect was specifically due to Tat, since Jurkat and U937 cells cotransfected either with tat cDNA in antisense orientation (tat/AS), tat carrying a mutation in the aminoacid cys22 - gly22 (tat 22/S) or with the backbone vector alone (pRPneo-SL3) did not show any significant difference in c-fos promoter activity as compared to cells transfected with FC3 plasmid alone. By using deletion mutants of the c-fos promoter, we found that the minimal DNA sequence required for Tat activity was located between nucleotides −404/−220 and that the serum responsive element (SRE, −317/−288), present within this region, was still responsive to Tat. A single point mutation in the SRE completely abrogated the responsiveness to tat/S. Exogenous recombinant Tat protein was also able to upregulate c-fos promoter activity in serum-activated Jurkat and U937 cells, as well as endogenous c-fos mRNA expression and c-Fos protein synthesis in both serum-activated cell lines and primary PBMC. c-Fos protein was shown essential for an optimal transactivation of the HIV-1 long terminal repeat (LTR) by Tat: incubation of Jurkat cells with antisense, but not sense, c-fos oligonucleotides significantly reduced either the Tat-enhanced expression of an LTR-CAT reporter construct or the levels of gag p24 in the culture supernatants of Jurkat cells and PBMC acutely infected with HIV-1. Our data suggest that the c-fos upregulation mediated by Tat might play a significant role in the control of viral gene transactivation.

scholarly journals Rabies Virus-Based Vectors Expressing Human Immunodeficiency Virus Type 1 (HIV-1) Envelope Protein Induce a Strong, Cross-Reactive Cytotoxic T-Lymphocyte Response against Envelope Proteins from Different HIV-1 Isolates

2001 ◽  
Vol 75 (9) ◽  
pp. 4430-4434 ◽  
Author(s):  
James P. McGettigan ◽  
Heather D. Foley ◽  
Igor M. Belyakov ◽  
Jay A. Berzofsky ◽  
Roger J. Pomerantz ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Rabies Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
T Lymphocyte ◽  
Envelope Protein ◽  
Cytotoxic T Lymphocyte ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Novel viral vectors that are able to induce both strong and long-lasting immune responses may be required as effective vaccines for human immunodeficiency virus type 1 (HIV-1) infection. Our previous experiments with a replication-competent vaccine strain-based rabies virus (RV) expressing HIV-1 envelope protein from a laboratory-adapted HIV-1 strain (NL4–3) and a primary HIV-1 isolate (89.6) showed that RV-based vectors are excellent for B-cell priming. Here we report that cytotoxic T-lymphocyte (CTL) responses against HIV-1 gp160 are induced by recombinant RVs. Our results indicated that a single inoculation of mice with an RV expressing HIV-1 gp160 induced a solid and long-lasting memory CTL response specific for HIV-1 envelope protein. Moreover, CTLs from immunized mice were not restricted to the homologous HIV-1 envelope protein and were able to cross-kill target cells expressing HIV-1 gp160 from heterologous HIV-1 strains. These studies further suggest promise for RV-based vectors to elicit a persistent immune response against HIV-1 and their potential utility as efficacious anti-HIV-1 vaccines.

scholarly journals Human Immunodeficiency Virus Type 1-Hepatitis C Virus Coinfection: Intraindividual Comparison of Cellular Immune Responses against Two Persistent Viruses

2002 ◽  
Vol 76 (6) ◽  
pp. 2817-2826 ◽  
Author(s):  
Georg M. Lauer ◽  
Tam N. Nguyen ◽  
Cheryl L. Day ◽  
Gregory K. Robbins ◽  
Theresa Flynn ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Immune Responses ◽  
T Lymphocyte ◽  
Viral Loads ◽  
Cellular Immune Responses ◽  
Immunodeficiency Virus ◽  
Cellular Immune ◽  
Lymphocyte Responses ◽  
Hiv 1

ABSTRACT Both human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) lead to chronic infection in a high percentage of persons, and an expanding epidemic of HIV-1-HCV coinfection has recently been identified. These individuals provide an opportunity for simultaneous assessment of immune responses to two viral infections associated with chronic plasma viremia. In this study we analyzed the breadth and magnitude of the CD8+- and CD4+-T-lymphocyte responses in 22 individuals infected with both HIV-1 and HCV. A CD8+-T-lymphocyte response against HIV-1 was readily detected in all subjects over a broad range of viral loads. In marked contrast, HCV-specific CD8+-T-lymphocyte responses were rarely detected, despite viral loads in plasma that were on average 1,000-fold higher. The few HCV-specific responses that were observed were relatively weak and limited in breadth. CD4-proliferative responses against HIV-1 were detected in about half of the coinfected subjects tested, but no proliferative response against any HCV protein was found in these coinfected persons. These data demonstrate a major discordance in immune responses to two persistent RNA viruses. In addition, they show a consistent and profound impairment in cellular immune responses to HCV compared to HIV-1 in HIV-1-HCV-coinfected persons.

scholarly journals ADAR2 editing enzyme is a novel human immunodeficiency virus-1 proviral factor

2011 ◽  
Vol 92 (5) ◽  
pp. 1228-1232 ◽  
Author(s):  
Margherita Doria ◽  
Sara Tomaselli ◽  
Francesca Neri ◽  
Silvia Anna Ciafrè ◽  
Maria Giulia Farace ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Jurkat Cells ◽  
Replication Process ◽  
Adenosine Deaminases ◽  
Immunodeficiency Virus ◽  
Editing Enzyme ◽  
Infectious Potential ◽  
Hiv 1

The adenosine deaminases acting on RNA (ADAR) enzymes catalyse conversion of adenosine to inosine in dsRNA. A positive effect of ADAR1 on human immunodeficiency virus type 1 (HIV-1) replication has recently been reported. Here, we show that another ADAR enzyme, ADAR2, positively affects the replication process of HIV-1. We found that, analogously to ADAR1, ADAR2 enhances the release of progeny virions by an editing-dependent mechanism. However, differently from the ADAR1 enzyme, ADAR2 does not increase the infectious potential of the virus. Importantly, downregulation of ADAR2 in Jurkat cells significantly impairs viral replication. Therefore, ADAR2 shares some but not all proviral functions of ADAR1. These results suggest a novel role of ADAR2 as a viral regulator.

scholarly journals Enhanced cellular immunity and systemic control of SHIV infection by combined parenteral and mucosal administration of a DNA prime MVA boost vaccine regimen

2004 ◽  
Vol 85 (8) ◽  
pp. 2407-2419 ◽  
Author(s):  
B. Mäkitalo ◽  
P. Lundholm ◽  
J. Hinkula ◽  
C. Nilsson ◽  
K. Karlén ◽  
...  
Keyword(s):  
Immune Responses ◽  
T Lymphocyte ◽  
Protective Efficacy ◽  
Viral Rna ◽  
Post Challenge ◽  
Cellular Immune Responses ◽  
Immunodeficiency Virus ◽  
Cellular Immune ◽  
Hiv 1 ◽  
Rna Levels

The immunogenicity and protective efficacy of a DNA and recombinant modified vaccinia Ankara (MVA) vaccine administered by two different routes were investigated. DNA expressing HIV-1 IIIB env, gag, RT, rev, tat and nef, and MVA expressing HIV-1 IIIB nef, tat and rev and simian immunodeficiency virus (SIV) macJ5 gag/pol and vaccinia HIV-1 env, were used as immunogens. Four cynomolgus macaques received DNA intramuscularly (i.m.) at month 0 and intrarectally (i.r.) and intra-orally (i.o.) at 2 months, followed by MVA i.m. at 4 months and i.r. and i.o. at 8 months. Another group of four monkeys received the same immunogens but only i.m.. Overall, stronger cellular immune responses measured by ELISPOT and T-cell proliferation assay were detected in the group primed i.m. and boosted mucosally. Following homologous intravenous simian-human immunodeficiency virus (SHIV) challenge, one of eight vaccinated animals was completely protected. This monkey, immunized i.m. and i.r.+i.o., exhibited the highest levels of HIV Env, Nef and Tat antibodies, high HIV Tat cytotoxic T-lymphocyte activity and T-lymphocyte proliferative responses to HIV Env. Four weeks post-challenge none of the monkeys immunized i.m. and i.r.+i.o., and only two out of four animals immunized i.m., demonstrated detectable plasma viral RNA levels. In contrast, all eight control animals had demonstrable plasma viral RNA levels 4 weeks post-challenge. Thus, stronger cellular immune responses and reduction of challenge virus burden were demonstrated in animals immunized i.m. as well as mucosally, compared with animals immunized i.m. only. The breadth and magnitude of the induced immune responses correlated with protective efficacy.

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