γ-Ketobenzyl-Modified Nucleoside Triphosphate Prodrugs as Potential Antivirals.

The antiviral activity of nucleoside reverse transcriptase inhibitors is often hampered by insufficient phosphorylation. Nucleoside triphosphate analogues are presented, in which the γ-phosphate was covalently modified by a non-bioreversible, lipophilic 4-alkylketobenzyl moiety. Interestingly, primer extension assays using human immunodeficiency virus reverse transcriptase (HIV-RT) and three DNA-polymerases showed a high selectivity of these γ-modified nucleoside triphosphates to act as substrates for HIV-RT, while they proved to be nonsubstrates for DNA-polymerases α, ß, and γ. In contrast to d4TTP, the γ-modified d4TTPs showed a high resistance toward dephosphorylation in cell extracts. A series of acyloxybenzyl-prodrugs of these γ-ketobenzyl nucleoside triphosphates was prepared. The aim was the intracellular delivery of a stable γ-modified nucleoside triphosphate to increase the selectivity of such compounds to act in infected versus noninfected cells. Delivery of γ-ketobenzyl-d4TTPs was proven in T-lymphocyte cell extracts. The prodrugs were potent inhibitors of HIV-1/2 in cultures of infected CEM/0 cells and more importantly in thymidine kinase-deficient CD4+ T-cells.

Advances of CCR5 antagonists: From small molecules to macromolecules.

C-C chemokine receptor 5(CCR5) is a cell membrane protein from G protein-coupled receptors (GPCR) family, which is an important modulator for leukocyte activation and mobilization. In the 1980s, several reports suggest that lack of the HIV-1 co-receptor, the chemokine receptor CCR5, offers protection against HIV infection. Later, it was shown that CCR5 was confirmed to be the most common co-receptor for the HIV-1 virus R5 strain. In recent years, many studies have shown that CCR5 is closely related to the development of various cancers and inflammations to facilitate the discovery of CCR5 antagonists. There are many types of CCR5 antagonists, mainly including chemokine derivatives, non-peptide small molecule compounds, monoclonal antibodies, and peptide compounds. This review focus on the recent research processes and pharmacological effects of CCR5 antagonists such as Maraviroc, TAK-779 and PRO 140. After focusing on the therapeutic effect of CCR5 antagonists on AIDS, it also discusses the therapeutic prospect of CCR5 in other diseases such as inflammation and tumor.

Selection and immune recognition of HIV-1 MPER mimotopes.

The membrane proximal external region (MPER) of HIV-1 gp41 is targeted by several neutralizing antibodies (NAbs) and is of interest for vaccine design. In this study, we identified novel MPER peptide mimotopes and evaluated their reactivity with HIV + plasma antibodies to characterize the diversity of the immune responses to MPER during natural infection. We utilized phage display technology to generate novel mimotopes that fit antigen-binding sites of MPER NAbs 4E10, 2F5 and Z13. Plasma antibodies from 10 HIV + patients were mapped by phage immunoprecipitation, to identify unique patient MPER binding profiles that were distinct from, and overlapping with, those of MPER NAbs. 4E10 mimotope binding profiles correlated with plasma neutralization of HIV-2/HIV-1 MPER chimeric virus, and with overall plasma neutralization breadth and potency. When administered as vaccines, 4E10 mimotopes elicited low titer NAb responses in mice. HIV mimotopes may be useful for detailed analysis of plasma antibody specificity.

Lipophilic Triphosphate Prodrugs of Various Nucleoside Analogues.

The antiviral efficacy of many nucleoside analogues is strongly dependent on their intracellular activation by host cellular kinases to yield ultimately the bioactive nucleoside analogue triphosphates (NTP). The metabolic conversion of nucleoside analogues into their triphosphates often proceeds insufficiently. We developed a nucleoside triphosphate (NTP) delivery system (the TriPPPro approach), in which the γ-phosphate is covalently modified by two different biodegradable masking units, one is the acyloxybenzyl (AB) moiety and the other is the alkoxycarbonyloxybenzyl (ACB) group. Such compounds formed NTPs with high selectivity by an enzyme-triggered mechanism in human T-lymphocyte CEM cell extracts loosing first the AB moiety, followed by the ACB group. This enables the bypass of all steps of the intracellular phosphorylation. This approach was applied here to convert some modestly active or even inactive nucleoside analogues into powerful biologically active metabolites. Potent antiviral activity profiles were obtained depending on the lipophilicity of the TriPPPro-NTP prodrugs against HIV-1 and HIV-2 replication in cultures of infected wild-type CD4+ CEM T-cells and more importantly in thymidine kinase-deficient CD4+ T-cells (CEM/TK-). This TriPPPro strategy offers high potential for future antiviral and antitumoral chemotherapies.

Prodrugs of γ-Alkyl-Modified Nucleoside Triphosphates: Improved Inhibition of HIV Reverse Transcriptase.

The development of nucleoside triphosphate prodrugs is one option to apply nucleoside reverse transcriptase inhibitors. Herein, we report the synthesis and evaluation of d4TTP analogues, in which the γ-phosphate was modified covalently by lipophilic alkyl residues, and acyloxybenzyl prodrugs of these γ-alkyl-modified d4TTPs, with the aim of delivering of γ-alkyl-d4TTP into cells. Selective formation of γ-alkyl-d4TTP was proven with esterase and in CD4+ -cell extracts. In contrast to d4TTP, γ-alkyl-d4TTPs proved highly stable against dephosphorylation. Primer extension assays with HIV reverse transcriptase (RT) and DNA-polymerases α, ß or γ showed that γ-alkyl-d4TTPs were substrates for HIV-RT only. In antiviral assays, compounds were highly potent inhibitors of HIV-1 and HIV-2 also in thymidine-kinase-deficient T-cell cultures (CEM/TK- ). Thus, the intracellular delivery of such γ-alkyl-nucleoside triphosphates may potentially lead to nucleoside triphosphates with a higher selectivity towards the viral polymerase that can act in virus-infected cells.

Design, Synthesis, and Mechanism Study of Benzenesulfonamide-Containing Phenylalanine Derivatives as Novel HIV-1 Capsid Inhibitors with Improved Antiviral Activities.

The HIV-1 CA protein has gained remarkable attention as a promising therapeutic target for the development of new antivirals, due to its pivotal roles in HIV-1 replication (structural and regulatory). Herein, we report the design and synthesis of three series of benzenesulfonamide-containing phenylalanine derivatives obtained by further structural modifications of PF-74 to aid in the discovery of more potent and drug-like HIV-1 CA inhibitors. Structure-activity relationship studies of these compounds led to the identification of new phenylalanine derivatives with a piperazinone moiety, represented by compound 11l, which exhibited anti-HIV-1NL4-3 activity 5.78-fold better than PF-74. Interestingly, 11l also showed anti-HIV-2ROD activity (EC50 = 31 nM), with almost 120 times increased potency over PF-74. However, due to the higher significance of HIV-1 as compared to HIV-2 for the human population, this manuscript focuses on the mechanism of action of our compounds in the context of HIV-1. SPR studies on representative compounds confirmed CA as the binding target. The action stage determination assay demonstrated that these inhibitors exhibited antiviral activities with a dual-stage inhibition profile. The early-stage inhibitory activity of compound 11l was 6.25 times more potent as compared to PF-74 but appeared to work via the accelerating capsid core assembly rather than stabilization. However, the mechanism by which they exert their antiviral activity in the late stage appears to be the same as PF-74 with less infectious HIV-1 virions produced in their presence, as judged p24 content studies. MD simulations provided the key rationale for the promising antiviral potency of 11l. Additionally, 11l exhibited a modest increase in HLM and human plasma metabolic stabilities as compared to PF-74, as well as a moderately improved pharmacokinetic profile, favorable oral bioavailability, and no acute toxicity. These studies provide insights and serve as a starting point for subsequent medicinal chemistry efforts in optimizing these promising HIV inhibitors.

Direct arylation of C60Cl6 and C70Cl8 with carboxylic acids: a synthetic avenue to water-soluble fullerene derivatives with promising antiviral activity.

We report unprecedented Friedel-Crafts arylation of chlorofullerenes C60Cl6 and C70Cl8 with unprotected carboxylic acids as an efficient single-step synthesis of the inherently stable water-soluble fullerene derivatives. Using this method, a series of previously unaccessible compounds was obtained without chromatographic purification in almost quantitative yields. Promising anti-HIV activity comparable to characteristics of commercial drugs was demonstrated for some of these compounds.

A Membrane-Anchored Short-Peptide Fusion Inhibitor Fully Protects Target Cells from Infections of Human Immunodeficiency Virus Type 1 (HIV-1), HIV-2, and Simian Immunodeficiency Virus.

Emerging studies demonstrate that the antiviral activity of viral fusion inhibitor peptides can be dramatically improved when being chemically or genetically anchored to the cell membrane, where viral entry occurs. We previously reported that the short-peptide fusion inhibitor 2P23 and its lipid derivative possess highly potent antiviral activities against human immunodeficiency virus type 1 (HIV-1), HIV-2, and simian immunodeficiency virus (SIV). To develop a sterilizing or functional-cure strategy, here we genetically linked 2P23 and two control peptides (HIV-1 fusion inhibitor C34 and hepatitis B virus [HBV] entry inhibitor 4B10) with a glycosylphosphatidylinositol (GPI) attachment signal. As expected, GPI-anchored inhibitors were efficiently expressed on the plasma membrane of transduced TZM-bl cells and primarily directed to the lipid raft site without interfering with the expression of CD4, CCR5, and CXCR4. GPI-anchored 2P23 (GPI-2P23) completely protected TZM-bl cells from infections of divergent HIV-1, HIV-2, and SIV isolates as well as a panel of enfuvirtide (T20)-resistant mutants. GPI-2P23 also rendered the cells resistant to viral envelope-mediated cell-cell fusion and cell-associated virion-mediated cell-cell transmission. Moreover, GPI-2P23-modified human CD4+ T cells (CEMss-CCR5) fully blocked both R5- and X4-tropic HIV-1 isolates and displayed a robust survival advantage over unmodified cells during HIV-1 infection. In contrast, it was found that GPI-anchored C34 was much less effective in inhibiting HIV-2, SIV, and T20-resistant HIV-1 mutants. Therefore, our studies have demonstrated that genetically anchoring a short-peptide fusion inhibitor to the target cell membrane is a viable strategy for gene therapy of both HIV-1 and HIV-2 infections.IMPORTANCE Antiretroviral therapy with multiple drugs in combination can efficiently suppress HIV replication and dramatically reduce the morbidity and mortality associated with AIDS-related illness; however, antiretroviral therapy cannot eradiate the HIV reservoirs, and lifelong treatment is required, which often results in cumulative toxicities, drug resistance, and a multitude of complications, thus necessitating the development of sterilizing-cure or functional-cure strategies. Here, we report that genetically anchoring the short-peptide fusion inhibitor 2P23 to the cell membrane can fully prevent infections from divergent HIV-1, HIV-2, and SIV isolates as well as a panel of enfuvirtide-resistant mutants. Membrane-bound 2P23 also effectively blocks HIV-1 Env-mediated cell-cell fusion and cell-associated virion-mediated cell-cell transmission, renders CD4+ T cells nonpermissive to infection, and confers a robust survival advantage over unmodified cells. Thus, our studies verify a powerful strategy to generate resistant cells for gene therapy of both the HIV-1 and HIV-2 infections.

BCL6 Inhibitor-Mediated Downregulation of Phosphorylated SAMHD1 and T Cell Activation Are Associated with Decreased HIV Infection and Reactivation.

Clearance of HIV-infected germinal center (GC) CD4+ follicular helper T cells (Tfh) after combination antiretroviral therapy (ART) is essential to an HIV cure. Blocking B cell lymphoma 6 (BCL6; the master transcription factor for Tfh cells) represses HIV infection of tonsillar CD4+ Tfh ex vivo, reduces GC formation, and limits immune activation in vivo We assessed the anti-HIV activity of a novel BCL6 inhibitor, FX1, in Tfh/non-Tfh CD4+ T cells and its impact on T cell activation and SAMHD1 phosphorylation (Thr592). FX1 repressed HIV-1 infection of peripheral CD4+ T cells and tonsillar Tfh/non-Tfh CD4+ T cells (P < 0.05) and total elongated and multispliced HIV-1 RNA production during the first round of viral life cycle (P < 0.01). Using purified circulating CD4+ T cells from uninfected donors, we demonstrate that FX1 treatment resulted in downregulation pSAMHD1 expression (P < 0.05) and T cell activation (HLA-DR, CD25, and Ki67; P < 0.01) ex vivo corresponding with inhibition of HIV-1 and HIV-2 replication. Ex vivo HIV-1 reactivation using purified peripheral CD4+ T cells from HIV-infected ART-suppressed donors was also blocked by FX1 treatment (P < 0.01). Our results indicate that BCL6 function contributes to Tfh/non-Tfh CD4+ T cell activation and cellular susceptibility to HIV infection. BCL6 inhibition represents a novel therapeutic strategy to potentiate HIV suppression in Tfh/non-Tfh CD4+ T cells without reactivation of latent virus.IMPORTANCE The expansion and accumulation of HIV-infected BCL6+ Tfh CD4+ T cells are thought to contribute to the persistence of viral reservoirs in infected subjects undergoing ART. Two mechanisms have been raised for the preferential retention of HIV within Tfh CD4+ T cells: (i) antiretroviral drugs have limited tissue distribution, resulting in insufficient tissue concentration and lower efficacy in controlling HIV replication in lymphoid tissues, and (ii) cytotoxic CD8+ T cells within lymphoid tissues express low levels of chemokine receptor (CXCR5), thus limiting their ability to enter the GCs to control/eliminate HIV-infected Tfh cells. Our results indicate that the BCL6 inhibitor FX1 can not only repress HIV infection of tonsillar Tfh ex vivo but also suppress HIV infection and reactivation in primary, non-Tfh CD4+ T cells. Our study provides a rationale for targeting BCL6 protein to extend ART-mediated reduction of persistent HIV and/or support strategies toward HIV remission beyond ART cessation.

Amino acid residues in HIV-2 reverse transcriptase that restrict the development of nucleoside analogue resistance through the excision pathway.

Nucleoside reverse transcriptase (RT) inhibitors (NRTIs) are the backbone of current antiretroviral treatments. However, the emergence of viral resistance against NRTIs is a major threat to their therapeutic effectiveness. In HIV-1, NRTI resistance-associated mutations either reduce RT-mediated incorporation of NRTI triphosphates (discrimination mechanism) or confer an ATP-mediated nucleotide excision activity that removes the inhibitor from the 3' terminus of DNA primers, enabling further primer elongation (excision mechanism). In HIV-2, resistance to zidovudine (3'-azido-3'-deoxythymidine (AZT)) and other NRTIs is conferred by mutations affecting nucleotide discrimination. Mutations of the excision pathway such as M41L, D67N, K70R, or S215Y (known as thymidine-analogue resistance mutations (TAMs)) are rare in the virus from HIV-2-infected individuals. Here, we demonstrate that mutant M41L/D67N/K70R/S215Y HIV-2 RT lacks ATP-dependent excision activity, and recombinant virus containing this RT remains susceptible to AZT inhibition. Mutant HIV-2 RTs were tested for their ability to unblock and extend DNA primers terminated with AZT and other NRTIs, when complexed with RNA or DNA templates. Our results show that Met73 and, to a lesser extent, Ile75 suppress excision activity when TAMs are present in the HIV-2 RT. Interestingly, recombinant HIV-2 carrying a mutant D67N/K70R/M73K RT showed 10-fold decreased AZT susceptibility and increased rescue efficiency on AZT- or tenofovir-terminated primers, as compared with the double-mutant D67N/K70R. Molecular dynamics simulations reveal that Met73influences ß3-ß4 hairpin loop conformation, whereas its substitution affects hydrogen bond interactions at position 70, required for NRTI excision. Our work highlights critical HIV-2 RT residues impeding the development of excision-mediated NRTI resistance.

Executive summary of the GESIDA/National AIDS Plan Consensus Document on Antiretroviral Therapy in Adults Infected by the Human Immunodeficiency Virus (Updated January 2017).

Antiretroviral therapy (ART) is recommended for all patients infected by HIV-1. The objective of ART is to achieve an undetectable plasma viral load (PVL). Initial ART should be based on a combination of 3 drugs, including 2 nucleoside reverse transcriptase inhibitors (tenofovir in either of its two formulations plus emtricitabine or abacavir plus lamivudine) and another drug from a different family. Four of the recommended regimens, all of which have an integrase inhibitor as the third drug (dolutegravir, elvitegravir boosted with cobicistat or raltegravir), are considered preferential, whereas a further 3 regimens (based on elvitegravir/cobicistat, rilpivirine, or darunavir boosted with cobicistat or ritonavir) are considered alternatives. We present the reasons and criteria for switching ART in patients with an undetectable PVL and in those who present virological failure, in which case salvage ART should include 3 (or at least 2) drugs that are fully active against HIV. We also update the criteria for ART in specific situations (acute infection, HIV-2 infection, pregnancy) and comorbidities (tuberculosis or other opportunistic infections, kidney disease, liver disease and cancer).

Facile functionalization at the C4 position of pyrimidine nucleosides via amide group activation with (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP) and biological evaluations of the products.

Reactions of O-t-butyldimethylsilyl-protected thymidine, 2'-deoxyuridine, and 3'-azidothymidine (AZT) with (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP) leads to activation of the C4 amide carbonyl by formation of putative O4-(benzotriazol-1-yl) derivatives. Subsequent substitution with alkyl and aryl amines, thiols, and alcohols leads to facile functionalization at this position. Reactions with amines and thiols were conducted either as a two-step, one-pot transformation, or as a one-step conversion. Reactions with alcohols were conducted as two-step, one-pot transformations. In the course of these investigations, the formation of 1-(4-pyrimidinyl)-1H-benzotriazole-3-oxide derivatives from the pyrimidine nucleosides was identified. However, these too underwent conversion to the desired products. Products obtained from AZT were converted to the 3'-amino derivatives by catalytic reduction. All products were assayed for their abilities to inhibit cancer cell proliferation and for antiviral activities. Many were seen to be active against HIV-1 and HIV-2, and one was active against herpes simplex virus-1 (HSV-1).

A Helical Short-Peptide Fusion Inhibitor with Highly Potent Activity against Human Immunodeficiency Virus Type 1 (HIV-1), HIV-2, and Simian Immunodeficiency Virus.

Human immunodeficiency virus type 2 (HIV-2) has already spread to different regions worldwide, and currently about 1 to 2 million people have been infected, calling for new antiviral agents that are effective on both HIV-1 and HIV-2 isolates. T20 (enfuvirtide), a 36-mer peptide derived from the C-terminal heptad repeat region (CHR) of gp41, is the only clinically approved HIV-1 fusion inhibitor, but it easily induces drug resistance and is not active on HIV-2. In this study, we first demonstrated that the M-T hook structure was also vital to enhancing the binding stability and inhibitory activity of diverse CHR-based peptide inhibitors. We then designed a novel short peptide (23-mer), termed 2P23, by introducing the M-T hook structure, HIV-2 sequences, and salt bridge-forming residues. Promisingly, 2P23 was a highly stable helical peptide with high binding to the surrogate targets derived from HIV-1, HIV-2, and simian immunodeficiency virus (SIV). Consistent with this, 2P23 exhibited potent activity in inhibiting diverse subtypes of HIV-1 isolates, T20-resistant HIV-1 mutants, and a panel of primary HIV-2 isolates, HIV-2 mutants, and SIV isolates. Therefore, we conclude that 2P23 has high potential to be further developed for clinical use, and it is also an ideal tool for exploring the mechanisms of HIV-1/2- and SIV-mediated membrane fusion. IMPORTANCE: The peptide drug T20 is the only approved HIV-1 fusion inhibitor, but it is not active on HIV-2 isolates, which have currently infected 1 to 2 million people and continue to spread worldwide. Recent studies have demonstrated that the M-T hook structure can greatly enhance the binding and antiviral activities of gp41 CHR-derived inhibitors, especially for short peptides that are otherwise inactive. By combining the hook structure, HIV-2 sequence, and salt bridge-based strategies, the short peptide 2P23 has been successfully designed. 2P23 exhibits prominent advantages over many other peptide fusion inhibitors, including its potent and broad activity on HIV-1, HIV-2, and even SIV isolates, its stability as a helical, oligomeric peptide, and its high binding to diverse targets. The small size of 2P23 would benefit its synthesis and significantly reduce production cost. Therefore, 2P23 is an ideal candidate for further development, and it also provides a novel tool for studying HIV-1/2- and SIV-mediated cell fusion.

Synthesis of arylated coumarins by Suzuki-Miyaura cross-coupling. Reactions and anti-HIV activity.

Arylated coumarins were prepared by site-selective Suzuki-Miyaura cross-coupling reaction of the bis(triflate) of 4-methyl-6,7-dihydroxycoumarin. Triarylated coumarins were prepared by Suzuki-Miyaura cross-coupling reactions of 3-bromo-4-methyl-2-oxo-2H-chromene-6,7-diylbis(trifluoromethanesulfonate). The in vitro anti-HIV activity of the products was investigated. Two lead structures with considerable activities were identified.

Antiviral Activity of Flexibilane and Tigliane Diterpenoids from Stillingia lineata.

In an effort to identify new potent and selective inhibitors of chikungunya virus and HIV-1 and HIV-2 virus replication, the endemic Mascarene species Stillingia lineata was investigated. LC/MS and bioassay-guided purification of the EtOAc leaf extract using a chikungunya virus-cell-based assay led to the isolation of six new (4-9) and three known (1-3) tonantzitlolones possessing the rare C20-flexibilane skeleton, along with tonantzitloic acid (10), a new linear diterpenoid, and three new (11, 13, and 15) and two known (12 and 14) tigliane-type diterpenoids. The planar structures of the new compounds and their relative configurations were determined by spectroscopic analysis, and their absolute configurations were determined through comparison with literature data and from biogenetic considerations. These compounds were investigated for selective antiviral activity against chikungunya virus (CHIKV), Semliki Forest virus, Sindbis virus, and, for compounds 11-15, the HIV-1 and HIV-2 viruses. Compounds 12-15 were found to be the most potent and are selective inhibitors of CHIKV, HIV-1, and HIV-2 replication. In particular, compound 14 inhibited CHIKV replication with an EC50 value of 1.2 µM on CHIKV and a selectivity index of >240, while compound 15 inhibited HIV-1 and HIV-2 with EC50 values of 0.043 and 0.018 µM, respectively. It was demonstrated further that potency and selectivity are sensitive to the substitution pattern on the tigliane skeleton. The cytotoxic activities of compounds 1-10 were evaluated against the HCT-116, MCF-7, and PC3 cancer cell lines.

Design, synthesis, and biological evaluation of unconventional aminopyrimidine, aminopurine, and amino-1,3,5-triazine methyloxynucleosides.

Herein we describe a class of unconventional nucleosides (methyloxynucleosides) that combine unconventional nucleobases such as substituted aminopyrimidines, aminopurines, or aminotriazines with unusual sugars in their structures. The allitollyl or altritollyl derivatives were pursued as ribonucleoside mimics, whereas the tetrahydrofuran analogues were pursued as their dideoxynucleoside analogues. The compounds showed poor, if any, activity against a broad range of RNA and DNA viruses, including human immunodeficiency virus (HIV). This inactivity may be due to lack of an efficient metabolic conversion into their corresponding 5'-triphosphates and poor affinity for their target enzymes (DNA/RNA polymerases). Several compounds showed cytostatic activity against proliferating human CD4(+) T-lymphocyte CEM cells and against several other tumor cell lines, including murine leukemia L1210 and human prostate PC3, kidney CAKI-1, and cervical carcinoma HeLa cells. A few compounds were inhibitory to Moloney murine sarcoma virus (MSV) in C3H/3T3 cell cultures, with the 2,6-diaminotri-O-benzyl-D-allitolyl- and -D-altritolyl pyrimidine analogues being the most potent among them. This series of unconventional nucleosides may represent a novel family of potential antiproliferative agents.

Cohort Profile: The Bissau HIV Cohort-a cohort of HIV-1, HIV-2 and co-infected patients.

The West African country Guinea-Bissau is home to the world's highest prevalence of HIV-2, and its HIV-1 prevalence is rising. Other chronic viral infections like human T-lymphotropic virus type 1 (HTLV-1) and hepatitis B virus are common as well. The Bissau HIV Cohort was started in 2007 to gain new insights into the overall effect of introducing antiretroviral treatment in a treatment-naïve population with concomitant infection with three retroviruses (HIV-1, HIV-2 and HTLV-1) and tuberculosis. The cohort includes patients from the HIV clinic at Hospital Nacional Simão Mendes, the main hospital in Bissau, the capital of the country. From July 2007 to June 2013, 3762 HIV-infected patients (69% HIV-1, 18% HIV-2, 11% HIV-1/2 and 2% HIV type unknown) were included in the world's largest single-centre HIV-2 cohort. Demographic and clinical data are collected at baseline and every 6 months, together with CD4 cell count and routine biochemistry analyses. Plasma and cells are stored in a biobank in Denmark. The Bissau HIV Cohort is administered by the Bissau HIV Cohort study group. Potential collaborators are invited to contact the chair of the cohort study group, Christian Wejse, e-mail: [wejse@dadlnet.dk].

A modular system to evaluate the efficacy of protease inhibitors against HIV-2.

The human immunodeficiency virus (HIV) protease is a homodimeric aspartyl protease that is crucial for the viral life-cycle, cleaving proviral polyproteins, hence creating mature protein components that are required for the formation of an infectious virus. With diagnostic measures and clinically used protease inhibitors focusing on HIV-1, due to its higher virulence and prevalence, studies of the efficacy of those inhibitors on HIV-2 protease remain widely lacking. Utilizing a wild-type HIV-2 vector backbone and cloning techniques we have developed a cassette system where the efficacy of clinically used protease inhibitors can be studied for various serotypes of HIV-2 protease both in enzymatic and cell culture assays. In our experiments, optimization of the expression protocol led to a relatively stable enzyme, for cell culture assays, the efficiency of transfection and transduction capability of the modified vector was tested and was not found to differ from that of the wild-type, moreover, a 2nd generation protease inhibitor was used to demonstrate the usefulness of the system. The combination of assays performed with our cassette system is expected to provide an accurate measure of the efficacy of currently used; as well as experimental protease inhibitors on HIV-2.

Design and synthesis of a new series of cyclopropylamino-linking diarylpyrimidines as HIV non-nucleoside reverse transcriptase inhibitors.

A new series of 29 diarylpyrimidine analogues featuring a cyclopropylamino group between the pyrimidine scaffold and the aryl wing have been synthesized. All of the new compounds have been characterized by spectra analysis. The target molecules were evaluated for their in vitro anti-HIV activity with FDA-approved drugs as references. Some of the compounds exhibited moderate to potent activities against wild-type HIV-1. The compound 4-((4-((cyclopropylamino)(2,5-difluorophenyl)methyl)pyrimidin-2-yl)amino)benzonitrile (1e) displayed potent anti-HIV-1 activity against WT HIV-1 with an IC50 of 0.099 µM and a selectivity index of 2302. The preliminary structure-activity relationship (SAR) of this new series of compounds was also investigated.