Drug-resistant HIV Strains Research Articles

Novel Acylguanidine-Based Inhibitor of HIV-1.

The emergence of transmissible HIV-1 strains with resistance to antiretroviral drugs highlights a continual need for new therapies. Here we describe a novel acylguanidine-containing compound, 1-(2-(azepan-1-yl)nicotinoyl)guanidine (or SM111), that inhibits in vitro replication of HIV-1, including strains resistant to licensed protease, reverse transcriptase, and integrase inhibitors, without major cellular toxicity. At inhibitory concentrations, intracellular p24(Gag) production was unaffected, but virion release (measured as extracellular p24(Gag)) was reduced and virion infectivity was substantially impaired, suggesting that SM111 acts at a late stage of viral replication. SM111-mediated inhibition of HIV-1 was partially overcome by a Vpu I17R mutation alone or a Vpu W22* truncation in combination with Env N136Y. These mutations enhanced virion infectivity and Env expression on the surface of infected cells in the absence and presence of SM111 but also impaired Vpu's ability to downregulate CD4 and BST2/tetherin. Taken together, our results support acylguanidines as a class of HIV-1 inhibitors with a distinct mechanism of action compared to that of licensed antiretrovirals. Further research on SM111 and similar compounds may help to elucidate knowledge gaps related to Vpu's role in promoting viral egress and infectivity. New inhibitors of HIV-1 replication may be useful as therapeutics to counteract drug resistance and as reagents to perform more detailed studies of viral pathogenesis. SM111 is a small molecule that blocks the replication of wild-type and drug-resistant HIV-1 strains by impairing viral release and substantially reducing virion infectivity, most likely through its ability to prevent Env expression at the infected cell surface. Partial resistance to SM111 is mediated by mutations in Vpu and/or Env, suggesting that the compound affects host/viral protein interactions that are important during viral egress. Further characterization of SM111 and similar compounds may allow more detailed pharmacological studies of HIV-1 egress and provide opportunities to develop new treatments for HIV-1.

HIV pre-exposure prophylaxis for women and infants prevents vaginal and oral HIV transmission in a preclinical model of HIV infection.

Approximately 1.5 million HIV-positive women become pregnant annually. Without treatment, up to 45% will transmit HIV to their infants, primarily through breastfeeding. These numbers highlight that HIV acquisition is a major health concern for women and children globally. They also emphasize the urgent need for novel approaches to prevent HIV acquisition that are safe, effective and convenient to use by women and children in places where they are most needed. 4'-Ethynyl-2-fluoro-2'-deoxyadenosine, a potent NRTI with low cytotoxicity, was administered orally to NOD/SCID/γc-/- mice and to bone marrow/liver/thymus (BLT) humanized mice, a preclinical model of HIV infection. HIV inhibitory activity in serum, cervicovaginal secretions and saliva was evaluated 4 h after administration. 4'-Ethynyl-2-fluoro-2'-deoxyadenosine's ability to prevent vaginal and oral HIV transmission was evaluated using highly relevant transmitted/founder viruses in BLT mice. Strong HIV inhibitory activity in serum, cervicovaginal secretions and saliva obtained from animals after a single oral dose of 4'-ethynyl-2-fluoro-2'-deoxyadenosine (10 mg/kg) demonstrated efficient drug penetration into relevant mucosal sites. A single daily oral dose of 4'-ethynyl-2-fluoro-2'-deoxyadenosine resulted in efficient prevention of vaginal and oral HIV transmission after multiple high-dose exposures to transmitted/founder viruses in BLT humanized mice. Our data demonstrated that 4'-ethynyl-2-fluoro-2'-deoxyadenosine efficiently prevents both vaginal and oral HIV transmission. Together with 4'-ethynyl-2-fluoro-2'-deoxyadenosine's relatively low toxicity and high potency against drug-resistant HIV strains, these data support further clinical development of 4'-ethynyl-2-fluoro-2'-deoxyadenosine as a potential pre-exposure prophylaxis agent to prevent HIV transmission in women and their infants.

Human DDX3 protein is a valuable target to develop broad spectrum antiviral agents

Targeting a host factor essential for the replication of different viruses but not for the cells offers a higher genetic barrier to the development of resistance, may simplify therapy regimens for coinfections, and facilitates management of emerging viral diseases. DEAD-box polypeptide 3 (DDX3) is a human host factor required for the replication of several DNA and RNA viruses, including some of the most challenging human pathogens currently circulating, such as HIV-1, Hepatitis C virus, Dengue virus, and West Nile virus. Herein, we showed for the first time, to our knowledge, that the inhibition of DDX3 by a small molecule could be successfully exploited for the development of a broad spectrum antiviral agent. In addition to the multiple antiviral activities, hit compound 16d retained full activity against drug-resistant HIV-1 strains in the absence of cellular toxicity. Pharmacokinetics and toxicity studies in rats confirmed a good safety profile and bioavailability of 16d. Thus, DDX3 is here validated as a valuable therapeutic target.

Focus on Chirality of HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors.

Chiral HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) are of great interest since one enantiomer is often more potent than the corresponding counterpart against the HIV-1 wild type (WT) and the HIV-1 drug resistant mutant strains. This review exemplifies the various studies made to investigate the effect of chirality on the antiretroviral activity of top HIV-1 NNRTI compounds, such as nevirapine (NVP), efavirenz (EFV), alkynyl- and alkenylquinazolinone DuPont compounds (DPC), diarylpyrimidine (DAPY), dihydroalkyloxybenzyloxopyrimidine (DABO), phenethylthiazolylthiourea (PETT), indolylarylsulfone (IAS), arylphosphoindole (API) and trifluoromethylated indole (TFMI) The chiral separation, the enantiosynthesis, along with the biological properties of these HIV-1 NNRTIs, are discussed.

Study on the threshold of HIV-1 drug resistance in Dehong prefecture of Yunnan province in 2014

To study the HIV-1 genotypes and transmitted drug resistance (TDR) in Dehong prefecture of Yunnan province in 2014. A total of 70 plasma samples of recently reported HIV-infected individuals between 16 and 25 years old were collected in Dehong prefecture from January to August 2014. Among them, 58 samples which met the criterion of HIV drug resistance threshold survey (HIVDR-TS) were subjected to genetic drug resistance detection. 50 plasma samples were successfully sequenced and analyzed. Among them, 34.0% were Chinese and 66.0% were Burmese. Based on pol sequences, all the identified HIV genotypes would include CRF01_AE (28.0%), subtype C(20.0%), URF(20.0% ), CRF62_BC(10.0% ), CRF08_BC(8.0% ), CRF07_BC (4.0%), CRF64_BC(4.0%), subtype B(4.0%) and CRF55_01B(2.0%). One drug, which resistant mutation to proteinase inhibitors had been detected in one sequence. Based on the statistical method of HIVDR-TS, the prevalence of transmitted HIV-1 drug resistance was adjusted as <5%. The proportion of Burmese was relatively higher among those newly reported HIV-infected individuals aged 16 to 25 in Dehong. We noticed that the novel circulating recombinant forms began to function. However, the level of transmission through HIV-1 drug resistant strains still kept low in Dehong.

PREVALENCE OF DRUG RESISTANT HIV STRAINS IN HIV-INFECTED PATIENTS OF REPRODUCTIVE AGE

The prevalence of drug resistant HIV strains among HIV-positive reproductive aged persons with ineffective antiretroviral therapy (ART) was assessed. The prevalence of drug resistant strains of HIV was 73.8% in the group of women and 89.29% in the group of men (totally in 80.0% of patients). In the spectrum of drug resistance mutations (DRMs) the most prevalent mutation associated with high-level resistance to nucleoside reverse transcriptase inhibitors was substitution M184V (80.36%); in addition, the high prevalence of K65R (26.79%) was indicated. The most common mutations causing a high-level resistance to nonnucleoside reverse transcriptase inhibitors were G190S/A (57.14%), Y181C (37.50%), K101E (33.93%). The DRMs to protease inhibitors were indicated with significantly less frequent (5.36%).

Epidemic Trend of HIV-1 Drug-Resistant Mutations Isolated From HIV-Infected Patients in Hebei, China from 2008 to 2013

Background: Widespread use of anti-HIV therapies has led to the global development of drug-resistant HIV strains. In China, our current knowledge of HIV- 1 strain variation, emerging epidemiological trends and viral genetics underlying drug resistance is limited. Method: Between 2008 and 2013, HIV-1 strains from 569 HIV-seropositive and AIDS patients undergoing antiviral treatment in Hebei province (China) were genotyped. ART-virological failure (viral load ≥ 1000 copies/ml) and HIV-1 mutations for these strains were analyzed, as were variations in mutation trends during this period. Results: ART-virological failure in HIV-infected patients decreased significantly between 2008 and 2013 (60.9% vs. 35.0%, p<0.05), and showed a significant decreasing trend (p<0.05). When all HIV-seropositive patients undergoing antiviral treatment were included in this analysis, however, differences or trends observed were not significant. Six mutations were detected in the HIV-1 protease coding region. Only one (A71V/T) showed a significant difference in prevalence during this period (p<0.05). Sixty-one mutations were found in the HIV-1 reverse transcriptase coding region, including 34 related to nucleoside reverse transcriptase inhibitor treatment and 27 related to non-nucleoside reverse transcriptase inhibitor treatment. Thirteen mutations (V75I, T215Y, M41L, L210W, T69D, D67DG, V118I, V75I/T, F77L, T215F, Q151M; NNRTI-related: V108I, M230L) exhibited significant decreasing trends between 2010 and 2013, and two mutations (K238T, V90I) showed significant increasing trends (p<0.05). Conclusion: Continuous monitoring of drug resistance is essential for the design of optimal regimens and improvement of therapeutic outcomes.

Design and Synthesis of DiselenoBisBenzamides (DISeBAs) as Nucleocapsid Protein 7 (NCp7) Inhibitors with anti-HIV Activity.

The interest in the synthesis of Se-containing compounds is growing with the discovery of derivatives exhibiting various biological activities. In this manuscript, we have identified a series of 2,2'-diselenobisbenzamides (DISeBAs) as novel HIV retroviral nucleocapsid protein 7 (NCp7) inhibitors. Because of its pleiotropic functions in the whole viral life cycle and its mutation intolerant nature, NCp7 represents a target of great interest which is not reached by any anti-HIV agent in clinical use. Using the diselenobisbenzoic scaffold, amino acid, and benzenesulfonamide derivatives were prepared and biologically profiled against different models of HIV infection. The incorporation of amino acids such as glycine and glutamate into DISeBAs 7 and 8 resulted in selective anti-HIV activity against both acutely and chronically infected cells as well as an interesting virucidal effect. DISeBAs demonstrated broad antiretroviral activity, encompassing HIV-1 drug-resistant strains including clinical isolates, as well as simian immunodeficiency virus (SIV). Time of addition experiments, along with the observed dose dependent inhibition of the Gag precursor proper processing, confirmed that their mechanism of action is based on NCp7 inhibition.

Kuwanon-L as a New Allosteric HIV-1 Integrase Inhibitor: Molecular Modeling and Biological Evaluation.

HIV-1 integrase (IN) active site inhibitors are the latest class of drugs approved for HIV treatment. The selection of IN strand-transfer drug-resistant HIV strains in patients supports the development of new agents that are active as allosteric IN inhibitors. Here, a docking-based virtual screening has been applied to a small library of natural ligands to identify new allosteric IN inhibitors that target the sucrose binding pocket. From theoretical studies, kuwanon-L emerged as the most promising binder and was thus selected for biological studies. Biochemical studies showed that kuwanon-L is able to inhibit the HIV-1 IN catalytic activity in the absence and in the presence of LEDGF/p75 protein, the IN dimerization, and the IN/LEDGF binding. Kuwanon-L also inhibited HIV-1 replication in cell cultures. Overall, docking and biochemical results suggest that kuwanon-L binds to an allosteric binding pocket and can be considered an attractive lead for the development of new allosteric IN antiviral agents.

Drug-resistance characteristics of CRF01_AE and CRF07_BC subtypes of HIV-1 strains in Sichuan province

To investigate the drug resistance of HIV patients to the HIV-1 CRF01_AE and CRF07_BC strains in Sichuan province during 2010 to 2013. 1.5 ml of plasma were collected from AIDS patients who had been receiving anti-retroviral treatment for over 6 months but still had a HIV-1 virus load of over 1 000 copies/ml from January 1, 2010 to December 31, 2013 in Sichuan province. Genetic analysis of the HIV-1 pol gene was performed using self-established method, and patients with a positive drug-resistant HIV-1 pol gene mutation were included. HIV-1 poly gene was successfully sequenced for a total of 1 213 patients. Drug resistance of different HIV-1 strains was compared with χ2 test or Fisher exact test. 558 cases (46.0%) of the 1 213 successfully sequenced patients were infected by HIV-1-strains with drug-resistant mutations, including 327 cases (58.6%) infected by CRF01_AE strain, 126 (22.6%) by CRF07_BC strain, 46 (8.2%) by CRF08_BC strain, 33 (5.9%) by B strain, 4 (0.7%) by C strain, 1 (0.2%) by CRF02_AG strain, and 21 (3.8%) by unidentified strains. Drug-resistant mutation analysis revealed that L33, F116, L74, Q151, and T69 resistance mutations occurred only in the CRF01_AE strain, while A71, K43, and Q58 resistance mutations occurred only in the CRF07_BC strain; in nuclear nucleoside reverse transcriptase inhibitors (NRTIs) and non nucleoside reverse transcriptase inhibitors (NNRTIs), CRF01_AE subtype strains showed highly resistant rate were higher than CRF07_BC, CRF08_BC and B subtype strains, with the differences were statistically significant (P<0.05). The drug-resistant HIV-1 strains in Sichuan mainly included the CRF01_AE and CRF07_BC strains, which had different resistance mutations.

HIV-1 Genetic Diversity and Transmitted Drug Resistance Among Recently Infected Individuals at Men Who Have Sex with Men Sentinel Surveillance Points in Hebei Province, China.

For this study, 50 HIV-1 plasma samples of recently infected men who have sex with men (MSM) were amplified and sequenced. Multiple subtypes were identified by phylogenetic analyses of HIV-1 gag, env, and pol gene regions, including CRF01_AE (56.0%), CRF07_BC (30.0%), subtype B (12.0%), and unique recombinant forms (URFs, 6.0%). CRF01_AE was the most frequent genotype in the epidemic. Three recombination patterns of URFs were identified: 01BC, 01B, and 01C. The rate of HIV-1 transmitted drug resistance (TDR) mutation (M46L) was 2.08% (1/48). URFs and TDR first identified in this study suggest that HIV-1 prevalence is more and more complicated, and HIV-1 drug-resistant strains have begun to spread among at risk populations in Hebei. Our findings can provide vital information for an efficient surveillance system and strategic HIV prevention and control measures in China by revealing the evolutionary status and HIV-1 TDR of HIV-1 strains among recently infected MSM in Hebei Province.

The R263K substitution in HIV-1 subtype C is more deleterious for integrase enzymatic function and viral replication than in subtype B

Dolutegravir is an integrase strand-transfer inhibitor that has shown unprecedented robustness against the emergence of HIV drug-resistant strains in treatment-naive individuals. The R263K substitution in integrase was identified through culture selection as a resistance-associated substitution for dolutegravir and was recently detected in two treatment-experienced participants in the SAILING clinical trial, who experienced dolutegravir-based treatment failure, one of whom was infected by a subtype C virus. The objective of this study was to characterize the R263K substitution in HIV-1 subtype C integrase. We used cell-free strand transfer assays and tissue culture experiments to characterize the R263K substitution in HIV-1 subtype C integrase in comparison with subtype B. Cell-free biochemical assays showed that the R263K substitution diminished subtype C integrase strand-transfer activity by decreasing the affinity of integrase for target DNA. Similarly, both viral infectiousness and replication capacity were reduced by the R263K substitution in tissue culture. Decrease in enzyme activity and viral infectiousness exceeded 35 and 50%, respectively - significantly more than in HIV-1 subtype B. R263K in HIV-1 subtype C also conferred low levels of resistance against dolutegravir and high levels of cross-resistance against elvitegravir, but not raltegravir. The R263K substitution is more deleterious to integrase strand-transfer activity and viral infectiousness in HIV-1 subtype C than in subtype B. Our results suggest that cross-resistance may prevent treatment-experienced individuals who are experiencing treatment failure with dolutegravir from being subsequently treated with elvitegravir.

Targeting of mTOR catalytic site inhibits multiple steps of the HIV-1 lifecycle and suppresses HIV-1 viremia in humanized mice

HIV necessitates host factors for successful completion of its life cycle. Mammalian target of rapamycin (mTOR) is a conserved serine/threonine kinase that forms two complexes, mTORC1 and mTORC2. Rapamycin is an allosteric inhibitor of mTOR that selectively inhibits mTORC1. Rapamycin interferes with viral entry of CCR5 (R5)-tropic HIV and with basal transcription of the HIV LTR, potently inhibiting replication of R5 HIV but not CXCR4 (X4)-tropic HIV in primary cells. The recently developed ATP-competitive mTOR kinase inhibitors (TOR-KIs) inhibit both mTORC1 and mTORC2. Using INK128 as a prototype TOR-KI, we demonstrate potent inhibition of both R5 and X4 HIV in primary lymphocytes (EC50 < 50 nM), in the absence of toxicity. INK128 inhibited R5 HIV entry by reducing CCR5 levels. INK128 also inhibited both basal and induced transcription of HIV genes, consistent with inhibition of mTORC2, whose activity is critical for phosphorylation of PKC isoforms and, in turn, induction of NF-κB. INK128 enhanced the antiviral potency of the CCR5 antagonist maraviroc, and had favorable antiviral interactions with HIV inhibitors of reverse transcriptase, integrase and protease. In humanized mice, INK128 decreased plasma HIV RNA by >2 log10 units and partially restored CD4/CD8 cell ratios. Targeting of cellular mTOR with INK128 (and perhaps others TOR-KIs) provides a potential strategy to inhibit HIV, especially in patients with drug resistant HIV strains.

The HEPT Analogue WPR-6 Is Active against a Broad Spectrum of Nonnucleoside Reverse Transcriptase Drug-Resistant HIV-1 Strains of Different Serotypes.

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are important components of the highly active antiretroviral therapy (HAART) used to treat human immunodeficiency type 1 virus (HIV-1). However, because of the emergence of drug resistance and the adverse effects of current anti-HIV drugs, it is essential to develop novel NNRTIs with an excellent safety profile, improved activity against NNRTI-resistant viruses, and enhanced activity against clinical isolates of different subtypes. Here, we have identified 1-[(benzyloxy)methyl]-6-(3,5-dimethylbenzyl)-5-iodopyrimidine-2,4(1H,3H)-dione (WPR-6), a novel NNRTI with a 50% effective concentration (EC50) of 2 to 4 nM against laboratory-adapted HIV-1 strain SF33 and an EC50 of 7 to 14 nM against nucleoside reverse transcriptase inhibitor-resistant HIV-1 strain 7391 with a therapeutic index of >1 × 10(4). A panel of five representative clinical virus isolates of different subtypes circulating predominantly in China was highly sensitive to WPR-6, with EC50s ranging from 1 to 6 nM. In addition, WPR-6 showed excellent antiviral potency against the most prevalent NNRTI-resistant viruses containing the K103N and Y181C mutations. To determine whether WPR-6 selects for novel resistant mutants, in vitro resistance selection was conducted with laboratory-adapted HIV-1 strain SF33 on MT-4 cells. The results demonstrated that V106I and Y188L were the two dominant NNRTI-associated resistance mutations detected in the breakthrough viruses. Taken together, these in vitro data indicate that WPR-6 has greater efficacy than the reference HEPT analogue TNK651 and the marketed drug nevirapine against HIV-1. However, to develop it as a new NNRTI, further improvement of its pharmacological properties is warranted.

Analysis on HIV-1 genetics and threshold of drug resistance in Dehong prefecture of Yunnan province in 2013

To study the HIV-1 genotypes and transmitted drug resistance (TDR) in Dehong prefecture of Yunnan province in 2013. Referring to the guidelines for HIV drug resistance threshold survey (HIVDR-TS), 54 plasma samples of recently reported HIV-infected individuals, aged between 16 and 25 years, were collected in Dehong prefecture from January to August 2013. Genotyping of partial pol gene was performed by using reverse transcriptional PCR. HIV-1 genotype. Prevalent levels of HIV-1 drug resistance transmission were analyzed. Forty-eight plasma samples were successfully sequenced and analyzed. Among them, 45.8% were Chinese and the rest 54.2% were all Burmese. Based on pol sequences, identified HIV genotypes included subtype C (41.7%), URF (31.3%), CRF01_AE (12.5%), CRF07_BC (10.4%), CRF08_BC (2.1%) and subtype B (2.1%), C subtype appeared dominated in Chinese while URF was dominated in Burmese. One drug resistant mutation to non-nucleoside reverse transcriptase inhibitors (NNRTIs) was detected in one sequence from Burmese. Based on the statistical method of HIVDR-TS, the prevalence of transmitted HIV-1 drug resistance was adjusted as < 5%. Diverse HIV-1 genotypes were found in this study, and the current HIV-1 drug resistant strains transmission was catalogued as at low prevalence level, in Dehong. To prevent the increase of the prevalence of transmitted HIV-1 drug resistance, standard treatment and scientific management for people living with HIV/AIDS should be strictly followed. Meanwhile, relevant surveillance, including drug resistance surveillance should also be performed among cross-border migrant population.

Transmitted Drug Resistance Mutations in Antiretroviral-Naïve Injection Drug Users with Chronic HIV-1 Infection in Iran.

The growing incidence and transmission of drug resistant HIV-1 strains due to widespread use of antiretroviral therapy (ART) can jeopardize the success of first-line ART. While there is a known moderate prevalence of transmitted drug resistance (TDR) among newly infected Iranians, no data exist about the rate of these primary resistance mutations among the ART-naïve, chronically infected individuals who are, in fact, the main candidates for ART initiation. To address this issue, we collected blood samples from 40 ART-naïve injection drug-users (IDUs) with chronic HIV-1 infection (seroconversion time ranging from 2 to 9 years) living in Sanandaj, Iran, followed by sequencing of the protease and reverse-transcriptase regions from their HIV-1 genome. Phylogenetic analyses of the sequenced regions revealed that all samples were CRF35_AD. Transmitted resistance mutations were interpreted as surveillance drug-resistant mutations (SDRMs) based on the world health organization (WHO) algorithm. The frequency of SDRMs to any class of antiretroviral drugs was 15%, which included mutations to nucleoside reverse transcriptase inhibitors (NRTIs, 10%), with M41L and M184V as the most common (5%), and non-nucleoside reverse transcriptase inhibitors (NNRTIs, 5%), with K103N as the only detected mutation (5%). Although not in the WHO SDRMs list, several minor protease inhibitor resistant mutations listed in the International Antiviral Society-USA panel were identified, of which M36I, H69K, L89M/V/I (each one 100%) and K20R/T (92.5%) can be considered as polymorphic signatures for CRF35_AD.The relatively high rate of TDR mutations in our study raises concerns about the risk of treatment failure in chronically infected IDUs of Sanandaj city. These results suggest that routine resistance testing should be considered before the therapy initiation in this area. Additional surveillance studies are required to generalize this deduction to other cities of Iran.

English

Antenatal zidovudine (AZT), intrapartal nevirapine (NVP) and postpartal lamivudine (3TC)/AZT to prevent mother-to-child transmission of human immunodeficiency virus (HIV)-1 as recommended in 2006 World Health Organization (WHO) guidelines has shown to select HIV-resistant plasma virus in Tanzanian women. During viral replication, HIV integrates into the cellular host genome where resistant strains may remain archived. This study analyzed the dimension of integration of drug-resistant HIV-strains into the host cells as provirus by analyzing corresponding peripheral blood mononuclear cells (PBMCs) for key resistance mutations selected by AZT/NVP/3TC, applying highly-sensitive allele-specific polymerase chain reaction (PCR). HIV-resistance was detected in PBMC-DNA of 10 (28%) and in plasma virus of 15 of 36 women (42%). Most resistance mutations were selected by AZT in comparable proportions in PBMCs (25%) and in plasma virus (22%). In conclusion, antenatal AZT may select for AZT-resistance potentially persisting as provirus, and therefore is likely to negatively impact future treatment options. Key words: Tanzania, prevention of mother-to-child transmission of human immunodeficiency virus (HIV)-1, triple prophylaxis, HIV-1 drug resistance, peripheral blood mononuclear cells (PBMCs), proviral DNA, minor variants, allele-specific polymerase chain reaction (PCR).

Enhanced Monitoring of Antiretroviral Resistance in Persons Living with HIV/AIDS

In recent years the transmission of HIV drug-resistant strains among infected persons has been an on-going concern. Measuring the burden of antiretroviral resistance has risen in importance, ranking alongside other major public health concerns when planning HIV prevention campaigns. The aim of this presentation is to illustrate a public health surveillance method for monitoring antiretroviral drug resistance in persons diagnosed with human immunodeficiency virus infection. We developed procedures for examining HIV related electronic laboratory reports (ELR) transmitted to our health department surveillance system that link to corresponding clinical and demographic data for patients with varying degrees of antiretroviral drug resistance.

Asking about adherence - from flipping the coin to strong evidence.

In the era of antiretroviral therapy (ART) as prevention for transmission of HIV as well as treatment for HIV-positive individuals irrespective of CD4 cell counts, the importance of adherence has grown. Although adherence is not the only determinant of treatment success, it is one of the only modifiable risk factors. Treatment failure reduces future treatment options and therefore long-term clinical success as well as increases the possibility of developing drug resistant mutations. Drug-resistant strains of HIV can then be transmitted to uninfected or drug-naïve individuals limiting their future treatment options, making adherence an important public-health topic, especially in resource-limited settings. Adherence should be monitored as a part of routine clinical care; however, no gold standard for assessment of adherence exists. For use in daily clinical practice, self-report is the most likely candidate for widespread use due to its many advantages over other measurement methods, such as low cost and ease of administration. Asking individuals about their adherence behaviour has been shown to yield valid and predictive data - well beyond the mere flip of a coin. However, there is still work to be done. This article reviews the literature and evidence on self-reported adherence, identifies gaps in adherence research, and makes recommendations for clinicians on how to best utilise self-reported adherence data to support patients in daily clinical practice.

Hydrophobic mutations in buried polar residues enhance HIV-1 gp41 N-terminal heptad repeat–C-terminal heptad repeat interactions and C-peptides’ anti-HIV activity

To investigate the effect of mutations in a highly conserved buried polar area on the function of HIV-1 gp41. During HIV-1 entry, a six helical bundle (6-HB) formation between the C-terminal and N-terminal heptad repeat (CHR and NHR) of gp41 provides energy for virus cell membrane fusion. In 6-HB, residues at a and d (a-d) positions of CHR directly interact with NHR and are buried. They are considered critical residues for 6-HB stability and for anti-HIV-1 activity of CHR-derived peptides (C-peptides). Most of a-d residues in CHR are hydrophobic, as buried hydrophobic residues facilitate protein stability. However, HIV-1 gp41 CHR contains a highly conserved polar area with four successive buried a-d polar residues: S649/Q652/N656/E659. We mutated these buried polar residues to hydrophobic residues, either Leu or Ile, and studied its effect on the gp41 NHR-CHR interactions and anti-HIV activities of the C-peptides. We measured the C-peptide mutants' ability to form 6-HB with NHR, thermal stability of the 6-HBs and C-peptides' inhibitory activity against both T20-sensitive and resistant HIV-1 strains. All the mutated C-peptides retained their ability to form stable 6-HB with NHR and strongly inhibited HIV-1 replication. Strikingly, S649L and E659I mutations endow C-peptide with a significantly enhanced activity against T20-resistant HIV-1 strains. The highly conserved buried a-d polar residues in HIV-1 gp41 CHR can be mutated as a means of developing new fusion inhibitors against drug-resistant HIV-1 strains. The concept can also be utilized to design fusion inhibitors against other viruses with similar mechanisms.