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A host cellular transmembrane protein, SERINC5, inhibits HIV-1 infectivity when incorporated into progeny virions. Recent studies suggest that certain Envelope glycoproteins can resist SERINC5-mediated restriction. However, the underlying mechanism of Envelope glycoprotein-mediated resistance to SERINC5 restriction remains unclear. Here, we investigated the extent of sensitivity of patient-derived HIV-1 Envelope sequences to SERINC5-mediated restriction and examined Envelopes’ characteristics in relation to SERINC5. A nef-deficient HIV-1 reporter was pseudotyped with Envelope sequences isolated from a total of 50 Tanzanians infected with non-B HIV-1 subtypes in the presence and absence of SERINC5 expression. The infectivity of resultant pseudoviruses was differentially reduced by SERINC5 by a median of 5.1-fold (IQR: 3.2–8.6) including five outliers showing ≥20-fold reduction, whereas the pseudovirus with the control NL4-3 envelope was reduced by 64-fold. The pseudovirus sensitivity to SERINC5-mediated restriction differed significantly among the subtypes of the envelope sequences but was not associated with any other Envelope characteristics or clinical parameters tested. Within some hosts, the pseudovirus sensitivity to SERINC5 varied substantially among Envelope sequences, with sensitive ones (as defined by ≥20-fold reduction) being underrepresented. Analysis of chimeric constructs between intra-host clones revealed that both N- and C-terminus of the Envelope sequences were responsible for SERINC5-mediated restriction. Taken together, these results demonstrate that the majority of naturally occurring Envelope sequences across multiple subtypes are relatively less sensitive to SERINC5-mediated restriction of infectivity and that naturally occurring polymorphisms at N- and C-terminal parts are important for this sensitivity. IMPORTANCE Pathogenesis of HIV-1 is enhanced through several viral-encoded proteins that counteract a range of host restriction molecules. HIV-1 Nef counteracts the cell membrane protein SERINC5 by downregulating it from the cell surface, thereby enhancing virion infectivity. Some subtype B reference Envelope sequences have shown the ability to bypass SERINC5 infectivity restriction independent of Nef. However, it is not clear if and to what extent circulating HIV-1 strains can exhibit resistance to SERINC5 restriction. Using a panel of Envelope sequences isolated from 50 Tanzanians infected with non-B HIV-1 subtypes, we show that the lentiviral reporters pseudotyped with patient-derived Envelopes have reduced sensitivity to SERINC5 and that this sensitivity differed among viral subtypes. Moreover, we found that SERINC5 sensitivity within patient-derived Envelopes can be modulated by separate regions, highlighting the complexity of viral/host interactions. [ABSTRACT FROM AUTHOR]

Background: The number of primary human immunodeficiency virus (HIV)-1 non-B subtype infections (non-B) and that of reports regarding the differences in the pathogenesis of subtype B and non-B infections are increasing. However, to the best of our knowledge, there have been no reports on gross deletion in the nef gene (gΔnef) in non-B infections. Methods: To determine whether there is a difference in the change in CD4+ T cells after treatment with Korean Red Ginseng (KRG) between patients with subtype B and non-B infections, we retrospectively analyzed and compared the annual decrease in CD4+ T cells (AD) and the proportion of gΔnef in 77 patients who were followed for more than 10 years in the absence of combination antiretroviral therapy. Results: Overall, AD was significantly faster in patients with non-B infections than in those with subtype B infections. Survival analysis showed that the survival probability was significantly higher in subtype B than in non B-infected patients. These differences mainly resulted from significant differences in the amount of KRG and age. In the patients treated with KRG, there was a significant correlation between the amount of KRG and the AD in both subtypes. Interestingly, there was a significant correlation between the amount of KRG and the proportion of gΔnef in patients infected with subtype B, but not in those infected with non-B. The same phenomenon was observed when the KRG dose was adjusted. Conclusion: Our results suggest that non-B may be biologically more stable than subtype B.

Small CD4-mimetic compound (CD4mc), which inhibits the interaction between gp120 with CD4, acts as an entry inhibitor and induces structural changes in the HIV-1 envelope glycoprotein trimer (Env) through its insertion within the Phe43 cavity of gp120. We recently developed YIR-821, a novel CD4mc, that has potent antiviral activity and lower toxicity than the prototype NBD-556. To assess the possibility of clinical application of YIR-821, we tested its antiviral activity using a panel of HIV-1 pseudoviruses from different subtypes. YIR-821 displayed entry inhibitor activity against 53.5% (21/40) of the pseudoviruses tested and enhanced neutralization mediated by coreceptor binding site (CoRBS) antibodies in 50% (16/ 32) of these. Furthermore, when we assessed the antiviral effects using a panel of pseudoviruses and autologous plasma IgG, enhancement of antibody-mediated neutralization activity was observed for 48% (15/31) of subtype B strains and 51% (28/55) of non-B strains. The direct antiviral activity of YIR-821 as an entry inhibitor was observed in 53% of both subtype B (27/51) and non-B subtype (40/75) pseudoviruses. Enhancement of antibody-dependent cellular cytotoxicity was also observed with YIR-821 for all six selected clinical isolates, as well as for the transmitted/founder (T/F) CH58 virus-infected cells. The sequence diversity in the CD4 binding site as well as other regions, such as the gp120 inner domain layers or gp41, may be involved in the multiple mechanisms related to the sensitive/resistant phenotype of the virus to YIR-821. Our findings may facilitate the clinical application of YIR-821.IMPORTANCE Small CD4-mimetic compound (CD4mc) interacts with the Phe43 cavity and triggers conformational changes, enhancing antibody-mediated neutralization and antibody-dependent cellular cytotoxicity (ADCC). Here, we evaluated the effect of YIR-821, a novel CD4mc, against clinical isolates, including both subtype B and non-B subtype viruses. Our results confirm the desirable properties of YIR-821, which include entry inhibition, enhancement of IgG-neutralization, binding, and ADCC, in addition to low toxicity and long half-life in a rhesus macaque model, that might facilitate the clinical application of this novel CD4mc. Our observation of primary viruses that are resistant to YIR-821 suggests that further development of CD4mcs with different structural properties is required. [ABSTRACT FROM AUTHOR]

Background: In Switzerland, HIV-1 transmission among men who have sex with men (MSM) has been dominated by subtype B, whilst non-B subtypes are commonly attributed to infections acquired abroad among heterosexuals. Here, we evaluated the temporal trends of non-B subtypes and the characteristics of molecular transmission clusters (MTCs) among MSM.Methods: Sociodemographic and clinical data and partial pol sequences were obtained from participants enrolled in the Swiss HIV Cohort Study. For non-B subtypes, maximum likelihood trees were constructed, from which Swiss MTCs were identified and analyzed by transmission group.Results: Non-B subtypes were identified in 8.1% (416/5116) of MSM participants. CRF01_AE was the most prevalent strain (3.5%), followed by subtype A (1.2%), F (1.1%), CRF02_AG (1.1%), C (0.9%), and G (0.3%). Between 1990 and 2019, an increase in the proportion of newly diagnosed individuals (0/123 [0%] to 11/32 [34%]) with non-B subtypes in MSM was found. Across all non-B subtypes, the majority of MSM MTCs were European. Larger MTCs were observed for MSM than heterosexuals.Conclusions: We found a substantial increase in HIV-1 non-B subtypes among MSM in Switzerland and the occurrence of large MTCs, highlighting the importance of molecular surveillance in guiding public health strategies targeting the HIV-1 epidemic. [ABSTRACT FROM AUTHOR]

HIV human immunodeficiency virus type I (HIV-1) entry inhibitor potency is dependent on viral co-receptor tropisms and thereby tropism determination is clinically important. However, phenotypic tropisms of HIV-1 non-B subtypes have been poorly investigated and the genotypic prediction algorithms remain insufficiently validated. To clarify this issue, we recruited 52 treatment-naïve, HIV-1-infected patients in Tanzania, where multiple HIV-1 non-B subtypes co-circulate. Sequence analysis of 93 infectious envelope clones isolated from their plasma viral RNA revealed the co-circulation of subtypes A1, C, D, and inter-subtype recombinant forms (isRFs). Phenotypic tropism assays revealed that lentivirus reporters pseudotyped with 75 (80.6%) and 5 (5.4%) envelope clones could establish infection toward U87.CD4 cells expressing CCR5 (R5) and CXCR4 (X4), respectively; whereas the remaining 13 (14%) clones could infect both cells. Genotypic analyses by widely used algorithms including V3 net charge, Geno2pheno, WebPSSM, and PhenoSeq showed that almost all phenotypic X4-tropic clones and only 15 of 75 phenotypic R5-tropic clones were concordantly predicted. However, the remaining 60 phenotypic R5-tropic clones were discordantly predicted by at least one algorithm. In particular, 2 phenotypic R5-tropic clones were discordantly predicted by all algorithms tested. Taken together, the results demonstrate the limitation of currently available genotypic algorithms for predicting co-receptor inference among co-circulating multiple non-B subtypes and emerging isRFs. Also, the phenotypic tropism dataset presented here could be valuable for retraining of the widely used genotypic prediction algorithms to enhance their performance.

HIV human immunodeficiency virus type I (HIV-1) entry inhibitor potency is dependent on viral co-receptor tropisms and thereby tropism determination is clinically important. However, phenotypic tropisms of HIV-1 non-B subtypes have been poorly investigated and the genotypic prediction algorithms remain insufficiently validated. To clarify this issue, we recruited 52 treatment-naïve, HIV-1-infected patients in Tanzania, where multiple HIV-1 non-B subtypes co-circulate. Sequence analysis of 93 infectious envelope clones isolated from their plasma viral RNA revealed the co-circulation of subtypes A1, C, D, and inter-subtype recombinant forms (isRFs). Phenotypic tropism assays revealed that lentivirus reporters pseudotyped with 75 (80.6%) and 5 (5.4%) envelope clones could establish infection toward U87.CD4 cells expressing CCR5 (R5) and CXCR4 (X4), respectively; whereas the remaining 13 (14%) clones could infect both cells. Genotypic analyses by widely used algorithms including V3 net charge, Geno2pheno, WebPSSM, and PhenoSeq showed that almost all phenotypic X4-tropic clones and only 15 of 75 phenotypic R5-tropic clones were concordantly predicted. However, the remaining 60 phenotypic R5-tropic clones were discordantly predicted by at least one algorithm. In particular, 2 phenotypic R5-tropic clones were discordantly predicted by all algorithms tested. Taken together, the results demonstrate the limitation of currently available genotypic algorithms for predicting co-receptor inference among co-circulating multiple non-B subtypes and emerging isRFs. Also, the phenotypic tropism dataset presented here could be valuable for retraining of the widely used genotypic prediction algorithms to enhance their performance. [ABSTRACT FROM AUTHOR]

HIV infection is a global health epidemic with current FDA-approved HIV-1 Protease inhibitors (PIs) designed against subtype B protease, yet they are used in HIV treatment world-wide regardless of patient HIV classification. In this study, double electron-electron resonance (DEER) electron paramagnetic resonance (EPR) spectroscopy was utilized to gain insights in how natural polymorphisms in several African and Brazilian protease (PR) variants affect the conformational landscape both in the absence and presence of inhibitors. Findings show that Subtypes F and H HIV-1 PR adopt a primarily closed conformation in the unbound state with two secondary mutations, D60E and I62V, postulated to be responsible for the increased probability for closed conformation. In contrast, subtype D, CRF_AG, and CRF_BF HIV-1 PR adopt a primarily semi-open conformation, as observed for PI-naïve-subtype B when unbound by substrate or inhibitor. The impact that inhibitor binding has on shifting the conformational land scape of these variants is also characterized, where analysis provides classification of inhibitor induced shifts away from the semi-open state into weak, moderate and strong effects. The findings are compared to those for prior studies of inhibitor induced conformational shifts in PI-naïve Subtype B, C and CRF_AE. • DEER spectroscopy reveals altered conformational landscapes of HIV-1 PR variants. • Brazilian/African natural polymorphisms increase curling/closing of HIV-1 PR flaps. • Subtypes H and F adopt >50% closed conformation in the absence of inhibitors. • Inhibitor-induced conformational shifts are compared to PI-naïve Subtype B. • Ritonavir weakly impacts flap conformation in Subtypes F and H and CRF_AG and CRF_BF. [ABSTRACT FROM AUTHOR]

Phylogenetics has been advanced as a structural framework to infer evolving trends in the regional spread of HIV-1 and guide public health interventions. In Quebec, molecular network analyses tracked HIV transmission dynamics from 2002–2020 using MEGA10-Neighbour-joining, HIV-TRACE, and MicrobeTrace methodologies. Phylogenetics revealed three patterns of viral spread among Men having Sex with Men (MSM, n = 5024) and heterosexuals (HET, n = 1345) harbouring subtype B epidemics as well as B and non-B subtype epidemics (n = 1848) introduced through migration. Notably, half of new subtype B infections amongst MSM and HET segregating as solitary transmissions or small cluster networks (2–5 members) declined by 70% from 2006–2020, concomitant to advances in treatment-as-prevention. Nonetheless, subtype B epidemic control amongst MSM was thwarted by the ongoing genesis and expansion of super-spreader large cluster variants leading to micro-epidemics, averaging 49 members/cluster at the end of 2020. The growth of large clusters was related to forward transmission cascades of untreated early-stage infections, younger at-risk populations, more transmissible/replicative-competent strains, and changing demographics. Subtype B and non-B subtype infections introduced through recent migration now surpass the domestic epidemic amongst MSM. Phylodynamics can assist in predicting and responding to active, recurrent, and newly emergent large cluster networks, as well as the cryptic spread of HIV introduced through migration.

Changes over time in HIV-1 subtype diversity within a population reflect changes in factors influencing the development of local epidemics. Here we report on the genetic diversity of 2364 reverse transcriptase sequences from people living with HIV-1 in New South Wales (NSW) notified between 2004 and 2018. These data represent >70% of all new HIV-1 notifications in the state over this period. Phylogenetic analysis was performed to identify subtype-specific transmission clusters. Subtype B and non-B infections differed across all demographics analysed (p < 0.001). We found a strong positive association for infections among females, individuals not born in Australia or reporting heterosexual transmission being of non-B origin. Further, we found an overall increase in non-B infections among men who have sex with men from 50 to 79% in the last 10 years. However, we also found differences between non-B subtypes; heterosexual transmission was positively associated with subtype C only. In addition, the majority of subtype B infections were associated with clusters, while the majority of non-B infections were singletons. However, we found seven non-B clusters (≥5 sequences) indicative of local ongoing transmission. In conclusion, we present how the HIV-1 epidemic has changed over time in NSW, becoming more heterogeneous with distinct subtype-specific demographic associations.

Primary HIV‐1 infections (PHI) with non‐B subtypes are increasing in developed countries while transmission of HIV‐1 harboring antiretroviral resistance‐associated mutations (RAMs) remains a concern. This study assessed non‐B HIV‐1 subtypes and RAMs prevalence among patients with PHI in university hospitals of Marseille, Southeastern France, in 2005‐2015 (11 years). HIV‐1 sequences were obtained by in‐house protocols from 115 patients with PHI, including 38 for the 2013‐2015 period. On the basis of the phylogenetic analysis of the reverse transcriptase region, non‐B subtypes were identified in 31% of these patients. They included 3 different subtypes (3A, 1C, 4F), 23 circulating recombinant forms (CRFs) (CRF02_AG, best BLAST hits being CRF 36_cpx and CRF30 in 7 and 1 cases, respectively), and 5 unclassified sequences (U). Non‐B subtypes proportion increased significantly, particularly in 2011‐2013 vs in 2005‐2010 (P = .03). CRF02_AG viruses largely predominated in 2005‐2013 whereas atypical strains more difficult to classify and undetermined recombinants emerged recently (2014‐2015). The prevalence of protease, nucleos(t)ide reverse transcriptase, and first‐generation nonnucleoside reverse transcriptase inhibitors–associated RAMs were 1.7% (World Health Organization [WHO] list, 2009/2.6% International AIDS Society [IAS] list, 2017), 5.2%/4.3%, and 5.2%/5.2%, respectively. Etravirine/rilpivirine‐associated RAM (IAS) prevalence was 4.3%. Men who have sex with men (MSM) were more frequently infected with drug‐resistant viruses than other patients (26% vs 7%; P = .011). The recent increase of these rare HIV‐1 strains and the spread of drug‐resistant HIV‐1 among MSM in Southeastern France might be considered when implementing prevention strategies and starting therapies. [ABSTRACT FROM AUTHOR]

There have been no studies related to groups at the highest risk for HIV-1 infection in Korea before 1993. In this study, for the first time, we report the distribution of HIV subtypes in overseas sailors (OSs) and prostitutes who worked in brothels near U.S. military bases in Korea. We retrospectively determined the sequences of nef in 131 patients using reverse transcription polymerase chain reaction (RT-PCR). These patients composed of 102 OSs, 14 OS spouses, and 15 prostitutes. Phylogenetic analysis was performed using 128 Korean OSs, OS spouses, and prostitutes. The distribution of non-B subtypes (n = 105) was as follows: 39, CRF02_AG; 15, CRF01_AE; 7, A1; 7, A2; 6, D; 2, CRF06_cpx; 3, C; 6, G; 11, untypable; and 1 each for CRF09_cpx, CRF12_BF, CRF50_A1D, A3, AFG, H, F1, F2, and A. Of the 116 OSs and OS spouses, 101 (87%), 11 (9%), and 4 (3%) subjects had non-B, Western B, and Korean subclade B (KSB) HIV-1s, respectively. Among the 15 prostitutes, 10 had Western B (67%), 4 non-B (27%), and 1 KSB (7%) HIV-1s. All 14 couples, each comprising of an OS and his spouse, had the same subtype. KSB (5%) was detected in OSs and prostitutes in 1990 and 1994, respectively. Of the 131 patients analyzed in this study, 105 (80%), 21 (16%), and 5 (4%) were infected with the non-B, Western B, and KSB subtypes of HIV, respectively. In future, these data may provide an important foundation for analysis of HIV-1 subtypes in Korea. [ABSTRACT FROM AUTHOR]

Introduction With the widespread introduction of the integrase (In) inhibitors into clinical practice, transmission of drug resistance to this class of antiretroviral medications may expand. The aim of this study was to analyze the recent patterns of In resistance in treatment naive individuals in Northern Poland and its association with transmitted protease (PR) and reverse transcriptase (RT) mutations. Methods Study included 172 PR, RT and InI sequences from antiretroviral treatment naive HIV-1 infected patients linked to care in Northern Poland from 2010 to 2015. Drug resistance was interpreted based on the WHO surveillance and IAS-USA mutation lists. For phylogeny maximum likelihood and Bayesian Monte Carlo Markov Chain analyses were used. Results Overall rate of transmitted drug resistance was 12.21%. Nucleoside reverse transcriptase inhibitor (NRTI) resistance associated substitutions were found in 11.05% of cases and non-nucleoside reverse transcriptase inhibitor resistance variants in 1.16%. In multivariate models transmitted resistance strongly associated with subtype D infections [66.67% compared to the 3.84% for subtype B (p = 0.001)]. No transmission of major protease or integrase mutations were observed. Polymorphisms associated with resistance against integrase inhibitor, mostly E157Q, were found in 21.5% sequences and associated with female (31.91% vs. 15.2% for male, p = 0.01), injection drug use (84.21% compared to 22.08% for heterosexual and 1.39% for men-who-have-sex-with-men transmissions, p < 0.0001) as well as hepatitis C coinfection [63.64% for positive, versus 8.57% for HCV antibody negative, p < 0.0001]. Clusters of nucleoside reverse transcriptase mutations in subtype D and integrase E157Q variants in subtype B were observed. Conclusions Transmitted drug resistance frequency was high in subtype D but limited to clustered NRTI mutations, being infrequent among subtype B infected cases. Despite lack of major integrase resistance in treatment naive patients, variants potentially affecting susceptibility to this class were common, which indicates the potential need for extended surveillance in the near future. [ABSTRACT FROM AUTHOR]

There are 31 million adults living with HIV‐1 non‐B subtypes globally, and about 10 million are on antiretroviral therapy (ART). Global evidence to guide clinical practice on ART response in HIV‐1 non‐B subtypes remains limited. We systematically searched 11 databases for the period 1996 to 2013 for evidence. Outcomes documented included time to development of AIDS and/or death, resistance mutations, opportunistic infections, and changes in CD4 cell counts and viral load. A lack of consistent reporting of all clinical end points precluded a meta‐analysis. In sum, genetic diversity that precipitated differences in disease progression in ART‐naïve populations was minimized in ART‐experienced populations, although variability in resistance mutations persisted across non‐B subtypes. To improve the quality of patient care in global settings, recording HIV genotypes at baseline and at virologic failure with targeted non‐B subtype‐based point‐of‐care resistance assays and timely phasing out of resistance‐inducing ART regimens is recommended.

Highlights: [•] We compare three real-time PCR assays for quantifying HIV-RNA in Congolese patients with highly diversified HIV-1 viruses. [•] The agreement among the assays was moderate in terms of HIV-1 RNA detectability and inconsistent in terms of quantitation. [•] The observed discrepancies suggest a cautious evaluation of HIV-1 RNA quantitation in patients harboring non-B viruses. [•] Updated and expanded coverage of HIV-1 clade diversity are advisable to challenge novel releases of HIV-1 RNA assays. [•] Knowledge of reliability and limits of available molecular tools represents a useful complement in African patients’ care. [ABSTRACT FROM AUTHOR]

There are 31 million adults living with HIV-1 non-B subtypes globally, and about 10 million are on antiretroviral therapy (ART). Global evidence to guide clinical practice on ART response in HIV-1 non-B subtypes remains limited.We systematically searched 11 databases for the period 1996 to 2013 for evidence. Outcomes documented included time to development of AIDS and/or death, resistance mutations, opportunistic infections, and changes in CD4 cell counts and viral load. A lack of consistent reporting of all clinical end points precluded a meta-analysis. In sum, genetic diversity that precipitated differences in disease progression in ART-naïve populations was minimized in ART-experienced populations, although variability in resistance mutations persisted across non-B subtypes. To improve the quality of patient care in global settings, recording HIV genotypes at baseline and at virologic failure with targeted non-B subtype-based point-of-care resistance assays and timely phasing out of resistanceinducing ART regimens is recommended. [ABSTRACT FROM AUTHOR]

HIV-1 subtype B is the most frequent strain in Sicily. To date, there is no available data about the genetic diversity of HIV-1 viral strains circulating in Sicily among antiretroviral (ARV) naïve subjects and the role of immigration as potential determinant of evolutionary dynamics of HIV-1 molecular epidemiology. For this purpose, HIV-1 polymerase (pol) sequences obtained from 155 ARV naïve individuals from 2004 to 2009 were phylogenetically analysed. The overall rate of HIV-1 non-B infections was 31.0% (n =48/155), increasing from 7.8% in 2004–2006 to 40.9% in 2009, and about one-third were identified as unique recombinant forms. CRF02_AG was the prevalent non-B clade (n =28/48, 58.3%), while subtype C-related strains were responsible for about 30% HIV-1 infections. Non-B viruses strictly associated with heterosexual transmission (85.4%) and were mostly found among immigrants (77.1%). Phylogenetic analysis of non-B sequences found in foreign-born subjects was geographically correlated to the respective country of origin. Moreover, the detection of non-B viral variants in the autochthonous population may support an increasing genetic diversity in Sicily as well as a local circulation of HIV strains also uncommon in our country. In Sicily, HIV-1 epidemic is still mostly attributable to the B subtype. Nevertheless, migration and population movements are progressively introducing novel HIV-1 subtypes causing a continuous increase of HIV-1 molecular dynamic at local level. Molecular surveillance is needed to monitor the genetic evolution of HIV-1 epidemic. [ABSTRACT FROM AUTHOR]

Clin Microbiol Infect 2012; 18: E485-E490 Abstract We have studied transmitted drug resistance (TDR) in 1.864 antiretroviral-naïve patients entering CoRIS (Spain) during 2007-2010. An overall 8.58% TDR was observed (3.92%, nucleoside reverse transcriptase inhibitors (NRTIs); 3.86%, non- nucleoside reverse transcriptase inhibitors (NNRTIs); 2.31%, protease inhibitors), with a significant decreasing trend over time for NNRTIs (5.53%, 2007; 2.45%, 2010; p for trend = 0.044). Non-B subtype prevalence was 15.93%, with a significant increase (11.95%, 2007; 18.14%, 2010; p for trend = 0.018), mainly related to immigration. Having no formal education increased the risk of TDR to NNRTIs (OR, 7.26), and carrying a non-B subtype reduced the risk of TDR to NRTIs (OR, 0.27). These findings may have important implications for treatment guidelines and laboratory testing recommendations. [ABSTRACT FROM AUTHOR]

Objectives Relatively little is known about the development of resistance to protease inhibitors (PIs) in non-B subtypes. In subtype B viruses, L89 is commonly found at position 89 in the HIV protease (PR) gene, whereas M89 is commonly observed as a polymorphism in other subtypes. We compared the frequencies of substitutions at position 89 in PR in tissue culture selections and in clinical databases of PI-naive and PI-experienced populations. Methods Representative subtype A/CRF01_AE (n = 2 and 3) and subtype C (n = 5) isolates were cultured in MT-2 cells and cord blood mononuclear cells (CBMCs), respectively, under increasing drug pressure with PIs, and drug resistance mutations were identified. Results The M89 natural polymorphism in non-B subtypes commonly led to the appearance of an M89T mutation in selections with atazanavir in subtypes A/AE and C, and was accompanied by other previously recognized atazanavir mutations. The M89T mutation contributed to phenotypic resistance to atazanavir and cross-resistance to lopinavir and nelfinavir, but not to other PIs. A shift from a L89 natural polymorphism to L89I/M arose in two of five subtype C selections with PIs. M89I/V/T mutations were acquired by 10%–11% of individuals harbouring non-B subtypes who were failing PI-based regimens, but were rarely observed in drug-naive persons and in patients failing non-PI-based regimens. Conclusions The M/L89 natural polymorphism present in non-B subtypes may lead to the M89T mutational pathway conferring resistance to atazanavir, lopinavir and nelfinavir. [ABSTRACT FROM PUBLISHER]

Introduction Tenofovir-containing regimens have demonstrated potential efficacy as pre-exposure prophylaxis (PrEP) in preventing HIV-1 infection. Transmitted drug resistance mutations associated with tenofovir, specifically the reverse transcriptase (RT) mutation K65R, may impact the effectiveness of PrEP. The worldwide prevalence of transmitted tenofovir resistance in different HIV-1 subtypes is unknown. Methods Sequences from treatment-naïve studies and databases were aggregated and analyzed by Stanford Database tools and as per the International AIDS Society (IAS-USA) resistance criteria. RT sequences were collected from GenBank, the Stanford HIV Sequence Database and the Los Alamos HIV Sequence Database. Sequences underwent rigorous quality control measures. Tenofovir-associated resistance mutations included K65R, K70E, T69-insertion and ≥3 thymidine analogue mutations (TAMs), inclusive of M41L or L210W. Results A total of 19,823 sequences were evaluated across diverse HIV-1 subtypes (Subtype A: 1549 sequences, B: 9783, C: 3198, D: 483, F: 372, G: 594, H: 41, J: 69, K: 239, CRF01_AE: 1797 and CRF02_AG: 1698). Overall, tenofovir resistance prevalence was 0.4% (n=77/19,823, 95% confidence interval or CI: 0.3 to 0.5). K65R was found in 20 sequences (0.1%, 95% CI: 0.06 to 0.15). Differences in the prevalence of K65R between HIV-1 subtypes were not statistically significant. K70E and ≥3 TAMs were found in 0.015% (95% CI: 0.004 to 0.04) and 0.27% (95% CI: 0.2 to 0.4) of sequences, respectively. Conclusions Prevalence of transmitted K65R and other tenofovir resistance mutations across diverse HIV-1 subtypes and recombinants is low, suggesting minimal effect on tenofovir-containing PrEP regimens. [ABSTRACT FROM AUTHOR]

The SnoB study analysed the variability of the integrase (IN) gene of non-B viruses from treatment-naïve patients to determine whether non-B subtypes carry natural resistance mutations to raltegravir (RAL). Plasma viral RNA from 427 patients was gained, and IN sequences were subtyped and screened for subtype-specific highly-variable residues. Seven viruses of different subtypes were phenotypically tested for RAL susceptibility; 359/427 samples could be sequenced. One hundred and seventy samples (47%) were classified as non-B subtypes. No primary RAL resistance-associated mutations (RRAMs) were detected. Certain secondary mutations were found, mostly related to specific non-B subtypes. L74 M was significantly more prevalent in subtype 02_AG, T97A in A and 06_cpx, V151I in 06_cpx, and G163R in 12_BF. Various additional mutations were also detected and could be associated with the subtype too. While K156 N and S230 N were correlated with B subtype, V72I, L74I, T112I, T125A, V201I and T206S were more frequent in certain non-B subtypes. The resistance factors (RF) of 7 viral strains of different subtypes ranged from 1.0 to 1.9. No primary or secondary but subtype-associated additional RRAMs were present. No correlation between RF and additional RRAMs was found. The prevalence of RRAMs was higher in non-B samples. However, the RFs for the analysed non-B subtypes showed lower values to those reported relevant to clinical failure. As the role of baseline secondary and additional mutations on RAL therapy failure is actually not known, baseline IN screening is necessary. [ABSTRACT FROM AUTHOR]

CoRIS is an open multicentre cohort of HIV seroprevalent ARV-naïve subjects who began treatment at 32 Spanish healthcare centres from January 2004. Up to November 2008, a total of 683 FASTA format sequences, encoding the HIV protease and reverse transcriptase (RT) derived from plasma samples at entry into the cohort, had been obtained for examination of transmitted drug resistance (TDR) and HIV clade. TDR was found in 8.5% of the patients (4.4% NRTIs, 4% NNRTIs, 2.2% PIs). The most prevalent resistance mutations were: T215 revertants (3.8%), D67NG (1.3%), K219QENR (1.2%) and M41L (1%), for NRTIs; K103N (3.2%), for NNRTIs; I54VLMSAT, M46I and L90M (0.7%), for PIs. Non-B subtypes were recognized in 104 patients (15.2%) and were more common in Sub-Saharan Africans (15/17, 88.2%), Eastern Europeans (7/12, 58.3%) and Northern Africans (8/16, 50%) than among Spaniards (53/479, 11%) (p <0.001). The most prevalent non-B subtype was CRF02_AG (4.4%), followed by subtype D (1.9%), CRF03_AB (1.5%), CRF07_BC and subtype F1 (1%). A trend was observed for the transmission of non-B subtypes to increase and for TDR to decrease. [ABSTRACT FROM AUTHOR]

We evaluated the accuracy of heat-denatured, amplification-boosted ultrasensitive p24 assay (Up24) compared with reverse transcriptase polymerase chain reaction (RT-PCR). We tested 394 samples from Ugandans infected with HIV-1 non-B subtypes. We compared Up24 levels (HIV-1 p24 Core Profile enzyme-linked immunosorbent assay (ELISA), NEN Life Science Products) to RNA viral loads (Amplicor HIV-1 Monitor 1.5, Roche) by linear regression, and calculated sensitivity, specificity, positive and negative predictive values. Median viral load was 4.9 log10 copies/mL (interquartile range [IQR], 2.6-5.5); 114 samples (29%) were undetectable (<400 copies/mL). Sensitivity of the Up24 assay to detect viral load ⩾400 copies/mL was 69%, specificity was 67%, and positive and negative predictive values were 84% and 47%, respectively. Sensitivity of Up24 was 90%, 80%, 68%, 62% and 45% to detect viral loads of >500,000, 250,000-500,000, 100,000-250,000, 50,000-100,000 and 400-50,000 copies/mL, respectively. In conclusion, when compared with RT-PCR for patients infected with non-B subtypes, the Up24 demonstrated limited sensitivity especially at low viral loads. Moreover, the Up24 was positive in 33% of samples deemed undetectable by RT-PCR, which may limit the use of the Up24 to detect viral suppression. [ABSTRACT FROM AUTHOR]

Abstract: Transcriptional activation of HIV-1 gene expression is partially controlled by the interaction between viral and cellular transcription factors acting at HIV-1 long terminal repeat (LTR) sequences. HIV-1 subtyping at LTR region and nucleotide LTR variability from clinical samples in 48 subjects carrying different HIV-1 subtypes (9A, 5C, 3D, 3F, 21G, 2H, 3J and 2 undefined) at the protease (PR) gene, were performed. LTR sequences from each HIV-1 clade were cloned in luciferase-expression vectors to determine basal and Tat-induced transcriptional activities in the presence and absence of PMA stimulation. A high number (37.8%) of recombinants at LTR/PR regions were identified. All HIV-1 promoters presented low basal transcriptional activity that was nevertheless induced by Tat and PMA. LTR activity was similar across the majority of HIV-1 variants in response to Tat and cell activation. Only subtype C and CRF01_AE LTRs presented higher basal and induced-PMA transcription activities than HXB2 clade B promoter. No basal or Tat/PMA induced activity was found in those promoters presenting G to A hypermutation compared to the wild type promoter activities. G to A hypermutation at some important transcription binding-factor sites within LTR compromised the activity of the viral promoter, decreasing the in vitro viral transcription of the luciferase gene. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the prevalence of HIV-1 non-B subtype cases in Maryland. Researchers analyzed various HIV non-B subtype strains at the Maryland Department of Health and Mental Hygiene and at the University of Maryland Medical Center. Results show that most HIV subtype B cases are from Baltimore metropolitan area, while most of the HIV non-B subtype cases are from the state's suburban areas.

Objectives: To analyse HIV Gag cleavage site (CS) and non-CS mutations in HIV non-B isolates from patients failing antiretroviral therapy. [ABSTRACT FROM PUBLISHER]

Abstract: The implementation of cost effective HIV-1 RNA quantitation assays in resource-poor settings is of paramount importance for monitoring HV-1 infection. A study comparing the analytical performance of three HIV-1 RNA assays (Generic HIV Viral Load®, Amplicor™ v1.5 and Nuclisens EasyQ® v1.2) was performed on 160 plasma samples from 160 consecutive antiretroviral treatment naive HIV-1-infected pregnant women assessed for eligibility in the Kesho Bora trial aimed at prevention of mother-to-child transmission of HIV-1 in three African countries (Burkina Faso, Kenya and South Africa). Correlation and agreement of results of the three assays were assessed for plasma HIV-1 RNA quantitation in specimens harbouring mainly sub-subtype A1, subtype C, and circulating recombinant form (CRF) 02_AG and CRF06_cpx. Good degrees of correlation and agreement were observed between these HIV-1 RNA assays. However, nine (9/160, 5.6%) strains detectable with the Generic HIV Viral Load® assay were not detected by either the Amplicor™ (n =7) or EasyQ® (n =2) test. One strain (0.6%) was missed with the Generic HIV Viral Load® assay. Further, concordantly positive plasma samples harbouring CRF02_AG and CRF06_cpx yielded significantly higher HIV-1 RNA concentrations when tested by Generic HIV Viral Load®, as compared to Amplicor™ v1.5 (mean differences, +0.33 and +0.67log10 copies/ml; P =0.0004 and P =0.002, respectively). The Generic HIV Viral Load® assay accurately quantified the majority of the non-B HIV-1 subtypes assessed in this study. Due to its low cost (∼10 US $/test), this assay performed with open real-time PCR instruments is now used routinely in the Kesho Bora trial and may be recommended in other African settings. [Copyright &y& Elsevier]

Background: Little is known about the extent and predictors of polymorphisms potentially influencing the susceptibility to HIV integrase inhibitors (INIs). [ABSTRACT FROM PUBLISHER]

Abstract: One hundred and ninety-two pol sequences of drug-naïve and drug-experienced subjects infected with non-B HIV-1 subtypes were analyzed to identify treatment-related amino acid changes which might be relevant for drug-resistance and possibly not included in the accepted mutation list for the B subtype. The correspondence analysis identified non-B-specific and subtype-specific polymorphisms which should not be mistaken for mutations. Multiple χ 2 were performed to detect the differences between naïve vs treated subjects and between different subtypes. To verify the contribution of each single mutation to the resistance levels as predicted by the Virtual Phenotype™—LM, simple univariate linear regression was used with fold resistance as a dependent variable and individual mutations as predictors. Commonly accepted protease (PR) and reverse transcriptase (RT) positions along with mutants at RT positions 118 and 90 were significantly associated with treatment. Two unusual PR (K14R and I66F) and five RT positions (E28K, S68G, H221Y, L228R/H and P294A) were also associated with treatment (p <0.01). Only minimal variations were observed with respect to commonly accepted amino acid changes. All amino acid changes correlated with treatment influenced the resistance levels to each single drug. Our findings demonstrate that there are no substantial differences regarding known resistance-associated mutations and the newly emergent substitutions between non-B and B subtype strains. [Copyright &y& Elsevier]

Abstract: Background: Genetic variation in the HIV-1 pol gene, which encodes the main targets for anti-HIV drugs, may favors different susceptibility and resistance pathways to antiretroviral agents. Several amino acid substitutions occur frequently in some non-B viruses at positions associated with drug resistance in clade B viruses. The clinical relevance of those polymorphisms is unclear. Objective: To evaluate the effect of two natural protease (PR) polymorphisms, K20I and M36I, which are frequently found in non-B subtypes, on the virus replicative capacity in the presence and absence of protease inhibitors (PI). Study design: Infectious HIV-1 clones carrying K20I, M36I or K20I/M36I were designed. Their replication kinetics were analyzed by viral competition in the absence of PI. Susceptibility to six different PI was phenotypically assessed in clones and in recombinant viruses carrying non-B proteases from 16 drug-naive individuals. Results: In the absence of drug, the M36I clone replicated more rapidly than wt (wild type) or the double mutant K20I/M36I. Natural polymorphisms 20I and/or 36I improved the virus replicative capacity under drug pressure, reducing the susceptibility to saquinavir and indinavir, with IC50 values 2–3.5-fold higher than wt. All but one drug-naive individual carrying non-B viruses were fully susceptibility to all tested PI, suggesting that additional substitutions within the PR might compensate the reduced PI susceptibility caused by K20I and/or M36I. Conclusion: Natural PR polymorphisms in non-B HIV-1 variants can influence in vitro the virus replication capacity in the presence and/or absence or certain PI. Hypothetically, the improved viral replication of mutant 36I might favor a more rapid spreading of non-B subtypes of HIV-1. [Copyright &y& Elsevier]

HAART has dramatically improved survival and quality of life among people living with HIV and AIDS globally. However, drug resistant mutations of HIV are a great challenge to the benefits of HAART. Antiviral resistance can be mediated either by changes in the molecular target of therapy (the primary mechanism observed in HIV-1) or in other viral proteins that indirectly interfere with a drug's activity. Drug resistant mutations easily evolve in the presence of sub-optimal adherence. With the introduction of generic HAART, there has been a steep increase in the number of patients put on HAART in India. It should also be noted that since most patients pay for medications out of their own pockets, interruptions in therapy due to monetary constraints are not uncommon. There is little information on HIV drug resistance in resource constrained settings like India where the predominant circulating HIV-1 sub-type is C. The transmissibility of drug-resistant forms of the virus is also a major concern especially when formulating treatment guidelines. This article reviews published data available on the patterns of HIV-1 drug resistance among treatment naïve in India. [ABSTRACT FROM AUTHOR]

The article presents comparison of the genetic barrier between subtypes using some HIV-1 sequences from anti-retroviral-naive patients in Europe. In collaboration with this study, such genetic barrier has been calculated as the sum transitions scored as one and transversions 2.5. Moreover, for every subtype, minor protease substitutions have been determined. As a result, the rate of drug immunity may be similar for different HIV subtypes.

Genotypic drug resistance interpretation algorithms have been developed on patients infected with HIV-1 subtype B to interpret complex patterns of mutations. As non-B strains are characterised by the natural presence of several resistance-related mutations, we examined to what extent this might result in interalgorithm discordances in naive and treated patients. We compared the prediction by three algorithms (ANRS, Stanford and Rega) of drug susceptibilities to diverse HIV-1 strains from 272 naive and 156 treated patients. In naive patients, higher levels of interalgorithm discordance were observed for predictions of protease inhibitor (0.60–39%) than for predictions of reverse transcriptase inhibitor susceptibility (0–4%). The main reason for discordant protease inhibitor interpretation was the presence of resistance mutations that were natural protease polymorphisms. In contrast, in the treated patients, more interalgorithm discordances were observed for predictions of reverse transcriptase inhibitor (5–48%) than protease inhibitor susceptibilities (10–31%). Discordances were related to disagreement between the intermediate and susceptible scores, the intermediate and resistant scores and the interpretations of complex mutation patterns, related to cross-resistance and antagonistic interactions. [ABSTRACT FROM AUTHOR]

Abstract: Genotypic assays are used often to guide clinicians in decisions concerning the treatment of patients. An optimized sequence-based genotypic assay was used to determine the whole protease and reverse transcriptase (RT) gene, including the gag cleavage site region and RNase H region. Since non-B subtypes are increasing in countries where subtype B was the most prevalent subtype, and treatment becomes more available in developing countries where the epidemic is characterized by a high prevalence of non-B subtypes, it was important that the genotypic test was evaluated using a panel of different subtypes. Amplification was successful for different subtypes: A, B, C, D, F, G, H, J, CRF01_AE, CRF02_AG, CRF11_cpx, CRF13_cpx and an uncharacterized recombinant sample. The detection limit of the PCR was 1000copies/ml, except for 1 subtype C sample (PL3) and 1 CRF02_AG sample (PL8). The detection limit for these samples was 5000copies/ml. A sequence could be obtained in both directions for most of the samples. [Copyright &y& Elsevier]

Abstract: The Nuclisens EasyQ HIV-1 v1.1 assay (Biomerieux) is a real-time detection method combined with NASBA technology designed to measure plasma HIV-RNA. Its performance was assessed in 1008 clinical specimens collected from individuals infected with clade B (774) and non-B (234) HIV-1 variants at four European laboratories. The results were compared with those obtained using three other commercial viral load assays: Cobas Amplicor Monitor HIV-1 v1.5 (Roche), Versant HIV-1 RNA assay (Bayer) and Nuclisens HIV-1 QT (Biomerieux). Overall, the linearity, specificity and reproducibility of the EasyQ assay was comparable with that from the other tests. The correlation coefficient (R) between methodologies was 0.85 for Amplicor; 0.87 for Versant; and 0.91 for Nuclisens. The specificity of the assay was 99.4%. Of note, Versant missed 17% of specimens with non-B subtypes which could be detected by EasyQ, while Amplicor provided similar results than EasyQ. HIV-1 group O specimens were only detected by the EasyQ assay. In conclusion, the performance of the EasyQ assay seems to be similar to that of other HIV-1 viral load tests currently on the market, but it is more sensitive than Versant for HIV-1 non-B subtypes and shows a wider dynamic range than Amplicor. Moreover, as it incorporates the advantage of real-time detection procedures, it facilitates high throughput and short turnaround time. [Copyright &y& Elsevier]

Background: Naturally-occurring polymorphisms at the human immunodeficiency virus type 1 (HIV-1) protease which have been associated to resistance to protease inhibitors (PIs) in clade B viruses are frequently found in non-B subtypes, with unknown clinical significance. Objective: To assess the susceptibility of non-B viruses to different PIs. Study design: Plasma samples from 58 drug-naive individuals infected with HIV-1 non-B subtypes (2A, 22C, 2D, 1F, 29G and 2J) defined by phylogenetic analyses of the protease gene were tested using a phenotypic assay (PhenoSense, ViroLogic, South San Francisco, CA, USA). Twenty of them were further analyzed with another assay (Antivirogram™, Virco, Mechelen, Belgium). All 58 non-B viruses harbored amino acid substitutions associated with reduced PI susceptibility in clade B (positions 10, 20, 36, 63, 70, 77 and 82). Results: Using PhenoSense-HIV™ assay, all but two individuals harbored viruses completely susceptible to all six PIs tested (indinavir (IDV), ritonavir (RTV), saquinavir (SQV), nelfinavir (NFV), amprenavir (APV), lopinavir (LPV)). The two viruses with reduced susceptibility belonged to clade G. The first virus, which had K20I, M36I and V82I, showed 2.9-fold decreased susceptibility to APV, while the second virus showed 3.9-fold decreased susceptibility to both NFV and RTV, with amino acid substitutions K20I, M36I, L63P and V82I. Of note, several other viruses displayed the same constellation of mutations but without showing any reduced susceptibility, suggesting that these polymorphisms per se do not affect PI susceptibility. Conclusion: PI susceptibility in HIV-1 non-B viruses seems to be preserved despite the presence of polymorphic changes which have been associated to PI resistance in clade B viruses. [Copyright &y& Elsevier]

Phylogenetics has been advanced as a structural framework to infer evolving trends in the regional spread of HIV-1 and guide public health interventions. In Quebec, molecular network analyses tracked HIV transmission dynamics from 2002–2020 using MEGA10-Neighbour-joining, HIV-TRACE, and MicrobeTrace methodologies. Phylogenetics revealed three patterns of viral spread among Men having Sex with Men (MSM, n = 5024) and heterosexuals (HET, n = 1345) harbouring subtype B epidemics as well as B and non-B subtype epidemics (n = 1848) introduced through migration. Notably, half of new subtype B infections amongst MSM and HET segregating as solitary transmissions or small cluster networks (2–5 members) declined by 70% from 2006–2020, concomitant to advances in treatment-as-prevention. Nonetheless, subtype B epidemic control amongst MSM was thwarted by the ongoing genesis and expansion of super-spreader large cluster variants leading to micro-epidemics, averaging 49 members/cluster at the end of 2020. The growth of large clusters was related to forward transmission cascades of untreated early-stage infections, younger at-risk populations, more transmissible/replicative-competent strains, and changing demographics. Subtype B and non-B subtype infections introduced through recent migration now surpass the domestic epidemic amongst MSM. Phylodynamics can assist in predicting and responding to active, recurrent, and newly emergent large cluster networks, as well as the cryptic spread of HIV introduced through migration. [ABSTRACT FROM AUTHOR]

Changes over time in HIV-1 subtype diversity within a population reflect changes in factors influencing the development of local epidemics. Here we report on the genetic diversity of 2364 reverse transcriptase sequences from people living with HIV-1 in New South Wales (NSW) notified between 2004 and 2018. These data represent >70% of all new HIV-1 notifications in the state over this period. Phylogenetic analysis was performed to identify subtype-specific transmission clusters. Subtype B and non-B infections differed across all demographics analysed (p < 0.001). We found a strong positive association for infections among females, individuals not born in Australia or reporting heterosexual transmission being of non-B origin. Further, we found an overall increase in non-B infections among men who have sex with men from 50 to 79% in the last 10 years. However, we also found differences between non-B subtypes; heterosexual transmission was positively associated with subtype C only. In addition, the majority of subtype B infections were associated with clusters, while the majority of non-B infections were singletons. However, we found seven non-B clusters (≥5 sequences) indicative of local ongoing transmission. In conclusion, we present how the HIV-1 epidemic has changed over time in NSW, becoming more heterogeneous with distinct subtype-specific demographic associations. [ABSTRACT FROM AUTHOR]