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Background: Acupuncture is one of the most popular forms of complementary and alternative medicine, and its usage is linked to an improvement of physical and psychological symptoms. Main Objectives: Determine whether the use of acupuncture as an adjunct to physiotherapy treatment is more effective than physiotherapy alone or acupuncture alone in MSK conditions. Methodology: A systematic review of the literature was conducted using three major databases, from March 2019 to May 2019, i.e., Cochrane Library, PubMed, and PEDro (Physiotherapy Evidence Database). The inclusion criteria were limited to randomized controlled trials (RCT) published in English, only studies published within the past decade, and investigating adult populations with MSK conditions. Results: From the 227 titles and abstracts that were identified, 75 were duplicates, leaving us with 152 studies for the initial screening. Eight studies [13-20] were included in this review for a qualitative analysis. The studies that assessed pain did not found statistically significant results that support the combination of physiotherapy and acupuncture, the same results were also obtained for Range of motion in knee osteoarthritis. Muscular tension was found statistically significant within-group improvements for all parameters in comparison with the baseline. For Isometric Neck Muscle Strength (INMS), the studies reported significant improvements within the groups, with Physiotherapy combined with Acupuncture being more effective than Acupuncture or Physiotherapy alone. The Constant Shoulder Assessment (CSA), for shoulder function was significantly higher in the exercise plus acupuncture group compared with the exercise group. Conclusion: As an integrative or complementary therapy for pain, acupuncture has been increasingly used. However, this review did not find significant evidence to support that the addition of acupuncture to physiotherapy treatment has an added benefit to pain relief. This review did, however, find benefits of adding acupuncture to treatment to reducing neck disability and improving muscular strength and shoulder function.

Funding Information: This work was funded by national funds through the FCT-Foundation for Science and Technology, I.P., under the project UIDB/04585/2020, by FCT and Aga Khan Development Network (AKDN)—Portugal Collaborative Research Network in Portuguese speaking countries in Africa, project 332821690 and by Ministry of Health, Portugal, project HIV/SAU/0008.11. Publisher Copyright: © 2023 by the authors. The development of immunogens that elicit broadly reactive neutralising antibodies (bNAbs) is the highest priority for an HIV vaccine. We have shown that a prime-boost vaccination strategy with vaccinia virus expressing the envelope glycoprotein gp120 of HIV-2 and a polypeptide comprising the envelope regions C2, V3 and C3 elicits bNAbs against HIV-2. We hypothesised that a chimeric envelope gp120 containing the C2, V3 and C3 regions of HIV-2 and the remaining parts of HIV-1 would elicit a neutralising response against HIV-1 and HIV-2. This chimeric envelope was synthesised and expressed in vaccinia virus. Balb/c mice primed with the recombinant vaccinia virus and boosted with an HIV-2 C2V3C3 polypeptide or monomeric gp120 from a CRF01_AG HIV-1 isolate produced antibodies that neutralised >60% (serum dilution 1:40) of a primary HIV-2 isolate. Four out of nine mice also produced antibodies that neutralised at least one HIV-1 isolate. Neutralising epitope specificity was assessed using a panel of HIV-1 TRO.11 pseudoviruses with key neutralising epitopes disrupted by alanine substitution (N160A in V2; N278A in the CD4 binding site region; N332A in the high mannose patch). The neutralisation of the mutant pseudoviruses was reduced or abolished in one mouse, suggesting that neutralising antibodies target the three major neutralising epitopes in the HIV-1 envelope gp120. These results provide proof of concept for chimeric HIV-1/HIV-2 envelope glycoproteins as vaccine immunogens that can direct the antibody response against neutralising epitopes in the HIV-1 and HIV-2 surface glycoproteins. publishersversion published

This paper focuses on the development of an RF sensor, essential to the deployment of the Licensed Shared Access (LSA) concept, in Portugal. This device, the “LSA warner”, which receives and processes RF signals, is used to detect the presence of long-term evolution (LTE) signals in the 2.3–2.4 GHz band. A field-programmable gate array (FPGA) alongside with a software-defined radio (SDR) are the foundation for the implementation of the sensor. By using a partial LTE cell search and the received signal power, the system is able to detect the presence of LTE signals and send that information, together with the location of the device, to a repository. A communication protocol between the LSA warner and the LSA repository was developed and tested to control the mobile network base stations through the sensor. The LSA warner was tested in the field under realistic operating conditions in a pilot network that reproduced an LSA network environment.

Submitted by Paula Saraiva (psaraiva@egasmoniz.edu.pt) on 2019-12-13T12:06:49Z No. of bitstreams: 1 Artigo_NTaveira_2019_11_acceptedmanuscript.pdf: 255816 bytes, checksum: fee12434a16773f4804ce22f7f9fb1ba (MD5) Approved for entry into archive by Paula Saraiva (psaraiva@egasmoniz.edu.pt) on 2019-12-13T12:07:01Z (GMT) No. of bitstreams: 1 Artigo_NTaveira_2019_11_acceptedmanuscript.pdf: 255816 bytes, checksum: fee12434a16773f4804ce22f7f9fb1ba (MD5) Made available in DSpace on 2019-12-13T12:07:01Z (GMT). No. of bitstreams: 1 Artigo_NTaveira_2019_11_acceptedmanuscript.pdf: 255816 bytes, checksum: fee12434a16773f4804ce22f7f9fb1ba (MD5) Previous issue date: 2019-11 info:eu-repo/semantics/acceptedVersion

Elicitation of potent neutralizing antibodies against genetically diverse HIV-1 isolates is important for an effective HIV-1 vaccine. Some HIV-1 infected patients produce such broadly neutralizing antibodies (bNAbs). Identification of host and viral correlates of bNAb production may help develop the next generation of HIV-1 vaccines. We carried out the first detailed characterization of the neutralizing antibody response and identify viral and host factors associated with the development of bNAbs in HIV-1 infected patients from Angola, one of the oldest, more dynamic, and diverse HIV-1 epidemics in the world. Plasma samples from 322 HIV-1 infected patients were collected in 2001, 2009 and 2014. Phylogenetic analysis of C2V3C3 envelope sequences identified a diverse array of subtypes including A1, A2, B, C, D, F1, G, H, J, untypable strains, and recombinant forms which prevailed over pure subtypes. Notably, 56% of the patients developed cross, broad, or elite neutralizing responses against a reference panel of tier 2 Env-pseudoviruses far exceeding results obtained elsewhere in the world. The frequency of elite neutralizers was higher in 2014, when patients were on ART and had low viremia, than in 2009 when patients were drug naive. In drug naïve patients, broad neutralization was associated with subtype C infection, lower CD4+ T cell counts, higher age, or higher titer of C2V3C3-specific antibodies relative to patients that did not develop bNAbs. Neutralizing antibodies targeted the V3-glycan supersite in most patients but antibodies specific for the V2 apex, the CD4 binding site, the gp41 membrane-proximal external region (MPER) and unknown epitopes were also found in some patients. V3 and C3 regions were significantly less variable and less subject to positive selection in elite neutralizers compared to weak or no neutralizers suggesting an active role of bNabs directed against these regions in controlling HIV-1 replication and diversification. Hence, development of broad and elite antibody neutralization against HIV-1 requires long-term and low-level envelope V3C3 stimulation from highly diverse subtype C isolates. These results have direct implications for the design of a new generation of HIV-1 vaccines.

Funding Information: This work was supported by Fundação para a Ciência e Tecnologia (FCT), Portugal, Aga Khan Development Network (AKDN)–Portugal Collaborative Research Network in Portuguese-speaking countries in Africa (project 332821690). CQC is supported by FCT through projects UIDB/00313/2020 and UIDP/QUI/00313/2020, co-funded by COMPETE2020-UE. iMed.ULisboa, Faculdade de Farmácia da Universidade de Lisboa, Portugal, is supported by FCT through projects UIDB/04138/2020 and UIDP/04138/2020. Inês Bártolo is supported by FCT through Norma Transitória–DL57/2016/CP1376/CT0012. Ana Rita Diniz (SFRH/BD/89140/2012), Francisco Martin (SFRH/BD/87488/2012), Inês Moranguinho (SFRH/BD/131062/2017), and Américo Alves (SFRH/BD/128910/2017) were supported by Ph.D. grants from FCT, Portugal. Publisher Copyright: © 2022 by the authors. Integrase inhibitors (INIs) are an important class of drugs for treating HIV-2 infection, given the limited number of drugs active against this virus. While the clinical efficacy of raltegravir and dolutegravir is well established, the clinical efficacy of bictegravir for treating HIV-2 infected patients has not been determined. Little information is available regarding the activity of bictegravir against HIV-2 isolates from patients failing raltegravir-based therapy. In this study, we examined the phenotypic and matched genotypic susceptibility of HIV-2 primary isolates from raltegravir-naïve and raltegravir-failing patients to raltegravir, dolutegravir, and bictegravir, and to the new spiro-β-lactam BSS-730A. The instantaneous inhibitory potential (IIP) was calculated to help predict the clinical activity of bictegravir and BSS-730A. Isolates from raltegravir-naïve patients were highly sensitive to all INIs and BSS-730A. Combined integrase mutations E92A and Q148K conferred high-level resistance to raltegravir, and E92Q and T97A conferred resistance to raltegravir and dolutegravir. The antiviral activity of bictegravir and BSS-730A was not affected by these mutations. BSS-730A displayed strong antiviral synergism with raltegravir. Mean IIP values at Cmax were similar for all INIs and were not significantly affected by resistance mutations. IIP values were significantly higher for BSS-730A than for INIs. The high IIP values of bictegravir and BSS-730A for raltegravir-naïve and raltegravir-resistant HIV-2 isolates highlight their potential value for treating HIV-2 infection. Overall, the results are consistent with the high clinical efficacy of raltegravir and dolutegravir for HIV-2 infection and suggest a promising clinical profile for bictegravir and BSS-730A. publishersversion published

Com o mundo cada vez mais digital é possível que a comercialização de seguros continue assente no modelo tradicional dos mediadores físicos? Para um millennial a resposta é um claro não, mas a indústria seguradora tem sido lenta na transição do modelo de negócio. Até muito recentemente, para contratar um seguro com uma das grandes seguradoras, o consumidor era obrigado a deslocar-se a um mediador físico para proceder à respetiva contratação. Todavia o mundo está a mudar e o marketing está a evoluir. Nesta dissertação será abordado o que é o marketing de base de dados direto, as suas práticas, a estrutura de uma estratégia que esteja em conformidade com o Regulamento Geral sobre a Proteção de Dados (RGPD) e será analisado o panorama do mercado segurador português. Esta revisão de literatura providencia uma base para o estudo desta forma de marketing no mercado segurador. Adotada uma abordagem mista, a pesquisa efetuada através de um método qualitativo de observação participante permite identificar como as seguradoras portuguesas estão a utilizar os dados dos seus potenciais clientes para finalidades de marketing e se, ao fazê-lo, respeitam as regras do RGPD. Quanto à vertente quantitativa, o questionário realizado a uma amostra da população de clientes de seguradoras portuguesas demonstra qual a perceção do consumidor relativamente ao marketing destas organizações e revela as suas preferências quanto aos canais marketing de base de dados direto.

ApneaLink is a portable device for the screening of sleep apnea, a prevalent and underdiagnosed comorbidity in heart failure patients. A prospective cross-sectional study in patients with chronic heart failure was carried out to assess the sensitivity and specificity of apnea-hypopnea index (AHI) measurements using ApneaLink against the standard polysomnography test. Adult patients with a prior hospitalization in an acute heart failure hospital unit were recruited for the study. All participants were tested for sleep apnea using ApneaLink and polysomnography simultaneously during an overnight stay at a sleep laboratory. Global sleep apnea was evaluated according to the AHI, which was analyzed and compared. Subpopulation comparison based on ejection fraction was not realized due to population size. Thirty-five patients with stable chronic heart failure completed the study (mean age 70.9 ± 10.5 years and body mass index 30.0 ± 4.7 kg/m2). Two patients were excluded due to insufficient study duration. ApneaLink had a sensitivity greater than 80% for all AHI measurements, and a specificity greater than 80% for all AHI measurements, except for AHI ≥ 5 events/h (61.5%). The results showed higher sensitivities and specificities at AHI values of ≥ 10 events/h (sensitivity 81.3% and specificity 84.2%) and ≥ 15 events/h (sensitivity 83.3% and specificity 91.3%). Correlation analysis showed that AHI measurements using ApneaLink and polysomnography had a strong and significant correlation (r = 0.794; P

New antiretroviral drugs are needed to treat HIV-2 infected patients failing therapy. Herein, we evaluate the activity of novel reverse transcriptase inhibitors tenofovir alafenamide (TAF) and OBP-601(2,3-didehydro-3-deoxy-4-ethynylthymidine) against primary isolates from HIV-2 infected patients experiencing virologic failure. TAF and OBP-601 were tested against twelve primary isolates obtained from nine drug-experienced patients failing therapy and three drug naïve patients using a single-round infectivity assay in TZM-bl cells. The RT-coding region of pol was sequenced and the GRADE algorithm was used to identify resistance profiles and mutations. TAF and OBP-601 inhibited the replication of almost all isolates at a median EC50 of 0.27 nM and 6.83 nM, respectively. Two isolates showed moderate-level resistance to OBP-601 or TAF and two other isolates showed high-level resistance to OBP-601 or to both drugs. With one exception, all resistant viruses had canonical nucleoside reverse transcriptase inhibitors (NRTIs)-associated resistance mutations (K65R, N69S, V111I, Y115F, Q151M and M184V). Our results show that TAF has potent activity against most multi-drug resistant HIV-2 isolates and should be considered for the treatment of HIV-2 infected patients failing therapy. info:eu-repo/semantics/publishedVersion

Any successful strategy to prevent and control HCV infection requires an understanding of the epidemic behaviour among the different genotypes. Here, we performed the first characterization of the epidemic history and transmission dynamics of HCV subtypes in Portugal. Direct sequencing of NS5B was performed on 230 direct-acting antiviral drugs (DAA)-treatment naïve patients in Lisbon. Phylogenetic analysis was used for subtyping and transmission cluster identification. Bayesian methods were used to reconstruct the epidemic history of HCV subtypes. Sequences were analysed for resistance-associated substitutions (RAS). The majority of strains were HCV-GT1 (62.6%), GT3 (18.3%, all subtype 3a) and GT4 (16.1%). Among GT1, the most frequent were subtypes 1a (75.5%) and 1b (24.5%). Polyphyletic patterns were found in all but 12 lineages suggesting multiple introductions of the different subtypes in this population. Five distinct epidemics were identified. The first significant HCV epidemic in Portugal occurred between 1930s and 1960s, was caused almost exclusively by GT1b and was likely associated with blood transfusions. Rapid expansion of GT3a occurred in the 1960s and GT1a in the 1980s, associated with intravenous drug use. The most recent epidemics were caused by GT4a and GT4d and seem to be associated with the resurgence of opioid use. The C316N substitution was found in 31.4% of GT1b-patients. Close surveillance of patients bearing this mutation and undergoing dasabuvir-based regimens will be important to determine its impact on treatment outcome. The authors would like to thank all the patients for their participation. C.P. is supported by the Portuguese ‘Fundação para a Ciência e Tecnologia’ (FCT) (grant number SFRH/BPD/77448/2011, part of the EDCTP2 program supported by the European Union). R.M. was supported by a Ph.D. scholarship by the Portuguese ‘Fundação para a Ciência e Tecnologia’ (FCT). V.B. is supported by the Miguel Servet program run by the ‘Fondo de Investigación Sanitaria’ (ISCIII) (grant number CP13/00098). I.M. is supported by the Portuguese ‘Fundação para a Ciência e Tecnologia’ (FCT) (grant number SFRH/BD/131062/2017). Sí

The migration from analog to digital television (TV) broadcasting has introduced significant improvements in terms of spectral efficiency. As a result, the number of radio channels required to ensure equivalent coverage has been dramatically reduced [1]. This efficiency gain has allowed the release of a valuable portion of spectrum (previously assigned to analog TV broadcasting) in the 790-862-MHz subband (channels 61-69), often called the digital dividend. This 72-MHz slice of the spectrum is now assigned exclusively to international mobile telecommunications (IMT) [2], [3]. Vis á vis the mobile communications markets, the current data dynamics demand more wireless access to cope with the growing user consumption of mobile services.

Background Prognosis of metastatic melanoma is changing due to advances in immunotherapy and targeted therapy. However, management of patients with brain metastases in day-to-day practice continues to be a challenge. Case Report We describe a 40-year-old woman diagnosed with symptomatic brain metastases from cutaneous melanoma and Eastern Cooperative Oncology Group 3. She was treated, off label, with BRAF inhibitor (dabrafenib) + MEK inhibitor (trametinib) and radiotherapy. There was significant, long-lasting, response (17 months), no clinically relevant toxicity, and clear improvement in quality of life. Conclusions This case is an example of real-life application of advances in targeted therapy.

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Microbicides are an important strategy for preventing the sexual transmission of HIV but, so far, the most advanced tenofovir-based microbicides have had modest efficacy. This has been related to adherence problems and high prevalence of tenofovir-resistant HIV-1 strains. P3 is a new peptide with potent activity against HIV that may be a good microbicide candidate. In this work P3 was formulated in a gel of hydroxyethyl cellulose and its activity, stability and safety profile in Balb/c mice were evaluated. HIV infection was fully blocked by a 1.5% gel containing P3 at the IC90 (366.4 nM) concentration. The antiviral activity did not change at 4°C during 4 months and at 25, 37 and 65°C for 1 week. P3 was stable and fully functional at acidic pH up to 24h, under different concentrations of hydrogen peroxide and in the presence of genital fluids up to 48h. P3 had no antibacterial activity and did not affect sperm motility and vitality. Finally, P3 didn't cause significant alterations in the vaginal epithelium of Balb/c mice at 0.06 (456.8 μM) and 0.2 mg/day (1522.7 μM) doses. These findings indicate that P3 is an excellent candidate for further development as a microbicide gel for the prevention of HIV transmission in women. info:eu-repo/semantics/publishedVersion

Submitted by Paula Saraiva (psaraiva@egasmoniz.edu.pt) on 2019-12-12T16:08:44Z No. of bitstreams: 1 Artigo_NTaveira_2019_06_acceptedmanuscript.pdf: 170896 bytes, checksum: a2600eae4891499d563cae74c5262968 (MD5) Approved for entry into archive by Paula Saraiva (psaraiva@egasmoniz.edu.pt) on 2019-12-12T16:08:57Z (GMT) No. of bitstreams: 1 Artigo_NTaveira_2019_06_acceptedmanuscript.pdf: 170896 bytes, checksum: a2600eae4891499d563cae74c5262968 (MD5) Made available in DSpace on 2019-12-12T16:08:57Z (GMT). No. of bitstreams: 1 Artigo_NTaveira_2019_06_acceptedmanuscript.pdf: 170896 bytes, checksum: a2600eae4891499d563cae74c5262968 (MD5) Previous issue date: 2017-11 info:eu-repo/semantics/publishedVersion

HIV plasma viral load is an established marker of disease progression and of response to antiretroviral therapy, but currently there is no commercial assay validated for the quantification of viral load in HIV-2-infected individuals. We sought to make the first clinical evaluation of Cavidi ExaVir Load (version 3) in HIV-2-infected patients. Samples were collected from a total of 102 individuals living in Cape Verde, and the HIV-2 viral load was quantified by both ExaVir Load and a reference in-house real-time quantitative PCR (qPCR) used in Portugal in 91 samples. The associations between viral load and clinical prognostic variables (CD4 + T cell counts and antiretroviral therapy status) were similar for measurements obtained using ExaVir Load and qPCR. There was no difference between the two methods in the capacity to discriminate between nonquantifiable and quantifiable HIV-2 in the plasma. In samples with an HIV-2 viral load quantifiable by both methods ( n = 27), the measurements were highly correlated (Pearson r = 0.908), but the ExaVir Load values were systematically higher relative to those determined by qPCR (median difference, 0.942 log 10 copies/ml). A regression model was derived that enables the conversion of ExaVir Load results to those that would have been obtained by the reference qPCR. In conclusion, ExaVir Load version 3 is a reliable commercial assay to measure viral load in HIV-2-infected patients and therefore a valuable alternative to the in-house assays in current use.

Objectives To produce new fusion inhibitor peptides for HIV-1 and HIV-2 based on ancestral envelope sequences. Methods HIV-2/simian immunodeficiency virus (SIV) ancestral transmembrane protein sequences were reconstructed and ancestral peptides were derived from the helical region 2 (HR2). The activity of one ancestral peptide (named P3) was examined against a panel of HIV-1 and HIV-2 primary isolates in TZM-bl cells and peripheral blood mononuclear cells and compared to T-20. Peptide secondary structure was analyzed by circular dichroism. Resistant viruses were selected and resistance mutations were identified by sequencing the env gene. Results P3 has 34 residues and overlaps the N-terminal pocket-binding region and heptad repeat core of HR2. In contrast to T-20, P3 forms a typical α-helical structure in solution, binds strongly to the transmembrane protein, and potently inhibits both HIV-2 (mean IC50, 63.8 nmol/l) and HIV-1 (11 nmol/l) infection, including T-20-resistant isolates. The N43K mutation in the HR1 region of HIV-1 leads to 120-fold resistance to P3 indicating that the HR1 region in transmembrane glycoprotein is the target of P3. No HIV-2-resistant mutations could be selected by P3 suggesting that the genetic barrier to resistance is higher in HIV-2 than in HIV-1. HIV-1-infected patients presented significantly lower P3-specific antibody reactivity compared to T-20. Conclusion P3 is an HIV-2/SIV ancestral peptide with low antigenicity, high stability, and potent activity against both HIV-1, including variants resistant to T-20, and HIV-2. Similar evolutionary biology strategies should be explored to enhance the production of antiviral peptide drugs, microbicides, and vaccines.

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.IMPORTANCEThe 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.

Although HIV-2 does not encode a vpu gene, the ability to antagonize bone marrow stromal antigen 2 (BST-2) is conserved in some HIV-2 isolates, where it is controlled by the Env glycoprotein. We previously reported that a single-amino-acid difference between the laboratory-adapted ROD10 and ROD14 Envs controlled the enhancement of virus release (referred to here as Vpu-like) activity. Here, we investigated how conserved the Vpu-like activity is in primary HIV-2 isolates. We found that half of the 34 tested primary HIV-2 Env isolates obtained from 7 different patients enhanced virus release. Interestingly, most HIV-2 patients harbored a mixed population of viruses containing or lacking Vpu-like activity. Vpu-like activity and Envelope functionality varied significantly among Env isolates; however, there was no direct correlation between these two functions, suggesting they evolved independently. In comparing the Env sequences from one HIV-2 patient, we found that similar to the ROD10/ROD14 Envs, a single-amino-acid change (T568I) in the ectodomain of the TM subunit was sufficient to confer Vpu-like activity to an inactive Env variant. Surprisingly, however, absence of Vpu-like activity was not correlated with absence of BST-2 interaction. Taken together, our data suggest that maintaining the ability to antagonize BST-2 is of functional relevance not only to HIV-1 but also to HIV-2 as well. Our data show that as with Vpu, binding of HIV-2 Env to BST-2 is important but not sufficient for antagonism. Finally, as observed previously, the Vpu-like activity in HIV-2 Env can be controlled by single-residue changes in the TM subunit. IMPORTANCE Lentiviruses such as HIV-1 and HIV-2 encode accessory proteins whose function is to overcome host restriction mechanisms. Vpu is a well-studied HIV-1 accessory protein that enhances virus release by antagonizing the host restriction factor BST-2. HIV-2 does not encode a vpu gene. Instead, the HIV-2 Env glycoprotein was found to antagonize BST-2 in some isolates. Here, we cloned multiple Env sequences from 7 HIV-2-infected patients and found that about half were able to antagonize BST-2. Importantly, most HIV-2 patients harbored a mixed population of viruses containing or lacking the ability to antagonize BST-2. In fact, in comparing Env sequences from one patient combined with site-directed mutagenesis, we were able to restore BST-2 antagonism to an inactive Env protein by a single-amino-acid change. Our data suggest that targeting BST-2 by HIV-2 Env is a dynamic process that can be regulated by simple changes in the Env sequence.

Background CCR5-coreceptor antagonists can be used for treating HIV-2 infected individuals. Before initiating treatment with coreceptor antagonists, viral coreceptor usage should be determined to ensure that the virus can use only the CCR5 coreceptor (R5) and cannot evade the drug by using the CXCR4 coreceptor (X4-capable). However, until now, no online tool for the genotypic identification of HIV-2 coreceptor usage had been available. Furthermore, there is a lack of knowledge on the determinants of HIV-2 coreceptor usage. Therefore, we developed a data-driven web service for the prediction of HIV-2 coreceptor usage from the V3 loop of the HIV-2 glycoprotein and used the tool to identify novel discriminatory features of X4-capable variants. Results Using 10 runs of tenfold cross validation, we selected a linear support vector machine (SVM) as the model for geno2pheno[coreceptor-hiv2], because it outperformed the other SVMs with an area under the ROC curve (AUC) of 0.95. We found that SVMs were highly accurate in identifying HIV-2 coreceptor usage, attaining sensitivities of 73.5% and specificities of 96% during tenfold nested cross validation. The predictive performance of SVMs was not significantly different (p value 0.37) from an existing rules-based approach. Moreover, geno2pheno[coreceptor-hiv2] achieved a predictive accuracy of 100% and outperformed the existing approach on an independent data set containing nine new isolates with corresponding phenotypic measurements of coreceptor usage. geno2pheno[coreceptor-hiv2] could not only reproduce the established markers of CXCR4-usage, but also revealed novel markers: the substitutions 27K, 15G, and 8S were significantly predictive of CXCR4 usage. Furthermore, SVMs trained on the amino-acid sequences of the V1 and V2 loops were also quite accurate in predicting coreceptor usage (AUCs of 0.84 and 0.65, respectively). Conclusions In this study, we developed geno2pheno[coreceptor-hiv2], the first online tool for the prediction of HIV-2 coreceptor usage from the V3 loop. Using our method, we identified novel amino-acid markers of X4-capable variants in the V3 loop and found that HIV-2 coreceptor usage is also influenced by the V1/V2 region. The tool can aid clinicians in deciding whether coreceptor antagonists such as maraviroc are a treatment option and enables epidemiological studies investigating HIV-2 coreceptor usage. geno2pheno[coreceptor-hiv2] is freely available at http://coreceptor-hiv2.geno2pheno.org. Electronic supplementary material The online version of this article (doi:10.1186/s12977-016-0320-7) contains supplementary material, which is available to authorized users.

This is the author’s version of a work that was accepted for publication in AIDS Research and Human Retroviruses . Final publication is available from Mary Ann Liebert, Inc., publishers http://dx.doi.org/10.1089/aid.2016.0084 "Angola has an extremely diverse HIV-1 epidemic fueled in part by the frequent interchange of people with the Democratic Republic of Congo (DRC) and Republic of Congo (RC). Characterization of HIV-1 strains circulating in Angola should help to better understand the origin of HIV-1 subtypes and recombinant forms and their transmission dynamics. In this study we characterize the first near full-length HIV-1 genomic sequences from HIV-1 infected individuals from Angola. Samples were obtained in 1993 from three HIV-1 infected patients living in Cabinda, Angola. Near full-length genomic sequences were obtained from virus isolates. Maximum likelihood phylogenetic tree inference and analyses of potential recombination patterns were performed to evaluate the sequence classifications and origins. Phylogenetic and recombination analyses revealed that one virus was a pure subtype J, another mostly subtype J with a small uncertain region, and the final virus was classified as a H/U/CRF02_AG recombinant. Consistent with their epidemiological data, the subtype J sequences were more closely related to each other than to other J sequences previously published. Based on the env gene, taxa from Angola occur throughout the global subtype J phylogeny. HIV-1 subtypes J and H are present in Angola at low levels since at least 1993. Low transmission efficiency and/or high recombination potential may explain their limited epidemic success in Angola and worldwide. The high diversity of rare subtypes in Angola suggests that Angola was part of the early establishment of the HIV-1 pandemic."

Background The baseline susceptibility of primary HIV-2 to maraviroc (MVC) and other entry inhibitors is currently unknown. Methods The susceptibility of 19 HIV-2 isolates obtained from asymptomatic and AIDS patients and seven HIV-1 clinical isolates to the fusion inhibitors enfuvirtide (ENF) and T-1249, and to the coreceptor antagonists AMD3100, TAK-779 and MVC, was measured using a TZM-bl cell-based assay. The 50% inhibitory concentration (IC50), 90% inhibitory concentration (IC90) and dose–response curve slopes were determined for each drug. Results ENF and T-1249 were significantly less active on HIV-2 than on HIV-1 (211- and 2-fold, respectively). AMD3100 and TAK-779 inhibited HIV-2 and HIV-1 CXCR4 tropic (X4) and CCR5 tropic (R5) variants with similar IC50 and IC90 values. MVC, however, inhibited the replication of R5 HIV-2 variants with significantly higher IC90 values (42.7 versus 9.7 nM; P+ T-cells. Conclusions T-1249 is a potent inhibitor of HIV-2 replication indicating that new fusion inhibitors might be useful to treat HIV-2 infection. Coreceptor antagonists TAK-779 and AMD3100 are also potent inhibitors of HIV-2 replication. The reduced sensitivity of R5 variants to MVC, especially in severely immunodeficient patients, indicates that the treatment of HIV-2-infected patients with MVC might require higher dosages than those used in HIV-1 patients, and should be adjusted to the disease stage.

Copyright © 2016 Wolters Kluwer Health, Inc., OBJECTIVE: To develop a novel and potent fusion inhibitor of HIV infection based on a rational strategy for synthetic antibody library construction. DESIGN: The reduced molecular weight of single-domain antibodies (sdAbs) allows targeting of cryptic epitopes, the most conserved and critical ones in the context of HIV entry. Heavy-chain sdAbs from camelids are particularly suited for this type of epitope recognition because of the presence of long and flexible antigen-binding regions [complementary-determining regions (CDRs)]. METHODS: We translated camelid CDR features to a rabbit light-chain variable domain (VL) and constructed a library of minimal antibody fragments with elongated CDRs. Additionally to elongation, CDRs' variability was restricted to binding favorable amino acids to potentiate the selection of high-affinity sdAbs. The synthetic library was screened against a conserved, hidden, and crucial-to-fusion sequence on the heptad-repeat 1 (HR1) region of the HIV-1 envelope glycoprotein. RESULTS: Two anti-HR1 VLs, named F63 and D104, strongly inhibited laboratory-adapted HIV-1 infectivity. F63 also inhibited infectivity of HIV-1 and HIV-2 primary isolates similarly to the Food and Drug Administration-approved fusion inhibitor T-20 and HIV-1 strains resistant to T-20. Moreover, epitope mapping of F63 revealed a novel target sequence within the highly conserved hydrophobic pocket of HR1. F63 was also capable of interacting with viral and cell lipid membrane models, a property previously associated with T-20's inhibitory mechanism. CONCLUSION: In summary, to our best knowledge, we developed the first potent and broad VL sdAb fusion inhibitor of HIV infection. Our study also gives insights into engineering strategies that could be explored to enhance the development of antiviral drugs., This work was supported by grants HIVERA/0002/2013, PTDC/SAU-EPI/122400/2010 and VIH/SAU/0029/2011 from Fundação para a Ciência e a Tecnologia– Ministério da Educação e Ciência (FCT-MEC), Portugal. C.C-S. and T.F. were supported by FCTMEC PhD fellowships SFRH/BD/73838/2010 and SFRH/52383/2013. F.A-S. and A.S.V. were supported by FCT Investigator Programme IF/01010/2013 and IF/00803/2012.

1. Scientific ToolBox Consulting. Lisbon. Portugal. 2. Instituto de Investigacao do Medicamento (iMed.ULisboa). Faculdade de Farmacia. Universidade de Lisboa. Lisboa. Portugal. 3. Centro de Investigacao Interdisciplinar Egas Moniz. Instituto Superior de Ciencias da Saude Egas Moniz. Monte de Caparica. Portugal.  Autor correspondente: Joao Bissau. joao.bissau@sctbx.com Recebido: 30 de Dezembro de 2014 Aceite: 26 de Marco de 2015 | Copyright © Ordem dos Medicos 2015 Joao BISSAU1, Pedro BORREGO1,2,3 Acta Med Port 2015 Sep-Oct;28(5):545-547

This is the author’s version of a work that was accepted for publication in Nanoscale. "The development of topical microbicide formulations for vaginal delivery to prevent HIV-2 sexual transmission is urgently needed. Second- and third-generation polyanionic carbosilane dendrimers with a silicon atom core and 16 sulfonate (G2-S16), napthylsulfonate (G2-NS16) and sulphate (G3-Sh16) end-groups have shown potent and broad-spectrum anti-HIV-1 activity. However, their antiviral activity against HIV-2 and mode of action have not been probed. Cytotoxicity, anti-HIV-2, anti-sperm and antimicrobial activities of dendrimers were determined. Analysis of combined effects of triple combinations with tenofovir and raltegravir was performed by using CalcuSyn software. We also assessed the mode of antiviral action on the inhibition of HIV-2 infection through a panel of different in vitro antiviral assays: attachment, internalization in PBMCs, inactivation and cell-based fusion. Vaginal irritation and histological analysis in female BALB/c mice were evaluated. Our results suggest that G2-S16, G2-NS16 and G3-Sh16 exert anti-HIV-2 activity at an early stage of viral replication inactivating the virus, inhibiting cell-to-cell HIV-2 transmission, and blocking the binding of gp120 to CD4, and the HIV-2 entry. Triple combinations with tenofovir and raltegravir increased the anti-HIV-2 activity, consistent with synergistic interactions (CIwt: 0.33–0.66). No vaginal irritation was detected in BALB/c mice after two consecutive applications for 2 days with 3% G2-S16. Our results have clearly shown that G2-S16, G2-NS16 and G3-Sh16 have high potency against HIV-2 infection. The modes of action confirm their multifactorial and non-specific ability, suggesting that these dendrimers deserve further studies as potential candidate microbicides to prevent vaginal/rectal HIV-1/HIV-2 transmission in humans."

In this paper, a new class of microstrip filter with dual-band lowpass/bandpass response is reported. It consists of a periodic-type circuit configuration made up of an original firstorder double-band lowpass/bandpass filtering cell. The operating principle of this lowpass/bandpass filter structure is explained, and guidelines for its systematic design are expounded. Besides, a four-stage prototype with 60-dB inter-band Long-Term-Evolution (LTE) service rejection is designed and simulated at the layout level for verification. This dual-function filter approach can find use in next-generation multi-purpose communications systems simultaneously operating for several standards, such as those handling UHF DVB-T signals — lowpass band — and other services — passband(s) — along with LTE interference mitigation.

The increasing attention devoted to the control of process variance has stimulated the development of a set of control charts, which includes the CUSUM-ln(\(S^{2}\)) control chart that is considered one of the most effective tools to control the variance and consequently one of the most used whenever a SPC is implemented. However, a common problem which arises with the application of CUSUM-ln(\(S^{2}\)) control charts is the limited set of tables of results for consultation. In general, only the most common situations are available. Therefore, these resources become ineffective when one need to cover other less common cases, but equally important and considered target of interest. On the other hand, there are not available the abacuses correspondent to the numerical tables. This paper intends to present a new approach (methodology), based on a computational tool (FCSCE), which provides us, not only with the abacuses, but also with the respective tables. This software tool, implemented in MATLAB environment, is a key instrument to deal with generic SPC case studies involving the CUSUM-ln(\(S^{2}\)) control chart, responding effectively to the previously listed impairments.

Background Differently from HIV-1, HIV-2 disease progression usually takes decades without antiretroviral therapy and the majority of HIV-2 infected individuals survive as elite controllers with normal CD4+ T cell counts and low or undetectable plasma viral load. Neutralizing antibodies (Nabs) are thought to play a central role in HIV-2 evolution and pathogenesis. However, the dynamic of the Nab response and resulting HIV-2 escape during acute infection and their impact in HIV-2 evolution and disease progression remain largely unknown. Our objective was to characterize the Nab response and the molecular and phenotypic evolution of HIV-2 in association with Nab escape in the first years of infection in two children infected at birth. Results CD4+ T cells decreased from about 50% to below 30% in both children in the first five years of infection and the infecting R5 viruses were replaced by X4 viruses within the same period. With antiretroviral therapy, viral load in child 1 decreased to undetectable levels and CD4+ T cells recovered to normal levels, which have been sustained at least until the age of 12. In contrast, viral load increased in child 2 and she progressed to AIDS and death at age 9. Beginning in the first year of life, child 1 raised high titers of antibodies that neutralized primary R5 isolates more effectively than X4 isolates, both autologous and heterologous. Child 2 raised a weak X4-specific Nab response that decreased sharply as disease progressed. Rate of evolution, nucleotide and amino acid diversity, and positive selection, were significantly higher in the envelope of child 1 compared to child 2. Rates of R5-to-X4 tropism switch, of V1 and V3 sequence diversification, and of convergence of V3 to a β-hairpin structure were related with rate of escape from the neutralizing antibodies. Conclusion Our data suggests that the molecular and phenotypic evolution of the human immunodeficiency virus type 2 envelope are related with the dynamics of the neutralizing antibody response providing further support for a model in which Nabs play an important role in HIV-2 pathogenesis.

Currently, there is a growing interest in using entry inhibitors to treat HIV-2-infected patients because, among the available drugs, few are fully active against HIV-2. Recent studies indicate that maraviroc and other experimental entry inhibitors, including new CCR5 and CXCR4 antagonists, inhibit primary isolates of HIV-2 as well as HIV-1 and may, therefore, expand the existing therapeutic armamentarium against HIV-2. There are, however, significant differences between the evolution of HIV-1 and HIV-2 envelope glycoproteins during infection that can lead to differences in the response to therapy with entry inhibitors over the course of the infection. Here, we review the available data on the susceptibility of HIV-2 to entry inhibitors in the context of the evolution of the sequence, structure, and function of envelope glycoproteins during infection.

This is a non-final version of an article published in final form in AIDS. 28 November 2012 - Volume 26 - Issue 18 - p 2275–2284 Objectives: To characterize the nature and dynamics of the neutralizing antibody (NAb) response and escape in chronically HIV-2 infected patients. Methods: Twenty-eight chronically infected adults were studied over a period of 1-4 years. The neutralizing activity of plasma IgG antibodies against autologous and heterologous primary isolates was analyzed using a standard assay in TZM-bl cells. Coreceptor usage was determined in GHOST cells. The sequence and predicted 3Dstructure of the C2V3C3 Env region were determined for all isolates. Results: Only 50% of the patients consistently produced IgG NAbs to autologous and contemporaneous virus isolates. In contrast, 96% of the patients produced IgG antibodies that neutralized at least two isolates of a panel of six heterologous R5 isolates. Breadth and potency of the neutralizing antibodies were positively associated with the number of CD4+ T cells and with the titer and avidity of C2V3C3-specific binding IgG antibodies. X4 isolates were obtained only from late stage disease patients and were fully resistant to neutralization. The V3 loop of X4 viruses was longer, had a higher net charge and differed markedly in secondary structure compared to R5 viruses. Conclusions: Most HIV-2 patients infected with R5 isolates produce C2V3C3-specific neutralizing antibodies whose potency and breadth decreases as the disease progresses. Resistance to antibody neutralization occurs in late stage disease and is usually associated with X4 viral tropism and major changes in V3 sequence and conformation. Our studies support a model of HIV-2 pathogenesis in which the neutralizing antibodies play a central role and have clear implications for the vaccine field. Fundação para a Ciência e Tecnologia, Portugal

Our aim was to characterize for the first time the genetic diversity of HIV in Cape Verde Islands as well as the drug resistance profiles in treated and untreated patients. Blood specimens were collected from 41 HIV-1 and 14 HIV-2 patients living in Santiago Island. Half of the patients were on antiretroviral treatment (ART). Pol and env gene sequences were obtained using in-house methods. Phylogenetic analysis was used for viral subtyping and the Stanford Algorithm was used for resistance genotyping. For HIV-1, the amplification of pol and env was possible in 27 patients (66%). HIV-1 patients were infected with subtypes G (13, 48%), B (2, 7%), F1 (2, 7%), and CRF02_AG (2, 7%), and complex recombinant forms including a new C/G variant (n =8, 30%). Drug resistance mutations were detected in the PR and RT of three (10%) treated patients. M41L and K103N transmitted drug resistance mutations were found in 2 of 17 (12%) untreated patients. All 14 HIV-2 isolates belonged to group A. The origin of 12 strains was impossible to determine whereas two strains were closely related to the historic ROD strain. In conclusion, in Cape Verde there is a long-standing HIV-2 epidemic rooted in ROD-like strains and a more recent epidemic of unknown origin. The HIV-1 epidemic is caused by multiple subtypes and complex recombinant forms. Drug resistance HIV-1 strains are present at moderate levels in both treated and untreated patients. Close surveillance in these two populations is crucial to prevent further transmission of drug-resistant strains.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Users must also make clear the license terms under which the work was published. CC BY Licence: http://creativecommons.org/licenses/by/4.0/ Background: CRF14_BG isolates, originally found in Spain, are characterized by CXCR4 tropism and rapid disease progression. This study aimed to identify the origin of CRF14_BG and reconstruct its epidemiological history based on new isolates from Portugal. Methodology/Principal Findings: C2V3C3 env gene sequences were obtained from 62 samples collected in 1993–1998 from Portuguese HIV-1 patients. Full-length genomic sequences were obtained from three patients. Viral subtypes, diversity, divergence rate and positive selection were investigated by phylogenetic analysis. The molecular structure of the genomes was determined by bootscanning. A relaxed molecular clock model was used to date the origin of CRF14_BG. Geno2pheno was used to predict viral tropism. Subtype B was the most prevalent subtype (45 sequences; 73%) followed by CRF14_BG (8; 13%), G (4; 6%), F1 (2; 3%), C (2; 3%) and CRF02_AG (1; 2%). Three CRF14_BG sequences were derived from 1993 samples. Near full-length genomic sequences were strongly related to the CRF14_BG isolates from Spain. Genetic diversity of the Portuguese isolates was significantly higher than the Spanish isolates (0.044 vs 0.014, P,0.0001). The mean date of origin of the CRF14_BG cluster was estimated to be 1992 (range, 1989 and 1996) based on the subtype G genomic region and 1989 (range, 1984–1993) based on the subtype B genomic region. Most CRF14_BG strains (78.9%) were predicted to be CXCR4. Finally, up to five amino acids were under selective pressure in subtype B V3 loop whereas only one was found in the CRF14_BG cluster. Conclusions: CRF14_BG emerged in Portugal in the early 1990 s soon after the beginning of the HIV-1 epidemics, spread to Spain in late 1990 s as a consequence of IVDUs migration and then to the rest of Europe. CXCR4 tropism is a general characteristic of this CRF that may have been selected for by escape from neutralizing antibody response.

Human immunodeficiency virus type 2 (HIV-2) infection affects about 1 to 2 million individuals, the majority living in West Africa, Europe, and India. As for HIV-1, new strategies for the prevention of HIV-2 infection are needed. Our aim was to produce new vaccine immunogens that elicit the production of broadly reactive HIV-2 neutralizing antibodies (NAbs). Native and truncated envelope proteins from the reference HIV-2ALI isolate were expressed in vaccinia virus or in bacteria. This source isolate was used due to its unique phenotype combining CD4 independence and CCR5 usage. NAbs were not elicited in BALB/c mice by single immunization with a truncated and fully glycosylated envelope gp125 (gp125t) or a recombinant polypeptide comprising the C2, V3, and C3 envelope regions (rpC2-C3). A strong and broad NAb response was, however, elicited in mice primed with gp125t expressed in vaccinia virus and boosted with rpC2-C3. Serum from these animals potently neutralized (median 50% neutralizing titer, 3,200) six of six highly divergent primary HIV-2 isolates. Coreceptor usage and the V3 sequence of NAb-sensitive isolates were similar to that of the vaccinating immunogen (HIV-2ALI). In contrast, NAbs were not reactive on three X4 isolates that displayed major changes in V3 loop sequence and structure. Collectively, our findings demonstrate that broadly reactive HIV-2 NAbs can be elicited by using a vaccinia virus vector-prime/rpC2-C3-boost immunization strategy and suggest a potential relationship between escape to neutralization and cell tropism.

The objective of this study was to estimate and compare the evolutionary rates of HIV-2 and HIV-1. Two HIV-2 data sets from patients with advanced disease were compared to matched HIV-1 data sets. The estimated mean evolutionary rate of HIV-2 was significantly higher than the estimated rate of HIV-1, both in the gp125 and in the V3 region of the env gene. In addition, the rate of synonymous substitutions in gp125 was significantly higher for HIV-2 than for HIV-1, possibly indicating a shorter generation time or higher mutation rate of HIV-2. Thus, the lower virulence of HIV-2 does not appear to translate into a lower rate of evolution.

This paper presents a new view on typical figures of merit for nonlinear distortion evaluation, mainly ACPR, for new wireless communication systems, that are based on time switched signals. Those systems are time switched, either due to the standard specifications as TDD systems, or due to new forms of radio communications as cognitive radio technologies. The most significant differences between conventional transient nonlinear figures of merit are explained, as well as, possible ways on how to measure them. Finally, this work is concluded with some comments upon future standards.

Objective: To examine the unspecific and envelope-specific IgA and IgG responses in acute and chronic HIV-2 infection. Methods: Twenty-eight chronically infected adults and two children with perinatal infection were studied. Total plasma concentrations of IgA and IgG were determined by nephelometry. IgA and IgG reactivity against the immunodominant region in gp36 and the C2V3C3 region in gp125 was tested with the enzyme-linked immunosorbent assay (ELISA)‐HIV-2 assay. Clonal sequences of the C2V3C3 env region were obtained for most patients. Results: Total plasma IgG concentration, but not IgA, was significantly higher than normal in HIV-2 patients and correlated inversely with CD4 þ T-cell counts. Seroconversion to gp36 occurred during thefirst year of life in both infants. The infant with rapid disease progression did not elicit C2V3C3-specific antibodies. Most chronically infected patients produced plasma IgG1, IgG3 and IgA antibodies against gp36 and C2V3C3. Lack of C2V3C3-specific IgG response in two patients was associated with a majorantigenic changein the V3 region.In longitudinalanalysis, there was a significant inverse association between the C2V3C3-specific IgG antibody response and the number of CD4 þ T cells. Conclusion: HIV-2promotesanearly,strongandbroadgp36andC2V3C3-specificIgG and IgA response. Increase in the IgG response against the envelope C2V3C3 region is associated with increased loss of CD4 þ T cells in chronically infected patients. These results provide further support for the immune protective role of the C2V3C3 envelope region during HIV-2 infection and have direct implications for HIV-2 diagnosis, clinical management and pathogenesis. 2008 Wolters Kluwer Health | Lippincott Williams & Wilkins AIDS 2008, 22:2257‐2265

BackgroundThis study was designed to investigate, for the first time, the short-term molecular evolution of the HIV-2 C2, V3 and C3 envelope regions and its association with the immune response. Clonal sequences of theenvC2V3C3 region were obtained from a cohort of eighteen HIV-2 chronically infected patients followed prospectively during 2–4 years. Genetic diversity, divergence, positive selection and glycosylation in the C2V3C3 region were analysed as a function of the number of CD4+ T cells and the anti-C2V3C3 IgG and IgA antibody reactivityResultsThe mean intra-host nucleotide diversity was 2.1% (SD, 1.1%), increasing along the course of infection in most patients. Diversity at the amino acid level was significantly lower for the V3 region and higher for the C2 region. The average divergence rate was 0.014 substitutions/site/year, which is similar to that reported in chronic HIV-1 infection. The number and position of positively selected sites was highly variable, except for codons 267 and 270 in C2 that were under strong and persistent positive selection in most patients. N-glycosylation sites located in C2 and V3 were conserved in all patients along the course of infection. Intra-host variation of C2V3C3-specific IgG response over time was inversely associated with the variation in nucleotide and amino acid diversity of the C2V3C3 region. Variation of the C2V3C3-specific IgA response was inversely associated with variation in the number of N-glycosylation sites.ConclusionThe evolutionary dynamics of HIV-2 envelope during chronic aviremic infection is similar to HIV-1 implying that the virus should be actively replicating in cellular compartments. Convergent evolution of N-glycosylation in C2 and V3, and the limited diversification of V3, indicates that there are important functional constraints to the potential diversity of the HIV-2 envelope. C2V3C3-specific IgG antibodies are effective at reducing viral population size limiting the number of virus escape mutants. The C3 region seems to be a target for IgA antibodies and increasing N-linked glycosylation may prevent HIV-2 envelope recognition by these antibodies. Our results provide new insights into the biology of HIV-2 and its relation with the human host and may have important implications for vaccine design.