The latest evidence for possible HIV-1 curative strategies

Breaking Barriers to an HIV-1 Cure: Innovations in Gene Editing, Immune Modulation, and Reservoir Eradication

Recent advances in virology, particularly in the study of HIV-1, have significantly progressed the pursuit of a definitive cure for the disease. Emerging therapeutic strategies encompass innovative gene-editing technologies, immune-modulatory interventions, and next-generation antiretroviral agents. Efforts to eliminate or control viral reservoirs have also gained momentum, with the aim of achieving durable viral remission without the continuous requirement for antiretroviral therapy. Despite these promising developments, critical challenges persist in bridging the gap between laboratory findings and clinical implementation. This review provides a comprehensive analysis of recent breakthroughs, ongoing clinical trials, and the barriers that must be addressed to translate these advancements into effective treatments, emphasizing the multifaceted approaches being pursued to achieve a curative solution for HIV-1 infection.

The immunosuppressive tuberculosis-associated microenvironment inhibits viral replication and promotes HIV-1 latency in CD4+ T cells

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is the most common coinfection among people living with HIV-1. This coinfection is associated with accelerated HIV-1 disease progression and reduced survival. However, the impact of the HIV-1/TB coinfection on HIV-1 replication and latency in CD4+ T cells remains poorly studied. Using the acellular fraction of tuberculous pleural effusion (TB-PE), we investigated whether viral replication and HIV-1 latency in CD4+ T cells are affected by a TB-associated microenvironment. Our results revealed that TB-PE impaired T cell receptor-dependent cell activation and decreased HIV-1 replication in CD4+ T cells. Moreover, this immunosuppressive TB microenvironment promoted viral latency and inhibited HIV-1 reactivation. This study indicates that the TB-induced immune response may contribute to the persistence of the viral reservoir by silencing HIV-1 expression, allowing the virus to persist undetected by the immune system, and increasing the size of the latent HIV-1 reservoir.

Alsayegh A, Ahmad FA, Akhtar MS, Alavudeen SS, Bantun F, Wahab S, Ahmed A, Ali M, Elbendary EY, Raposo A, Kambal N, H. Abdelrahman M. Ganoderma lucidum: Insight into antimicrobial and antioxidant properties with development of secondary metabolites

Ganoderma lucidum is a versatile mushroom. Polysaccharides and triterpenoids are the major bioactive compounds and have been used as traditional medicinal mushrooms since ancient times. They are currently used as nutraceuticals and functional foods. G. lucidum extracts and their bioactive compounds have been used as an alternative to antioxidants and antimicrobial agents. Secondary metabolites with many medicinal properties make it a possible substitute that could be applied as immunomodulatory, anticancer, antimicrobial, anti-oxidant, anti-inflammatory, and anti-diabetic. The miraculous properties of secondary metabolites fascinate researchers for their development and production. Recent studies have paid close attention to the different physical, genetic, biochemical, and nutritional parameters that potentiate the production of secondary metabolites. This review is an effort to collect biologically active constituents from G. lucidum that reveal potential actions against diseases with the latest improvement in a novel technique to get maximum production of secondary metabolites. Studies are going ahead to determine the efficacy of numerous compounds and assess the valuable properties achieved by G. lucidum in favor of antimicrobial and antioxidant outcomes.

Lopinavir-menthol co-crystals for enhanced dissolution rate and intestinal absorption

Lopinavir is an antiretroviral, antiparasitic agent and recently utilized in treatment of COVID-19. Unfortunately, lopinavir exhibited poor oral bioavailability due to poor dissolution, extensive pre-systemic metabolism, and significant P-glycoprotein intestinal efflux. Accordingly, the aim was to enhance dissolution rate and intestinal absorption of lopinavir. This employed co-processing with menthol which is believed to modify crystalline structures and inhibit intestinal efflux. Lopinavir was mixed with menthol at different molar ratios before ethanol assisted kneading. Formulations were evaluated using FTIR spectroscopy, differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and dissolution studies. Optimum ratio was utilized to assess lopinavir intestinal permeability. This employed in situ rabbit intestinal perfusion technique. FTIR, DSC and XRD indicated formation of lopinavir-menthol co-crystals at optimum molar ratio of 1:2. Additional menthol underwent phase separation due to possible self-association. Co-crystallization significantly enhanced lopinavir dissolution rate compared with pure drug to increase the dissolution efficiency from 24.96% in case of unprocessed lopinavir to 91.43% in optimum formulation. Lopinavir showed incomplete absorption from duodenum and jejuno-iliac segments with lower absorptive clearance from jejuno-ileum reflecting P-gp efflux. Co-perfusion with menthol increased lopinavir intestinal permeability. The study introduced menthol as co-crystal co-former for enhanced dissolution and augmented intestinal absorption of lopinavir.

Computational Approaches for Designing Highly Specific and Efficient sgRNAs

The easily programmable CRISPR/Cas9 system has found applications in biomedical research as well as microbial and crop applications, due to its ability to create site-specific edits. This powerful and flexible system has also been modified to enable inducible gene regulation, epigenome modifications and high-throughput screens. Designing efficient and specific guides for the nuclease is a key step and also a major challenge in effective application. This chapter describes rules for sgRNA design and important features to consider while touching upon bioinformatics advances in predicting efficient guides. Computational tools that suggest improved guides, depending on application, or predict off-targets have also been mentioned and compared.

Resveratrol Promotes HIV-1 Tat Accumulation via AKT/FOXO1 Signaling Axis and Potentiates Vorinostat to Antagonize HIV-1 Latency

BACKGROUND

The latent reservoir of HIV-1 is a major barrier to achieving the eradication of HIV-1/AIDS. One strategy is termed "shock and kill", which aims to awaken the latent HIV-1 using latency reversing agents (LRAs) to replicate and produce HIV-1 particles. Subsequently, the host cells containing HIV-1 can be recognized and eliminated by the immune response and anti-retroviral therapy. Although many LRAs have been found and tested, their clinical trials were dissatisfactory.

OBJECTIVE

To aim of the study was to investigate how resveratrol reactivates silent HIV-1 transcription and assess if resveratrol could be a candidate drug for the "shock" phase in "shock and kill" strategy.

METHODS

We used established HIV-1 transcription cell models (HeLa-based NH1 and NH2 cells) and HIV-1 latent cell models (J-Lat A72 and Jurkat 2D10 cells). We performed resveratrol treatment on these cell lines and studied the mechanism of how resveratrol stimulates HIV-1 gene transcription. We also tested resveratrol's bioactivity on primary cells isolated from HIV-1 latent infected patients.

RESULTS

Resveratrol promoted HIV-1 Tat protein levels, and resveratrol-induced Tat promotion was found to be dependent on the AKT/FOXO1 signaling axis. Resveratrol could partially dissociate P-TEFb (Positive Transcription Elongation Factor b) from 7SK snRNP (7SK small nuclear Ribonucleoprotein) and promote Tat-SEC (Super Elongation Complex) interaction. Preclinical studies showed that resveratrol potentiated Vorinostat to awaken HIV-1 latency in HIV-1 latent infected cells isolated from patients.

CONCLUSION

We found a new mechanism of resveratrol stimulating the production of HIV-1. Resveratrol could be a promising candidate drug to eradicate HIV-1 reservoirs.

Predictors of antiretroviral therapy interruptions and factors influencing return to care at the Nkolndongo Health District, Cameroon

BACKGROUND

Antiretroviral therapy is a lifelong commitment that requires consistent intake of tablets to optimize health outcomes, attain and maintain viral suppression.

OBJECTIVE

We aimed to elicit predictors of treatment interruption amongst PLHIV and identify motivating factors influencing return to care.

METHOD

We conducted a cross-sectional study using a mixed-method approach in four hospitals in Yaoundé. Sociodemographic and clinical data were collected from ART registers. Using purposeful sampling, thirteen participants were enrolled for interviews. Quantitative data were analyzed using Epi-Info and Atlas-TI for qualitative analysis. Ethical clearance approved by CBCHS-IRB.

RESULTS

A total of 271 participants records were assessed. The mean age was 33 years (SD±11years). Private facilities CASS and CMNB registered respectively 53 (19.6%) and 14 (5.2%) participants while CMA Nkomo and IPC had 114 (42.1%) and 90 (33.2%) participants. Most participants (75.3%) were females [OR 1.14; CI 0.78-1.66] compare with males. 78% had no viral load test results. Transport cost and stigmatization constituted the most prominent predictors of treatment interruption (47.5%) and (10.5%) respectively. Belief in the discovery of an eminent HIV cure and the desire to raise offspring motivated 30% and 61%, respectively to resume treatment.

CONCLUSION

Structural barriers like exposed health facility, and dispensing ARVs in open spaces stigmatizes clients and increases odds of attrition. Attrition of patients on ART will be minimized through implementation of client centered approaches like multiplying proxy ART pick points, devolving stable clients to community ARV model.

Timing, Dosage, and Adherence of Antiretroviral Therapy and Risk of Osteoporosis in Patients With Human Immunodeficiency Virus Infection in Taiwan: A Nested Case-Control Study

The progression of acquired immunodeficiency syndrome is delayed in patients with human immunodeficiency virus (HIV) infection receiving antiretroviral therapy (ART). However, long-term ART is associated with adverse effects. Osteoporosis is one of the adverse effects and is a multifactorial systemic skeletal disease associated with bone fragility and an increased risk of fracture. We performed a longitudinal, comprehensive, nested case-control study to explore the effect of ART on the risk of osteoporosis in 104 osteoporotic and 416 non-osteoporotic patients with HIV infection at their average age about 29 years old in Taiwan. Patients with history of ART, current exposure to ART, higher cumulative defined daily doses (DDDs), or higher ART adherence were at a higher risk of osteoporosis (p < 0.05). Patients receiving nucleoside/nucleotide reverse transcriptase inhibitor (NRTI)-containing regimen (zidovudine-lamivudine combination, lamivudine-abacavir combination, and abacavir alone) and protease inhibitor (PI)-containing regimen (lopinavir-ritonavir combination, ritonavir, and atazanavir) had a higher risk of osteoporosis (p < 0.05). Especially, patients receiving high doses of the PIs lopinavir-ritonavir combination had an increased risk of osteoporosis (p < 0.05). In conclusion, history of ART, current exposure to ART, higher cumulative DDDs, and higher ART adherence were associated with an increased risk of osteoporosis. Furthermore, NRTI- and PI-containing regimens and high doses of PIs lopinavir-ritonavir combination may be associated with an increased risk of osteoporosis in patients with HIV infection in Taiwan.

Chinese Herbal Medicine Usage Reduces Overall Mortality in HIV-Infected Patients With Osteoporosis or Fractures

The survival of patients with HIV has greatly improved, due to Anti-Retroviral Therapy (ART). However, long-term HIV survivors often develop serious bone abnormalities, possibly due to the interplay of osteoblasts, osteoclasts, HIV ad ART. We evaluated in a nation-wide study in Taiwan the effect of Chinese herbal medicine (CHM) on overall mortality in HIV patients with osteoporosis or fractures. Enrollment period was between 1998 and 2011. Patients with osteoporosis or fractures before the HIV infection, and those with less than 14 days CHM use, were excluded. This left 498 patients, 160 CHM users, 338 without CHM. Univariate Kaplan-Meier and multivariate Cox regression analysis were used to compare the overall mortality in these 2 groups. Due to the nature of Chinese medicine, CHMs inevitably varied. We therefore also used rule mining and network analysis to determine which major CHM clusters were prescribed to the patients. CHM users had a much Lower mortality (hazard ratio (HR) = 0.43, 95% confidence interval (CI): 0.24–0.77, p < 0.005) and higher survival (p = 0.004, log-rank test). Although the CHMs greatly varied, network analysis identified one main cluster of strongly related CHM combinations (Chuan-Xiong-Cha-Tiao-San (CXCTS), Gan-Cao (GC; Glycyrrhiza uralensis Fisch.), Liu-He-Tang (LHT), Huang-Qin-Tang (HQT), Jia-Wei-Ping-Wei-San (JWPWS), and Dang-Gui-Long-Hui-Wan (DGLHuiW)). CHM as an additional treatment strongly improves overall survival in HIV-infected patients with osteoporosis and fractures.

HIV-1 Envelope Glycosylation and the Signal Peptide

The RV144 trial represents the only vaccine trial to demonstrate any protective effect against HIV-1 infection. While the reason(s) for this protection are still being evaluated, it serves as justification for widespread efforts aimed at developing new, more effective HIV-1 vaccines. Advances in our knowledge of HIV-1 immunogens and host antibody responses to these immunogens are crucial to informing vaccine design. While the envelope (Env) protein is the only viral protein present on the surface of virions, it exists in a complex trimeric conformation and is decorated with an array of variable N-linked glycans, making it an important but difficult target for vaccine design. Thus far, efforts to elicit a protective humoral immune response using structural mimics of native Env trimers have been unsuccessful. Notably, the aforementioned N-linked glycans serve as a component of many of the epitopes crucial for the induction of potentially protective broadly neutralizing antibodies (bnAbs). Thus, a greater understanding of Env structural determinants, most critically Env glycosylation, will no doubt be of importance in generating effective immunogens. Recent studies have identified the HIV-1 Env signal peptide (SP) as an important contributor to Env glycosylation. Further investigation into the mechanisms by which the SP directs glycosylation will be important, both in the context of understanding HIV-1 biology and in order to inform HIV-1 vaccine design.

A Review of Current Strategies Towards the Elimination of Latent HIV-1 and Subsequent HIV-1 Cure

Background

During the past 35 years, highly effective ART has saved the lives of millions of people worldwide by suppressing viruses to undetectable levels. However, this does not translate to the absence of viruses in the body as HIV persists in latent reservoirs. Indeed, rebounded HIV has been recently observed in the Mississippi and California infants previously thought to have been cured. Hence, much remains to be learned about HIV latency, and the search for the best strategy to eliminate the reservoir is the direction current research is taking. A systems-level approach that fully recapitulates the dynamics and complexity of HIV-1 latency In vivo and is applicable in human therapy is prudent for HIV eradication to be more feasible.

Objectives

The main barriers preventing the cure of HIV with antiretroviral therapy have been identified, progress has been made in the understanding of the therapeutic targets to which potentially eradicating drugs could be directed, integrative strategies have been proposed, and clinical trials with various alternatives are underway. The aim of this review is to provide an update on the main advances in HIV eradication, with particular emphasis on the obstacles and the different strategies proposed. The core challenges of each strategy are highlighted and the most promising strategy and new research avenues in HIV eradication strategies are proposed.

Methods

A systematic literature search of all English-language articles published between 2015 and 2019, was conducted using MEDLINE (PubMed) and Google scholar. Where available, medical subject headings (MeSH) were used as search terms and included: HIV, HIV latency, HIV reservoir, latency reactivation, and HIV cure. Additional search terms consisted of suppression, persistence, establishment, generation, and formation. A total of 250 articles were found using the above search terms. Out of these, 89 relevant articles related to HIV-1 latency establishment and eradication strategies were collected and reviewed, with no limitation of study design. Additional studies (commonly referenced and/or older and more recent articles of significance) were selected from bibliographies and references listed in the primary resources.

Results

In general, when exploring the literature, there are four main strategies heavily researched that provide promising strategies to the elimination of latent HIV: Haematopoietic Stem-Cell Transplantation, Shock and Kill Strategy, Gene-specific transcriptional activation using RNA-guided CRISPR-Cas9 system, and Block and Lock strategy. Most of the studies of these strategies are applicable in vitro, leaving many questions about the extent to which, or if any, these strategies are applicable to complex picture In vivo. However, the success of these strategies at least shows, in part, that HIV-1 can be cured, though some strategies are too invasive and expensive to become a standard of care for all HIV-infected patients.

Conclusion

Recent advances hold promise for the ultimate cure of HIV infection. A systems-level approach that fully recapitulates the dynamics and complexity of HIV-1 latency In vivo and applicable in human therapy is prudent for HIV eradication to be more feasible. Future studies aimed at achieving a prolonged HIV remission state are more likely to be successful if they focus on a combination strategy, including the block and kill, and stem cell approaches. These strategies propose a functional cure with minimal toxicity for patients. It is believed that the cure of HIV infection will be attained in the short term if a strategy based on purging the reservoirs is complemented with an aggressive HAART strategy.

Identification of an Antiretroviral Small Molecule That Appears To Be a Host-Targeting Inhibitor of HIV-1 Assembly

Given the projected increase in multidrug-resistant HIV-1, there is an urgent need for development of antiretrovirals that act on virus life cycle stages not targeted by drugs currently in use. Host-targeting compounds are of particular interest because they can offer a high barrier to resistance. Here, we report identification of two related small molecules that inhibit HIV-1 late events, a part of the HIV-1 life cycle for which potent and specific inhibitors are lacking. This chemotype was discovered using cell-free protein synthesis and assembly systems that recapitulate intracellular host-catalyzed viral capsid assembly pathways. These compounds inhibit replication of HIV-1 in human T cell lines and peripheral blood mononuclear cells, and are effective against a primary isolate. They reduce virus production, likely by inhibiting a posttranslational step in HIV-1 Gag assembly. Notably, the compound colocalizes with HIV-1 Gag in situ; however, unexpectedly, selection experiments failed to identify compound-specific resistance mutations in gag or pol, even though known resistance mutations developed upon parallel nelfinavir selection. Thus, we hypothesized that instead of binding to Gag directly, these compounds localize to assembly intermediates, the intracellular multiprotein complexes containing Gag and host factors that form during immature HIV-1 capsid assembly. Indeed, imaging of infected cells shows compound colocalized with two host enzymes found in assembly intermediates, ABCE1 and DDX6, but not two host proteins found in other complexes. While the exact target and mechanism of action of this chemotype remain to be determined, our findings suggest that these compounds represent first-in-class, host-targeting inhibitors of intracellular events in HIV-1 assembly.IMPORTANCE The success of antiretroviral treatment for HIV-1 is at risk of being undermined by the growing problem of drug resistance. Thus, there is a need to identify antiretrovirals that act on viral life cycle stages not targeted by drugs in use, such as the events of HIV-1 Gag assembly. To address this gap, we developed a compound screen that recapitulates the intracellular events of HIV-1 assembly, including virus-host interactions that promote assembly. This effort led to the identification of a new chemotype that inhibits HIV-1 replication at nanomolar concentrations, likely by acting on assembly. This compound colocalized with Gag and two host enzymes that facilitate capsid assembly. However, resistance selection did not result in compound-specific mutations in gag, suggesting that the chemotype does not directly target Gag. We hypothesize that this chemotype represents a first-in-class inhibitor of virus production that acts by targeting a virus-host complex important for HIV-1 Gag assembly.

Re-examining the HIV 'functional cure' oxymoron: Time for precise terminology?

For over a decade, the binary concepts of 'sterilizing' versus 'functional' cure have provided an organizing framework for the field of HIV cure-related research. In this article, we examine how the expression 'functional cure' is employed within the field, published literature, and community understanding of HIV cure research. In our synthesis of the different meanings attributed to 'functional cure' within contemporary biomedical discourse, we argue that employing the 'functional cure' terminology poses a series of problems. The expression itself is contradictory and inconsistently used across a wide array of HIV cure research initiatives. Further, the meaning and acceptability of 'functional cure' within communities of people living with and affected by HIV is highly variable. After drawing lessons from other fields, such as cancer and infectious hepatitis cure research, we summarize our considerations and propose alternative language that may more aptly describe the scientific objectives in question. We call for closer attention to language used to describe HIV cure-related research, and for continued, significant, and strategic engagement to ensure acceptable and more precise terminology.

Emergence and molecular mechanisms of SARS-CoV-2 and HIV to target host cells and potential therapeutics

The emergence of a new coronavirus, in around late December 2019 which had first been reported in Wuhan, China has now developed into a massive threat to global public health. The World Health Organization (WHO) has named the disease caused by the virus as COVID-19 and the virus which is the culprit was renamed from the initial novel respiratory 2019 coronavirus to SARS-CoV-2. The person-to-person transmission of this virus is ongoing despite drastic public health mitigation measures such as social distancing and movement restrictions implemented in most countries. Understanding the source of such an infectious pathogen is crucial to develop a means of avoiding transmission and further to develop therapeutic drugs and vaccines. To identify the etiological source of a novel human pathogen is a dynamic process that needs comprehensive and extensive scientific validations, such as observed in the Middle East respiratory syndrome (MERS), severe acute respiratory syndrome (SARS), and human immunodeficiency virus (HIV) cases. In this context, this review is devoted to understanding the taxonomic characteristics of SARS-CoV-2 and HIV. Herein, we discuss the emergence and molecular mechanisms of both viral infections. Nevertheless, no vaccine or therapeutic drug is yet to be approved for the treatment of SARS-CoV-2, although it is highly likely that new effective medications that target the virus specifically will take years to establish. Therefore, this review reflects the latest repurpose of existing antiviral therapeutic drug choices available to combat SARS-CoV-2.

Variations in Trim5α and Cyclophilin A genes among HIV-1 elite controllers and non controllers in Uganda: a laboratory-based cross-sectional study

BACKGROUND

Tripartite Motif Containing 5 alpha (TRIM5α), a restriction factor produced ubiquitously in cells and tissues of the body plays an important role in the immune response against HIV. TRIM5α targets the HIV capsid for proteosomal destruction. Cyclophilin A, an intracellular protein has also been reported to influence HIV infectivity in a cell-specific manner. Accordingly, variations in TRIM5α and Cyclophilin A genes have been documented to influence HIV-1 disease progression. However, these variations have not been documented among Elite controllers in Uganda and whether they play a role in viral suppression remains largely undocumented. Our study focused on identifying the variations in TRIM5α and Cyclophilin A genes among HIV-1 Elite controllers and non-controllers in Uganda.

RESULTS

From the sequence analysis, the rs10838525 G > A mutation in exon 2 of TRIM5α was only found among elite controllers (30%) while the rs3824949 in the 5'UTR was seen among 25% of the non-controllers. In the Cyclophilin A promoter, rs6850 was seen among 62.5% of the non-controllers and only among 10% elite controllers. Furthermore, rs17860048 in the Cyclophillin A promoter was predominantly seen among elite controllers (30%) and 12.5% non-controllers. From gene expression analysis, we noted that the respective genes were generally elevated among elite controllers, however, this difference was not statistically significant (TRIM5α p = 0.6095; Cyclophilin A p = 0.6389).

CONCLUSION

Variations in TRIM5α and Cyclophillin A promoter may influence HIV viral suppression. The rs10838525 SNP in TRIM5α may contribute to viral suppression among HIV-1 elite controllers. The rs6850 in the cyclophillin A gene may be responsible for HIV-1 rapid progression among HIV-1 non-controllers. These SNPs should be investigated mechanistically to determine their precise role in HIV-1 viral suppression.

Diversity of small molecule HIV-1 latency reversing agents identified in low- and high-throughput small molecule screens

The latency phenomenon produced by human immunodeficiency virus (HIV-1) prevents viral clearance by current therapies, and consequently development of a cure for HIV-1 disease represents a formidable challenge. Research over the past decade has resulted in identification of small molecules that are capable of exposing HIV-1 latent reservoirs, by reactivation of viral transcription, which is intended to render these infected cells sensitive to elimination by immune defense recognition or apoptosis. Molecules with this capability, known as latency-reversing agents (LRAs) could lead to realization of proposed HIV-1 cure strategies collectively termed "shock and kill," which are intended to eliminate the latently infected population by forced reactivation of virus replication in combination with additional interventions that enhance killing by the immune system or virus-mediated apoptosis. Here, we review efforts to discover novel LRAs via low- and high-throughput small molecule screens, and summarize characteristics and biochemical properties of chemical structures with this activity. We expect this analysis will provide insight toward further research into optimized designs for new classes of more potent LRAs.

Prevalence of CCR5delta32 in Northeastern Iran

Background

A 32-base pair deletion (∆32) in the open reading frame (ORF) of C-C motif chemokine receptor 5 (CCR5) seems to be a protective variant against immune system diseases, especially human immunodeficiency virus type 1 (HIV-1). We aimed to assess the frequency of CCR5∆32 in the healthy Iranian population.

Methods

In this study, 400 normal samples from Khorasan, northeastern Iran, were randomly selected. The frequency of CCR5∆32 carriers was investigated using PCR analysis. Allele prevalence and the fit to the Hardy-Weinberg equilibrium were analyzed.

Results

The prevalence of CCR5∆32 in the northeastern population of Iran was 0.016. Four hundred samples were studied, among which one with CCR5^∆32/∆32 and 11 with CCR5^Wild/∆32 genotype were detected.

Conclusion

This study was the first investigation for an assessment of the prevalence of CCR5∆32 in northeastern Iran. The low prevalence of CCR5∆32 allele in the Iranian population may result in the increased susceptibility to HIV-1. In addition, this prevalence is the same as that of reported in East Asia, while is lower than that in the Europeans.

Single-Chain Variable Fragment-Based Bispecific Antibodies: Hitting Two Targets with One Sophisticated Arrow

Despite the success of monoclonal antibodies (mAbs) to treat some disorders, the monospecific molecular entity of mAbs as well as the presence of multiple factors and pathways involved in the pathogenesis of disorders, such as various malignancies, infectious diseases, and autoimmune disorders, and resistance to therapy have restricted the therapeutic efficacy of mAbs in clinical use. Bispecific antibodies (bsAbs), by concurrently recognizing two targets, can partly circumvent these problems. Serial killing of tumor cells by bsAb-redirected T cells, simultaneous blocking of two antigens involved in the HIV-1 infection, and concurrent targeting of the activating and inhibitory receptors on B cells to modulate autoimmunity are part of the capabilities of bsAbs. After designing and developing a large number of bsAbs for years, catumaxomab, a full-length bsAb targeting EpCAM and CD3, was approved in 2009 to treat EpCAM-positive carcinomas besides blinatumomab, a bispecific T cell engager antibody targeting CD19 and CD3, which was approved in 2014 to treat relapsed or refractory acute lymphoblastic leukemia. Furthermore, approximately 60 bsAbs are under investigation in clinical trials. The current review aims at portraying different formats of the single-chain variable fragment (scFv)-based bsAbs and shedding light on the scFv-based bsAbs in preclinical development, different phases of clinical trials, and the market.

Protein and Glycan Mimicry in HIV Vaccine Design

Antigenic mimicry is a fundamental tenet of structure-based vaccinology. Vaccine strategies for the human immunodeficiency virus type 1 (HIV-1) focus on the mimicry of its envelope spike (Env) due to its exposed location on the viral membrane and role in mediating infection. However, the virus has evolved to minimize the immunogenicity of conserved epitopes on the envelope spike. This principle is starkly illustrated by the presence of an extensive array of host-derived glycans, which act to shield the underlying protein from antibody recognition. Despite these hurdles, a subset of HIV-infected individuals eventually develop broadly neutralizing antibodies that recognize these virally presented glycans. Effective HIV-1 immunogens are therefore likely to involve some degree of mimicry of both the protein and glycan components of Env. As such, considerable efforts have been made to characterize the structure of the envelope spike and its glycan shield. This review summarizes the recent progress made in this field, with an emphasis on our growing understanding of the factors shaping the glycan shield of Env derived from both virus and soluble immunogens. We argue that recombinant mimics of the envelope spike are currently capable of capturing many features of the native viral glycan shield. Finally, we explore strategies through which the immunogenicity of Env glycans may be enhanced in the development of future immunogens.

Impact of LEDGIN treatment during virus production on residual HIV-1 transcription

Background

Persistence of latent, replication-competent provirus is the main impediment towards the cure of HIV infection. One of the critical questions concerning HIV latency is the role of integration site selection in HIV expression. Inhibition of the interaction between HIV integrase and its chromatin tethering cofactor LEDGF/p75 is known to reduce integration and to retarget residual provirus to regions resistant to reactivation. LEDGINs, small molecule inhibitors of the interaction between HIV integrase and LEDGF/p75, provide an interesting tool to study the underlying mechanisms. During early infection, LEDGINs block the interaction with LEDGF/p75 and allosterically inhibit the catalytic activity of IN (i.e. the early effect). When present during virus production, LEDGINs interfere with proper maturation due to enhanced IN oligomerization in the progeny virions (i.e. the late effect).

Results

We studied the effect of LEDGINs present during virus production on the transcriptional state of the residual virus. Infection of cells with viruses produced in the presence of LEDGINs resulted in a residual reservoir that was refractory to activation. Integration of residual provirus was less favored near epigenetic markers associated with active transcription. However, integration near H3K36me3 and active genes, both targeted by LEDGF/p75, was not affected. Also in primary cells, LEDGIN treatment induced a reservoir resistant to activation due to a combined early and late effect.

Conclusion

LEDGINs present a research tool to study the link between integration and transcription, an essential question in retrovirology. LEDGIN treatment during virus production altered integration of residual provirus in a LEDGF/p75-independent manner, resulting in a reservoir that is refractory to activation.

Electronic supplementary material

The online version of this article (10.1186/s12977-019-0472-3) contains supplementary material, which is available to authorized users.

Revisiting the 'sterilising cure' terminology: a call for more patient-centred perspectives on HIV cure-related research

The literature on HIV therapeutics research is rife with terminology associating 'sterilisation' with HIV cure. We find connotations of the word 'sterilising' problematic for the HIV cure research field. In this viewpoint, we review associations of sterilising with concepts of disinfection or cleansing, as well as coerced sterilisation. We discuss emerging findings from socio-behavioural research that show aversion from people living with HIV towards the 'sterilising cure' nomenclature. We call for more collaborations with people with HIV as partners to help define what would be a more acceptable terminology for describing an HIV cure.

Clinical pharmacology in HIV cure research - what impact have we seen?

Introduction: Combined antiretroviral therapy (cART) has transformed an inexorably fatal disease into a chronic pathology, shifting the focus of research from the control of viral replication to the possibility of HIV cure. Areas covered: The present review assesses the principal pharmacological strategies that have been tested for an HIV cure starting from the in vitro proof of concept and the potential rationale of their in vivo applicability. We evaluated the possible pharmacological procedures employed during the early-stage HIV infection and the possibility of cART-free remission. We then analyzed the shock and kill approach from the single compounds in vitro mechanism of action, to the in vivo application of single or combined actions. Finally, we briefly considered the novel immunological branch through the discovery and development of broadly neutralizing antibodies in regard to the current and future in vivo therapeutic strategies aiming to verify the clinical applicability of these compounds. Expert opinion: Despite an incredible effort in HIV research cure, the likelihood of completely eradicating HIV is unreachable within our current knowledge. A better understanding of the mechanism of viral latency and the full characterization of HIV reservoir are crucial for the discovery of new therapeutic targets and novel pharmacological entities.

Current and Future Therapeutic Strategies for Lentiviral Eradication from Macrophage Reservoirs

Macrophages, one of the most abundant populations of leukocytes in the body, function as the first line of defense against pathogen invaders. Human Immunodeficiency virus 1 (HIV-1) remains to date one of the most extensively studied viral infections. Naturally occurring lentiviruses in domestic and primate species serve as valuable models to investigate lentiviral pathogenesis and novel therapeutics. Better understanding of the role macrophages play in HIV pathogenesis will aid in the advancement towards a cure. Even with current efficacy of first- and second-line Antiretroviral Therapy (ART) guidelines and future efficacy of Long Acting Slow Effective Release-ART (LASER-ART); ART alone does not lead to a cure. The major challenge of HIV eradication is viral latency. Latency Reversal Agents (LRAs) show promise as a possible means to eradicate HIV-1 from the body. It has become evident that complete eradication will need to include combinations of various effective therapeutic strategies such as LASER-ART, LRAs, and gene editing. Review of the current literature indicates the most promising HIV eradication strategy appears to be LASER-ART in conjunction with viral and receptor gene modifications via the CRISPR/Cas9 system. Graphical abstract A multimodal approach to HIV treatment including gene editing, LASER-ART, and latency reversal agents may provide a means to achieve HIV eradication.