Development of an anti-HIV vaccine eliciting broadly neutralizing antibodies

Advancements in Immunology and Microbiology Research: A Comprehensive Exploration of Key Areas

Immunology and microbiology research has witnessed remarkable growth and innovation globally, playing a pivotal role in advancing our understanding of immune mechanisms, disease pathogenesis, and therapeutic interventions. This manuscript presents a comprehensive exploration of the key areas in immunology research, spanning from the utilisation of bacterial proteins as antibody reagents to the intricate realms of clinical immunology and disease management. The utilisation of bacterial immunoglobulin-binding proteins (IBPs), including protein A (SpA), protein G (SpG), and protein L (SpL), has revolutionised serological diagnostics, showing promise in early disease detection and precision medicine. Microbiological studies have shed light on antimicrobial resistance patterns, particularly the emergence of extended-spectrum beta-lactamases (ESBLs), guiding antimicrobial stewardship programmes and informing therapeutic strategies. Clinical immunology research has elucidated the molecular pathways underlying immune-mediated disorders, resulting in tailored management strategies for conditions such as severe combined immunodeficiency (SCID), neuropsychiatric systemic lupus erythematosus (NPSLE), etc. Additionally, significant efforts in vaccine development against tuberculosis and HIV are highlighted, underscoring the ongoing global pursuit of effective preventive measures against these infectious diseases. In summary, immunology and microbiology research have provided significant contributions to global healthcare, fostering collaboration, innovation, and improved patient outcomes.

Anti-HIV Humoral Response Induced by Different Anti-Idiotype Antibody Formats: An In Silico and In Vivo Approach

Despite advancements in vaccinology, there is currently no effective anti-HIV vaccine. One strategy under investigation is based on the identification of epitopes recognized by broadly neutralizing antibodies to include in vaccine preparation. Taking into account the benefits of anti-idiotype molecules and the diverse biological attributes of different antibody formats, our aim was to identify the most immunogenic antibody format. This format could serve as a foundational element for the development of an oligo-polyclonal anti-idiotype vaccine against HIV-1. For our investigation, we anchored our study on an established b12 anti-idiotype, referred to as P1, and proposed four distinct formats: two single chains and two minibodies, both in two different orientations. For a deeper characterization of these molecules, we used immunoinformatic tools and tested them on rabbits. Our studies have revealed that a particular minibody conformation, MbVHVL, emerges as the most promising candidate. It demonstrates a significant binding affinity with b12 and elicits a humoral anti-HIV-1 response in rabbits similar to the Fab format. This study marks the first instance where the minibody format has been shown to provoke a humoral response against a pathogen. Furthermore, this format presents biological advantages over the Fab format, including bivalency and being encoded by a monocistronic gene, making it better suited for the development of RNA-based vaccines.

Clinical Analysis and Applications of mRNA Vaccines in Infectious Diseases and Cancer Treatment

Vaccination, for centuries, has been a potent preventive technique to treat morbidities. The messenger RNA (mRNA) vaccine technology is an innovative biomedical approach utilized in developing antigen-specific vaccines that can generate adaptive immune responses, triggering both humoral and cellular immunity to enhance the body's defense against specific infections. This review provides a comprehensive, comparative analysis of mRNA vaccine technology and conventional vaccines by focusing on the structures, components, and classifications. An exploratory analysis of the similarities and differences between mRNA vaccine technology and live-attenuated vaccines highlights the mechanisms by which mRNA vaccines elicit immune responses. This review extensively discusses the production, stability, synthesis, and delivery processes associated with mRNA vaccines, showcasing the advancements and technological superiority of this approach over conventional vaccine technologies. Additionally, the potential of mRNA vaccine technology as a potent alternative for the development of vaccine candidates targeting HIV and cancer is examined.

Contribution of the HIV-1 Envelope Glycoprotein to AIDS Pathogenesis and Clinical Progression

In the absence of antiviral therapy, HIV-1 infection progresses to a wide spectrum of clinical manifestations that are the result of an entangled contribution of host, immune and viral factors. The contribution of these factors is not completely established. Several investigations have described the involvement of the immune system in the viral control. In addition, distinct HLA-B alleles, HLA-B27, -B57-58, were associated with infection control. The combination of these elements and antiviral host restriction factors results in different clinical outcomes. The role of the viral proteins in HIV-1 infection has been, however, less investigated. We will review contributions dedicated to the pathogenesis of HIV-1 infection focusing on studies identifying the function of the viral envelope glycoprotein (Env) in the clinical progression because of its essential role in the initial events of the virus life-cycle. Some analysis showed that inefficient viral Envs were dominant in non-progressor individuals. These poorly-functional viral proteins resulted in lower cellular activation, viral replication and minor viral loads. This limited viral antigenic production allows a better immune response and a lower immune exhaustion. Thus, the properties of HIV-1 Env are significant in the clinical outcome of the HIV-1 infection and AIDS pathogenesis.

Maximum antigen diversification in a lyme bacterial population and evolutionary strategies to overcome pathogen diversity

Natural populations of pathogens and their hosts are engaged in an arms race in which the pathogens diversify to escape host immunity while the hosts evolve novel immunity. This co-evolutionary process poses a fundamental challenge to the development of broadly effective vaccines and diagnostics against a diversifying pathogen. Based on surveys of natural allele frequencies and experimental immunization of mice, we show high antigenic specificities of natural variants of the outer surface protein C (OspC), a dominant antigen of a Lyme Disease-causing bacterium (Borrelia burgdorferi). To overcome the challenge of OspC antigenic diversity to clinical development of preventive measures, we implemented a number of evolution-informed strategies to broaden OspC antigenic reactivity. In particular, the centroid algorithm-a genetic algorithm to generate sequences that minimize amino-acid differences with natural variants-generated synthetic OspC analogs with the greatest promise as diagnostic and vaccine candidates against diverse Lyme pathogen strains co-existing in the Northeast United States. Mechanistically, we propose a model of maximum antigen diversification (MAD) mediated by amino-acid variations distributed across the hypervariable regions on the OspC molecule. Under the MAD hypothesis, evolutionary centroids display broad cross-reactivity by occupying the central void in the antigenic space excavated by diversifying natural variants. In contrast to vaccine designs based on concatenated epitopes, the evolutionary algorithms generate analogs of natural antigens and are automated. The novel centroid algorithm and the evolutionary antigen designs based on consensus and ancestral sequences have broad implications for combating diversifying pathogens driven by pathogen-host co-evolution.

Engineering well-expressed, V2-immunofocusing HIV-1 envelope glycoprotein membrane trimers for use in heterologous prime-boost vaccine regimens

HIV-1 vaccine immunofocusing strategies may be able to induce broadly-reactive neutralizing antibodies (NAbs). Here, we engineered a panel of diverse, membrane-resident native HIV-1 trimers vulnerable to two broad targets-the V2 apex and fusion peptide (FP). Selection criteria included i) high expression and ii) infectious function, so that trimer neutralization sensitivity can be profiled in pseudovirus (PV) assays. Initially, we boosted the expression of 17 candidate trimers by truncating gp41 and introducing a gp120-gp41 SOS disulfide to prevent gp120 shedding. "Repairs" were made to fill glycan holes and eliminate other strain-specific aberrations. A new neutralization assay allowed PV infection when our standard assay was insufficient. Trimers with exposed V3 loops, a target of non-NAbs, were discarded. To try to increase V2-sensitivity, we removed clashing glycans and modified the C-strand. Notably, a D167N mutation improved V2-sensitivity in several cases. Glycopeptide analysis of JR-FL trimers revealed near complete sequon occupation and that filling the N197 glycan hole was well-tolerated. In contrast, sequon optimization and inserting/removing glycans at other positions frequently had global "ripple" effects on glycan maturation and sequon occupation throughout the gp120 outer domain and gp41. V2 MAb CH01 selectively bound to trimers with small high mannose glycans near the base of the V1 loop, thereby avoiding clashes. Knocking in a rare N49 glycan was found to perturb gp41 glycans, increasing FP NAb sensitivity-and sometimes improving expression. Finally, a biophysical analysis of VLPs revealed that i) ~25% of particles bear Env spikes, ii) spontaneous particle budding is high and only increases 4-fold upon Gag transfection, and iii) Env+ particles express ~30-40 spikes. Taken together, we identified 7 diverse trimers with a range of sensitivities to two targets to allow rigorous testing of immunofocusing vaccine concepts.

Clinical Trials of Broadly Neutralizing Monoclonal Antibodies for Human Immunodeficiency Virus Prevention: A Review

Passive immunization with broadly neutralizing antibodies (bnAbs) is a promising approach to reduce the 1.7 million annual human immunodeficiency virus (HIV) infections globally. Early studies on bnAbs showed safety in humans, but short elimination half-lives and low potency and breadth. Since 2010, several new highly potent bnAbs have been assessed in clinical trials alone or in combination for HIV prevention. Published data indicate that these bnAbs are safe and have a half-life ranging from 15 to 71 days. Only intravenous VRC01 has advanced to an efficacy trial, with results expected in late 2020. If bnAbs are shown to be effective in preventing HIV infection, they could fast-track vaccine development as correlates of protection, and contribute as passive immunization to achieving the goal of epidemic control. The purpose of the current review is to describe the current status and provide a synopsis of the available data on bnAbs in clinical trials for HIV prevention.

Broadly neutralizing HIV-1 antibody reactivity in HIV tests: implications for diagnostics

OBJECTIVE

Passive immunization with broadly neutralizing antibodies (bNAbs) is under evaluation for HIV prevention. BNAbs target gp120 or gp41, two HIV envelope antigens commonly present in diagnostic tests. Depending on bNAb type and dose administered to humans, serum levels can reach nearly 1 mg/ml and wane over several weeks to months. We investigated the reactivity of bNAbs in HIV serological tests to inform diagnostic testing practices for persons treated with these products.

DESIGN AND METHODS

The antigp120 bNAbs VRCO1, PGT121, PGT145, 3BNC117, 10-1074 and N6 and antigp41 bNAbs 10E8 and 10E8v4 were tested with the laboratory-based Bio-Rad Ag/Ab Combo assay, the point-of-care single-use Determine Combo, OraQuick, Reveal G4, SureCheck, Uni-Gold, INSTI and DPP HIV-1/2 assays, and the supplemental Geenius and HIV-1 Western Blot assays.

RESULTS

At 1 mg/ml, all bNAbs were nonreactive in four screening tests. OraQuick, SureCheck, Reveal G4 and INSTI detected at least two bNAbs each; SureCheck exhibited reactivity to six bNAbs. Geenius was HIV-1 indeterminate (gp160+) with all bNAbs except PGT121, which was HIV antibody-negative. HIV-1 Western Blot was indeterminate (gp41+/gp160+) with 10E8 and 10E8v4 and negative with the remaining bNAbs. There was no correlation between the test antigen construct(s) and bNAb reactivity.

CONCLUSION

We identified a laboratory-based Ag/Ab EIA and three single-use rapid HIV tests that are nonreactive against a panel of bNAbs supporting some diagnostic tests can distinguish HIV-1 infection events among persons receiving bNAb immunoprophylaxis. Evaluation of HIV diagnostic tests prior to clinical use may identify suitable serologic assays for persons administered bNAbs.

Employing Broadly Neutralizing Antibodies as a Human Immunodeficiency Virus Prophylactic & Therapeutic Application

Despite the discovery that the human immunodeficiency virus 1 (HIV-1) is the pathogen of acquired immunodeficiency syndrome (AIDS) in 1983, there is still no effective anti-HIV-1 vaccine. The major obstacle to the development of HIV-1 vaccine is the extreme diversity of viral genome sequences. Nonetheless, a number of broadly neutralizing antibodies (bNAbs) against HIV-1 have been made and identified in this area. Novel strategies based on using these bNAbs as an efficacious preventive and/or therapeutic intervention have been applied in clinical. In this review, we summarize the recent development of bNAbs and its application in HIV-1 acquisition prevention as well as discuss the innovative approaches being used to try to convey protection within individuals at risk and being treated for HIV-1 infection.

Nano-based approaches in the development of antiviral agents and vaccines

Outbreaks and the rapid transmission of viruses, such as coronaviruses and influenza viruses, are serious threats to human health. A major challenge in combating infectious diseases caused by viruses is the lack of effective methods for prevention and treatment. Nanotechnology has provided a basis for the development of novel antiviral strategies. Owing to their large modifiable surfaces that can be functionalized with multiple molecules to realize sophisticated designs, nanomaterials have been developed as nanodrugs, nanocarriers, and nano-based vaccines to effectively induce sufficient immunologic memory. From this perspective, we introduce various nanomaterials with diverse antiviral mechanisms and summarize how nano-based antiviral agents protect against viral infection at the molecular, cellular, and organismal levels. We summarize the applications of nanomaterials for defense against emerging viruses by trapping and inactivating viruses and inhibiting viral entry and replication. We also discuss recent progress in nano-based vaccines with a focus on the mechanisms by which nanomaterials contribute to immunogenicity. We further describe how nanotechnology may improve vaccine efficacy by delivering large amounts of antigens to target immune cells and enhancing the immune response by mimicking viral structures and activating dendritic cells. Finally, we provide an overview of future prospects for nano-based antiviral agents and vaccines.

Major Scientific Hurdles in HIV Vaccine Development: Historical Perspective and Future Directions

Following the discovery of HIV as a causative agent of AIDS, the expectation was to rapidly develop a vaccine; but thirty years later, we still do not have a licensed vaccine. Progress has been hindered by the extensive genetic variability of HIV and our limited understanding of immune responses required to protect against HIV acquisition. Nonetheless, valuable knowledge accrued from numerous basic and translational science research studies and vaccine trials has provided insight into the structural biology of the virus, immunogen design and novel vaccine delivery systems that will likely constitute an effective vaccine. Furthermore, stakeholders now appreciate the daunting scientific challenges of developing an effective HIV vaccine, hence the increased advocacy for collaborative efforts among academic research scientists, governments, pharmaceutical industry, philanthropy, and regulatory entities. In this review, we highlight the history of HIV vaccine development efforts, highlighting major challenges and future directions.

Isolating Human Monoclonal Antibodies Against Adeno-Associated Virus From Donors With Pre-existing Immunity

With the advent of single B-cell cloning technology, we can isolate antibodies against virtually any antigen to study the interaction of a given pathogen with the immune system and develop novel therapeutic strategies. Antibodies directed against the capsid of adeno-associated viruses (AAV) are a significant obstacle to effectively leveraging AAV as a gene-delivery vector in seropositive individuals. In order to design next-generation vectors that can evade neutralization by these antibodies, studies have mapped the epitopes of mouse monoclonal antibodies generated by immunization with AAV. Although these studies provide critical information regarding capsid immunogenicity, they cannot address (1) differences in the antibody repertoire generated in humans following AAV natural infection; or (2) how reactions can vary when generated in response to vector administration. Here, we isolated and evaluated a panel of novel, fully human anti-AAV antibodies by cloning single memory B cells from a seropositive normal donor. We have validated the utility of this approach to study AAV immunology. Our goal is to leverage this knowledge to design novel AAV variants that can effectively transduce target tissues in individuals with AAV-neutralizing antibodies.

Mapping Polyclonal Antibody Responses in Non-human Primates Vaccinated with HIV Env Trimer Subunit Vaccines

Rational immunogen design aims to focus antibody responses to vulnerable sites on primary antigens. Given the size of these antigens, there is, however, potential for eliciting unwanted, off-target responses. Here, we use our electron microscopy polyclonal epitope mapping approach to describe the antibody specificities elicited by immunization of non-human primates with soluble HIV envelope trimers and subsequent repeated viral challenge. An increased diversity of epitopes recognized and the approach angle by which these antibodies bind constitute a hallmark of the humoral response in most protected animals. We also show that fusion peptide-specific antibodies are likely responsible for some neutralization breadth. Moreover, cryoelectron microscopy (cryo-EM) analysis of a fully protected animal reveals a high degree of clonality within a subset of putatively neutralizing antibodies, enabling a detailed molecular description of the antibody paratope. Our results provide important insights into the immune response against a vaccine candidate that entered into clinical trials in 2019.

Pathways towards human immunodeficiency virus elimination

Antiretroviral therapy (ART) suppresses human immunodeficiency virus (HIV) infection. Research seeking to transform viral suppression into elimination has generated novel immune, chemical and molecular antiviral agents. However, none, to date, have excised latent integrated proviral DNA or removed infected cells from infected persons. These efforts included, but are not limited to, broadly neutralizing antibodies, "shock" and "kill" latency-reversing agents, innate immune regulators, and sequential long-acting antiretroviral nanoformulated prodrugs and CRISPR-Cas9 gene editing. While, the latter, enabled the complete excision of latent HIV-1 from the host genome success was so far limited. We contend that improvements in antiretroviral delivery, potency, agent specificity, or combinatorial therapies can provide a pathway towards complete HIV elimination.

Interleukin-21 enhances the antibody avidity elicited by DNA prime and MVA boost vaccine

Enhancement of the magnitude or affinity of protective antibodies (Abs) induced by vaccine adjuvant is highly desirable to prevent challenging pathogens such as HIV-1. IL-21 plays a crucial role in germinal center reactions during humoral immune responses. However, the effect of IL-21 as a vaccine adjuvant on the quantity and quality of antigen-specific Abs elicited by DNA prime and MVA boost vaccine, a commonly used vaccine strategy, remains unknown. To close this knowledge gap, female adult B6N mice were primed with DNA vaccine twice (days 0, 14, 100 µg, I.M.) and boosted with MVA vaccine (day 28, 2 × 10⁷ pfu, I.M.) with or without an IL-21 DNA adjuvant (days 3, 17, 31, 40 µg, I.M.), in which HIV-1 gag was expressed as a model antigen. With the addition of an IL-21 adjuvant, we found significantly increased avidity of antigen-specific Abs at multiple time points in a longitudinal follow up. Collectively, our results suggest that an IL-21 immune adjuvant can significantly increase Ab quality induced by heterologous DNA-MVA prime-boost vaccine strategy.

The breadth of HIV-1 neutralizing antibodies depends on the conservation of key sites in their epitopes

Developing HIV-1 vaccines that trigger broadly neutralizing antibodies (bnAbs) is a priority as bnAbs are considered key to elicitation of a protective immune response. To investigate whether the breadth of a neutralizing antibody (nAb) depended on the conservation of its epitope among circulating viruses, we examined Antibody:Envelope (Ab:Env) interactions and worldwide Env diversity. We found that sites corresponding to bnAb epitopes were as variable as other accessible, non-hypervariable Env sites (p = 0.50, Mann-Whitney U-test) with no significant relationship between epitope conservation and neutralization breadth (Spearman’s ρ = -0.44, adjusted p = 0.079). However, when accounting for key sites in the Ab:Env interaction, we showed that the broadest bnAbs targeted more conserved epitopes (Spearman’s ρ = -0.70, adjusted p = 5.0e-5). Neutralization breadth did not stem from the overall conservation of Ab epitopes but depended instead on the conservation of key sites of the Ab:Env interaction, revealing a mechanistic basis for neutralization breadth that could be exploited for vaccine design.

So far, no HIV-1 vaccine has elicited broadly neutralizing antibodies (bnAbs) in humans. HIV-1, one of the most rapidly evolving pathogens, is remarkable for its high variability across individuals and adaptability within hosts. We tested the relationship between HIV-1 diversity and neutralization breadth. While bnAbs did not specifically target more conserved regions of HIV-1 Env, we found that the broadest bnAbs relied forcibly more on structural interactions at key sites of the Ab:Env interaction than other Abs. Understanding mechanisms underlying neutralization breadth provides guidelines to design more efficacious vaccines and antibody-based therapeutics.

Frequencies of Circulating Th1-Biased T Follicular Helper Cells in Acute HIV-1 Infection Correlate with the Development of HIV-Specific Antibody Responses and Lower Set Point Viral Load

Despite decades of focused research, the field has yet to develop a prophylactic vaccine for HIV-1 infection. In the RV144 vaccine trial, nonneutralizing antibody responses were identified as a correlate for prevention of HIV acquisition. However, factors that predict the development of such antibodies are not fully elucidated. We sought to define the contribution of circulating T follicular helper (cTfh) subsets to the development of nonneutralizing antibodies in HIV-1 clade C infection. Study participants were recruited from an acute HIV-1 clade C infection cohort. Plasma anti-gp41, -gp120, -p24, and -p17 antibodies were screened using a customized multivariate Luminex assay. Phenotypic and functional characterizations of cTfh cells were performed using HLA class II tetramers and intracellular cytokine staining. In this study, we found that acute HIV-1 clade C infection skewed the differentiation of functional cTfh subsets toward increased Tfh1 (P = 0.02) and Tfh2 (P < 0.0001) subsets, with a concomitant decrease in overall Tfh1-17 (which shares both Tfh1 and Tfh17 properties) (P = 0.01) and Tfh17 (P < 0.0001) subsets, compared to the subsets found in HIV-negative subjects. Interestingly, the frequencies of Tfh1 cells during acute infection (5.0 to 8.0 weeks postinfection) correlated negatively with the set point viral load (P = 0.03, Spearman rho [r] = -60) and were predictive of p24-specific plasma IgG titers at 1 year of infection (P = 0.003, r = 0.85). Taken together, our results suggest that the circulating Tfh1 subset plays an important role in the development of anti-HIV antibody responses and contributes to HIV suppression during acute HIV-1 infection. These results have implications for vaccine studies aimed at inducing long-lasting anti-HIV antibody responses.IMPORTANCE The HIV epidemic in southern Africa accounts for almost half of the global HIV burden, with HIV-1 clade C being the predominant strain. It is therefore important to define immune correlates of clade C HIV control that might have implications for vaccine design in this region. T follicular helper (Tfh) cells are critical for the development of HIV-specific antibody responses and could play a role in viral control. Here we showed that the early induction of circulating Tfh1 cells during acute infection correlated positively with the magnitude of p24-specific IgG and was associated with a lower set point viral load. This study highlights a key Tfh cell subset that could limit HIV replication by enhancing antibody generation. This study underscores the importance of circulating Tfh cells in promoting nonneutralizing antibodies during HIV-1 infection.

Antibody-Mediated Therapy against HIV/AIDS: Where Are We Standing Now?

Acquired immunodeficiency syndrome (AIDS) cases are on the rise globally. To date, there is still no effective measure to eradicate the causative agent, human immunodeficiency virus (HIV). Highly active antiretroviral therapy (HAART) is being used in HIV/AIDS management, but it results in long-term medication and has major drawbacks such as multiple side effects, high cost, and increasing the generation rate of escape mutants. In addition, HAART does not control HIV-related complications, and hence more medications and further management are required. With this, other alternatives are urgently needed. In the past, small-molecule inhibitors have shown potent antiviral effects, and some of them are now being evaluated in clinical trials. The challenges in developing these small molecules for clinical use include the off-target effect, poor stability, and low bioavailability. On the other hand, antibody-mediated therapy has emerged as an important therapeutic modality for anti-HIV therapeutics development. Many antiviral antibodies, namely, broad neutralizing antibodies (bnAbs) against multiple strains of HIV, have shown promising effects in vitro and in animal studies; further studies are ongoing in clinical trials to evaluate their uses in clinical applications. This short review aims to discuss the current development of therapeutic antibodies against HIV and the challenges in adopting them for clinical use.

Recent developments of nanotherapeutics for targeted and long-acting, combination HIV chemotherapy

Combination antiretroviral therapy (cART) given orally has transformed HIV from a terminal illness to a manageable chronic disease. Yet despite the recent development of newer and more potent drugs for cART and suppression of virus in blood to undetectable levels, residual virus remains in tissues. Upon stopping cART, virus rebounds and progresses to AIDS. Current oral cART regimens have several drawbacks including (1) challenges in patient adherence due to pill fatigue or side-effects, (2) the requirement of life-long daily drug intake, and (3) limited penetration and retention in cells within lymph nodes. Appropriately designed injectable nano-drug combinations that are long-acting and retained in HIV susceptible cells within lymph nodes may address these challenges. While a number of nanomaterials have been investigated for delivery of HIV drugs and drug combinations, key challenges involve developing and scaling delivery systems that provide a drug combination targeted to HIV host cells and tissues where residual virus persists. With validation of the drug-insufficiency hypothesis in lymph nodes, progress has been made in the development of drug combination nanoparticles that are long-acting and targeted to lymph nodes and cells. Unique drug combination nanoparticles (DcNPs) composed of three HIV drugs-lopinavir, ritonavir, and tenofovir-have been shown to provide enhanced drug levels in lymph nodes; and elevated drug-combination levels in HIV-host cells in the blood and plasma for two weeks. This review summarizes the progress in the development of nanoparticle-based drug delivery systems for HIV therapy. It discusses how injectable nanocarriers may be designed to enable delivery of drug combinations that are long-lasting and target-selective in physiological contexts (in vivo) to provide safe and effective use. Consistent drug combination exposure in the sites of residual HIV in tissues and cells may overcome drug insufficiency observed in patients on oral cART.

Development of an HIV vaccine using a vesicular stomatitis virus vector expressing designer HIV-1 envelope glycoproteins to enhance humoral responses

Vesicular stomatitis virus (VSV), like many other Rhabdoviruses, have become the focus of intense research over the past couple of decades based on their suitability as vaccine vectors, transient gene delivery systems, and as oncolytic viruses for cancer therapy. VSV as a vaccine vector platform has multiple advantages over more traditional viral vectors including low level, non-pathogenic replication in diverse cell types, ability to induce both humoral and cell-mediate immune responses, and the remarkable expression of foreign proteins cloned into multiple intergenic sites in the VSV genome. The utility and safety of VSV as a vaccine vector was recently demonstrated near the end of the recent Ebola outbreak in West Africa where VSV pseudotyped with the Ebola virus (EBOV) glycoprotein was proven safe in humans and provided protective efficacy against EBOV in a human phase III clinical trial. A team of Canadian scientists, led by Dr. Gary Kobinger, is now working with International AIDS Vaccine Initiative (IAVI) in developing a VSV-based HIV vaccine that will combine unique Canadian research on the HIV-1 Env glycoprotein and on the VSV vaccine vector. The goal of this collaboration is to develop a vaccine with a robust and potent anti-HIV immune response with an emphasis on generating quality antibodies to protect against HIV challenges.