HIV Vaccination: A Roadmap among Advancements and Concerns

Potency and durability of T and B cell immune responses after homologous and heterologous vector delivery of a trimer-stabilized, membrane-displayed HIV-1 clade ConC Env protein

Introduction

The generation of an HIV-1 vaccine able to induce long-lasting protective immunity remains a main challenge. Here, we aimed to modify next-generation soluble, prefusion-stabilized, close-to-native, glycan-engineered clade C gp140 envelope (Env) trimers (sC23v4 KIKO and ConCv5 KIKO) for optimal display on the cell surface following homologous or heterologous vector delivery.

Methods

A combination of the following modifications scored best regarding the preservation of closed, native-like Env trimer conformation and antigenicity when using a panel of selected broadly neutralizing (bnAb) and non-neutralizing (nnAb) monoclonal antibodies for flow cytometry: i) replacing the natural cleavage site with a native flexible linker and introducing a single amino acid substitution to prevent CD4 binding (*), ii) fusing a heterologous VSV-G-derived transmembrane moiety to the gp140 C-terminus, and iii) deleting six residues proximal to the membrane.

Results

When delivering membrane-tethered sC23v4 KIKO* and ConCv5 KIKO* via DNA, VSV-GP, and NYVAC vectors, the two native-like Env trimers provide differential antigenicity profiles. Whereas such patterns were largely consistent among the different vectors for either Env trimer, the membrane-tethered ConCv5 KIKO* trimer adopted a more closed and native-like structure than sC23v4 KIKO*. In immunized mice, VSV-GP and NYVAC vectors expressing the membrane-tethered ConCv5 KIKO* administered in prime/boost combination were the most effective regimens for the priming of Env-specific CD4 T cells among all tested combinations. The subsequent booster administration of trimeric ConCv5 KIKO* Env protein preserved the T cell activation levels between groups. The evaluation of the HIV-1-specific humoral responses induced in the different immunization groups after protein boosts showed that the various prime/boost protocols elicited broad and potent antibody responses, preferentially of a Th1-associated IgG2a subclass, and that the obtained antibody levels remained high at the memory phase.

Discussion

In summary, we provide a feasible strategy to display multiple copies of native-like Env trimers on the cell surface, which translates into efficient priming of sustained CD4+ T cell responses after vector delivery as well as broad, potent, and sustained antibody responses following booster immunizations with the homologous, prefusion-stabilized, close-to-native ConCv5 KIKO* gp140 Env trimer.

Tracing the recent updates on vaccination approaches and significant adjuvants being developed against HIV

INTRODUCTION

Human Immunodeficiency Virus type 1 (HIV1); the causative agent of Acquired Immunodeficiency Syndrome (AIDS), has been a major target of the scientific community to develop an anti-viral therapy. Some successful discoveries have been made during the last two decades in the form of availability of antiviral therapy in endemic regions. Nevertheless, a total cure and safety vaccine has not yet been designed to eradicate HIV from the world.

AREAS COVERED

The purpose of this comprehensive study is to compile recent data regarding therapeutic interventions against HIV and to determine future research needs in this field. A systematic research strategy has been used to gather data from recent, most advanced published electronic sources. Literature based results show that experiments at the invitro level and animal models are continuously in research annals and are providing hope for human trials.

EXPERT OPINION

There is still a gap and more work is needed in the direction of modern drug and vaccination designs. Moreover coordination is necessary among researchers, educationists, public health workers, and the general community to communicate and coordinate the repercussions associated with the deadly disease. It is important for taking timely measures regarding mitigation and adaptation with HIV in future.

Early and Long-Term HIV-1 Immunogenicity Induced in Macaques by the Combined Administration of DNA, NYVAC and Env Protein-Based Vaccine Candidates: The AUP512 Study

To control HIV infection there is a need for vaccines to induce broad, potent and long-term B and T cell immune responses. With the objective to accelerate and maintain the induction of substantial levels of HIV-1 Env-specific antibodies and, at the same time, to enhance balanced CD4 and CD8 T cell responses, we evaluated the effect of concurrent administration of MF59-adjuvanted Env protein together with DNA or NYVAC vectors at priming to establish if early administration of Env leads to early induction of antibody responses. The primary goal was to assess the immunogenicity endpoint at week 26. Secondary endpoints were (i) to determine the quality of responses with regard to RV144 correlates of protection and (ii) to explore a potential impact of two late boosts. In this study, five different prime/boost vaccination regimens were tested in rhesus macaques. Animals received priming immunizations with either NYVAC or DNA alone or in combination with Env protein, followed by NYVAC + protein or DNA + protein boosts. All regimens induced broad, polyfunctional and well-balanced CD4 and CD8 T cell responses, with DNA-primed regimens eliciting higher response rates and magnitudes than NYVAC-primed regimens. Very high plasma binding IgG titers including V1/V2 specific antibodies, modest antibody-dependent cellular cytotoxicity (ADCC) and moderate neutralization activity were observed. Of note, early administration of the MF59-adjuvanted Env protein in parallel with DNA priming leads to more rapid elicitation of humoral responses, without negatively affecting the cellular responses, while responses were rapidly boosted after repeated immunizations, indicating the induction of a robust memory response. In conclusion, our findings support the use of the Env protein component during priming in the context of an heterologous immunization regimen with a DNA and/or NYVAC vector as an optimized immunization protocol against HIV infection.

Evaluation of transduced dendritic cells expressing HIV-1 p24-Nef antigens in HIV-specific cytotoxic T cells induction as a therapeutic candidate vaccine

Various approaches have been investigated to prevent or eliminate HIV-1 since 1981. However, the virus has been affecting human population worldwide with no effective vaccine yet. The conserved regions among the viral genes are suitable targets in mutable viruses to induce the immune responses via an effective delivery platform. In this study, we aimed at evaluation of p24 and nef in two forms of full and truncated genes as two fusion antigenic forms according to our previous bioinformatics analysis. The designed antigens were then transferred through ex vivo generated dendritic cells and also proteins in BALB/c to assess and compare immunogenicity. p24 and Nef amino acid sequences were aligned, then, the most conserved regions were selected and two fusion forms as the truncated (p24:80-231aa-Nef:120-150aa) and the full from (p24-Nef) were cloned and expressed in prokaryotic and eukaryotic systems. Lentiviral vectors were applied to generate recombinant virions harboring the genes of interest to transduce generated murine dendritic cells. BALB/c mice received the recombinant DCs or recombinant proteins according to the defined schedule. IgG development was assessed to determine humoral immune activity and cellular immune responses were evaluated by IL-5 and IFN-y induction. Granzyme B secretion was also investigated to determine CTL activity in different immunized groups. The data showed high induction of cellular immune responses in dendritic cell immunization specifically in immunized mice with the truncated form of the p24 and Nef by high secretion of IFN-y and strong CTL activity. Moreover, protein/ DC prime-boost formulation led to stronger Th1 pathway and strong CTL activation in comparison with other formulations. The generated recombinant dendritic cells expressing p24-Nef induced humoral and cellular immunity in a Th1 pathway specifically with the in silico predicted truncated antigen which could be of high value as a dendritic cell therapeutic vaccine candidate against HIV-1.

Interactions of HIV-1 Capsid with Host Factors and Their Implications for Developing Novel Therapeutics

The Human Immunodeficiency Virus type 1 (HIV-1) virion contains a conical shell, termed capsid, encasing the viral RNA genome. After cellular entry of the virion, the capsid is released and ensures the protection and delivery of the HIV-1 genome to the host nucleus for integration. The capsid relies on many virus-host factor interactions which are regulated spatiotemporally throughout the course of infection. In this paper, we will review the current understanding of the highly dynamic HIV-1 capsid-host interplay during the early stages of viral replication, namely intracellular capsid trafficking after viral fusion, nuclear import, uncoating, and integration of the viral genome into host chromatin. Conventional anti-retroviral therapies primarily target HIV-1 enzymes. Insights of capsid structure have resulted in a first-in-class, long-acting capsid-targeting inhibitor, GS-6207 (Lenacapavir). This inhibitor binds at the interface between capsid protein subunits, a site known to bind host factors, interferes with capsid nuclear import, HIV particle assembly, and ordered assembly. Our review will highlight capsid structure, the host factors that interact with capsid, and high-throughput screening techniques, specifically genomic and proteomic approaches, that have been and can be used to identify host factors that interact with capsid. Better structural and mechanistic insights into the capsid-host factor interactions will significantly inform the understanding of HIV-1 pathogenesis and the development of capsid-centric antiretroviral therapeutics.

Comparison of the efficacy of HIV-1 Nef-Tat-Gp160-p24 polyepitope vaccine candidate with Nef protein in different immunization strategies

OBJECTIVES

One of the promising strategies for effective HIV-1 vaccine design involves finding the polyepitope immunogens using T cell epitopes.

METHODS

Herein, an HIV-1 polyepitope construct (i.e., Nef-Tat-Gp160-P24) comprising of several epitopes from Nef, Tat, Gp160, and P24 proteins was designed. To improve its immunogenicity in BALB/c mice, cell-penetrating peptides (HR9 & MPG for DNA delivery, and LDP-NLS & CyLoP-1 for protein transfer), Montanide adjuvant, and heterologous DNA prime/polypeptide boost strategy were used. To compare the immunogenicity, Nef was utilized as a vaccine candidate. The levels of total IgG and its subclasses, cytokines, and Granzyme B were assessed using ELISA.

RESULTS

Immunological studies showed that heterologous prime-boost regimens for both antigens could considerably augment the levels of IgG2a, IgG2b, IFN-γ, and Granzyme B directed toward Th1 and CTL immune responses in comparison with homologous prime-boost strategies. The levels of IFN-γ, IL-10, total IgG, IgG1, and IgG2b were drastically higher in groups immunized with Nef-Tat-Gp160-P24 in heterologous prime-boost regimens than those in groups immunized with Nef.

CONCLUSIONS

The use of the Nef-Tat-Gp160-P24 polyepitope immunogen in heterologous prime-boost strategy could generate the mixture of Th1 and Th2 responses directed further toward Th1 response as a hopeful method for improvement of HIV-1 vaccine.

Anti-HIV-1 Antibodies: An Update

Even after more than 30 years since its discovery, there is no cure for HIV-1 infection. Combination antiretroviral therapy (cART) is currently the only HIV-1 infection management option in clinics. Despite its success in suppressing viral replication and converting HIV-1 from a lethal infection to a chronic and manageable disease, cART treatment is life long and long-term use can result in major drawbacks such as high cost, multiple side effects, and an increase in the development of multidrug-resistant escape mutants. Recently, antibody-based anti-HIV-1 treatment has emerged as a potential alternative therapeutic modality for HIV-1 treatment and cure strategies. These antibody-based anti-HIV-1 treatments comprising either receptor-targeting antibodies or broad neutralizing antibodies (bNAbs) are currently being developed and evaluated in clinical trials. These antibodies have demonstrated potent antiviral effects against multiple strains of HIV-1, and shown promise for prevention, maintenance, and prolonged remission of HIV-1 infection. This review gives an update on the current status of these antibody-based treatments for HIV-1, discusses their mechanism of action and the challenges in developing them, providing insight for their development as novel clinical therapies against HIV-1 infection.

The impact of human vaccines on bacterial antimicrobial resistance. A review

At present, the dramatic rise in antimicrobial resistance (AMR) among important human bacterial pathogens is reaching a state of global crisis threatening a return to the pre-antibiotic era. AMR, already a significant burden on public health and economies, is anticipated to grow even more severe in the coming decades. Several licensed vaccines, targeting both bacterial (Haemophilus influenzae type b, Streptococcus pneumoniae, Salmonella enterica serovar Typhi) and viral (influenza virus, rotavirus) human pathogens, have already proven their anti-AMR benefits by reducing unwarranted antibiotic consumption and antibiotic-resistant bacterial strains and by promoting herd immunity. A number of new investigational vaccines, with a potential to reduce the spread of multidrug-resistant bacterial pathogens, are also in various stages of clinical development. Nevertheless, vaccines as a tool to combat AMR remain underappreciated and unfortunately underutilized. Global mobilization of public health and industry resources is key to maximizing the use of licensed vaccines, and the development of new prophylactic vaccines could have a profound impact on reducing AMR.

Stabilized diverse HIV-1 envelope trimers for vaccine design

One of the major goals in HIV-1 vaccine development is to achieve properly folded and stabilized envelope glycoprotein (Env) trimers that mimic the native Env on the mature virion. Here, we design and characterize uncleaved prefusion-optimized (UFO) trimers for 12 Envs currently circulating in China. Biochemical and biophysical characterization of these UFO trimers identified two subtype B/B' Envs, CNE6 and MG13, which exhibited the highest trimer content and stability at a level comparable to the subtype A reference, BG505. Replacing the gp41 ectodomain (gp41ECTO) of CRF01_AE trimers with that of CNE6, MG13, and BG505 resulted in chimeric constructs with significantly improved trimer content and stability. Negative-stain electron microscopy (EM) confirmed the structural integrity of these chimeric UFO trimers with CNE6 gp41ECTO. Antibody binding assays showed that the chimeric trimers shared similar antigenic profiles to those with their original gp41ECTO domains. Our results thus revealed the intrinsic differences among HIV-1 Envs of diverse origins and the critical role of gp41ECTO in stabilizing the trimeric spike. By taking advantage of naturally stable Envs, gp41ECTO swapping may represent a universal approach for the generation of stable trimers with the desired structural and antigenic properties for downstream in vivo evaluation and vaccine development.

Increased vaccine tolerability and protection via NF-κB modulation

Improving adjuvant responses is a promising pathway to develop vaccines against some pathogens (e.g., HIV or dengue). One challenge in adjuvant development is modulating the inflammatory response, which can cause excess side effects, while maintaining immune activation and protection. No approved adjuvants yet have the capability to independently modulate inflammation and protection. Here, we demonstrate a method to limit inflammation while retaining and often increasing the protective responses. To accomplish this goal, we combined a partial selective nuclear factor kappa B (NF-kB) inhibitor with several current adjuvants. The resulting vaccines reduce systemic inflammation and boost protective responses. In an influenza challenge model, we demonstrate that this approach enhances protection. This method was tested across a broad range of adjuvants and antigens. We anticipate these studies will lead to an alternative approach to vaccine formulation design that may prove broadly applicable to a wide range of adjuvants and vaccines.

The combination of artificial intelligence and systems biology for intelligent vaccine design

INTRODUCTION

A new body of evidence depicts the applications of artificial intelligence and systems biology in vaccine design and development. The combination of both approaches shall revolutionize healthcare, accelerating clinical trial processes and reducing the costs and time involved in drug research and development.

AREAS COVERED

This review explores the basics of artificial intelligence and systems biology approaches in the vaccine development pipeline. The topics include a detailed description of epitope prediction tools for designing epitope-based vaccines and agent-based models for immune system response prediction, along with a focus on their potentiality to facilitate clinical trial phases.

EXPERT OPINION

Artificial intelligence and systems biology offer the opportunity to avoid the inefficiencies and failures that arise in the classical vaccine development pipeline. One promising solution is the combination of both methodologies in a multiscale perspective through an accurate pipeline. We are entering an 'in silico era' in which scientific partnerships, including a more and more increasing creation of an 'ecosystem' of collaboration and multidisciplinary approach, are relevant for addressing the long and risky road of vaccine discovery and development. In this context, regulatory guidance should be developed to qualify the in silico trials as evidence for intelligent vaccine development.

Network-Based Analysis of OMICs Data to Understand the HIV-Host Interaction

The interaction of human immunodeficiency virus with human cells is responsible for all stages of the viral life cycle, from the infection of CD4+ cells to reverse transcription, integration, and the assembly of new viral particles. To date, a large amount of OMICs data as well as information from functional genomics screenings regarding the HIV–host interaction has been accumulated in the literature and in public databases. We processed databases containing HIV–host interactions and found 2910 HIV-1-human protein-protein interactions, mostly related to viral group M subtype B, 137 interactions between human and HIV-1 coding and non-coding RNAs, essential for viral lifecycle and cell defense mechanisms, 232 transcriptomics, 27 proteomics, and 34 epigenomics HIV-related experiments. Numerous studies regarding network-based analysis of corresponding OMICs data have been published in recent years. We overview various types of molecular networks, which can be created using OMICs data, including HIV–human protein–protein interaction networks, co-expression networks, gene regulatory and signaling networks, and approaches for the analysis of their topology and dynamics. The network-based analysis can be used to determine the critical pathways and key proteins involved in the HIV life cycle, cellular and immune responses to infection, viral escape from host defense mechanisms, and mechanisms mediating different susceptibility of humans to infection. The proteins and pathways identified in these studies represent a basis for developing new anti-HIV therapeutic strategies such as new drugs preventing infection of CD4+ cells and viral replication, effective vaccines, “shock and kill” and “block and lock” approaches to cure latent infection.

Production and Evaluation of the Properties of HIV-1-Nef-MPER-V3 Fusion Protein Harboring IMT-P8 Cell Penetrating Peptide

BACKGROUND

Finding a safe and effective vaccine for HIV-1 infection is still a major concern.

OBJECTIVE

This study aimed to design and produce a recombinant Nef-MPER V3 protein fused with IMT-P8 using E. coli expression system to provide a potential HIV vaccine with high cellular penetrance.

METHODS

After synthesizing the DNA sequence of the fusion protein, the construct was inserted into the pET-28 expression vector. The recombinant protein expression was induced using 1 mM IPTG and the product was purified through affinity chromatography. Characterization of cellular delivery, toxicity and immunogenicity of the protein was carried out.

RESULTS

The recombinant protein was expressed and confirmed by the anti-Nef antibody through western blotting. Data analyses showed that the protein possessed no considerable toxicity effect and has improved the IMT-P8 penetration rate in comparison to a control sample. Moreover, the antigen immunogenicity of the protein induced specific humoral response in mice.

CONCLUSION

It was concluded that IMT-P8-Nef-MPER-V3 fusion protein has a high penetrance rate in mammalian cell line and low toxicity, thus it can be potentially considered as a vaccine against HIV-1.

CTLA-4 Blockade, during HIV Virus-Like Particles Immunization, Alters HIV-Specific B-Cell Responses

Studies have shown that blockade of CTLA-4 promoted the expansion of germinal center B-cells in viral infection or immunization with model antigens. Few studies have evaluated the immunological consequences of CTLA-4 blockade during immunization against relevant vaccine candidates. Here, we investigated the effects of CTLA-4 blockade on HIV virus-like particles (VLPs) vaccination in a C57BL/6J mouse model. We found that CTLA-4 blockade during HIV VLP immunization resulted in increased CD4+ T-cell activation, promoted the expansion of HIV envelope (Env)-specific follicular helper T cell (Tfh) cells, and significantly increased HIV Gag- and Env-specific IgG with higher avidity and antibody-dependent cellular cytotoxicity (ADCC) capabilities. Furthermore, after only a single immunization, CTLA-4 blockade accelerated T-cell dependent IgG class switching and the induction of significantly high serum levels of the B-cell survival factor, A proliferation-inducing ligand (APRIL). Although no significant increase in neutralizing antibodies was observed, increased levels of class-switched Env- and Gag-specific IgG are indicative of increased polyclonal B-cell activation, which demonstrated the ability to mediate and enhance ADCC in this study. Altogether, our findings show that CTLA-4 blockade can increase the levels of HIV antigen-specific B-cell and antigen-specific Tfh cell activity and impact humoral immune responses when combined with a clinically relevant HIV VLP-based vaccine.

Updated Studies on the Development of HIV Therapeutic Vaccine

BACKGROUND

Among the various types of pharmaceuticals, vaccines have a special place. However, in the case of HIV, nearly after 40 years of its discovery, an effective vaccine still is not available. The reason lies in several facts mainly the variability and smartness of HIV as well as the complexity of the interaction between HIV and immune responses. A robust, effective, and longterm immunity is undoubtedly what a successful preventive vaccine should induce in order to prevent the infection of HIV. Failure of human trials to this end has led to the idea of developing therapeutic vaccines with the purpose of curing already infected patients by boosting their immune responses against the virus. Nevertheless, the exceptional ability of the virus to escape the immune system based on the genetically diverse envelope and variable protein products have made it difficult to achieve an efficient therapeutic vaccine.

OBJECTIVE

We aimed at studying and comparing different approaches to HIV therapeutic vaccines.

METHODS

In this review, we summarized the human trials undergoing on HIV therapeutic vaccination which are registered in the U.S. clinical trial database (clinicaltrials.gov). These attempts are divided into different tables, according to the type of formulation and application in order to classify and compare their results.

RESULT/CONCLUSION

Among several methods applied in studied clinical trials which are mainly divided into DNA, Protein, Peptide, Viral vectors, and Dendritic cell-based vaccines, protein vaccine strategy is based on Tat protein-induced anti-Tat Abs in 79% HIV patients. However, the studies need to be continued to achieve a durable efficient immune response against HIV-1.

What's Hot in HIV in 2019-A Basic and Translational Science Summary for Clinicians From IDWeek 2019

The field of HIV research is constantly evolving, and every year brings advances that draw us closer to ending the HIV epidemic. Here, we present a nonexhaustive overview of select notable studies in HIV prevention, cure, and treatment, published in the last year as presented at IDWeek 2019: What’s Hot in HIV Basic Science. The past year brought interesting results on the use of broadly neutralizing antibodies for treatment and prevention, gene-editing approaches to HIV cure, and new ways to measure the HIV reservoir. We also saw encouraging results on novel HIV vaccine delivery strategies and how these may influence effective immune responses. Lastly, in the area of inflammation, some mechanistic insights were made into the contribution of cotrimoxazole prophylaxis and potential new targets to reduce HIV-associated chronic inflammation. The future from where we stand is bright for HIV research, with much more to look forward to in 2020.

A Computational Approach for the Prediction of Treatment History and the Effectiveness or Failure of Antiretroviral Therapy

Human Immunodeficiency Virus Type 1 (HIV-1) infection is associated with high mortality if no therapy is provided. Currently, the treatment of an HIV-1 positive patient requires that several drugs should be taken simultaneously. The resistance of the virus to an antiretroviral drug may lead to treatment failure. Our approach focuses on predicting the exposure of a particular viral variant to an antiretroviral drug or drug combination. It also aims at the prediction of drug treatment success or failure. We utilized nucleotide sequences of HIV-1 encoding protease and reverse transcriptase to perform such types of prediction. The PASS (Prediction of Activity Spectra for Substances) algorithm based on the naive Bayesian classifier was used to make a prediction. We calculated the probability of whether a sequence belonged (P₁) or did not belong (P₀) to the class associated with exposure of the viral sequence to the set of drugs that can be associated with resistance to the set of drugs. The accuracy calculated as the average Area Under the ROC (Receiver Operating Characteristic) Curve (AUC/ROC) for classifying exposure of the sequence to the HIV-1 protease inhibitors was 0.81 (±0.07), and for HIV-1 reverse transcriptase, it was 0.83 (±0.07). To predict cases of treatment effectiveness or failure, we used P₁ and P₀ values, obtained in PASS, along with the binary vector constructed based on short nucleotide descriptors and the applied random forest classifier. Average AUC/ROC prediction accuracy for the prediction of treatment effectiveness or failure for the combinations of HIV-1 protease inhibitors was 0.82 (±0.06) and of HIV-1 reverse transcriptase was 0.76 (±0.09).

Dendritic Cells in HIV/SIV Prophylactic and Therapeutic Vaccination

Dendritic cells (DCs) are involved in human and simian immunodeficiency virus (HIV and SIV) pathogenesis but also play a critical role in orchestrating innate and adaptive vaccine-specific immune responses. Effective HIV/SIV vaccines require strong antigen-specific CD4 T cell responses, cytotoxic activity of CD8 T cells, and neutralizing/non-neutralizing antibody production at mucosal and systemic sites. To develop a protective HIV/SIV vaccine, vaccine regimens including DCs themselves, protein, DNA, mRNA, virus vectors, and various combinations have been evaluated in different animal and human models. Recent studies have shown that DCs enhanced prophylactic HIV/SIV vaccine efficacy by producing pro-inflammatory cytokines, improving T cell responses, and recruiting effector cells to target tissues. DCs are also targets for therapeutic HIV/SIV vaccines due to their ability to reverse latency, present antigen, and augment T and B cell immunity. Here, we review the complex interactions of DCs over the course of HIV/SIV prophylactic and therapeutic immunizations, providing new insights into development of advanced DC-targeted HIV/SIV vaccines.

Heterologous Combination of VSV-GP and NYVAC Vectors Expressing HIV-1 Trimeric gp145 Env as Vaccination Strategy to Induce Balanced B and T Cell Immune Responses

The generation of a vaccine against HIV-1 able to induce durable protective immunity continues a major challenge. The modest efficacy (31.2%) of the phase III RV144 clinical trial provided the first demonstration that a prophylactic HIV/AIDS vaccine is achievable but emphasized the need for further refinements of vaccine candidates, formulations, and immunization regimens. Here, we analyzed in mice the immunogenicity profile elicited by different homologous and heterologous prime/boost combinations using the modified rhabdovirus VSV-GP combined with DNA or poxviral NYVAC vectors, all expressing trimeric membrane-bound Env (gp145) of HIV-1 96ZM651 clade C, with or without purified gp140 protein component. In cultured cells infected with recombinant VSV-GP or NYVAC viruses, gp145 epitopes at the plasma membrane were recognized by human HIV-1 broadly neutralizing antibodies (bNAbs). In immunized mice, the heterologous combination of VSV-GP and NYVAC recombinant vectors improved the induction of HIV-1 Env-specific humoral and cellular immune responses compared to homologous prime/boost protocols. Specifically, the combination of VSV-GP in the prime and NYVAC in the boost induced higher HIV-1 Env-specific T cell (CD4/CD8 T cells and T follicular helper -Tfh- cells) immune responses compared to the use of DNA or NYVAC vectors in the prime and VSV-GP in the boost. Such enhanced T cell responses correlated with an enhancement of the Env-specific germinal center (GC) B cell population and with a heavily biased Env-specific response toward the Th1-associated IgG2a and IgG3 subclasses, while the other groups showed a Th2-associated IgG1 bias. In summary, our T and B cell population data demonstrated that VSV-GP-based vectors could be taken into consideration as an optimized immunogenic HIV-1 vaccine candidate component against HIV-1 when used for priming in heterologous combinations with the poxvirus vector NYVAC as a boost.

The Extended Impact of Human Immunodeficiency Virus/AIDS Research

Human immunodeficiency virus (HIV) is one of the most extensively studied viruses in history, and numerous extraordinary scientific advances, including an in-depth understanding of viral biology, pathogenesis, and life-saving antiretroviral therapies, have resulted from investments in HIV/AIDS research. While the substantial investments in HIV/AIDS research are validated solely on these advances, the collateral broader scientific progress resulting from the support of HIV/AIDS research over the past 30 years is extraordinary as well. The positive impact has ranged from innovations in basic immunology and structural biology to treatments for immune-mediated diseases and cancer and has had an enormous effect on the research and public and global health communities well beyond the field of HIV/AIDS. This article highlights a few select examples of the unanticipated and substantial positive spin-offs of HIV/AIDS research on other scientific areas.

Reduction of peak viremia by an integration-defective SIV proviral DNA vaccine in rhesus macaques

An integrase-defective SIV (idSIV) vaccine delivered by a DNA prime and viral particle boost approach can suppress viral loads (VLs) during the acute infection stage after intravenous SIVmac239 challenge. This study investigated how idSIV DNA and viral particle immunization alone contributed to the suppression of VLs in Chinese rhesus macaques after SIV challenge. Two macaques were immunized with idSIV DNA five times and two macaques were immunized with idSIV viral particles three times. Cellular and humoral immune responses were measured in the vaccinated macaques after immunization. The VLs and CD4⁺ T cell counts were monitored for 28 weeks after the intravenous SIVmac239 challenge. The SIV-specific T cell responses were only detected in the DNA-vaccinated macaques. However, binding and neutralizing antibodies against autologous and heterologous viruses were moderately better in macaques immunized with viral particles than in macaques immunized with DNA. After the challenge, the mean peak viremia in the DNA group was 2.3 logs lower than that in the control group, while they were similar between the viral particle immunization and control groups. Similar CD4⁺ T cell counts were observed among all groups. These results suggest that idSIV DNA immunization alone reduces VLs during acute infection after SIV challenge in macaques and may serve as a key component in combination with other immunogens as prophylactic vaccines.

Antigenicity and immunogenicity of HIV-1 gp140 with different combinations of glycan mutation and V1/V2 region or V3 crown deletion

The carbohydrate moieties on HIV-1 envelope glycoprotein (Env) act as shields to mask conserved neutralizing epitopes, while the hyperimmunogenic variable regions are immunodominant in inducing non-neutralizing antibodies, representing the major challenge for using Env as a vaccine candidate to induce broadly neutralizing antibodies (bNAbs). In this study, we designed a series of HIV-1 gp140 constructs with the removal of N276/N463 glycans, deletion of the V1/V2 region and the V3 crown, alone or in combination. We first demonstrated that all the constructs had a comparable level of expression and were mainly expressed as trimers. Following purification of gp140s from mammalian cells, we measured their binding to bNAbs and non-NAbs in vitro and capability in inducing bNAbs in vivo. Antibody binding assay showed that removal of N276/N463 glycans together with the deletion of V1/V2 region enhanced the binding of gp140s to CD4-binding site-targeting bNAbs VRC01 and 3BNC117, and CD4-induced epitopes-targeting non-NAbs A32, 17b and F425 A1g8, whereas further deletion of V3 crown in the gp140 mutants demonstrated slightly compromised binding capability to these Abs. Immunogenicity study showed that the above mutations did not lead to the induction of a higher Env-specific IgG response via either DNA-DNA or DNA-protein prime-boost strategies in mice, while neutralization assay did not show an apparent difference between wild type and mutated gp140s. Taken together, our results indicate that removal of glycans at N276/N463 and deletion of the V1/V2 region can expose the CD4-binding site and CD4-induced epitopes, but such exposure alone appears incapable of enhancing the induction of bNAbs in mice, informing that additional modification or/and immunization strategies are needed. In addition, the strategies which we established for producing gp140 proteins and for analyzing the antigenicity and immunogenicity of gp140 provide useful means for further vaccine design and assessment.

Induction of a Robust Humoral Response using HIV-1 VLPMPER-V3 as a Novel Candidate Vaccine in BALB/c Mice

Background:

Several approaches have not been successful to suppress HIV (Human immunodeficiency virus) infection among infected individuals or to prevent it yet. In order to expand strong HIV specific humoral and cellular responses, Virus-like particles (VLPs) as potential vaccines show significant increase in neutralizing antibodies secretion, T-cell count and also secretion of cytokines.

Objective:

This study aimed at immunological evaluation of VLPs harboring high copy of MPERV3 in BALB/c mice.

Methods:

Female BALB/c mice were immunized with homologous and heterologous primeboosting regimens of HIV-1 VLPMPER-V3. Their immune responses were evaluated for humoral responses (Total IgG and IgG isotyping) and cellular responses (IFN-γ, IL-5 secretion, in vitro CTL assay and T cell proliferation) and compared in immunized mice.

Results:

The data showed robust induction of humoral response in mice groups which received different regimens of VLP. Furthermore, analysis of cytokine profile indicated that the highest IL-5 secretion was related to VLP+M50 group and confirmed the dominance of Th2 immunity in this group.

Conclusion:

This study showed that VLP MPER-V3 as a potential vaccine candidate has the potency as an effective prophylactic vaccine and this finding guarantees further investigations to achieve a promising HIV-1 vaccine candidate.

Advances and challenges in recombinant Mycobacterium bovis BCG-based HIV vaccine development: lessons learned

INTRODUCTION

Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome, tuberculosis, and malaria are responsible for most human deaths produced by infectious diseases worldwide. Vaccination against HIV requires generation of memory T cells and neutralizing antibodies, mucosal immunity, and stimulation of an innate immune responses. In this context, the use of Mycobacterium bovis bacillus Calmette-Guérin (BCG) as a live vaccine vehicle is a promising approach for T-cell induction.

AREAS COVERED

In this review, we provide a comprehensive summary of the literature regarding immunogenicity studies in animal models performed since 2005. Furthermore, we provide expert commentary and 5-year view on how the development of potential recombinant BCG-based HIV vaccines involves careful selection of the HIV antigen, expression vectors, promoters, BCG strain, preclinical animal models, influence of preexisting immunity, and safety issues, for the rational design of recombinant BCG:HIV vaccines to prevent HIV transmission in the general population.

EXPERT COMMENTARY

The three critical issues to be considered when developing a rBCG:HIV vaccine are codon optimization, antigen localization, and plasmid stability in vivo. The use of integrative expression vectors are likely to improve the mycobacterial vaccine stability and immunogenicity to develop not only recombinant BCG-based vaccines expressing second generation of HIV-1 immunogens but also other major pediatric pathogens to prime protective responses shortly following birth.

HIV Apheresis Tags (HIVAT) Aided Elimination of Viremia

INTRODUCTION

HIV viremia is the essential element for progression of an initial HIV infection into AIDS and death. The currently approved management relies primarily on chemotherapy repressing the HIV replication in the infected CD4+ cells, although with severe systemic adverse effects. The problem is that it does not physically eliminate viruses, which then not only keep infecting healthy cells of these patients, but also promote infections of other people.

SPECIFIC AIM

An overall objective of our work is biomolecular engineering of virus apheresis tags (VAT) that eliminate viremias without adverse effects. The specific aim of this project was biomolecular engineering of Human Immunodeficiency Virus Apheresis Tags (HIVAT): CD4-Au-Fe3O4, CD4-SiO2-Fe3O4, anti-gp120-Au-Fe3O4, and anti-gp120-SiO2-Fe3O4.

HEALTHY DONORS AND PATIENTS

Per the Institutional Review Board's approval and in compliance with Declaration of Helsinki, healthy donors and patients were presented with Patient Bill of Rights and provided Patient Informed Consent, while all the procedures were pursued by the licensed physicians.

MATERIALS AND METHODS

CD4, gp120, gp41, gp160, anti-gp120, p24 were transgenomically expressed. Superparamagnetic core-shell particles (SPM-CSP) were synthesized. SPM-CSP were used as the nucleation centers for assembling the expressed molecules upon them to create virus apheresis tags (VAT). VAT were injected into the blood or lymph acquired from the HIV+ and HBV+ patients followed by apheresis at 0.47 - 9.4 T. VAT efficacy in eliminating viremia was determined through immunoblots, NMR and q-RT-PCR.

RESULTS

Treatment of blood or lymph of the HIV+ patients' with VAT followed by virus apheresis resulted in rapid elimination of the HIV viremia. Efficacy of apheresis was contingent upon the gravity of viremia versus doses and regimens of VAT. Importantly, administration of VAT also effectively improved levels of non-infected CD4+ lymphocytes.

DISCUSSION / CONCLUSIONS

Herein, we present the proof of concept for a new, effective treatment with virus apheresis tags (VAT), specifically Human Immunodeficiency Virus Apheresis Tags (HIVAT), of the HIV+ patients' blood and lymph, which is eliminating the HIV viremia.It can be easily adapted as treatments of viremias perpetrated by other deadly viruses, which we vigorously pursue.

HIV Apheresis Tags (HIVAT) Aided Elimination of Viremia

INTRODUCTION

HIV viremia is the essential element for progression of an initial HIV infection into AIDS and death. The currently approved management relies primarily on chemotherapy repressing the HIV replication in the infected CD4+ cells, although with severe systemic adverse effects. The problem is that it does not physically eliminate viruses, which then not only keep infecting healthy cells of these patients, but also promote infections of other people.

SPECIFIC AIM

An overall objective of our work is biomolecular engineering of virus apheresis tags (VAT) that eliminate viremias without adverse effects. The specific aim of this project was biomolecular engineering of Human Immunodeficiency Virus Apheresis Tags (HIVAT): CD4-Au-Fe3O4, CD4-SiO2-Fe3O4, anti-gp120-Au-Fe3O4, and anti-gp120-SiO2-Fe3O4.

HEALTHY DONORS AND PATIENTS

Per the Institutional Review Board's approval and in compliance with Declaration of Helsinki, healthy donors and patients were presented with Patient Bill of Rights and provided Patient Informed Consent, while all the procedures were pursued by the licensed physicians.

MATERIALS AND METHODS

CD4, gp120, gp41, gp160, anti-gp120, p24 were transgenomically expressed. Superparamagnetic core-shell particles (SPM-CSP) were synthesized. SPM-CSP were used as the nucleation centers for assembling the expressed molecules upon them to create virus apheresis tags (VAT). VAT were injected into the blood or lymph acquired from the HIV+ and HBV+ patients followed by apheresis at 0.47 - 9.4 T. VAT efficacy in eliminating viremia was determined through immunoblots, NMR and q-RT-PCR.

RESULTS

Treatment of blood or lymph of the HIV+ patients' with VAT followed by virus apheresis resulted in rapid elimination of the HIV viremia. Efficacy of apheresis was contingent upon the gravity of viremia versus doses and regimens of VAT. Importantly, administration of VAT also effectively improved levels of non-infected CD4+ lymphocytes.

DISCUSSION / CONCLUSIONS

Herein, we present the proof of concept for a new, effective treatment with virus apheresis tags (VAT), specifically Human Immunodeficiency Virus Apheresis Tags (HIVAT), of the HIV+ patients' blood and lymph, which is eliminating the HIV viremia.It can be easily adapted as treatments of viremias perpetrated by other deadly viruses, which we vigorously pursue.