FIG 4 - uploaded by David C Montefiori
Content may be subject to copyright.
Binding of CON6 gp120 and gp140CF to sCD4 and anti-Env MAbs. (A and B) Each of the indicated MAbs and sCD4 were covalently immobilized to a CM5 sensor chip (BIAcore), and CON6 gp120 (A) or gp140CF (B) was injected over each surface (100 and 300 g/ml, respectively). (C and D) To determine induction of 17b MAb binding to CON6 gp120 and gp140CF, CON6 gp120 (C) or gp140CF (D) proteins were captured (400 to 580 response units) on individual flow cells immobilized with sCD4 or MAb A32 or T8. Following stabilization of each of the surfaces, MAb 17b was injected and allowed to flow over each of the immobilized flow cells. (E) To determine binding of CON6 gp120 and gp140CF to human MAbs in ELISA, titers of stock solutions of 20 g of MAbs 447-52D, F39F, A32, IgG1b12, and 2F5 were determined with CON6 gp120 and gp140CF glycoproteins. MAbs 447-52D (V3), F39F (V3) A32 (gp120), and IgG1b12 (CD4 binding site) each bound to both CON6 gp120 and gp140CF well, while 2F5 (anti-gp41 ELDKWAS) bound only CON6 gp140CF. The concentrations at the end point titer (end titer where the experimental versus the control value was Ն 3.0) with gp120 for MAb 447-52D and F39F binding were Ͻ 0.003 and 0.006 g/ml, respectively; that for MAb A32 was Ͻ 0.125 g/ml; that for IgG1b12 was Ͻ 0.002 g/ml; and that for 2F5 with gp140CF was 0.016 g/ml.
Source publication
Genetic variation of human immunodeficiency virus (HIV-1) represents a major obstacle for AIDS vaccine development. To decrease
the genetic distances between candidate immunogens and field virus strains, we have designed and synthesized an artificial
group M consensus env gene (CON6 gene) to be equidistant from contemporary HIV-1 subtypes and recom...
Similar publications
The effects of genetic adjuvants on humoral and cell-mediated immunity to two human immunodeficiency virus antigens, Env and Nef, have been examined in mice. Despite similar levels of gene expression and the same gene delivery vector, the immune responses to these two gene products differed following DNA immunization. Intramuscular immunization wit...
Interactions between the viral envelope glycoprotein gp120 and the cell surface receptor CD4 are responsible for the entry of human immunodeficiency virus type 1 (HIV-1) into host cells in the vast majority of cases. HIV-1 replication is commonly followed by the disappearance or receptor downmodulation of cell surface CD4. This potentially renders...
The major envelope glycoproteins gp120 and gp41 of human immunodeficiency virus type 1, the causative agent for human AIDS, contain numerous N-linked oligosaccharides. We report here our discovery that N-acetylglucosamine residues within the complex-type N-linked oligosaccharides of both gp120 and its precursor, gp160, are sulfated. When human Molt...
Human CD4+ T cell clones and cell lines were shown to lyse recombinant vaccinia virus-infected cells that synthesize the HIV-1 envelope glycoprotein gp160. The processing of endogenously synthesized gp160 for recognition by CD4+ T cells required that the protein, after synthesis on the rough endoplasmic reticulum and during subsequent cellular tran...
The ability of cytokines to steer CD4(+) T(h) cell responses toward a T(h)1 or T(h)2 phenotype and enhance the magnitude of both CD8(+) cytotoxic T lymphocytes (CTL) and antibody responses has clearly been demonstrated by our lab and others, but the influence of cytokines on protective immune responses is much less clear. Here we show an essential...
Citations
... Although vaccinations against diseases like measles and hepatitis have been shown to be effective, numerous obstacles stand in the way of the general use of this approach against emerging viral kinds [3]. For instance, during each round of viral replication, the human immunodeficiency virus (HIV) exhibits a high rate of mutation as well as recombination [4]. Nine kilobases of the HIV genome encode for sixteen different proteins, including regulatory (Tat and Rev), auxiliary (Nef, Vif, Vpu, and Vpr), and important structural (Gag, Pol, and Env) proteins. ...
The continuous evolution of new viruses poses a danger to world health. Rampant outbreaks may advance to pandemic level, often straining financial and medical resources to breaking point. While vaccination remains the gold standard to prevent viral illnesses, these are mostly prophylactic and offer minimal assistance to those who have already developed viral illnesses. Moreover, the timeline to vaccine development and testing can be extensive, leading to a lapse in controlling the spread of viral infection during pandemics. Antiviral therapeutics can provide a temporary fix to tide over the time lag when vaccines are not available during the commencement of a disease outburst. At times, these medications can have negative side effects that outweigh the benefits, and they are not always effective against newly emerging virus strains. Several limitations with conventional antiviral therapies may be addressed by nanotechnology. By using nano delivery vehicles, for instance, the pharmacokinetic profile of antiviral medications can be significantly improved while decreasing systemic toxicity. The virucidal or virus-neutralizing qualities of other special nanomaterials can be exploited. This review focuses on the recent advancements in nanomedicine against RNA viruses, including nano-vaccines and nano-herbal therapeutics.
... The high mutation and replication rates of HIV pose significant challenges to vaccine development. 27,28 However, bNAbs have the potential to combat the virus by participating in the body's innate response. 29 The administration of potent anti-HIV-1 monoclonal antibodies is emerging as a promising strategy for HIV-1 prevention and treatment. ...
Introduction:
Broadly neutralizing antibodies (bNAbs) have the ability to neutralize a considerable breadth of genetically diverse human immunodeficiency virus (HIV) strains. Passive immunization can potentially provide protection against HIV infection in animal models. However, the direct antibody infusion effect is limited due to the short half-life and deficient immunogenicity of the antibody. As an alternative strategy, we propose the use of nano viral vectors, specifically the adeno-associated virus (AAV), to continuously and systematically produce bNAbs against HIV.
Methods:
Plasmids expressing bNAbs PG9, PG16, 10E8, and NIH45-46 antibodies were constructed, targeting three different epitopes of HIV. Additionally, the bNAbs gene mediated by rAAV8 was administered to generate long-term expression with a single injection. We established both single and combined immunization groups. The neutralizing activity of antibodies expressed in mice sera was subsequently evaluated.
Results:
The expression of bNAbs in BALB/c mice can last for >24 weeks after a single intramuscular injection of rAAV8. Further studies show that neutralization of the HIV pseudovirus by sera from co-immunized mice with rAAV8 expressing 10E8 and PG16 was enhanced compared with mice immunized with 10E8 or PG16 alone.
Conclusion:
The prolonged expression of neutralizing antibodies can be maintained over long periods in BALB/c mice. This combined immunization is a promising candidate strategy for HIV treatment.
... HIV-1 infection is characterized by a high-level viral replication and elevated mutation rates, quantified at about one mutation every replication cycle [147]. This mutation rate leads to an extensive virus variation which has been estimated in an env gene sequence at 0.6-1% substitutions per year within infected patients [148][149][150][151]. Furthermore, when comparing HIV-1 env sequences from patients infected by different HIV-1 subtypes, they could differ on average by 25% and by as much as 35% [150,152], and this variation could reach a 1-2% of genetic variation within a transmission pair or within a single individual. ...
... HIV-1 infection is characterized by a high-level viral replication and elevated mutation rates, quantified at about one mutation every replication cycle [147]. This mutation rate leads to an extensive virus variation which has been estimated in an env gene sequence at 0.6-1% substitutions per year within infected patients [148][149][150][151]. Furthermore, when comparing HIV-1 env sequences from patients infected by different HIV-1 subtypes, they could differ on average by 25% and by as much as 35% [150,152], and this variation could reach a 1-2% of genetic variation within a transmission pair or within a single individual. Furthermore, HIV-1 Env shows extensive conformational adaptability and massive glycan shielding (i.e., Env glycans accounts for about 1/2 the mass of the molecule) that allow the virus to evade the effects of neutralizing antibodies (nAbs) and other viral antigen-triggered immune responses [46,47,150,151,[153][154][155][156][157][158][159][160][161]. ...
... This mutation rate leads to an extensive virus variation which has been estimated in an env gene sequence at 0.6-1% substitutions per year within infected patients [148][149][150][151]. Furthermore, when comparing HIV-1 env sequences from patients infected by different HIV-1 subtypes, they could differ on average by 25% and by as much as 35% [150,152], and this variation could reach a 1-2% of genetic variation within a transmission pair or within a single individual. Furthermore, HIV-1 Env shows extensive conformational adaptability and massive glycan shielding (i.e., Env glycans accounts for about 1/2 the mass of the molecule) that allow the virus to evade the effects of neutralizing antibodies (nAbs) and other viral antigen-triggered immune responses [46,47,150,151,[153][154][155][156][157][158][159][160][161]. It is thought that transmitted HIV-1 tends to display Env proteins with less glycosylation than those that are poorly transmitted [162][163][164]. ...
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.
... Such sequences are useful as references for bioinformatic processing in, for instance, alignments and contig assembly, for detection of hypermutants, gene detection and annotation, and for representing simplified views and data from complex populations (Rose and Korber, 2000;Lee, 2003;Seah et al., 2020;Domingo et al., 2021;Frith et al., 2021;Kulikova et al., 2021;Zhang et al., 2021). Consensus sequences have also been used in studies of protein functions, binding, and vaccine designs (Novitsky et al., 2002;Gao et al., 2005;Nickle et al., 2007;Yan et al., 2007;Sternke et al., 2019). ...
HIV consensus sequences are used in various bioinformatic, evolutionary, and vaccine related research. Since the previous HIV-1 subtype and CRF consensus sequences were constructed in 2002, the number of publicly available HIV-1 sequences have grown exponentially, especially from non-EU and US countries. Here, we reconstruct 90 new HIV-1 subtype and CRF consensus sequences from 3,470 high-quality, representative, full genome sequences in the LANL HIV database. While subtypes and CRFs are unevenly spread across the world, in total 89 countries were represented. For consensus sequences that were based on at least 20 genomes, we found that on average 2.3% (range 0.8–10%) of the consensus genome site states changed from 2002 to 2021, of which about half were nucleotide state differences and the rest insertions and deletions. Interestingly, the 2021 consensus sequences were shorter than in 2002, and compared to 4,674 HIV-1 worldwide genome sequences, the 2021 consensuses were somewhat closer to the worldwide genome sequences, i.e., showing on average fewer nucleotide state differences. Some subtypes/CRFs have had limited geographical spread, and thus sampling of subtypes/CRFs is uneven, at least in part, due to the epidemiological dynamics. Thus, taken as a whole, the 2021 consensus sequences likely are good representations of the typical subtype/CRF genome nucleotide states. The new consensus sequences are available at the LANL HIV database.
... In the past, numerous approaches for the development of an effective HIV vaccine have been tried. They include the use of cleverly chosen natural HIV proteins, the design of a consensus (9) or "center-of-tree" (10) antigens, and the creation of a mosaic protein from different HIV strains (11). All these methods used a single optimized antigen in the vaccine and were shown to be ineffective at eliciting bnAbs (12,13). ...
Significance
A solution to the global AIDS epidemic is to develop a vaccine against HIV. This has been difficult to achieve because the virus mutates rapidly, and the antibodies induced by vaccination would need to recognize many different HIV variants. We have developed a computational framework to design panels of antigens for eliciting broadly neutralizing antibodies (bnAbs) for an HIV vaccine. An important aspect of the method is its use of the gp160 fitness landscape, which measures the ability of the virus to tolerate mutations. Most designed antigens assembled as well-ordered native-like trimers with antigenic properties favorable for vaccine studies. These antigens can be used to make meaningful proposals for immunization schedules, a significant advance in HIV vaccine design.
... For this, gBlock DNA templates corresponding to HCV-NS3 and HCV-NS5 antigens of HCV genotype 1b were purchased from IDT (Integrated DNA Technologies, IA, USA). The template used for the production of the HIV-1 gp160-ConS peptides were kindly provided by Dr. Barton Haynes (12). Oligonucleotide primer-pairs (sense and anti-sense) were designed to enable PCR amplification of each of the specific overlapping and shifted domains, using the DNA templates described above. ...
The presence of pathogen-specific antibodies in an individual’s blood-sample is used as an indication of previous exposure and infection to that specific pathogen (e.g., virus or bacterium). Measurement of the diagnostic antibodies is routinely achieved using solid phase immuno-assays such as ELISA tests and western blots. Here, we describe a sero-diagnostic approach based on phage-display of epitope arrays we term “Domain-Scan”. We harness Next-generation sequencing (NGS) to measure the serum binding to dozens of epitopes derived from HIV-1 and HCV simultaneously. The distinction of healthy individuals from those infected with either HIV-1 or HCV, is modeled as a machine-learning classification problem, in which each determinant (“domain”) is considered as a feature, and its NGS read-out provides values that correspond to the level of determinant-specific antibodies in the sample. We show that following training of a machine-learning model on labeled examples, we can very accurately classify unlabeled samples and pinpoint the domains that contribute most to the classification. Our experimental/computational Domain-Scan approach is general and can be adapted to other pathogens as long as sufficient training samples are provided.
... Over the years, the greatest challenge in developing an effective HIV vaccine has been the high rate of mutation and recombination during viral replication (9). The enormous genetic diversity of HIV is mainly driven by the high rate of variability of the viral envelope (Env) glycoprotein, which ironically happens to be the main target of neutralizing antibodies (10). ...
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.
... Serum samples were tested for IgG and IgG3 binding Ab responses to gp41, Con S gp140 [78][79][80] , Con6 gp120, and gp70_B.CaseA_V1V2 at primary and longitudinal timepoints as described previously 3,54,81,82 . Briefly, samples were incubated with antigen-coated beads in BAMA assay diluent (5% Normal Goat serum (v/v), 1% milk blotto (w/v), 0.05% Tween-20 (v/v) in PBS), washed, then incubated with either biotinylated anti-human IgG (Southern Biotech) or biotinylated anti-human IgG3 (Calbiochem) followed by washing and incubation with Streptavidin-PE (BD Biosciences). ...
Efficacious HIV-1 vaccination requires elicitation of long-lived antibody responses. However, our understanding of how different vaccine types elicit durable antibody responses is lacking. To assess the impact of vaccine type on antibody responses, we measured IgG isotypes against four consensus HIV antigens from 2 weeks to 10 years post HIV-1 vaccination and used mixed effects models to estimate half-life of responses in four human clinical trials. Compared to protein-boosted regimens, half-lives of gp120-specific antibodies were longer but peak magnitudes were lower in Modified Vaccinia Ankara (MVA)-boosted regimens. Furthermore, gp120-specific B cell transcriptomics from MVA-boosted and protein-boosted vaccines revealed a distinct signature at a peak (2 weeks after last vaccination) including CD19, CD40, and FCRL2-5 activation along with increased B cell receptor signaling. Additional analysis revealed contributions of RIG-I-like receptor pathway and genes such as SMAD5 and IL-32 to antibody durability. Thus, this study provides novel insights into vaccine induced antibody durability and B-cell receptor signaling.
... Although TZM-bl is not a T cell line, this cell line was artificially modified with surface CD4 and CCR5 and is susceptible to infection by both R5 and X4 HIV-1 isolates (43). The widely-adopted protocols for evaluating viral infectivity, 50% inhibitory concentration (IC50) of antiviral reagent and 50% inhibitory dose (ID50) of neutralizing antibody are built on this cell line (51)(52)(53). Therefore, it would be convenient to use SAMHD1 transiently-transfected TZM-bl cells to detect the antiviral activity of SAMHD1 in vitro. ...
SAM and HD domain–containing deoxynucleoside triphosphate triphosphohydrolase 1 (SAMHD1) is a host factor that restricts reverse transcription of lentiviruses such as HIV in myeloid cells and resting T cells through its dNTP triphosphohydrolase (dNTPase) activity. Lentiviruses counteract this restriction by expressing the accessory protein Vpx or Vpr, which targets SAMHD1 for proteasomal degradation. SAMHD1 is conserved among mammals, and the feline and bovine SAMHD1 proteins (fSAM and bSAM) restrict lentiviruses by reducing cellular dNTP concentrations. However, the functional regions of fSAM and bSAM that are required for their biological functions are not well characterized. Here, to establish alternative models to investigate SAMHD1 in vivo, we studied the restriction profile of fSAM and bSAM against different primate lentiviruses. We found that both fSAM and bSAM strongly restrict primate lentiviruses and that Vpx induces the proteasomal degradation of both fSAM and bSAM. Further investigation identified one and five amino-acid sites in the C-terminal domain (CTD) of fSAM and bSAM, respectively, that are required for Vpx-mediated degradation. We also found that the CTD of bSAM is directly involved in mediating bSAM’s antiviral activity by regulating dNTPase activity, whereas the CTD of fSAM is not. Our results suggest that the CTDs of fSAM and bSAM have important roles in their antiviral functions. These findings advance our understanding of the mechanism of fSAM- and bSAM-mediated viral restriction and might inform strategies for improving HIV animal models.
... Despite their artificial origin, several examples of functional immunogens based on centralized env sequences were reported prior to the emergence of soluble native-like Env trimers [115][116][117][118][119][120]. However, these immunogens were focused on enhancing T-cell responses and only elicited low NAb titres [115][116][117][118]120], probably because they were delivered by genetic vaccination or did not present a native-like conformation. ...
... Despite their artificial origin, several examples of functional immunogens based on centralized env sequences were reported prior to the emergence of soluble native-like Env trimers [115][116][117][118][119][120]. However, these immunogens were focused on enhancing T-cell responses and only elicited low NAb titres [115][116][117][118]120], probably because they were delivered by genetic vaccination or did not present a native-like conformation. Liao et al. compared transmitter/founder (T/F), consensus and chronic Envs from different clades in immunization experiments in guinea pigs. ...
Introduction: Despite intensive research efforts, there is still no effective prophylactic vaccine available against HIV-1. Currently, substantial efforts are devoted to the development of vaccines aimed at inducing broadly neutralizing antibodies (bNAbs), which are capable of neutralizing most HIV-1 strains. All bNAbs target the HIV-1 envelope glycoprotein (Env), but Env immunizations usually only induce neutralizing antibodies (NAbs) against the sequence-matched virus and not against other strains.
Areas covered: We describe the different strategies that have been explored to improve the breadth and potency of anti-HIV-1 NAb responses. The discussed strategies include the application of engineered Env immunogens, optimization of (bNAb) epitopes, different cocktail and sequential vaccination strategies, nanoparticles and nucleic acid-based vaccines.
Expert opinion: A combination of the strategies described in this review and future approaches are probably needed to develop an effective HIV-1 vaccine that can induce broad, potent and long-lasting NAb responses.
