RESUMEN
A subset of people living with HIV (PLWH) can produce broadly neutralizing antibodies (bNAbs) against HIV, but the lymph node (LN) dynamics that promote the generation of these antibodies are poorly understood. Here, we explored LN-associated histological, immunological, and virological mechanisms of bNAb generation in a cohort of anti-retroviral therapy (ART)-naïve PLWH. We found that participants who produce bNAbs, termed neutralizers, have a superior LN-associated B cell follicle architecture compared with PLWH who do not. The latter was associated with a significantly higher in situ prevalence of Bcl-6hi follicular helper CD4 T cells (TFH), expressing a molecular program that favors their differentiation and stemness, and significantly reduced IL-10 follicular suppressor CD4 T cells. Furthermore, our data reveal possible molecular targets mediating TFH- B cell interactions in neutralizers. Together, we identify cellular and molecular mechanisms that contribute to the development of bNAbs in PLWH.
RESUMEN
Human immunodeficiency virus type 1 (HIV-1) vaccine immunogens capable of inducing broadly neutralizing antibodies (bNAbs) remain obscure. HIV-1 evades immune responses through enormous diversity and hides its conserved vulnerable epitopes on the envelope glycoprotein (Env) by displaying an extensive immunodominant glycan shield. In elite HIV-1 viremic controllers, glycan-dependent bNAbs targeting conserved Env epitopes have been isolated and are utilized as vaccine design templates. However, immunological tolerance mechanisms limit the development of these antibodies in the general population. The well characterized bNAbs monoclonal variants frequently exhibit extensive levels of somatic hypermutation, a long third heavy chain complementary determining region, or a short third light chain complementarity determining region, and some exhibit poly-reactivity to autoantigens. This review elaborates on the obstacles to engaging and manipulating the Env glycoprotein as an effective immunogen and describes an alternative reverse vaccinology approach to develop a novel category of bNAb-epitope-derived non-cognate immunogens for HIV-1 vaccine design.
Asunto(s)
Vacunas contra el SIDA , Anticuerpos Neutralizantes , Anticuerpos Anti-VIH , VIH-1 , VIH-1/inmunología , Humanos , Vacunas contra el SIDA/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Anti-VIH/inmunología , Polisacáridos/inmunología , Infecciones por VIH/inmunología , Imitación Molecular/inmunología , Epítopos/inmunología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología , LigandosRESUMEN
Anti-human immunodeficiency virus (HIV) broadly neutralizing antibodies (bNAbs) offer a promising approach for the treatment of HIV-1. The current paradigm for antibody therapy involves passive antibody transfer, requiring regular delivery of bNAbs in treating chronic diseases such as HIV-1. An alternative strategy is to use AAV-mediated gene transfer to enable in vivo production of desirable anti-HIV-1 antibodies. In this study, we investigated two sets of triple combinations of AAV9-vectors encoding different bNAbs: N6, 10E8, 10-1074 (CombiMab1), and VRC07-523, PGDM1400, 10-1074 (CombiMab2). We used CBAxC57Bl and C57BL/6 mouse models to characterize rAAV-induced antibody expression and to evaluate the neutralization capacity of mouse sera against a global panel of HIV-1 viral strains. rAAV9-mediated IgG expression varied between bNAb clones and mouse strains, with C57BL/6 mice exhibiting higher bNAb titers following rAAV delivery. Although CombiMab2 treatment elicited a higher IgG titer than CombiMab1, both combinations resulted in neutralization of all the viral strains from the global HIV-1 panel. Our data highlight the potential of AAV vectors as a long-term option for HIV-1 therapy.
Asunto(s)
Anticuerpos Neutralizantes , Dependovirus , Vectores Genéticos , Anticuerpos Anti-VIH , Infecciones por VIH , VIH-1 , Inmunoglobulina G , Ratones Endogámicos C57BL , Animales , Dependovirus/genética , Dependovirus/inmunología , VIH-1/inmunología , VIH-1/genética , Humanos , Ratones , Anticuerpos Anti-VIH/inmunología , Anticuerpos Neutralizantes/inmunología , Vectores Genéticos/genética , Inmunoglobulina G/inmunología , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Infecciones por VIH/terapia , Femenino , Células HEK293RESUMEN
BACKGROUND: Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is a significant swine pathogen, yet the immune response components contributing to protection remain incompletely understood. Broadly reactive neutralizing antibodies (bNAs) may play a crucial role in preventing reinfections by heterologous viruses, although their occurrence is considered low under both field and experimental conditions. This study aimed to assess the frequency of sows exhibiting bNAs against PRRSV under field conditions and to analyze the epidemiological factors influencing the occurrence of these elite neutralizers. Blood samples were collected from breeding sows across eleven unrelated pig farms, with samples categorized by parity. Serum obtained was utilized in virus neutralization assays (VNs) against six PRRSV field isolates and two MLV strains. RESULTS: Approximately 7% of the sows exhibited neutralization activity against all viruses in the panel, with a geometric mean of the titer (GMT) of NAs at or exceeding 4 log2. Exclusion of the PRRSV-2 isolate from the panel increased the proportion of elite neutralizers to around 15%. Farm-specific analysis revealed significant variations in both GMT of NAs and proportion of elite neutralizers. PRRSV unstable farms and those with a PRRS outbreak in the last 12 months displayed higher GMT of NAs compared to stable farms without recent outbreaks. The GMT of NAs showed a gradual, albeit moderate, increase with the parity of the sows. Parity's impact on bNA response was consistently observed in stable farms but not necessarily in unstable farms or those with recent outbreaks. Finally, the results indicated that vaccinated animals had higher NA titers against the vaccine virus used in the farm than against field viruses. CONCLUSION: bNAs against heterologous isolates induced by PRRSV infection under field conditions are generally low, often falling below titers necessary for protection against reproductive failure. However, a subset of sows (approximately 15%) can be considered elite neutralizers, efficiently recognizing various PRRSV strains. Repeated exposures to PRRSV play a crucial role in eliciting these bNAs, with a higher frequency observed in unstable farms and those with recent outbreaks. In stable farms, parity only marginally influences bNA titers, highlighting its limited role compared to the impact of PRRSV exposure history.
RESUMEN
Viral infection generally induces polyclonal neutralizing antibody responses. However, how many lineages of antibody responses can fully represent the neutralization activities in sera has not been well studied. Using the newly designed stable HIV-1 Env trimer as hook, we isolated two distinct broadly neutralizing antibodies (bnAbs) from Chinese rhesus macaques infected with SHIV1157ipd3N4 for 5 years. One lineage of neutralizing antibodies (JT15 and JT16) targeted the V2-apex in the Env trimers, similar to the J038 lineage bnAbs identified in our previous study. The other lineage neutralizing antibody (JT18) targeted the V3 crown region in the Env, which strongly competed with human 447-52D. Each lineage antibody neutralized a different set of viruses. Interestingly, when the two neutralizing antibodies from different lineages isolated from the same macaque were combined, the mixture had a neutralization breath very similar to that from the cognate sera. Our study demonstrated that a minimum of two different neutralizing antibodies can fully recapitulate the serum neutralization breadth. This observation can have important implications in AIDS vaccine design.
Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos Anti-VIH , VIH-1 , Macaca mulatta , Síndrome de Inmunodeficiencia Adquirida del Simio , Macaca mulatta/inmunología , Animales , VIH-1/inmunología , Anticuerpos Anti-VIH/inmunología , Anticuerpos Anti-VIH/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Neutralizantes/sangre , Humanos , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/sangre , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Infecciones por VIH/sangre , Virus de la Inmunodeficiencia de los Simios/inmunología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología , Pruebas de NeutralizaciónRESUMEN
Development of a safe and effective human immunodeficiency virus (HIV) vaccine is a persistent challenge despite decades of research. Previous strategies utilizing protein subunit and viral vector vaccines were safe but not protective. Current strategies seek to induce broadly neutralizing antibodies, with multiple early phase trials in progress seeking to achieve this through sequential vaccination, mRNA, or updated viral-vectored vaccines. A safe and effective vaccine is critical to ending the HIV epidemic.
Asunto(s)
Vacunas contra el SIDA , Infecciones por VIH , Humanos , Vacunas contra el SIDA/inmunología , Vacunas contra el SIDA/administración & dosificación , Infecciones por VIH/prevención & control , Anticuerpos Neutralizantes/inmunología , VIH-1/inmunología , Anticuerpos Anti-VIH/inmunología , Desarrollo de VacunasRESUMEN
An important approach to stopping the AIDS epidemic is the development of a vaccine that elicits antibodies that block virus capture, the initial interactions of HIV-1 with the target cells, and replication. We utilized a previously developed qRT-PCR-based assay to examine the effects of broadly neutralizing antibodies (bNAbs), plasma from vaccine trials, and monoclonal antibodies (mAbs) on virus capture and replication. A panel of bNAbs inhibited primary HIV-1 replication in PBMCs but not virus capture. Plasma from RV144 and RV305 trial vaccinees demonstrated inhibition of virus capture with the HIV-1 subtype prevalent in Thailand. Several RV305 derived V2-specific mAbs inhibited virus replication. One of these RV305 derived V2-specific mAbs inhibited both virus capture and replication, demonstrating that it is possible to elicit antibodies by vaccination that inhibit virus capture and replication. Induction of a combination of such antibodies may be the key to protection from HIV-1 acquisition.
Asunto(s)
Anticuerpos Monoclonales , Anticuerpos Neutralizantes , Anticuerpos Anti-VIH , VIH-1 , Replicación Viral , VIH-1/inmunología , Humanos , Anticuerpos Anti-VIH/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Monoclonales/inmunología , Infecciones por VIH/virología , Infecciones por VIH/inmunología , Vacunas contra el SIDA/inmunología , Proteína gp120 de Envoltorio del VIH/inmunología , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/virología , Anticuerpos ampliamente neutralizantes/inmunologíaRESUMEN
An effective HIV-1 vaccine is still not available, and most vaccine efficacy trials conducted over the years resulted in no significant overall protection. Here we highlight several insights gained from these trials as well as emerging questions that may be important for further guidance to advance current research directions.
RESUMEN
Currently, SARS-CoV-2 has evolved into various variants, including the numerous highly mutated Omicron sub-lineages, significantly increasing immune evasion ability. The development raises concerns about the possibly diminished effectiveness of available vaccines and antibody-based therapeutics. Here, we describe those representative categories of broadly neutralizing antibodies (bnAbs) that retain prominent effectiveness against emerging variants including Omicron sub-lineages. The molecular characteristics, epitope conservation, and resistance mechanisms of these antibodies are further detailed, aiming to offer suggestion or direction for the development of therapeutic antibodies, and facilitate the design of vaccines with broad-spectrum potential.
Asunto(s)
Anticuerpos Antivirales , Anticuerpos ampliamente neutralizantes , COVID-19 , Epítopos , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , SARS-CoV-2/inmunología , Humanos , Anticuerpos Antivirales/inmunología , COVID-19/inmunología , COVID-19/virología , Anticuerpos ampliamente neutralizantes/inmunología , Epítopos/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Glicoproteína de la Espiga del Coronavirus/genética , Anticuerpos Neutralizantes/inmunología , Evasión Inmune , Vacunas contra la COVID-19/inmunologíaRESUMEN
BACKGROUND: Although antiretroviral therapy (ART) effectively halts disease progression in HIV infection, the complete eradication of the virus remains elusive. Additionally, challenges such as long-term ART toxicity, drug resistance, and the demanding regimen of daily and lifelong adherence required by ART highlight the imperative need for alternative therapeutic and preventative approaches. In recent years, broadly neutralizing antibodies (bNAbs) have emerged as promising candidates, offering potential for therapeutic, preventative, and possibly curative interventions against HIV infection. OBJECTIVE: This review aims to provide a comprehensive overview of the current state of knowledge regarding the passive immunization of bNAbs in HIV-1-infected individuals. MAIN FINDINGS: Recent findings from clinical trials have highlighted the potential of bNAbs in the treatment, prevention, and quest for an HIV-1 cure. While monotherapy with a single bNAb is insufficient in maintaining viral suppression and preventing viral escape, ultimately leading to viral rebound, combination therapy with potent, non-overlapping epitope-targeting bNAbs have demonstrated prolonged viral suppression and delayed time to rebound by effectively restricting the emergence of escape mutations, albeit largely in individuals with bNAb-sensitive strains. Additionally, passive immunization with bNAb has provided a "proof of concept" for antibody-mediated prevention against HIV-1 acquisition, although complete prevention has not been obtained. Therefore, further research on the use of bNAbs in HIV-1 treatment and prevention remains imperative.
Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos Anti-VIH , Infecciones por VIH , VIH-1 , Humanos , Infecciones por VIH/inmunología , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/prevención & control , Infecciones por VIH/virología , VIH-1/inmunología , Anticuerpos Anti-VIH/inmunología , Anticuerpos Anti-VIH/uso terapéutico , Anticuerpos Neutralizantes/inmunología , Anticuerpos Neutralizantes/uso terapéutico , Inmunización Pasiva/métodos , Anticuerpos ampliamente neutralizantes/inmunología , Anticuerpos ampliamente neutralizantes/uso terapéutico , Fármacos Anti-VIH/uso terapéutico , AnimalesRESUMEN
BACKGROUND: People living with HIV (PLWH) with multidrug-resistant (MDR) viruses have limited therapeutic options and present challenges regarding clinical management. Recent studies have shown that passive transfer of combination broadly neutralizing antibodies (bNAbs) against HIV and anti-domain 1 CD4 antibody UB-421 can sustain virologic suppression in PLWH in the absence of antiretroviral therapy (ART). Yet studies addressing the therapeutic potential of these antibodies and/or detailed characterization of immunologic and virologic parameters in PLWH with MDR HIV are lacking. METHODS: We examined levels of immune activation and exhaustion markers on CD8+ T cells and the intact HIV proviral DNA burden in 11 PLWH with MDR viruses. For comparison purposes, we included a control group consisting of 27 ART-naïve viremic PLWH. In addition, we determined the sensitivity of infectious viral isolates obtained from the participants against eight bNAbs (3BNC117, 10-1074, VRC01, VRC07, N6, 10E8, PGDM1400, and PGT121) and two anti-CD4 antibodies (ibalizumab and UB-421) using a TZM-bl-based neutralization/suppression assay. FINDINGS: The level of intact HIV proviral DNA was comparable between the two groups (P = 0.29). The levels of activation and exhaustion markers PD-1 (P = 0.0019), TIGIT (P = 0.0222), 2B4 (P = 0.0015), CD160 (P = 0.0015), and CD38+/HLA-DR+ (P = 0.0138) were significantly lower in the MDR group. The infectious viral isolates from each study participant with MDR HIV were resistant to at least 2 bNAbs; however, they were sensitive to at least one of the CD4-binding and non-CD4-binding site antibodies. The majority of participants had ibalizumab-sensitive viruses although the isolates from some participants showed reduced sensitivity to ibalizumab. Notably, none of the 93 viral isolates obtained from the participants were resistant to UB-421. INTERPRETATION: Our data suggest that combination therapy with HIV-specific bNAbs and/or UB-421 in the presence of optimized background therapy could potentially provide sustained virologic suppression in PLWH with MDR HIV. However, this therapeutic strategy needs to be evaluated in human clinical trials. FUNDING: Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health.
Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos ampliamente neutralizantes , Anticuerpos Anti-VIH , Infecciones por VIH , VIH-1 , Humanos , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Infecciones por VIH/tratamiento farmacológico , VIH-1/inmunología , Masculino , Femenino , Adulto , Anticuerpos Neutralizantes/inmunología , Persona de Mediana Edad , Anticuerpos ampliamente neutralizantes/inmunología , Anticuerpos Anti-VIH/inmunología , Antígenos CD4/metabolismo , Antígenos CD4/inmunología , Farmacorresistencia Viral Múltiple , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Carga Viral , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismoRESUMEN
SUMMARYThe human immunodeficiency virus (HIV) epidemic remains a formidable global health concern, with 39 million people living with the virus and 1.3 million new infections reported in 2022. Despite anti-retroviral therapy's effectiveness in pre-exposure prophylaxis, its global adoption is limited. Broadly neutralizing antibodies (bNAbs) offer an alternative strategy for HIV prevention through passive immunization. Historically, passive immunization has been efficacious in the treatment of various diseases ranging from oncology to infectious diseases. Early clinical trials suggest bNAbs are safe, tolerable, and capable of reducing HIV RNA levels. Although challenges such as bNAb resistance have been noted in phase I trials, ongoing research aims to assess the additive or synergistic benefits of combining multiple bNAbs. Researchers are exploring bispecific and trispecific antibodies, and fragment crystallizable region modifications to augment antibody efficacy and half-life. Moreover, the potential of other antibody isotypes like IgG3 and IgA is under investigation. While promising, the application of bNAbs faces economic and logistical barriers. High manufacturing costs, particularly in resource-limited settings, and logistical challenges like cold-chain requirements pose obstacles. Preliminary studies suggest cost-effectiveness, although this is contingent on various factors like efficacy and distribution. Technological advancements and strategic partnerships may mitigate some challenges, but issues like molecular aggregation remain. The World Health Organization has provided preferred product characteristics for bNAbs, focusing on optimizing their efficacy, safety, and accessibility. The integration of bNAbs in HIV prophylaxis necessitates a multi-faceted approach, considering economic, logistical, and scientific variables. This review comprehensively covers the historical context, current advancements, and future avenues of bNAbs in HIV prevention.
Asunto(s)
Anticuerpos Anti-VIH , Infecciones por VIH , Humanos , Infecciones por VIH/prevención & control , Infecciones por VIH/inmunología , Anticuerpos Anti-VIH/inmunología , Anticuerpos Anti-VIH/uso terapéutico , Anticuerpos Neutralizantes/inmunología , Anticuerpos Neutralizantes/uso terapéutico , Anticuerpos ampliamente neutralizantes/inmunología , Anticuerpos ampliamente neutralizantes/uso terapéutico , Inmunización Pasiva/métodos , VIH-1/inmunologíaRESUMEN
A major goal of HIV-1 vaccine development is the induction of broadly neutralizing antibodies (bnAbs). Although success has been achieved in initiating bnAb B cell lineages, design of boosting immunogens that select for bnAb B cell receptors with improbable mutations required for bnAb affinity maturation remains difficult. Here, we demonstrate a process for designing boosting immunogens for a V3-glycan bnAb B cell lineage. The immunogens induced affinity-matured antibodies by selecting for functional improbable mutations in bnAb precursor knockin mice. Moreover, we show similar success in prime and boosting with nucleoside-modified mRNA-encoded HIV-1 envelope trimer immunogens, with improved selection by mRNA immunogens of improbable mutations required for bnAb binding to key envelope glycans. These results demonstrate the ability of both protein and mRNA prime-boost immunogens for selection of rare B cell lineage intermediates with neutralizing breadth after bnAb precursor expansion, a key proof of concept and milestone toward development of an HIV-1 vaccine.
Asunto(s)
Vacunas contra el SIDA , Anticuerpos Neutralizantes , Linfocitos B , Anticuerpos Anti-VIH , VIH-1 , Vacunas contra el SIDA/inmunología , Vacunas contra el SIDA/genética , Animales , Anticuerpos Anti-VIH/inmunología , VIH-1/inmunología , VIH-1/genética , Ratones , Anticuerpos Neutralizantes/inmunología , Linfocitos B/inmunología , Humanos , Infecciones por VIH/inmunología , Infecciones por VIH/prevención & control , Anticuerpos ampliamente neutralizantes/inmunología , Mutación , Desarrollo de Vacunas , Inmunización Secundaria , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/genéticaRESUMEN
Snakebite envenomings kill ~100 000 victims each year and leave many more with permanent sequelae. Antivenoms have been available for more than 125 years but are in need of innovation. A new study by Khalek et al. highlights broadly neutralizing human monoclonal antibodies (mAbs) that might be used to develop recombinant antivenoms with superior therapeutic benefits.
Asunto(s)
Antivenenos , Mordeduras de Serpientes , Humanos , Animales , Antivenenos/uso terapéutico , Mordeduras de Serpientes/tratamiento farmacológico , Anticuerpos Monoclonales/uso terapéutico , SerpientesRESUMEN
The early appearance of broadly neutralizing antibodies (bNAbs) in serum is associated with spontaneous hepatitis C virus (HCV) clearance, but to date, the majority of bNAbs have been isolated from chronically infected donors. Most of these bNAbs use the VH1-69 gene segment and target the envelope glycoprotein E2 front layer. Here, we performed longitudinal B cell receptor (BCR) repertoire analysis on an elite neutralizer who spontaneously cleared multiple HCV infections. We isolated 10,680 E2-reactive B cells, performed BCR sequencing, characterized monoclonal B cell cultures, and isolated bNAbs. In contrast to what has been seen in chronically infected donors, the bNAbs used a variety of VH genes and targeted at least three distinct E2 antigenic sites, including sites previously thought to be non-neutralizing. Diverse front-layer-reactive bNAb lineages evolved convergently, acquiring breadth-enhancing somatic mutations. These findings demonstrate that HCV clearance-associated bNAbs are genetically diverse and bind distinct antigenic sites that should be the target of vaccine-induced bNAbs.
Asunto(s)
Hepacivirus , Hepatitis C , Humanos , Anticuerpos ampliamente neutralizantes , Epítopos , Anticuerpos Neutralizantes , Proteínas del Envoltorio Viral/genéticaRESUMEN
The envelope glycoprotein (Env) trimer on the surface of human immunodeficiency virus type I (HIV-1) mediates viral entry into host CD4+ T cells and is the sole target of neutralizing antibodies. Broadly neutralizing antibodies (bnAbs) that target gp120 V3-glycan of HIV-1 Env trimer are potent and block the entry of diverse HIV-1 strains. Most V3-glycan bnAbs interact, to a different extent, with a glycan attached to N332, but Asn at this position is not absolutely conserved or required for HIV-1 entry based on the prevalence of N332 in different circulating HIV-1 strains from diverse clades. Here, we studied the effects of amino acid changes at position 332 of HIV-1AD8 Envs on HIV-1 sensitivity to antibodies, cold exposure, and soluble CD4. We further investigated how these changes affect Env function and HIV-1 infectivity in vitro. Our results suggest robust tolerability of HIV-1AD8 Env N332 to changes, with specific changes that resulted in extended exposure of gp120 V3 loop, which is typically concealed in most primary HIV-1 isolates. Viral evolution leading to Asn at position 332 of HIVAD8 Envs is supported by the selection advantage of high levels of cell-cell fusion, transmission, and infectivity with high levels of cell surface expression and slightly higher gp120 shedding than most N332 variants. Thus, tolerance of HIV-1AD8 Envs to different amino acids at position 332 provides increased flexibility to respond to changing conditions/environments and evade the immune system. Modeling studies of the distance between N332 glycan and specific bnAbs were in agreement with N332 glycan dependency on bnAb neutralization. Overall, our studies provide insights into the contribution of specific amino acids at position 332 to Env antigenicity, stability on ice, and conformational states. IMPORTANCE: Glycan attached to amino acid asparagine at position 332 of HIV-1 envelope glycoproteins is a main target of a subset of broadly neutralizing antibodies that block HIV-1 infection. Here, we defined the contribution of different amino acids at this position to Env antigenicity, stability on ice, and conformational states.
Asunto(s)
Infecciones por VIH , Seropositividad para VIH , VIH-1 , Humanos , Aminoácidos , Anticuerpos Neutralizantes , Anticuerpos ampliamente neutralizantes , Productos del Gen env del Virus de la Inmunodeficiencia Humana , Glicoproteínas , Anticuerpos Anti-VIH , Proteína gp120 de Envoltorio del VIH/genética , Hielo , PolisacáridosRESUMEN
Broadly-neutralizing monoclonal antibodies are becoming increasingly important tools for treating infectious diseases and animal envenomings. However, designing and developing broadly-neutralizing antibodies can be cumbersome using traditional low-throughput iterative protein engineering methods. Here, we present a new high-throughput approach for the standardized discovery of broadly-neutralizing monoclonal antibodies relying on phage display technology and consensus antigens representing average sequences of related proteins. We showcase the utility of this approach by applying it to toxic sphingomyelinases from the venoms of species from very distant orders of the animal kingdom, the recluse spider and Gadim scorpion. First, we designed a consensus sphingomyelinase and performed three rounds of phage display selection, followed by DELFIA-based screening and ranking, and benchmarked this to a similar campaign involving cross-panning against recombinant versions of the native toxins. Second, we identified two scFvs that not only bind the consensus toxins, but which can also neutralize sphingomyelinase activity of native whole venom in vitro. Finally, we conclude that the phage display campaign involving the use of the consensus toxin was more successful in yielding cross-neutralizing scFvs than the phage display campaign involving cross-panning.
Asunto(s)
Esfingomielina Fosfodiesterasa , Venenos de Araña , Animales , Araña Reclusa Parda , Escorpiones , Anticuerpos ampliamente neutralizantes , Consenso , Anticuerpos MonoclonalesRESUMEN
BACKGROUND: Acceptability and preference research play a crucial role in the design, evaluation, and implementation of any new prevention product in any geographical setting. They also play a critical role in the development of clinical guidelines and policies. A wide range of acceptability studies have been conducted in diverse general and key populations for various new HIV prevention products worldwide. As clinical development strategies are being developed for clinical studies of broadly neutralizing antibodies (bNAbs) as potential HIV prevention products, appropriately tailoring them to address the type of HIV epidemic at hand would be critical for efficient uptake within in-country public health systems and decrease adoption and adherence challenges. Accomplishing this will require comprehensive acceptability and feasibility studies to inform multisectoral efforts that increase access to these products and national policies supportive of access to health care for those in most need. Thus, it is both opportune and important to undertake focused efforts toward informing product development strategies. OBJECTIVE: This study aims to understand preferences for product attributes and key behavioral factors influencing adoption and uptake of bNAb prevention products among end-users including female sex workers, men who have sex with men, transgender women, people who inject drugs, and adolescent girls and young women in India and understand the key health system and programmatic perspectives toward the introduction of bNAb prevention products from health service providers and policy makers in India. METHODS: A multisite study will be conducted in Delhi, Mumbai, and Chennai to capture the differences in perspectives among diverse end-users and key informants across the country. The study will use a multimethods design using focus group discussions, in-depth interviews, simulated behavioral experiments, and key informant interviews. A total of 30 focus group discussions, 45 in-depth interviews, 15 simulated behavioral experiments sessions, and 15 key informant interviews will be conducted across 3 sites. RESULTS: The data collected and analyzed will enable insights on which specific product attributes matter the most to the populations and why some attributes are less preferred; contextual drivers of preferences and choices at individual, interpersonal, social, and structural levels; and relative positioning of bNAb products among other potential HIV prevention products. Insights from the health service providers and policy makers will provide a critical understanding of the need perception of the potential product in the existing product landscape and what additional efforts and resources are required for potential introduction, delivery, and uptake of the bNAb products in the Indian context. CONCLUSIONS: Insights generated from the abovementioned objectives will represent perspectives of populations of interest across geographies in India, will provide an overview of the acceptability of bNAb products and the feasibility of their introduction in this region, and will inform product development strategies. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/47700.
RESUMEN
Antibodies targeting an envelope dimer epitope (EDE) cross-neutralize Zika virus (ZIKV) and dengue virus (DENV) and have thus inspired an epitope-focused vaccine design. There are two EDE antibody subclasses (EDE1, EDE2) distinguished by their dependence on viral envelope protein N-linked glycosylation at position N153 (DENV) or N154 (ZIKV) for binding. Here, we determined how envelope glycosylation site mutations affect neutralization by EDE and other broadly neutralizing antibodies. Consistent with structural studies, mutations abolishing the N153/N154 glycosylation site increased DENV and ZIKV sensitivity to neutralization by EDE1 antibodies. Surprisingly, despite their location at predicted contact sites, these mutations also increased sensitivity to EDE2 antibodies. Moreover, despite preserving the glycosylation site motif (N-X-S/T), substituting the threonine at ZIKV envelope residue 156 with a serine resulted in loss of glycan occupancy accompanied with increased neutralization sensitivity to EDE antibodies. For DENV, the presence of a serine instead of a threonine at envelope residue 155 retained glycan occupancy, but nonetheless increased sensitivity to EDE antibodies, in some cases to a similar extent as mutation at N153, which abolishes glycosylation. Envelope glycosylation site mutations also increased ZIKV and DENV sensitivity to other non-EDE broadly neutralizing antibodies, but had limited effects on ZIKV- or DENV-specific antibodies. Thus, envelope protein glycosylation is context-dependent and modulates the potency of broadly neutralizing antibodies in a manner not predicted by existing structures. Manipulating envelope protein glycosylation could be a novel strategy for engineering vaccine antigens to elicit antibodies that broadly neutralize ZIKV and DENV.IMPORTANCEAntibodies that potently cross-neutralize Zika (ZIKV) and dengue (DENV) viruses are attractive to induce via vaccination to protect against these co-circulating flaviviruses. Structural studies have shown that viral envelope protein glycosylation is important for binding by one class of these so-called broadly neutralizing antibodies, but less is known about its effect on neutralization. Here, we investigated how envelope protein glycosylation site mutations impact the potency of broadly neutralizing antibodies against ZIKV and DENV. We found that glycan occupancy was not always predicted by an intact N-X-S/T sequence motif. Moreover, envelope protein glycosylation site mutations alter the potency of broadly neutralizing antibodies in a manner unexpected from their predicted binding mechanism as determined by existing structures. We therefore highlight the complex role and determinants of envelope protein glycosylation that should be considered in the design of vaccine antigens to elicit broadly neutralizing antibodies.
Asunto(s)
Virus del Dengue , Dengue , Flavivirus , Vacunas , Infección por el Virus Zika , Virus Zika , Humanos , Anticuerpos ampliamente neutralizantes , Glicosilación , Anticuerpos Neutralizantes , Virus del Dengue/genética , Proteínas del Envoltorio Viral/química , Anticuerpos Antivirales , Epítopos/genética , Mutación , Polisacáridos , Serina/genética , Treonina/genéticaRESUMEN
The CD4-binding site (CD4bs) is a conserved epitope on HIV-1 envelope (Env) that can be targeted by protective broadly neutralizing antibodies (bnAbs). HIV-1 vaccines have not elicited CD4bs bnAbs for many reasons, including the occlusion of CD4bs by glycans, expansion of appropriate naive B cells with immunogens, and selection of functional antibody mutations. Here, we demonstrate that immunization of macaques with a CD4bs-targeting immunogen elicits neutralizing bnAb precursors with structural and genetic features of CD4-mimicking bnAbs. Structures of the CD4bs nAb bound to HIV-1 Env demonstrated binding angles and heavy-chain interactions characteristic of all known human CD4-mimicking bnAbs. Macaque nAb were derived from variable and joining gene segments orthologous to the genes of human VH1-46-class bnAb. This vaccine study initiated in primates the B cells from which CD4bs bnAbs can derive, accomplishing the key first step in the development of an effective HIV-1 vaccine.