RESUMO
Passive transfer of broadly neutralizing anti-HIV-1 antibodies (bNAbs) protects against infection, and therefore, eliciting bNAbs by vaccination is a major goal of HIV-1 vaccine efforts. bNAbs that target the CD4 binding site (CD4bs) on HIV-1 Env are among the most broadly active, but to date, responses elicited against this epitope in vaccinated animals have lacked potency and breadth. We hypothesized that CD4bs bNAbs resembling the antibody IOMA might be easier to elicit than other CD4bs antibodies that exhibit higher somatic mutation rates, a difficult-to-achieve mechanism to accommodate Env's N276gp120 N-glycan, and rare five-residue light chain complementarity-determining region 3. As an initial test of this idea, we developed IOMA germline-targeting Env immunogens and evaluated a sequential immunization regimen in transgenic mice expressing germline-reverted IOMA. These mice developed CD4bs epitope-specific responses with heterologous neutralization, and cloned antibodies overcame neutralization roadblocks, including accommodating the N276gp120 glycan, with some neutralizing selected HIV-1 strains more potently than IOMA. The immunization regimen also elicited CD4bs-specific responses in mice containing polyclonal antibody repertoires as well as rabbits and rhesus macaques. Thus, germline targeting of IOMA-class antibody precursors represents a potential vaccine strategy to induce CD4bs bNAbs.
Assuntos
Animais Selvagens , HIV-1 , Animais , Coelhos , Camundongos , Animais Selvagens/metabolismo , Anticorpos Amplamente Neutralizantes , Macaca mulatta , Anticorpos Neutralizantes , Anticorpos Anti-HIV , Sítios de Ligação , Antígenos CD4/metabolismo , Animais Geneticamente Modificados , Epitopos , Moléculas de Adesão Celular , PolissacarídeosRESUMO
Opioid-related fatal overdoses have reached epidemic proportions. Because existing treatments for opioid use disorders offer limited long-term protection, accelerating the development of newer approaches is critical. Monoclonal antibodies (mAbs) are an emerging treatment strategy that targets and sequesters selected opioids in the bloodstream, reducing drug distribution across the blood-brain barrier, thus preventing or reversing opioid toxicity. We previously identified a series of murine mAbs with high affinity and selectivity for oxycodone, morphine, fentanyl, and nicotine. To determine their binding mechanism, we used X-ray crystallography to solve the structures of mAbs bound to their respective targets, to 2.2 Å resolution or higher. Structural analysis showed a critical convergent hydrogen bonding mode that is dependent on a glutamic acid residue in the mAbs' heavy chain and a tertiary amine of the ligand. Characterizing drug-mAb complexes represents a significant step toward rational antibody engineering and future manufacturing activities to support clinical evaluation.
Assuntos
Analgésicos Opioides , Nicotina , Camundongos , Animais , Analgésicos Opioides/uso terapêutico , Anticorpos Monoclonais/química , Oxicodona/uso terapêutico , Morfina/uso terapêuticoRESUMO
Epstein-Barr virus (EBV) is a cancer-associated pathogen responsible for 165,000 deaths annually. EBV is also the etiological agent of infectious mononucleosis and is linked to multiple sclerosis and rheumatoid arthritis. Thus, an EBV vaccine would have a significant global health impact. EBV is orally transmitted and has tropism for epithelial and B cells. Therefore, a vaccine would need to prevent infection of both in the oral cavity. Passive transfer of monoclonal antibodies against the gH/gL glycoprotein complex prevent experimental EBV infection in humanized mice and rhesus macaques, suggesting that gH/gL is an attractive vaccine candidate. Here, we evaluate the immunogenicity of several gH/gL nanoparticle vaccines. All display superior immunogenicity relative to monomeric gH/gL. A nanoparticle displaying 60 copies of gH/gL elicits antibodies that protect against lethal EBV challenge in humanized mice, whereas antibodies elicited by monomeric gH/gL do not. These data motivate further development of gH/gL nanoparticle vaccines for EBV.
Assuntos
Infecções por Vírus Epstein-Barr , Nanopartículas , Vacinas , Animais , Herpesvirus Humano 4 , Imunização , Macaca mulatta , CamundongosRESUMO
An effective HIV-1 vaccine will likely need to elicit broadly neutralizing antibodies (bNAbs). Broad and potent VRC01-class bNAbs have been isolated from multiple infected individuals, suggesting that they could be reproducibly elicited by vaccination. Several HIV-1 envelope-derived germline-targeting immunogens have been designed to engage naive VRC01-class precursor B cells. However, they also present off-target epitopes that could hinder development of VRC01-class bNAbs. We characterize a panel of anti-idiotypic monoclonal antibodies (ai-mAbs) raised against inferred-germline (iGL) VRC01-class antibodies. By leveraging binding, structural, and B cell sorting data, we engineered a bispecific molecule derived from two ai-mAbs; one specific for VRC01-class heavy chains and one specific for VRC01-class light chains. The bispecific molecule preferentially activates iGL-VRC01 B cells in vitro and induces specific antibody responses in a murine adoptive transfer model with a diverse polyclonal B cell repertoire. This molecule represents an alternative non-envelope-derived germline-targeting immunogen that can selectively activate VRC01-class precursors in vivo.
Assuntos
Vacinas contra a AIDS/imunologia , Células Germinativas/metabolismo , Anticorpos Anti-HIV/imunologia , HIV-1/imunologia , Animais , Humanos , CamundongosRESUMO
BACKGROUND: Epstein-Barr virus (EBV) infection is a major cause of malignancy worldwide. Maternal antibody is thought to prevent EBV infection because it is uncommon in early infancy. Maternal HIV infection is associated with an increased incidence of EBV infection in exposed infants, which we hypothesized results from impaired transfer of EBV-neutralizing maternal antibodies. METHODS: Among Ugandan infants followed for EBV acquisition from birth, we measured antibody binding to EBV glycoproteins (gp350, gH/gL) involved in B-cell and epithelial-cell entry, as well as viral neutralization and antibody-dependent cellular cytotoxicity (ADCC) activity in plasma samples prior to infection. These serologic data were analyzed for differences between HIV-exposed uninfected (HEU) and HIV-unexposed (HUU) infants, and for associations with incident infant EBV infection. RESULTS: HEU infants had significantly higher titers than HUU infants for all EBV-binding and neutralizing antibodies measured (P < .01) but not ADCC activity, which was similar between groups. No antibody measure was associated with a decreased risk of EBV acquisition in the cohort. CONCLUSIONS: Our findings indicate that in this cohort maternal antibody did not protect infants against EBV infection through viral neutralization. The identification of protective nonneutralizing antibody functions would be invaluable for the development of an EBV vaccine.
Assuntos
Anticorpos Antivirais/imunologia , Infecções por Vírus Epstein-Barr , Infecções por HIV , Imunidade Materno-Adquirida , Infecções por Vírus Epstein-Barr/epidemiologia , Feminino , Infecções por HIV/complicações , Herpesvirus Humano 4 , Humanos , Lactente , Uganda/epidemiologiaRESUMO
The isolation of human monoclonal antibodies (mAbs) arising from natural infection with human pathogens has proven to be a powerful technology, facilitating the understanding of the host response to infection at a molecular level. mAbs can reveal sites of vulnerability on pathogens and illuminate the biological function of the antigenic targets. Moreover, mAbs have the potential to be used directly for therapeutic applications such as passive delivery to prevent infection in susceptible target populations, and as treatment of established infection. The isolation of antigen-specific B cells from vaccine trials can also assist in deciphering whether the desired B cells are being targeted by a given vaccine. Several different processes have been developed to isolate mAbs, but all are generally labor-intensive and result in varying degrees of efficiency. Here, we describe the development of a cost-effective feeder cell line that stably expresses CD40-ligand, interleukin-2 and interleukin-21. Sorting of single B cells onto a layer of irradiated feeder cells sustained antibody production that permits functional screening of secreted antibodies in a manner that enables subsequent recovery of B cells for recombinant antibody cloning. As a proof of concept, we show that this approach can be used to isolate B cells that secrete antibodies that neutralize human papilloma virus (HPV) from participants of an HPV vaccine study.
Assuntos
Anticorpos Monoclonais/metabolismo , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Linfócitos B/metabolismo , Separação Celular , Ensaios de Triagem em Larga Escala , Imunoglobulina G/metabolismo , Vacinas contra Papillomavirus/administração & dosagem , Células 3T3 , Adolescente , Adulto , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Diferenciação Celular , Proliferação de Células , Técnicas de Cocultura , Ensaio de Imunoadsorção Enzimática , Células Alimentadoras , Feminino , Humanos , Imunogenicidade da Vacina , Imunoglobulina G/imunologia , Camundongos , Vacinas contra Papillomavirus/imunologia , Estudo de Prova de Conceito , Fatores de Tempo , Vacinação , Adulto JovemRESUMO
The emergence of SARS-CoV-2 has resulted in >90,000 infections and >3,000 deaths. Coronavirus spike (S) glycoproteins promote entry into cells and are the main target of antibodies. We show that SARS-CoV-2 S uses ACE2 to enter cells and that the receptor-binding domains of SARS-CoV-2 S and SARS-CoV S bind with similar affinities to human ACE2, correlating with the efficient spread of SARS-CoV-2 among humans. We found that the SARS-CoV-2 S glycoprotein harbors a furin cleavage site at the boundary between the S1/S2 subunits, which is processed during biogenesis and sets this virus apart from SARS-CoV and SARS-related CoVs. We determined cryo-EM structures of the SARS-CoV-2 S ectodomain trimer, providing a blueprint for the design of vaccines and inhibitors of viral entry. Finally, we demonstrate that SARS-CoV S murine polyclonal antibodies potently inhibited SARS-CoV-2 S mediated entry into cells, indicating that cross-neutralizing antibodies targeting conserved S epitopes can be elicited upon vaccination.
Assuntos
Betacoronavirus/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/ultraestrutura , Sequência de Aminoácidos , Enzima de Conversão de Angiotensina 2 , Anticorpos Neutralizantes/metabolismo , Anticorpos Neutralizantes/farmacologia , Antígenos Virais/química , Antígenos Virais/imunologia , Antígenos Virais/metabolismo , Betacoronavirus/química , Linhagem Celular , Microscopia Crioeletrônica , Humanos , Modelos Moleculares , Peptidil Dipeptidase A/metabolismo , Receptores Virais/química , Receptores Virais/metabolismo , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/metabolismo , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Internalização do Vírus/efeitos dos fármacosRESUMO
Many tested vaccines fail to provide protection against disease despite the induction of antibodies that bind the pathogen of interest. In light of this, there is much interest in rationally designed subunit vaccines that direct the antibody response to protective epitopes. Here, we produced a panel of anti-idiotype antibodies able to specifically recognize the inferred germline version of the human immunodeficiency virus 1 (HIV-1) broadly neutralizing antibody b12 (iglb12). We determined the crystal structure of two anti-idiotypes in complex with iglb12 and used these anti-idiotypes to identify rare naive human B cells expressing B cell receptors with similarity to iglb12. Immunization with a multimerized version of this anti-idiotype induced the proliferation of transgenic murine B cells expressing the iglb12 heavy chain in vivo, despite the presence of deletion and anergy within this population. Together, our data indicate that anti-idiotypes are a valuable tool for the study and induction of potentially protective antibodies.
Assuntos
Anticorpos Anti-Idiotípicos/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Células Precursoras de Linfócitos B/imunologia , Adulto , Animais , Feminino , Infecções por HIV/genética , HIV-1/genética , Humanos , Masculino , Camundongos , Camundongos TransgênicosRESUMO
Human anti-HIV-1 broadly neutralizing antibodies (bNAbs) protect against infection in animal models. However, bNAbs have not been elicited by vaccination in diverse wild-type animals or humans, in part because B cells expressing the precursors of these antibodies do not recognize most HIV-1 envelopes (Envs). Immunogens have been designed that activate these B cell precursors in vivo, but they also activate competing off-target responses. Here we report on a complementary approach to expand specific B cells using an anti-idiotypic antibody, iv8, that selects for naive human B cells expressing immunoglobulin light chains with 5-amino acid complementarity determining region 3s, a key feature of anti-CD4 binding site (CD4bs)-specific VRC01-class antibodies. In mice, iv8 induced target cells to expand and mature in the context of a polyclonal immune system and produced serologic responses targeting the CD4bs on Env. In summary, the results demonstrate that an anti-idiotypic antibody can specifically recognize and expand rare B cells that express VRC01-class antibodies against HIV-1.
Assuntos
Anticorpos Anti-Idiotípicos/imunologia , Anticorpos Neutralizantes/imunologia , Linfócitos B/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp160 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Animais , Proteína gp160 do Envelope de HIV/genética , Infecções por HIV/genética , Humanos , Camundongos , Camundongos TransgênicosRESUMO
GABAergic interneurons are essential for neural circuit function, and their loss or dysfunction is implicated in human neuropsychiatric disease. In vitro methods for interneuron generation hold promise for studying human cellular and functional properties and, ultimately, for therapeutic cell replacement. Here we describe a protocol for generating cortical interneurons from hESCs and analyze the properties and maturation time course of cell types using single-cell RNA-seq. We find that the cell types produced mimic in vivo temporal patterns of neuron and glial production, with immature progenitors and neurons observed early and mature cortical neurons and glial cell types produced late. By comparing the transcriptomes of immature interneurons to those of more mature neurons, we identified genes important for human interneuron differentiation. Many of these genes were previously implicated in neurodevelopmental and neuropsychiatric disorders.
Assuntos
Diferenciação Celular/fisiologia , Movimento Celular/fisiologia , Neurônios GABAérgicos/citologia , Interneurônios/citologia , Proteínas do Tecido Nervoso/metabolismo , Neuroglia/citologia , Células Cultivadas , Humanos , Neurogênese/fisiologia , Análise de Célula Única , Fatores de Transcrição/metabolismoRESUMO
The structures of three aspartate aminotransferases (AATs) from eukaryotic pathogens were solved within the Seattle Structural Genomics Center for Infectious Disease (SSGCID). Both the open and closed conformations of AAT were observed. Pyridoxal phosphate was bound to the active site via a Schiff base to a conserved lysine. An active-site mutant showed that Trypanosoma brucei AAT still binds pyridoxal phosphate even in the absence of the tethering lysine. The structures highlight the challenges for the structure-based design of inhibitors targeting the active site, while showing options for inhibitor design targeting the N-terminal arm.