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2.
Int J Mol Sci ; 23(19)2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36232695

RESUMO

Bone Marrow Stromal Cell Antigen 2 (BST2) is a type II transmembrane protein expressed on various cell types that tethers the release of viruses. Natural killer (NK) cells express low levels of BST2 under normal conditions but exhibit increased expression of BST2 upon activation. In this study, we show for the first time that murine BST2 can control the cytotoxicity of NK cells. The cytoplasmic tail of murine BST2 contains an immunoreceptor tyrosine-based inhibitory motif (ITIM). The absence of BST2 on NK cells can enhance their cytotoxicity against tumor cells compared to wild type NK cells. NK cells isolated from NZW mice, which express ITIM-deficient BST2, also showed higher cytotoxicity than wild type NK cells. In addition, we found that galectin-8 and galectin-9 were ligands of BST2, since blocking galectin-8 or -9 with monoclonal antibodies enhanced the cytotoxicity of NK cells. These results suggested that BST2 might be a novel NK cell inhibitory receptor as it was involved in regulating NK cell cytotoxicity through its interaction with galectins.


Assuntos
Antígeno 2 do Estroma da Médula Óssea , Citotoxicidade Imunológica , Células Matadoras Naturais , Animais , Anticorpos Monoclonais/imunologia , Antígenos CD/genética , Antígenos CD/imunologia , Antígeno 2 do Estroma da Médula Óssea/genética , Antígeno 2 do Estroma da Médula Óssea/imunologia , Proteínas de Transporte/imunologia , Citotoxicidade Imunológica/genética , Citotoxicidade Imunológica/imunologia , Galectinas/imunologia , Células Matadoras Naturais/imunologia , Ligantes , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Camundongos , Tirosina/metabolismo
3.
J Biol Chem ; 298(10): 102468, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36087840

RESUMO

The immune system produces a diverse collection of antiglycan antibodies that are critical for host defense. At present, however, we know very little about the binding properties, origins, and sequences of these antibodies because of a lack of access to a variety of defined individual antibodies. To address this challenge, we used a glycan microarray with over 800 different components to screen a panel of 516 human monoclonal antibodies that had been randomly cloned from different B-cell subsets originating from healthy human subjects. We obtained 26 antiglycan antibodies, most of which bound microbial carbohydrates. The majority of the antiglycan antibodies identified in the screen displayed selective binding for specific glycan motifs on our array and lacked polyreactivity. We found that antiglycan antibodies were about twice as likely than expected to originate from IgG+ memory B cells, whereas none were isolated from naïve, early emigrant, or immature B cells. Therefore, our results indicate that certain B-cell subsets in our panel are enriched in antiglycan antibodies, and IgG+ memory B cells may be a promising source of such antibodies. Furthermore, some of the newly identified antibodies bound glycans for which there are no reported monoclonal antibodies available, and these may be useful as research tools, diagnostics, or therapeutic agents. Overall, the results provide insight into the types and properties of antiglycan antibodies produced by the human immune system and a framework for the identification of novel antiglycan antibodies in the future.


Assuntos
Anticorpos Monoclonais , Polissacarídeos , Humanos , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/isolamento & purificação , Carboidratos , Imunoglobulina G/imunologia , Análise em Microsséries , Polissacarídeos/metabolismo , Células B de Memória/imunologia
5.
Monoclon Antib Immunodiagn Immunother ; 41(4): 173-180, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36027043

RESUMO

Monoclonal antibodies (mAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, are the important tools both for the diagnosis and therapeutics of this infectious disease. The high-performance antibody against spike protein of SARS-CoV-2 is expected to inhibit the binding of viruses to their receptors on the surface of their target cells. In this study, we propose the novel screening method for mAbs against the pathogenic infectious virus using exosome. By this method, the exosome that artificially expresses SARS-CoV-2 spike protein was purified and used as a virus-like vesicle, which could bind to the viral receptor, angiotensin-converting enzyme 2 (ACE2). As a result, seven mAbs that could bind to the spike protein were obtained and six of these clones could strongly inhibit the binding to ACE2 of both the protein corresponding to the receptor binding domain (RBD) and the exosome expressing the spike protein. Interestingly, some of these antibodies seemed to share their epitopes in RBD, suggesting that highly antigenic sites exist in the spike protein. In view of the neutralizing activities on infection, five clones of these antibodies could inhibit the internalization of vesicular stomatitis virus-based pseudo viruses expressing various types of spike proteins derived from SARS-CoV-2 variants. In addition, these antibodies inhibited the infection of SARS-CoV-2 to cultured mammalian cells. These antibodies are expected to be utilized for both diagnosis and therapeutics of COVID-19.


Assuntos
Anticorpos Monoclonais , COVID-19 , Exossomos , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2 , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes , Anticorpos Antivirais , Humanos , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/imunologia , Proteínas Virais
6.
PLoS One ; 17(7): e0269681, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35802580

RESUMO

Fungal agglutinin-like sequence (Als) cell-surface glycoproteins, best characterized in Candida albicans, mediate adhesive and aggregative interactions with host cells, other microbes, and abiotic surfaces. Monoclonal antibodies (MAbs) specific for each C. albicans Als protein are valuable reagents for gaining insight into Als protein localization and function. This manuscript describes development and validation of MAbs specific for C. albicans Als2, as well as for C. albicans Als9-1 and Als9-2, two protein variants produced from the ALS9 locus. Native C. albicans ALS9 expression levels were not sufficiently high to produce detectable Als9 protein on the wild-type cell surface so MAb validation required production of overexpression strains, each featuring one of the two ALS9 alleles. An anti-Als2 MAb was raised against an N-glycosylated form of the protein immunogen, as well as an Endoglycosidase H-treated immunogen. The MAb raised against the N-glycosylated immunogen proved superior and immunolabeled C. albicans yeast cells and germ tubes, and the surface of Candida dubliniensis and Candida tropicalis yeasts. Als2 was visible on C. albicans yeast cells recovered from a murine model of oral candidiasis, demonstrating Als2 production both in vivo and in vitro. These new MAbs add to the collection of anti-Als MAbs that are powerful tools to better understand the role of Als proteins in C. albicans biology and pathogenesis.


Assuntos
Anticorpos Monoclonais , Candida albicans , Proteínas Fúngicas , Aglutininas , Animais , Anticorpos Monoclonais/imunologia , Candidíase Bucal , Proteínas Fúngicas/imunologia , Camundongos
7.
Science ; 377(6607): 728-735, 2022 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-35857439

RESUMO

The potential for future coronavirus outbreaks highlights the need to broadly target this group of pathogens. We used an epitope-agnostic approach to identify six monoclonal antibodies that bind to spike proteins from all seven human-infecting coronaviruses. All six antibodies target the conserved fusion peptide region adjacent to the S2' cleavage site. COV44-62 and COV44-79 broadly neutralize alpha- and betacoronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants BA.2 and BA.4/5, albeit with lower potency than receptor binding domain-specific antibodies. In crystal structures of COV44-62 and COV44-79 antigen-binding fragments with the SARS-CoV-2 fusion peptide, the fusion peptide epitope adopts a helical structure and includes the arginine residue at the S2' cleavage site. COV44-79 limited disease caused by SARS-CoV-2 in a Syrian hamster model. These findings highlight the fusion peptide as a candidate epitope for next-generation coronavirus vaccine development.


Assuntos
Anticorpos Monoclonais , Anticorpos Antivirais , Anticorpos Amplamente Neutralizantes , COVID-19 , Epitopos , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/química , Vacinas contra COVID-19/imunologia , Epitopos/química , Epitopos/imunologia , Humanos , Peptídeos/imunologia , Conformação Proteica em alfa-Hélice , Domínios Proteicos , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia
8.
Science ; 377(6607): 735-742, 2022 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-35857703

RESUMO

The coronavirus spike glycoprotein attaches to host receptors and mediates viral fusion. Using a broad screening approach, we isolated seven monoclonal antibodies (mAbs) that bind to all human-infecting coronavirus spike proteins from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune donors. These mAbs recognize the fusion peptide and acquire affinity and breadth through somatic mutations. Despite targeting a conserved motif, only some mAbs show broad neutralizing activity in vitro against alpha- and betacoronaviruses, including animal coronaviruses WIV-1 and PDF-2180. Two selected mAbs also neutralize Omicron BA.1 and BA.2 authentic viruses and reduce viral burden and pathology in vivo. Structural and functional analyses showed that the fusion peptide-specific mAbs bound with different modalities to a cryptic epitope hidden in prefusion stabilized spike, which became exposed upon binding of angiotensin-converting enzyme 2 (ACE2) or ACE2-mimicking mAbs.


Assuntos
Enzima de Conversão de Angiotensina 2 , Anticorpos Monoclonais , Anticorpos Antivirais , Anticorpos Amplamente Neutralizantes , COVID-19 , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2/química , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/isolamento & purificação , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/imunologia , Humanos , Peptídeos/imunologia , Ligação Proteica , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia
9.
J Virol ; 96(15): e0055822, 2022 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-35867572

RESUMO

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, several variants of concern (VOCs) have arisen which are defined by multiple mutations in their spike proteins. These VOCs have shown variable escape from antibody responses and have been shown to trigger qualitatively different antibody responses during infection. By studying plasma from individuals infected with either the original D614G, Beta, or Delta variants, we showed that the Beta and Delta variants elicit antibody responses that are overall more cross-reactive than those triggered by D614G. Patterns of cross-reactivity varied, and the Beta and Delta variants did not elicit cross-reactive responses to each other. However, Beta-elicited plasma was highly cross-reactive against Delta Plus (Delta+), which differs from Delta by a single K417N mutation in the receptor binding domain, suggesting that the plasma response targets the N417 residue. To probe this further, we isolated monoclonal antibodies from a Beta-infected individual with plasma responses against Beta, Delta+, and Omicron, which all possess the N417 residue. We isolated an N417-dependent antibody, 084-7D, which showed similar neutralization breadth to the plasma. The 084-7D MAb utilized the IGHV3-23*01 germ line gene and had somatic hypermutations similar to those of previously described public antibodies which target the 417 residue. Thus, we have identified a novel antibody which targets a shared epitope found on three distinct VOCs, enabling their cross-neutralization. Understanding antibodies targeting escape mutations, such as K417N, which repeatedly emerge through convergent evolution in SARS-CoV-2 variants, may aid in the development of next-generation antibody therapeutics and vaccines. IMPORTANCE The evolution of SARS-CoV-2 has resulted in variants of concern (VOCs) with distinct spike mutations conferring various immune escape profiles. These variable mutations also influence the cross-reactivity of the antibody response mounted by individuals infected with each of these variants. This study sought to understand the antibody responses elicited by different SARS-CoV-2 variants and to define shared epitopes. We show that Beta and Delta infections resulted in antibody responses that were more cross-reactive than the original D614G variant, but they had differing patterns of cross-reactivity. We further isolated an antibody from Beta infection which targeted the N417 site, enabling cross-neutralization of Beta, Delta+, and Omicron, all of which possess this residue. The discovery of antibodies which target escape mutations common to multiple variants highlights conserved epitopes to target in future vaccines and therapeutics.


Assuntos
Anticorpos Antivirais , Reações Cruzadas , Epitopos , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/virologia , Reações Cruzadas/imunologia , Epitopos/química , Epitopos/genética , Epitopos/imunologia , Humanos , Evasão da Resposta Imune/imunologia , Testes de Neutralização , SARS-CoV-2/química , SARS-CoV-2/classificação , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia
10.
Clin Cancer Res ; 28(18): 3905-3907, 2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-35834593

RESUMO

Glucocorticoid-induced TNF receptor (TNFR)-related protein (GITR) agonistic antibodies are expected to increase the antitumor response mainly by reducing the effect of Foxp3+ T-regulatory cells. TRX-518 is a novel GITR agonist that has shown good pharmacodynamic activity by depleting regulatory T cells (Tregs) in preclinical models, with limited clinical activity demonstrated in patients with advanced solid tumors. See related article by Davar et al., p. 3990.


Assuntos
Neoplasias , Nivolumabe , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados , Linhagem Celular Tumoral , Desoxicitidina/análogos & derivados , Proteína Relacionada a TNFR Induzida por Glucocorticoide/imunologia , Humanos , Neoplasias/metabolismo , Linfócitos T Reguladores/imunologia
11.
J Immunol ; 209(1): 5-15, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35697384

RESUMO

Computationally optimized broadly reactive Ag (COBRA) hemagglutinin (HA) immunogens have previously been generated for several influenza subtypes to improve vaccine-elicited Ab breadth. As nearly all individuals have pre-existing immunity to influenza viruses, influenza-specific memory B cells will likely be recalled upon COBRA HA vaccination. We determined the epitope specificity and repertoire characteristics of pre-existing human B cells to H1 COBRA HA Ags. Cross-reactivity between wild-type HA and H1 COBRA HA proteins P1, X6, and Y2 were observed for isolated mAbs. The mAbs bound five distinct epitopes on the pandemic A/California/04/2009 HA head and stem domains, and most mAbs had hemagglutination inhibition and neutralizing activity against 2009 pandemic H1 strains. Two head-directed mAbs, CA09-26 and CA09-45, had hemagglutination inhibition and neutralizing activity against a prepandemic H1 strain. One mAb, P1-05, targeted the stem region of H1 HA, but did not compete with a known stem-targeting H1 mAb. We determined that mAb P1-05 recognizes a recently discovered HA epitope, the anchor epitope, and we identified similar mAbs using B cell repertoire sequencing. In addition, the trimerization domain distance from HA was critical to recognition of this epitope by mAb P1-05, suggesting the importance of protein design for vaccine formulations. Overall, these data indicate that seasonally vaccinated individuals possess a population of functional H1 COBRA HA-reactive B cells that target head, central stalk, and anchor epitopes, and they demonstrate the importance of structure-based assessment of subunit protein vaccine candidates to ensure accessibility of optimal protein epitopes.


Assuntos
Anticorpos Antivirais , Glicoproteínas de Hemaglutininação de Vírus da Influenza , Vacinas contra Influenza , Influenza Humana , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Epitopos , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle
12.
Proc Natl Acad Sci U S A ; 119(25): e2202059119, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35714289

RESUMO

The bacterial genus Bartonella comprises numerous emerging pathogens that cause a broad spectrum of disease manifestations in humans. The targets and mechanisms of the anti-Bartonella immune defense are ill-defined and bacterial immune evasion strategies remain elusive. We found that experimentally infected mice resolved Bartonella infection by mounting antibody responses that neutralized the bacteria, preventing their attachment to erythrocytes and suppressing bacteremia independent of complement or Fc receptors. Bartonella-neutralizing antibody responses were rapidly induced and depended on CD40 signaling but not on affinity maturation. We cloned neutralizing monoclonal antibodies (mAbs) and by mass spectrometry identified the bacterial autotransporter CFA (CAMP-like factor autotransporter) as a neutralizing antibody target. Vaccination against CFA suppressed Bartonella bacteremia, validating CFA as a protective antigen. We mapped Bartonella-neutralizing mAb binding to a domain in CFA that we found is hypervariable in both human and mouse pathogenic strains, indicating mutational antibody evasion at the Bartonella subspecies level. These insights into Bartonella immunity and immune evasion provide a conceptual framework for vaccine development, identifying important challenges in this endeavor.


Assuntos
Anticorpos Neutralizantes , Antígenos de Bactérias , Bacteriemia , Infecções por Bartonella , Bartonella , Sistemas de Secreção Tipo V , Animais , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/imunologia , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Bacteriemia/imunologia , Bacteriemia/microbiologia , Bacteriemia/prevenção & controle , Vacinas Bacterianas/genética , Vacinas Bacterianas/imunologia , Vacinas Bacterianas/uso terapêutico , Bartonella/genética , Bartonella/imunologia , Infecções por Bartonella/imunologia , Infecções por Bartonella/microbiologia , Infecções por Bartonella/prevenção & controle , Clonagem Molecular , Evasão da Resposta Imune , Camundongos , Sistemas de Secreção Tipo V/imunologia , Vacinação
13.
Proc Natl Acad Sci U S A ; 119(29): e2205784119, 2022 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35767670

RESUMO

Many neutralizing antibodies (nAbs) elicited to ancestral severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through natural infection and vaccination have reduced effectiveness to SARS-CoV-2 variants. Here, we show that therapeutic antibody ADG20 is able to neutralize SARS-CoV-2 variants of concern (VOCs) including Omicron (B.1.1.529) as well as other SARS-related coronaviruses. We delineate the structural basis of this relatively escape-resistant epitope that extends from one end of the receptor binding site (RBS) into the highly conserved CR3022 site. ADG20 can then benefit from high potency through direct competition with ACE2 in the more variable RBS and interaction with the more highly conserved CR3022 site. Importantly, antibodies that are able to target this site generally neutralize a broad range of VOCs, albeit with reduced potency against Omicron. Thus, this conserved and vulnerable site can be exploited for the design of universal vaccines and therapeutic antibodies.


Assuntos
Anticorpos Monoclonais , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19 , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/imunologia , COVID-19/virologia , Epitopos/imunologia , Humanos , Testes de Neutralização , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia
14.
Nature ; 606(7913): 375-381, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35650437

RESUMO

Antiretroviral therapy is highly effective in suppressing human immunodeficiency virus (HIV)1. However, eradication of the virus in individuals with HIV has not been possible to date2. Given that HIV suppression requires life-long antiretroviral therapy, predominantly on a daily basis, there is a need to develop clinically effective alternatives that use long-acting antiviral agents to inhibit viral replication3. Here we report the results of a two-component clinical trial involving the passive transfer of two HIV-specific broadly neutralizing monoclonal antibodies, 3BNC117 and 10-1074. The first component was a randomized, double-blind, placebo-controlled trial that enrolled participants who initiated antiretroviral therapy during the acute/early phase of HIV infection. The second component was an open-label single-arm trial that enrolled individuals with viraemic control who were naive to antiretroviral therapy. Up to 8 infusions of 3BNC117 and 10-1074, administered over a period of 24 weeks, were well tolerated without any serious adverse events related to the infusions. Compared with the placebo, the combination broadly neutralizing monoclonal antibodies maintained complete suppression of plasma viraemia (for up to 43 weeks) after analytical treatment interruption, provided that no antibody-resistant HIV was detected at the baseline in the study participants. Similarly, potent HIV suppression was seen in the antiretroviral-therapy-naive study participants with viraemia carrying sensitive virus at the baseline. Our data demonstrate that combination therapy with broadly neutralizing monoclonal antibodies can provide long-term virological suppression without antiretroviral therapy in individuals with HIV, and our experience offers guidance for future clinical trials involving next-generation antibodies with long half-lives.


Assuntos
Fármacos Anti-HIV , Anticorpos Neutralizantes , Anticorpos Anti-HIV , Infecções por HIV , HIV-1 , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/efeitos adversos , Fármacos Anti-HIV/imunologia , Fármacos Anti-HIV/uso terapêutico , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/efeitos adversos , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Amplamente Neutralizantes/administração & dosagem , Anticorpos Amplamente Neutralizantes/efeitos adversos , Anticorpos Amplamente Neutralizantes/imunologia , Anticorpos Amplamente Neutralizantes/uso terapêutico , Método Duplo-Cego , Anticorpos Anti-HIV/administração & dosagem , Anticorpos Anti-HIV/efeitos adversos , Anticorpos Anti-HIV/imunologia , Anticorpos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/imunologia , HIV-1/isolamento & purificação , Humanos , Carga Viral/efeitos dos fármacos , Viremia/tratamento farmacológico , Viremia/imunologia , Viremia/virologia
15.
Nature ; 608(7923): 593-602, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35714668

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineages BA.2.12.1, BA.4 and BA.5 exhibit higher transmissibility than the BA.2 lineage1. The receptor binding and immune-evasion capability of these recently emerged variants require immediate investigation. Here, coupled with structural comparisons of the spike proteins, we show that BA.2.12.1, BA.4 and BA.5 (BA.4 and BA.5 are hereafter referred collectively to as BA.4/BA.5) exhibit similar binding affinities to BA.2 for the angiotensin-converting enzyme 2 (ACE2) receptor. Of note, BA.2.12.1 and BA.4/BA.5 display increased evasion of neutralizing antibodies compared with BA.2 against plasma from triple-vaccinated individuals or from individuals who developed a BA.1 infection after vaccination. To delineate the underlying antibody-evasion mechanism, we determined the escape mutation profiles2, epitope distribution3 and Omicron-neutralization efficiency of 1,640 neutralizing antibodies directed against the receptor-binding domain of the viral spike protein, including 614 antibodies isolated from people who had recovered from BA.1 infection. BA.1 infection after vaccination predominantly recalls humoral immune memory directed against ancestral (hereafter referred to as wild-type (WT)) SARS-CoV-2 spike protein. The resulting elicited antibodies could neutralize both WT SARS-CoV-2 and BA.1 and are enriched on epitopes on spike that do not bind ACE2. However, most of these cross-reactive neutralizing antibodies are evaded by spike mutants L452Q, L452R and F486V. BA.1 infection can also induce new clones of BA.1-specific antibodies that potently neutralize BA.1. Nevertheless, these neutralizing antibodies are largely evaded by BA.2 and BA.4/BA.5 owing to D405N and F486V mutations, and react weakly to pre-Omicron variants, exhibiting narrow neutralization breadths. The therapeutic neutralizing antibodies bebtelovimab4 and cilgavimab5 can effectively neutralize BA.2.12.1 and BA.4/BA.5, whereas the S371F, D405N and R408S mutations undermine most broadly sarbecovirus-neutralizing antibodies. Together, our results indicate that Omicron may evolve mutations to evade the humoral immunity elicited by BA.1 infection, suggesting that BA.1-derived vaccine boosters may not achieve broad-spectrum protection against new Omicron variants.


Assuntos
Anticorpos Antivirais , Deriva e Deslocamento Antigênicos , COVID-19 , Epitopos de Linfócito B , Tolerância Imunológica , Mutação , SARS-CoV-2 , Enzima de Conversão de Angiotensina 2/metabolismo , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Deriva e Deslocamento Antigênicos/genética , Deriva e Deslocamento Antigênicos/imunologia , COVID-19/imunologia , COVID-19/transmissão , COVID-19/virologia , Vacinas contra COVID-19/imunologia , Epitopos de Linfócito B/química , Epitopos de Linfócito B/genética , Epitopos de Linfócito B/imunologia , Humanos , Imunidade Humoral , Imunização Secundária , Testes de Neutralização , SARS-CoV-2/classificação , SARS-CoV-2/genética , SARS-CoV-2/imunologia , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo
16.
Proc Natl Acad Sci U S A ; 119(22): e2122769119, 2022 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-35617431

RESUMO

Hendra virus (HeV) and Nipah virus (NiV) are deadly zoonotic Henipaviruses (HNVs) responsible for recurrent outbreaks in humans and domestic species of highly fatal (50 to 95%) disease. A HeV variant (HeV-g2) of unprecedented genetic divergence has been identified in two fatally diseased horses, and in two flying fox species in regions of Australia not previously considered at risk for HeV spillover. Given the HeV-g2 divergence from HeV while retaining equivalent pathogenicity and spillover potential, understanding receptor usage and antigenic properties is urgently required to guide One Health biosecurity. Here, we show that the HeV-g2 G glycoprotein shares a conserved receptor tropism with prototypic HeV and that a panel of monoclonal antibodies recognizing the G and F glycoproteins potently neutralizes HeV-g2­ and HeV G/F­mediated entry into cells. We determined a crystal structure of the Fab fragment of the hAH1.3 antibody bound to the HeV G head domain, revealing an antigenic site associated with potent cross-neutralization of both HeV-g2 and HeV. Structure-guided formulation of a tetravalent monoclonal antibody (mAb) mixture, targeting four distinct G head antigenic sites, results in potent neutralization of HeV and HeV-g2 and delineates a path forward for implementing multivalent mAb combinations for postexposure treatment of HNV infections.


Assuntos
Anticorpos Monoclonais , Anticorpos Neutralizantes , Anticorpos Antivirais , Vírus Hendra , Fragmentos Fab das Imunoglobulinas , Proteínas do Envelope Viral , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Cristalografia por Raios X , Epitopos/química , Epitopos/genética , Vírus Hendra/genética , Vírus Hendra/imunologia , Humanos , Fragmentos Fab das Imunoglobulinas/química , Testes de Neutralização , Profilaxia Pós-Exposição , Domínios Proteicos , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia
17.
Cancer Lett ; 541: 215750, 2022 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-35609735

RESUMO

Immune checkpoint blockade (ICB) therapy is an important treatment option for individuals with cancer, but it has certain limitations. Identifying a better target that can overcome tumor immune escape and stimulate T cell activity is critical. This research aimed to delve into the molecular mechanism underlying the immunoregulatory function of metadherin (MTDH), which is a novel and potential therapeutic target in hepatocellular cancer (HCC). A small interfering RNA library was screened using the luciferase reporter assay and PD-L1 promoter. The Cancer Genome Atlas database and HCC tissues were used to investigate the relationship between MTDH and PD-L1. The association between MTDH and ß-catenin/lymphoid enhancer binding factor (LEF-1) was discovered by co-immunoprecipitation. The chromatin immunoprecipitation assay was used to investigate the interaction of MTDH with the PD-L1 promoter when LEF-1 expression was silenced. Locked nucleic acid antisense oligonucleotides (ASOs) were used to inhibit MTDH. We utilized in vitro co-cultures and in vivo syngeneic tumor development experiments to confirm the effectiveness of MTDH ASO combined with PD-1 monoclonal antibody (mAb). MTDH was demonstrated to be a PD-L1 modulator. MTDH increased PD-L1 expression and upregulated PD-L1 transcriptional activity through ß-catenin/LEF-1 signaling. More importantly, MTDH ASO improved the anti-PD-1 response and increased cytotoxic T-cell infiltration in PD-1 mAb-treated malignancies. MTDH effectively predicts the therapeutic efficacy of ICB therapy. Our results imply that combining MTDH ASO with PD-1 mAb could be a promising therapeutic strategy for HCC. In addition, MTDH is a potential novel biomarker for predicting the effectiveness of immune checkpoint inhibitor treatment.


Assuntos
Anticorpos Monoclonais , Antígeno B7-H1 , Carcinoma Hepatocelular , Inibidores de Checkpoint Imunológico , Neoplasias Hepáticas , Proteínas de Membrana , Oligonucleotídeos Antissenso , Proteínas de Ligação a RNA , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/genética , Antígeno B7-H1/imunologia , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/imunologia , Linhagem Celular Tumoral , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/imunologia , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Oligonucleotídeos Antissenso/imunologia , Receptor de Morte Celular Programada 1/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/imunologia , Microambiente Tumoral , beta Catenina/genética , beta Catenina/imunologia
18.
Neuromuscul Disord ; 32(8): 678-681, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35618575

RESUMO

We report the case of a patient with a very severe predominantly demyelinating sensorimotor polyneuropathy (with axonal loss) that had developed over several months, along with an immunoglobulin-M monoclonal gammopathy without anti-myelin associated glycoprotein antibodies (or other antibodies against myelin). Widening of myelin lamellae were frequently observed by electron microscopic examination of a nerve biopsy: immunoglobulin-M targeting an unknown myelin antigen appears to be responsible for the nerve lesions similar to those observed in anti-myelin associated glycoprotein polyneuropathy. Usually, if in anti-myelin associated glycoprotein neuropathy the response to immunotherapies is not optimal, in this case the combination of plasma exchanges and rituximab was effective, suggesting an autoimmune origin.


Assuntos
Anticorpos Monoclonais/imunologia , Paraproteinemias , Polineuropatias , Humanos , Imunoglobulina M , Gamopatia Monoclonal de Significância Indeterminada , Bainha de Mielina/patologia , Glicoproteína Associada a Mielina , Paraproteinemias/complicações , Paraproteinemias/patologia , Polineuropatias/tratamento farmacológico , Polineuropatias/patologia
19.
Mol Cell Biochem ; 477(8): 2015-2024, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35397683

RESUMO

Daratumumab (DAR) is novel human anti-CD38 IgG1, high-affinity human monoclonal antibody having broad-spectrum killing activity. The antibody is recommended to treat multiple myeloma. Recently Antibody-dependent cellular phagocytosis (ADCP) have been identified as the potential mechanism of DAR in addition to complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC). In the present study we evaluated the effect of Daratumumab on other effector cells of multiple myeloma. Luciferase+ MM.1R GFP cells were selected for the study. For immune-compromised multiple myeloma tumour xenograft mouse model we used severe combined immunodeficient beige (SCID-beige), NOD SCID gamma (NSG) and C57Bl/6j mice. Bioluminescence imaging was carried by injecting luciferin, and in vivo confocal microscopy was done for tracing bone marrow niches. Spleen and tumours were submitted to immunophenotypic analysis. MTT assay was done for cell proliferation studies. We established tumour xenograft mouse model. It was found that DAR showed significant anti-tumour effect in tumour xenograft multiple myeloma mice. We found that DAR showed anti-tumour activity via Fc-FcγR interaction with macrophages. DAR induced phenotypic activation of macrophages in mice and resulted in ADCP of cancerous cells via interacting Fc-FcγR in vitro. The study suggested that DAR exerted anti-tumour activity in multiple myeloma by interacting with Fc-FcγR.


Assuntos
Anticorpos Monoclonais , Macrófagos , Mieloma Múltiplo , Receptores de IgG , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Humanos , Macrófagos/imunologia , Macrófagos/patologia , Camundongos , Camundongos SCID , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/patologia , Receptores de IgG/imunologia
20.
Proc Natl Acad Sci U S A ; 119(15): e2123111119, 2022 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-35380898

RESUMO

In vivo fluorescence/luminescence imaging in the near-infrared-IIb (NIR-IIb, 1,500 to 1,700 nm) window under <1,000 nm excitation can afford subcentimeter imaging depth without any tissue autofluorescence, promising high-precision intraoperative navigation in the clinic. Here, we developed a compact imager for concurrent visible photographic and NIR-II (1,000 to 3,000 nm) fluorescence imaging for preclinical image-guided surgery. Biocompatible erbium-based rare-earth nanoparticles (ErNPs) with bright down-conversion luminescence in the NIR-IIb window were conjugated to TRC105 antibody for molecular imaging of CD105 angiogenesis markers in 4T1 murine breast tumors. Under a ∼940 ± 38 nm light-emitting diode (LED) excitation, NIR-IIb imaging of 1,500- to 1,700-nm emission afforded noninvasive tumor­to­normal tissue (T/NT) signal ratios of ∼40 before surgery and an ultrahigh intraoperative tumor-to-muscle (T/M) ratio of ∼300, resolving tumor margin unambiguously without interfering background signal from surrounding healthy tissues. High-resolution imaging resolved small numbers of residual cancer cells during surgery, allowing thorough and nonexcessive tumor removal at the few-cell level. NIR-IIb molecular imaging afforded 10-times-higher and 100-times-higher T/NT and T/M ratios, respectively, than imaging with IRDye800CW-TRC105 in the ∼900- to 1,300-nm range. The vastly improved resolution of tumor margin and diminished background open a paradigm of molecular imaging-guided surgery.


Assuntos
Érbio , Neoplasias Mamárias Experimentais , Nanopartículas Metálicas , Imagem Óptica , Espectroscopia de Luz Próxima ao Infravermelho , Cirurgia Assistida por Computador , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Fluorescência , Corantes Fluorescentes/química , Neoplasias Mamárias Experimentais/diagnóstico por imagem , Neoplasias Mamárias Experimentais/cirurgia , Camundongos , Neoplasia Residual/diagnóstico por imagem , Imagem Óptica/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Cirurgia Assistida por Computador/métodos
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