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1.
Science ; 371(6531): 850-854, 2021 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-33495308

RESUMO

Antibodies are a potential therapy for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the risk of the virus evolving to escape them remains unclear. Here we map how all mutations to the receptor binding domain (RBD) of SARS-CoV-2 affect binding by the antibodies in the REGN-COV2 cocktail and the antibody LY-CoV016. These complete maps uncover a single amino acid mutation that fully escapes the REGN-COV2 cocktail, which consists of two antibodies, REGN10933 and REGN10987, targeting distinct structural epitopes. The maps also identify viral mutations that are selected in a persistently infected patient treated with REGN-COV2 and during in vitro viral escape selections. Finally, the maps reveal that mutations escaping the individual antibodies are already present in circulating SARS-CoV-2 strains. These complete escape maps enable interpretation of the consequences of mutations observed during viral surveillance.


Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Antivirais/imunologia , Mutação , /imunologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Substituição de Aminoácidos , Anticorpos Monoclonais Humanizados/metabolismo , Anticorpos Monoclonais Humanizados/uso terapêutico , Anticorpos Antivirais/metabolismo , Anticorpos Antivirais/uso terapêutico , Células Cultivadas , Combinação de Medicamentos , Humanos , Imunização Passiva , Ligação Proteica , Domínios Proteicos , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo
2.
Science ; 371(6526): 300-305, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33446559

RESUMO

Signaling through the CD19-CD81 co-receptor complex, in combination with the B cell receptor, is a critical determinant of B cell development and activation. It is unknown how CD81 engages CD19 to enable co-receptor function. Here, we report a 3.8-angstrom structure of the CD19-CD81 complex bound to a therapeutic antigen-binding fragment, determined by cryo-electron microscopy (cryo-EM). The structure includes both the extracellular domains and the transmembrane helices of the complex, revealing a contact interface between the ectodomains that drives complex formation. Upon binding to CD19, CD81 opens its ectodomain to expose a hydrophobic CD19-binding surface and reorganizes its transmembrane helices to occlude a cholesterol binding pocket present in the apoprotein. Our data reveal the structural basis for CD19-CD81 complex assembly, providing a foundation for rational design of therapies for B cell dysfunction.


Assuntos
Antígenos CD19/química , Receptores de Antígenos de Linfócitos B/química , Tetraspanina 28/química , Sequência de Aminoácidos , Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/imunologia , Antígenos CD19/imunologia , Linfócitos B/imunologia , Microscopia Crioeletrônica , Humanos , Maitansina/análogos & derivados , Maitansina/química , Maitansina/imunologia , Modelos Moleculares , Mutação , Ligação Proteica , Domínios Proteicos , Receptores de Antígenos de Linfócitos B/imunologia , Tetraspanina 28/genética , Tetraspanina 28/imunologia
3.
Sci Rep ; 10(1): 17100, 2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-33051534

RESUMO

Off-label tocilizumab use in COVID-19 patients reflects concern for cytokine release syndrome. Comparison of matched COVID-19 pneumonia patients found elevated IL-6 levels correlated with mortality that did not change with tocilizumab administration. Correlating mortality with increased IL-6 doesn't imply causality however lack of improvement by tocilizumab requires further clinical trial alterations.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Infecções por Coronavirus/tratamento farmacológico , Pneumonia Viral/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados/imunologia , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/virologia , Feminino , Ferritinas/análise , Humanos , Interleucina-6/análise , Masculino , Pessoa de Meia-Idade , Razão de Chances , Pandemias , Pneumonia Viral/mortalidade , Pneumonia Viral/virologia , Modelos de Riscos Proporcionais , Receptores de Interleucina-6/imunologia , Taxa de Sobrevida
4.
PLoS One ; 15(9): e0239595, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32970735

RESUMO

Immunotherapy checkpoint inhibitors, such as antibodies targeting PD-1 and CTLA-4, have demonstrated the potential of harnessing the immune system to treat cancer. However, despite encouraging results particularly with respect to survival, only a minority of patients benefit from these therapies. In clinical studies aimed at understanding changes in the immune system following immunotherapy treatment, ICOS (Inducible T cell CO-Stimulator) was shown to be significantly up-regulated on CD4+ T cells and this was associated with clinical activity, indicating that ICOS stimulatory activity may be beneficial in the treatment of solid tumors. In this report, we describe the generation of specific, species cross-reactive, agonist antibodies to ICOS, including the humanized clinical candidate, JTX-2011 (vopratelimab). Preclinical studies suggest that the ICOS stimulating antibodies require Fc receptor cross-linking for optimal agonistic activity. Notably, the ICOS antibodies do not exhibit superagonist properties but rather require T cell receptor (TCR)-mediated upregulation of ICOS for agonist activity. Treatment with the ICOS antibodies results in robust anti-tumor benefit and long-term protection in preclinical syngeneic mouse tumor models. Additional benefit is observed when the ICOS antibodies are administered in combination with anti-PD-1 and anti-CTLA-4 therapies. Based on the preclinical data, JTX-2011 is currently being developed in the clinical setting for the treatment of solid tumors.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Apresentação Cruzada , Imunoterapia/métodos , Proteína Coestimuladora de Linfócitos T Induzíveis/imunologia , Neoplasias Experimentais/terapia , Linfócitos T/imunologia , Animais , Anticorpos Monoclonais Humanizados/imunologia , Células CHO , Células Cultivadas , Cricetinae , Cricetulus , Feminino , Humanos , Células Jurkat , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Neoplasias Experimentais/imunologia , Receptores Fc/imunologia
5.
Anticancer Res ; 40(10): 5329-5341, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32988851

RESUMO

Investigation of the efficacy and mechanisms of human immuno-oncology agents has been hampered due to species-specific differences when utilizing preclinical mouse models. Peripheral blood mononuclear cell (PBMC) humanized mice provide a platform for investigating the modulation of the human immune-mediated antitumor response while circumventing the limitations of syngeneic model systems. Use of humanized mice has been stymied by model-specific limitations, some of which include the development of graft versus host disease, technical difficulty and cost associated with each humanized animal, and insufficient engraftment of some human immune subsets. Recent advances have addressed many of these limitations from which have emerged humanized models that are more clinically relevant. This review characterizes the expanded usage, advantages and limitations of humanized mice and provides insights into the development of the next generation of murine humanized models to further inform clinical applications of cancer immunotherapeutic agents.


Assuntos
Imunidade Celular/efeitos dos fármacos , Imunoterapia , Leucócitos Mononucleares/imunologia , Neoplasias/tratamento farmacológico , Animais , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Monoclonais Humanizados/farmacologia , Antineoplásicos/imunologia , Antineoplásicos/farmacologia , Modelos Animais de Doenças , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Camundongos , Neoplasias/imunologia , Neoplasias/patologia
6.
EBioMedicine ; 60: 102999, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32950003

RESUMO

BACKGROUND: The virological and immunological effects of the immunomodulatory drugs used for COVID-19 remain unknown. We evaluated the impact of interleukin (IL)-6 blockade with tocilizumab on SARS-CoV-2 viral kinetics and the antibody response in patients with COVID-19. METHODS: Prospective cohort study in patients admitted with COVID-19. Serial nasopharyngeal and plasma samples were measured for SARS-CoV-2 RNA and S-IgG/N-IgG titers, respectively. FINDINGS: 138 patients with confirmed infection were included; 76 (55%) underwent IL-6 blockade. Median initial SOFA (p = 0•016) and SARS-CoV-2 viral load (p<0•001, Mann-Whitney-Wilcoxon test) were significantly higher among anti-IL-6 users. Patients under IL-6 blockade showed delayed viral clearance in the Kaplan-Meier curves (HR 0•35 [95%CI] [0•15-0•81], log-rank p = 0•014), but an adjusted propensity score matching model did not demonstrate a significant relationship of IL-6 blockade with viral clearance (HR 1•63 [0•35-7•7]). Cox regression showed an inverse association between SARS-CoV-2 RNA clearance and the initial viral load (HR 0•35 [0•11-0•89]). Patients under the IL-6 blocker showed shorter median time to seropositivity, higher peak antibody titers, and higher cumulative proportion of seropositivity in the Kaplan Meier curves (HR 3•1 [1•9-5] for S-IgG; and HR 3•0 [1•9-4•9] for N-IgG; log-rank p<0•001 for both). However, no significant differences between groups were found in either S-IgG (HR 1•56 [0•41-6•0]) nor N-IgG (HR 0•96 [0•26-3•5]) responses in an adjusted propensity score analysis. INTERPRETATION: Our results suggest that in patients infected with SARS-CoV-2, IL-6 blockade does not impair the viral specific antibody responses. Although a delayed viral clearance was observed, it was driven by a higher initial viral load. The study supports the safety of this therapy in patients with COVID-19. FUNDING: Instituto de salud Carlos III (Spain).


Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Betacoronavirus/fisiologia , Infecções por Coronavirus/patologia , Interleucina-6/imunologia , Pneumonia Viral/patologia , Idoso , Anticorpos Monoclonais Humanizados/uso terapêutico , Anticorpos Antivirais/sangue , Formação de Anticorpos , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Feminino , Humanos , Imunoglobulina G/sangue , Interleucina-6/análise , Cinética , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/virologia , Modelos de Riscos Proporcionais , Estudos Prospectivos , RNA Viral/sangue , Carga Viral
7.
PLoS One ; 15(8): e0238150, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866159

RESUMO

Immunogenicity is an important concern for therapeutic antibodies during drug development. By analyzing co-crystal structures of idiotypic antibodies and their antibodies, we found that anti-idiotypic antibodies usually bind the Complementarity Determining Regions (CDR) of idiotypic antibodies. Sequence and structural features were identified for distinguishing immunogenic antibodies from non-immunogenic antibodies. For example, non-immunogenic antibodies have a significantly larger cavity volume at the CDR region and a more hydrophobic CDR-H3 loop than immunogenic antibodies. Antibodies containing no Gly at the turn of CDR-H2 loop are often immunogenic. We integrated these features together with a machine learning platform to Predict Immunogenicity for humanized and full human THerapeutic Antibodies (PITHA). This method achieved an accuracy of 83% in leave-one-out experiment for 29 therapeutic antibodies with available crystal structures. The accuracy decreased to 65% for 23 test antibodies with modeled structures, because their crystal structures were not available, and the prediction was made with modeled structures. The server of this method is accessible at http://mabmedicine.com/PITHA.


Assuntos
Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/imunologia , Formação de Anticorpos/imunologia , Cristalografia por Raios X/métodos , Desenvolvimento de Medicamentos/métodos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Conformação Proteica
8.
Biosensors (Basel) ; 10(9)2020 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-32847008

RESUMO

Cytokines are a family of proteins which play a major role in the regulation of the immune system and the development of several diseases, from rheumatoid arthritis to cancer and, more recently, COVID-19. Therefore, many efforts are currently being developed to improve therapy and diagnosis, as well as to produce inhibitory drugs and biosensors for a rapid, minimally invasive, and effective detection. In this regard, even more efficient cytokine receptors are under investigation. In this paper we analyze a set of IL-6 cytokine receptors, investigating their topological features by means of a theoretical approach. Our results suggest a topological indicator that may help in the identification of those receptors having the highest complementarity with the protein, a feature expected to ensure a stable binding. Furthermore, we propose and discuss the use of these receptors in an idealized experimental setup.


Assuntos
Técnicas Biossensoriais/métodos , Interleucina-6/análise , Receptores de Interleucina-6/análise , Anticorpos Monoclonais/análise , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/imunologia , Aptâmeros de Nucleotídeos/química , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/metabolismo , Infecções por Coronavirus/virologia , Humanos , Fragmentos Fab das Imunoglobulinas/análise , Fragmentos Fab das Imunoglobulinas/imunologia , Interleucina-6/imunologia , Limite de Detecção , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/metabolismo , Pneumonia Viral/virologia , Receptores de Interleucina-6/imunologia
9.
Science ; 369(6505): 793-799, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32792392

RESUMO

Monoclonal antibodies (mAbs) targeting human antigen CD20 (cluster of differentiation 20) constitute important immunotherapies for the treatment of B cell malignancies and autoimmune diseases. Type I and II therapeutic mAbs differ in B cell binding properties and cytotoxic effects, reflecting differential interaction mechanisms with CD20. Here we present 3.7- to 4.7-angstrom cryo-electron microscopy structures of full-length CD20 in complexes with prototypical type I rituximab and ofatumumab and type II obinutuzumab. The structures and binding thermodynamics demonstrate that upon binding to CD20, type II mAbs form terminal complexes that preclude recruitment of additional mAbs and complement components, whereas type I complexes act as molecular seeds to increase mAb local concentration for efficient complement activation. Among type I mAbs, ofatumumab complexes display optimal geometry for complement recruitment. The uncovered mechanisms should aid rational design of next-generation immunotherapies targeting CD20.


Assuntos
Anticorpos Monoclonais Humanizados/química , Complexo Antígeno-Anticorpo/química , Antígenos CD20/química , Antineoplásicos/química , Imunoterapia , Linfoma de Células B/terapia , Rituximab/química , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Monoclonais Humanizados/uso terapêutico , Complexo Antígeno-Anticorpo/imunologia , Antígenos CD20/imunologia , Antineoplásicos/imunologia , Linfócitos B/imunologia , Ativação do Complemento , Microscopia Crioeletrônica , Humanos , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/imunologia , Ligação Proteica , Conformação Proteica , Rituximab/imunologia , Rituximab/uso terapêutico
10.
Sheng Wu Gong Cheng Xue Bao ; 36(6): 1069-1082, 2020 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-32597058

RESUMO

Monoclonal antibody (mAb) is an important biological macromolecule and widely used in immune detection, in vitro diagnostics, and drug discovery. However, the inherent properties of mAb restrict its further development, such as high molecular weight and complex structure. Therefore, there is an urgent need to develop alternatives for mAb. Various types of miniaturized antibodies have been developed, among which the variable domain of immunoglobulin new antigen receptor (VNAR) is very attractive. The shark single-domain antibody, also known as shark VNAR, is an antigen-binding domain obtained by genetic engineering technology based on the immunoglobulin new antigen receptor (IgNAR) that naturally exists in selachimorpha. It has a molecular weight of 12 kDa, which is the smallest antigen-binding domain found in the known vertebrates at present. Compared with mAb, the shark VNAR exhibits various superiorities, such as low molecular weight, high affinity, tolerance to the harsh environment, good water solubility, strong tissue penetration, and recognition of the hidden epitopes. It has attracted wide attention in the fields of immunochemical reagents and drug discovery. In this review, various aspects of shark VNAR are elaborated, including the structural and functional characteristics, generating and humanization techniques, affinity maturation strategies, application fields, advantages and disadvantages, and prospects.


Assuntos
Anticorpos Monoclonais , Receptores de Antígenos , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais Humanizados/imunologia , Antígenos , Epitopos/metabolismo , Domínios Proteicos/imunologia , Receptores de Antígenos/química , Receptores de Antígenos/imunologia , Tubarões
11.
Emerg Microbes Infect ; 9(1): 1034-1036, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32403995

RESUMO

Coronaviruses cause severe human viral diseases including SARS, MERS and COVID-19. Most recently SARS-CoV-2 virus (causing COVID-19) has led to a pandemic with no successful therapeutics. The SARS-CoV-2 infection relies on trimeric spike (S) proteins to facilitate virus entry into host cells by binding to ACE2 receptor on host cell membranes. Therefore, blocking this interaction with antibodies are promising agents against SARS-CoV-2. Here we describe using humanized llama antibody VHHs against SARS-CoV-2 that would overcome the limitations associated with polyclonal and monoclonal combination therapies. From two llama VHH libraries, unique humanized VHHs that bind to S protein and block the S/ACE2 interaction were identified. Furthermore, pairwise combination of VHHs showed synergistic blocking. Multi-specific antibodies with enhanced affinity and avidity, and improved S/ACE2 blocking are currently being developed using an in-silico approach that also fuses VHHs to Fc domains. Importantly, our current bi-specific antibody shows potent S/ACE2 blocking (KD - 0.25 nM, IC100 ∼ 36.7 nM, IC95 ∼ 12.2 nM, IC50 ∼ 1 nM) which is significantly better than individual monoclonal VHH-Fcs. Overall, this design would equip the VHH-Fcs multiple mechanisms of actions against SARS-CoV-2. Thus, we aim to contribute to the battle against COVID-19 by developing therapeutic antibodies as well as diagnostics.


Assuntos
Antagonistas de Receptores de Angiotensina/imunologia , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , Camelídeos Americanos/imunologia , Peptidil Dipeptidase A/imunologia , Animais , Anticorpos Biespecíficos/imunologia , Humanos , Peptidil Dipeptidase A/metabolismo , Glicoproteína da Espícula de Coronavírus/imunologia
12.
PLoS One ; 15(5): e0231892, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32384086

RESUMO

Complement is a key component of the innate immune system. Inappropriate complement activation underlies the pathophysiology of a variety of diseases. Complement component 5 (C5) is a validated therapeutic target for complement-mediated diseases, but the development of new therapeutics has been limited by a paucity of preclinical models to evaluate the pharmacokinetic (PK) and pharmacodynamic (PD) properties of candidate therapies. The present report describes a novel humanized C5 mouse and its utility in evaluating a panel of fully human anti-C5 antibodies. Surprisingly, humanized C5 mice revealed marked differences in clearance rates amongst a panel of anti-C5 antibodies. One antibody, pozelimab (REGN3918), bound C5 and C5 variants with high affinity and potently blocked complement-mediated hemolysis in vitro. In studies conducted in both humanized C5 mice and cynomolgus monkeys, pozelimab demonstrated prolonged PK and durable suppression of hemolytic activity ex vivo. In humanized C5 mice, a switch in dosing from in-house eculizumab to pozelimab was associated with normalization of serum C5 concentrations, sustained suppression of hemolytic activity ex vivo, and no overt toxicity. Our findings demonstrate the value of humanized C5 mice in identifying new therapeutic candidates and treatment options for complement-mediated diseases.


Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Complemento C5/imunologia , Animais , Anticorpos Monoclonais Humanizados/farmacocinética , Anticorpos Monoclonais Humanizados/farmacologia , Reações Antígeno-Anticorpo , Sítios de Ligação , Ativação do Complemento/efeitos dos fármacos , Complemento C5/química , Complemento C5/genética , Variação Genética , Meia-Vida , Hemólise/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Macaca fascicularis , Camundongos , Estrutura Quaternária de Proteína
13.
J Pharmacol Exp Ther ; 374(1): 93-103, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32366601

RESUMO

ALD403 is a genetically engineered, humanized immunoglobulin G1 monoclonal antibody that inhibits the action of human calcitonin gene-related peptide (CGRP). Clinical trial data indicate that ALD403 is effective as a preventive therapy for migraine and has an acceptable safety profile. For preclinical characterization of ALD403, rabbit antibodies targeting α-CGRP were humanized and modified to eliminate fragment crystallizable (Fc) γ receptor (FcγR) and complement interactions. The ability of ALD403 to inhibit CGRP-induced cAMP production was assessed using a cAMP bioassay (Meso Scale Discovery). The IC50 for inhibition of cAMP release was 434 and 288 pM with the rabbit-human chimera antibody and the humanized ALD403, respectively. ALD403 inhibited α-CGRP binding with an IC50 of 4.7 × 10-11 and 1.2 × 10-10 M for the α-CGRP and AMY1 receptors, respectively. ALD403 did not induce antibody-dependent cellular cytotoxicity or complement-dependent cytotoxicity and did not stably interact with any of the FcγR mediating these functions, exhibiting only weak binding to FcγRI. ALD403 significantly lowered capsaicin-induced blood flow responses in rodents at all time points starting at 5 minutes postapplication in a dose-dependent manner. In conclusion, ALD403 is a potent functional ligand inhibitor of α-CGRP‒driven pharmacology. SIGNIFICANCE STATEMENT: α-Calcitonin gene-related peptide blockade by ALD403 was assessed via radiolabeled ligand displacement, in vitro inhibition of cell signaling, and in vivo inhibition of capsaicin-induced vasodilation. Lack of engagement of fragment crystallizable-mediated immune-effector functions by ALD403 was shown.


Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Neutralizantes/imunologia , Peptídeo Relacionado com Gene de Calcitonina/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais Humanizados/química , Anticorpos Neutralizantes/química , Especificidade de Anticorpos , Humanos , Cinética , Coelhos , Transdução de Sinais
15.
Lancet Infect Dis ; 20(8): 983-991, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32333847

RESUMO

BACKGROUND: Raxibacumab is a monoclonal antibody against protective antigen, which is the cell-binding part of Bacillus anthracis toxin, and is approved for treatment and postexposure prophylaxis of inhalational anthrax. Anthrax Vaccine Adsorbed (AVA), for anthrax prophylaxis, consists primarily of adsorbed protective antigen. We did a postapproval study to assess the effect of raxibacumab on immunogenicity of AVA. METHODS: We did an open-label, parallel-group, randomised non-inferiority study at three centres in the USA. We enrolled healthy volunteers (aged 18-65 years) with no evidence of exposure to protective antigen. Participants were randomly allocated (1:1) according to a pregenerated balanced independent randomisation schedule to either subcutaneous 0·5 mL AVA on days 1, 15, and 29 or raxibacumab intravenous infusion (40 mg/kg) immediately before AVA on day 1, followed by AVA only on days 15 and 29. It was an open-label study to investigators and participants; however, the sponsor remained blinded during the study. The primary outcome was the ratio of geometric mean concentrations (GMCs) of anti-protective antigen antibodies (attributable to the immune response to AVA) between AVA and AVA plus raxibacumab 4 weeks after the first AVA dose in the per-protocol population. The per-protocol population comprised all individuals who received the allocated treatment within the protocol-specified visit window and completed the primary study outcome assessment, without a protocol deviation requiring exclusion. The non-inferiority margin for the ratio of GMCs was predefined (upper limit of 90% CI <1·5). This trial is registered with ClinicalTrials.gov, NCT02339155. FINDINGS: Between Feb 24, 2015, and June 6, 2017, 873 participants were screened for eligibility, of whom 300 were excluded. 573 were randomly allocated either AVA (n=287) or AVA plus raxibacumab (n=286). The per-protocol population comprised 276 individuals assigned AVA and 269 allocated AVA plus raxibacumab. At week 4, the GMC of anti-protective antigen antibodies in participants allocated AVA was 26·5 µg/mL (95% CI 23·6-29·8) compared with 22·5 µg/mL (20·1-25·1) among individuals allocated AVA plus raxibacumab. The ratio between groups was 1·18 (90% CI 1·03-1·35; p=0·0019), which met the predefined non-inferiority margin. Adverse events in the safety population were similar across groups (87 [30%] of 286 in the AVA group vs 80 [29%] of 280 in the AVA plus raxibacumab group) and no treatment-related serious adverse events were reported. INTERPRETATION: Co-administration of raxibacumab with AVA does not negatively affect AVA immunogenicity. This finding suggests that combining raxibacumab with AVA might provide added benefit in postexposure prophylaxis against inhalational anthrax. FUNDING: US Biomedical Advanced Research and Development Authority, and GlaxoSmithKline.


Assuntos
Vacinas contra Antraz/imunologia , Antraz/prevenção & controle , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/imunologia , Imunogenicidade da Vacina/efeitos dos fármacos , Imunoglobulina G/administração & dosagem , Imunoglobulina G/imunologia , Adolescente , Adulto , Idoso , Vacinas contra Antraz/administração & dosagem , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/farmacocinética , Feminino , Humanos , Imunoglobulina G/efeitos adversos , Imunoglobulina G/farmacologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
16.
J Surg Res ; 252: 16-21, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32217350

RESUMO

BACKGROUND: Tumor-associated glycoprotein (TAG)-72 is a pancarcinoma antigen that is overexpressed in greater than 80% of colorectal adenocarcinomas. CC49 is a TAG-72-specific antibody. The aim of the present study was to demonstrate selective imaging of colon tumors and metastases with the humanized TAG-72 antibody (anti-huCC49) conjugated to a near-infrared fluorophore in orthotopic mouse models. METHODS: Anti-huCC49 was conjugated to near-infrared dye IR800CW. Mouse imaging was performed with the Pearl Trilogy Small Animal and FLARE Imaging Systems. Subcutaneous mouse models of colon cancer cell line LS174T were used to determine the optimal dose of administration and timing of imaging. Orthotopic mouse models of LS174T were established by surgical orthotopic implantation of LS174T tumors onto the serosa of the cecum. Peritoneal carcinomatosis models were established by injection of LS174T cells into the peritoneum of nude mice. Mice were administered anti-huCC49-IR800 via tail vein injection. Mice were euthanized 72 h later and imaged after laparotomy. RESULTS: Subcutaneous LS174T xenografts demonstrated optimal tumor detection 72 h after administration with 50 µg anti-huCC49-IR800CW. Tumors were visualized with fluorescence imaging with a mean tumor-to-liver ratio of 7.39 (standard deviation: 2.76). In the orthotopic model, metastases smaller than 1 mm were fluorescently visualized that were invisible with bright light. CONCLUSIONS: Anti-huCC49-IR800CW provides sensitive and specific imaging of colon cancer and metastases at a submillimeter resolution in metastatic nude mice models. This provides a promising near-infrared probe for the imaging of colon cancer and metastases for preoperative diagnosis and fluorescence-guided surgery.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Antineoplásicos/administração & dosagem , Antígenos de Neoplasias/imunologia , Neoplasias do Colo/diagnóstico por imagem , Neoplasias Peritoneais/diagnóstico por imagem , Ácidos Alcanossulfônicos/administração & dosagem , Ácidos Alcanossulfônicos/química , Animais , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Antineoplásicos/química , Anticorpos Antineoplásicos/imunologia , Linhagem Celular Tumoral , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Neoplasias do Colo/cirurgia , Corantes Fluorescentes/administração & dosagem , Corantes Fluorescentes/química , Humanos , Imunoconjugados/administração & dosagem , Imunoconjugados/química , Imunoconjugados/imunologia , Indóis/administração & dosagem , Indóis/química , Camundongos , Neoplasias Peritoneais/imunologia , Neoplasias Peritoneais/secundário , Neoplasias Peritoneais/cirurgia , Cuidados Pré-Operatórios/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Cirurgia Assistida por Computador/métodos , Ensaios Antitumorais Modelo de Xenoenxerto
17.
Lancet Infect Dis ; 20(4): 445-454, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32027842

RESUMO

BACKGROUND: The monoclonal antibody m102.4 is a potent, fully human antibody that neutralises Hendra and Nipah viruses in vitro and in vivo. We aimed to investigate the safety, tolerability, pharmacokinetics, and immunogenicity of m102.4 in healthy adults. METHODS: In this double-blind, placebo-controlled, single-centre, dose-escalation, phase 1 trial of m102.4, we randomly assigned healthy adults aged 18-50 years with a body-mass index of 18·0-35·0 kg/m2 to one of five cohorts. A sentinel pair for each cohort was randomly assigned to either m102.4 or placebo. The remaining participants in each cohort were randomly assigned (5:1) to receive m102.4 or placebo. Cohorts 1-4 received a single intravenous infusion of m102.4 at doses of 1 mg/kg (cohort 1), 3 mg/kg (cohort 2), 10 mg/kg (cohort 3), and 20 mg/kg (cohort 4), and were monitored for 113 days. Cohort 5 received two infusions of 20 mg/kg 72 h apart and were monitored for 123 days. The primary outcomes were safety and tolerability. Secondary outcomes were pharmacokinetics and immunogenicity. Analyses were completed according to protocol. The study was registered on the Australian New Zealand Clinical Trials Registry, ACTRN12615000395538. FINDINGS: Between March 27, 2015, and June 16, 2016, 40 (52%) of 77 healthy screened adults were enrolled in the study. Eight participants were assigned to each cohort (six received m102.4 and two received placebo). 86 treatment-emergent adverse events were reported, with similar rates between placebo and treatment groups. The most common treatment-related event was headache (12 [40%] of 30 participants in the combined m102.4 group, and three [30%] of ten participants in the pooled placebo group). No deaths or severe adverse events leading to study discontinuation occurred. Pharmacokinetics based on those receiving m102.4 (n=30) were linear, with a median half-life of 663·3 h (range 474·3-735·1) for cohort 1, 466·3 h (382·8-522·3) for cohort 2, 397·0 h (333·9-491·8) for cohort 3, and 466·7 h (351·0-889·6) for cohort 4. The elimination kinetics of those receiving repeated dosing (cohort 5) were similar to those of single-dose recipients (median elimination half-time 472·0 [385·6-592·0]). Anti-m102.4 antibodies were not detected at any time-point during the study. INTERPRETATION: Single and repeated dosing of m102.4 were well tolerated and safe, displayed linear pharmacokinetics, and showed no evidence of an immunogenic response. This study will inform future dosing regimens for m102.4 to achieve prolonged exposure for systemic efficacy to prevent and treat henipavirus infections. FUNDING: Queensland Department of Health, the National Health and Medical Research Council, and the National Hendra Virus Research Program.


Assuntos
Anticorpos Monoclonais Humanizados/farmacocinética , Glicoproteínas/imunologia , Voluntários Saudáveis , Henipavirus/imunologia , Imunogenicidade da Vacina , Segurança , Adulto , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/imunologia , Austrália , Método Duplo-Cego , Feminino , Cefaleia/etiologia , Humanos , Infusões Intravenosas , Masculino
18.
PLoS Pathog ; 16(2): e1008312, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32069329

RESUMO

TNF-α- as well as non-TNF-α-targeting biologics are prescribed to treat a variety of immune-mediated inflammatory disorders. The well-documented risk of tuberculosis progression associated with anti-TNF-α treatment highlighted the central role of TNF-α for the maintenance of protective immunity, although the rate of tuberculosis detected among patients varies with the nature of the drug. Using a human, in-vitro granuloma model, we reproduce the increased reactivation rate of tuberculosis following exposure to Adalimumab compared to Etanercept, two TNF-α-neutralizing biologics. We show that Adalimumab, because of its bivalence, specifically induces TGF-ß1-dependent Mycobacterium tuberculosis (Mtb) resuscitation which can be prevented by concomitant TGF-ß1 neutralization. Moreover, our data suggest an additional role of lymphotoxin-α-neutralized by Etanercept but not Adalimumab-in the control of latent tuberculosis infection. Furthermore, we show that, while Secukinumab, an anti-IL-17A antibody, does not revert Mtb dormancy, the anti-IL-12-p40 antibody Ustekinumab and the recombinant IL-1RA Anakinra promote Mtb resuscitation, in line with the importance of these pathways in tuberculosis immunity.


Assuntos
Mycobacterium tuberculosis/metabolismo , Tuberculose/imunologia , Inibidores do Fator de Necrose Tumoral/farmacologia , Adalimumab/farmacologia , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Monoclonais Humanizados/metabolismo , Anticorpos Monoclonais Humanizados/farmacologia , Etanercepte/farmacologia , Granuloma/tratamento farmacológico , Granuloma/metabolismo , Humanos , Fatores Imunológicos/metabolismo , Tuberculose Latente/imunologia , Modelos Biológicos , Mycobacterium tuberculosis/imunologia , Fator de Crescimento Transformador beta1/metabolismo , Inibidores do Fator de Necrose Tumoral/metabolismo , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismo
19.
Clin Exp Immunol ; 200(3): 260-271, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32056202

RESUMO

Obinutuzumab is thought to exert its effects through its high antibody-dependent cellular cytotoxicity (ADCC) via glyco-engineering of the Fc region. In addition, obinutuzumab causes direct binding-induced cell death (DCD) only by specifically binding to its target CD20, a Ca2+ channel. However, the specific features of CD20 related to obinutuzumab binding-induction of cell death are not clearly understood. In this study, we evaluated the relationship between the Ca2+ channel features of CD20 as a store-operated Ca2+ channel (SOC) and obinutuzumab binding-induced cell death. Ca2+ channel function and biochemical analysis revealed that CD20 is an Orai1- and stromal interaction molecule (STIM1)-dependent Ca2+ pore. However, binding of obinutuzumab on CD20 did not have any effect on Ca2+ influx activity of CD20; the direct cell death rate mediated by obinutuzumab binding was almost equivalent with or without the extracellular Ca2+ condition. Given the apparent interaction between STIM1 and CD20, we observed Triton-X solubilized obinutuzumab-bound CD20 accompanied by STIM1. Subsequently, obinutuzumab binding and cell death were decreased by STIM1 knock-down in Ramos B cells. Thus, STIM1 directly contributes to cell death by increasing the affinity of cells for obinutuzumab by transferring CD20 to the Triton-soluble membrane region.


Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Antígenos CD20/imunologia , Membrana Celular/imunologia , Técnicas de Silenciamento de Genes , Proteínas de Neoplasias/imunologia , Molécula 1 de Interação Estromal/imunologia , Animais , Antígenos CD20/genética , Células CHO , Membrana Celular/genética , Cricetulus , Humanos , Proteínas de Neoplasias/genética , Octoxinol/química , Solubilidade , Molécula 1 de Interação Estromal/genética
20.
Sci Rep ; 10(1): 1194, 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31988343

RESUMO

Nimotuzumab is a humanized monoclonal antibody against the Epidermal Growth Factor Receptor with a long history of therapeutic use, recognizing an epitope different from the ones targeted by other antibodies against the same antigen. It is also distinguished by much less toxicity resulting in a better safety profile, which has been attributed to its lower affinity compared to these other antibodies. Nevertheless, the ideal affinity window for optimizing the balance between anti-tumor activity and toxic effects has not been determined. In the current work, the paratope of the phage-displayed nimotuzumab Fab fragment was evolved in vitro to obtain affinity-matured variants. Soft-randomization of heavy chain variable region CDRs and phage selection resulted in mutated variants with improved binding ability. Two recombinant antibodies were constructed using these variable regions, which kept the original fine epitope specificity and showed moderate affinity increases against the target (3-4-fold). Such differences were translated into a greatly enhanced inhibitory capacity upon ligand-induced receptor phosphorylation on tumor cells. The new antibodies, named K4 and K5, are valuable tools to explore the role of affinity in nimotuzumab biological properties, and could be used for applications requiring a fine-tuning of the balance between binding to tumor cells and healthy tissues.


Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Monoclonais Humanizados/farmacologia , Afinidade de Anticorpos/imunologia , Neoplasias/imunologia , Anticorpos Monoclonais Humanizados/metabolismo , Bacteriófagos/genética , Bacteriófagos/imunologia , Linhagem Celular Tumoral , Simulação por Computador , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/metabolismo , Vetores Genéticos/genética , Humanos , Idiótipos de Imunoglobulinas/imunologia , Região Variável de Imunoglobulina/genética , Neoplasias/patologia , Proteínas Recombinantes/imunologia , Transfecção
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