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1.
Cell Rep ; 37(3): 109869, 2021 10 19.
Article in English | MEDLINE | ID: covidwho-1517084

ABSTRACT

The dramatically expanding coronavirus disease 2019 (COVID-19) needs multiple effective countermeasures. Neutralizing nanobodies (Nbs) are a potential therapeutic strategy for treating COVID-19. Here, we characterize several receptor binding domain (RBD)-specific Nbs isolated from an Nb library derived from an alpaca immunized with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein (S); among them, three Nbs exhibit picomolar potency against SARS-CoV-2 live virus, pseudotyped viruses, and circulating SARS-CoV-2 variants. To improve their efficacy, various configurations of Nbs are engineered. Nb15-NbH-Nb15, a trimer constituted of three Nbs, is constructed to be bispecific for human serum albumin (HSA) and RBD of SARS-CoV-2. Nb15-NbH-Nb15 exhibits single-digit ng/ml neutralization potency against the wild-type and Delta variants of SARS-CoV-2 with a long half-life in vivo. In addition, we show that intranasal administration of Nb15-NbH-Nb15 provides effective protection for both prophylactic and therapeutic purposes against SARS-CoV-2 infection in transgenic hACE2 mice. Nb15-NbH-Nb15 is a potential candidate for both the prevention and treatment of SARS-CoV-2 through respiratory administration.


Subject(s)
Administration, Intranasal , Angiotensin-Converting Enzyme 2/immunology , Antibodies, Bispecific/immunology , COVID-19/immunology , SARS-CoV-2 , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Neutralizing , Antibodies, Viral/immunology , Camelids, New World , Epitopes/chemistry , Female , Humans , Kinetics , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neutralization Tests , Protein Binding , Protein Domains , Protein Engineering/methods , Serum Albumin, Human/chemistry , Single-Domain Antibodies , Spike Glycoprotein, Coronavirus/immunology
3.
J Immunol Methods ; 496: 113099, 2021 09.
Article in English | MEDLINE | ID: covidwho-1292808

ABSTRACT

Bispecific antibodies (BsAbs) are engineered to simultaneously bind two different antigens, and offer promising clinical outcomes for various diseases. The dual binding properties of BsAbs may enable superior efficacies and/or potencies compared to standard monoclonal antibodies (mAbs) or combination mAb therapies. Characterizing BsAb binding properties is critical during biotherapeutic development, where data is leveraged to predict efficacy and potency, assess critical quality attributes and improve antibody design. Traditional single-target, single-readout approaches (e.g., ELISA) have limited usefulness for interpreting complex bispecific binding, and double the benchwork. To address these deficiencies, we developed and implemented a new dual-target/readout binding assay that accurately dissects the affinities of both BsAb binding domains directly and simultaneously. This new assay uses AlphaPlex® technology, which eliminates traditional ELISA wash steps and can be miniaturized for automated workflows. The optimized BsAb AlphaPlex assay demonstrates 99-107% accuracy within a 50-150% linear range, and detected >50% binding degradation from photo- and thermal stress conditions. To the best of our knowledge, this is the first instance of a dual-target/readout BsAb AlphaPlex assay with GMP-suitable linear range, accuracy, specificity, and stability-indicating properties. As a highly customizable and efficient assay, BsAb AlphaPlex may be applicable to numerous bispecific formats and/or co-formulations against a variety of antigens beyond the clinical therapeutic space.


Subject(s)
Antibodies, Bispecific/immunology , Antibody Specificity , Antigens/immunology , CTLA-4 Antigen/immunology , Immunoassay , Programmed Cell Death 1 Receptor/immunology , Antibodies, Bispecific/metabolism , Antigen-Antibody Complex , Antigens/metabolism , Binding Sites, Antibody , Buffers , CTLA-4 Antigen/metabolism , Enzyme-Linked Immunosorbent Assay , Epitopes , Humans , Hydrogen-Ion Concentration , Kinetics , Predictive Value of Tests , Programmed Cell Death 1 Receptor/metabolism , Protein Binding , Reproducibility of Results
4.
Nature ; 593(7859): 424-428, 2021 05.
Article in English | MEDLINE | ID: covidwho-1152859

ABSTRACT

Neutralizing antibodies that target the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein are among the most promising approaches against COVID-191,2. A bispecific IgG1-like molecule (CoV-X2) has been developed on the basis of C121 and C135, two antibodies derived from donors who had recovered from COVID-193. Here we show that CoV-X2 simultaneously binds two independent sites on the RBD and, unlike its parental antibodies, prevents detectable spike binding to the cellular receptor of the virus, angiotensin-converting enzyme 2 (ACE2). Furthermore, CoV-X2 neutralizes wild-type SARS-CoV-2 and its variants of concern, as well as escape mutants generated by the parental monoclonal antibodies. We also found that in a mouse model of SARS-CoV-2 infection with lung inflammation, CoV-X2 protects mice from disease and suppresses viral escape. Thus, the simultaneous targeting of non-overlapping RBD epitopes by IgG-like bispecific antibodies is feasible and effective, and combines the advantages of antibody cocktails with those of single-molecule approaches.


Subject(s)
Antibodies, Bispecific/immunology , Antibodies, Neutralizing/immunology , COVID-19/immunology , COVID-19/virology , Immunoglobulin G/immunology , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Bispecific/therapeutic use , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/therapeutic use , Body Weight , COVID-19/drug therapy , COVID-19/prevention & control , Dependovirus/genetics , Disease Models, Animal , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Female , Humans , Immune Evasion/genetics , Mice , Mice, Inbred C57BL , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology
5.
Int J Mol Sci ; 22(5)2021 Feb 28.
Article in English | MEDLINE | ID: covidwho-1120888

ABSTRACT

Immunotherapy is a highly emerging form of breast cancer therapy that enables clinicians to target cancers with specific receptor expression profiles. Two popular immunotherapeutic approaches involve chimeric antigen receptor-T cells (CAR-T) and bispecific antibodies (BsAb). Briefly mentioned in this review as well is the mRNA vaccine technology recently popularized by the COVID-19 vaccine. These forms of immunotherapy can highly select for the tumor target of interest to generate specific tumor lysis. Along with improvements in CAR-T, bispecific antibody engineering, and therapeutic administration, much research has been done on novel molecular targets that can especially be useful for triple-negative breast cancer (TNBC) immunotherapy. Combining emerging immunotherapeutics with tumor marker discovery sets the stage for highly targeted immunotherapy to be the future of cancer treatments. This review highlights the principles of CAR-T and BsAb therapy, improvements in CAR and BsAb engineering, and recently identified human breast cancer markers in the context of in vitro or in vivo CAR-T or BsAb treatment.


Subject(s)
Breast Neoplasms/therapy , Immunotherapy/methods , Animals , Antibodies, Bispecific/immunology , Antibodies, Bispecific/therapeutic use , Biomarkers, Tumor , Breast Neoplasms/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , COVID-19 Vaccines/immunology , Cancer Vaccines/administration & dosage , Cancer Vaccines/immunology , Female , Humans , Immunotherapy, Adoptive/methods , Molecular Targeted Therapy , Receptors, Chimeric Antigen/immunology , SARS-CoV-2/immunology , Triple Negative Breast Neoplasms/immunology , Triple Negative Breast Neoplasms/therapy , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunology
6.
MAbs ; 13(1): 1893426, 2021.
Article in English | MEDLINE | ID: covidwho-1118886

ABSTRACT

Numerous neutralizing antibodies that target SARS-CoV-2 have been reported, and most directly block binding of the viral Spike receptor-binding domain (RBD) to angiotensin-converting enzyme II (ACE2). Here, we deliberately exploit non-neutralizing RBD antibodies, showing they can dramatically assist in neutralization when linked to neutralizing binders. We identified antigen-binding fragments (Fabs) by phage display that bind RBD, but do not block ACE2 or neutralize virus as IgGs. When these non-neutralizing Fabs were assembled into bispecific VH/Fab IgGs with a neutralizing VH domain, we observed a ~ 25-fold potency improvement in neutralizing SARS-CoV-2 compared to the mono-specific bi-valent VH-Fc alone or the cocktail of the VH-Fc and IgG. This effect was epitope-dependent, reflecting the unique geometry of the bispecific antibody toward Spike. Our results show that a bispecific antibody that combines both neutralizing and non-neutralizing epitopes on Spike-RBD is a promising and rapid engineering strategy to improve the potency of SARS-CoV-2 antibodies.


Subject(s)
Antibodies, Bispecific/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , Epitopes/immunology , Immunoglobulin Fab Fragments/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Bispecific/genetics , Antibodies, Bispecific/therapeutic use , Antibodies, Neutralizing/genetics , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/genetics , Antibodies, Viral/therapeutic use , COVID-19/drug therapy , COVID-19/genetics , Epitopes/genetics , HEK293 Cells , Humans , Immunoglobulin Fab Fragments/genetics , Immunoglobulin Fab Fragments/therapeutic use , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
7.
Int Immunopharmacol ; 86: 106760, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-634138

ABSTRACT

Due to the vastness of the science virology, it is no longer an offshoot solely of the microbiology. Viruses have become as the causative agents of major epidemics throughout history. Many therapeutic strategies have been used for these microorganisms, and in this way the recognizing of potential targets of viruses is of particular importance for success. For decades, antibodies and antibody fragments have occupied a significant body of the treatment approaches against infectious diseases. Because of their high affinity, they can be designed and engineered against a variety of purposes, mainly since antibody fragments such as scFv, nanobody, diabody, and bispecific antibody have emerged owing to their small size and interesting properties. In this review, we have discussed the antibody discovery and molecular and biological design of antibody fragments as inspiring therapeutic and diagnostic agents against viral targets.


Subject(s)
Antibodies, Viral/therapeutic use , Betacoronavirus/immunology , Biological Products/therapeutic use , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , Animals , Antibodies, Bispecific/immunology , Antibodies, Bispecific/therapeutic use , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Viral/immunology , Biological Products/immunology , COVID-19 , Coronavirus Infections/epidemiology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Disease Models, Animal , Drug Design , Drug Discovery , Humans , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , SARS-CoV-2 , Single-Domain Antibodies/immunology , Single-Domain Antibodies/therapeutic use
8.
Emerg Microbes Infect ; 9(1): 1034-1036, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-260384

ABSTRACT

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.


Subject(s)
Angiotensin Receptor Antagonists/immunology , Antibodies, Monoclonal, Humanized/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Camelids, New World/immunology , Peptidyl-Dipeptidase A/immunology , Angiotensin-Converting Enzyme 2 , Animals , Antibodies, Bispecific/immunology , Humans , Peptidyl-Dipeptidase A/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/immunology
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