A non-ACE2 competing human single-domain antibody confers broad neutralization against SARS-CoV-2 and circulating variants

AbstractThe current COVID-19 pandemic has heavily burdened the global public health system and may keep simmering for years. The frequent emergence of immune escape variants have spurred the search for prophylactic vaccines and therapeutic antibodies that confer broad protection against SARS-CoV-2 variants. Here we show that the bivalency of an affinity maturated fully human single-domain antibody (n3113.1-Fc) exhibits exquisite neutralizing potency against SARS-CoV-2 pseudovirus, and confers effective prophylactic and therapeutic protection against authentic SARS-CoV-2 in the host cell receptor angiotensin-converting enzyme 2 (ACE2) humanized mice. The crystal structure of n3113 in complex with the receptor-binding domain (RBD) of SARS-CoV-2, combined with the cryo-EM structures of n3113 and spike ecto-domain, reveals that n3113 binds to the side surface of up-state RBD with no competition with ACE2. The binding of n3113 to this novel epitope stabilizes spike in up-state conformations but inhibits SARS-CoV-2 S mediated membrane fusion, expanding our recognition of neutralization by antibodies against SARS-CoV-2. Binding assay and pseudovirus neutralization assay show no evasion of recently prevalent SARS-CoV-2 lineages, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) for n3113.1-Fc with Y58L mutation, demonstrating the potential of n3113.1-Fc (Y58L) as a promising candidate for clinical development to treat COVID-19.

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The Molecular Mechanism of Shiga Toxin Stx2e Neutralization by a Single-domain Antibody Targeting the Cell Receptor-binding Domain

Journal of Biological Chemistry ◽

10.1074/jbc.m114.566257 ◽

2014 ◽

Vol 289 (36) ◽

pp. 25374-25381 ◽

Cited By ~ 19

Author(s):

Alvin W. H. Lo ◽

Kristof Moonens ◽

Maia De Kerpel ◽

Lea Brys ◽

Els Pardon ◽

...

Keyword(s):

Molecular Mechanism ◽

Receptor Binding ◽

Shiga Toxin ◽

Cell Receptor ◽

Binding Domain ◽

Single Domain ◽

Receptor Binding Domain ◽

Single Domain Antibody ◽

Domain Antibody ◽

Antibody Targeting

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Single Domain Antibody-Mediated Blockade of Programmed Death-Ligand 1 on Dendritic Cells Enhances CD8 T-cell Activation and Cytokine Production

Vaccines ◽

10.3390/vaccines7030085 ◽

2019 ◽

Vol 7 (3) ◽

pp. 85 ◽

Cited By ~ 3

Author(s):

Broos ◽

Lecocq ◽

Keersmaecker ◽

Raes ◽

Corthals ◽

...

Keyword(s):

T Cell ◽

T Cell Activation ◽

Immune Cells ◽

Cell Activation ◽

Cell Receptor ◽

Single Domain ◽

Single Domain Antibody ◽

Programmed Death Ligand 1 ◽

Domain Antibody ◽

Programmed Death

Dendritic cell [DC] vaccines can induce durable clinical responses, at least in a fraction of previously treated, late stage cancer patients. Several preclinical studies suggest that shielding programmed death-ligand 1 [PD-L1] on the DC surface may be an attractive strategy to extend such clinical benefits to a larger patient population. In this study, we evaluated the use of single domain antibody [sdAb] K2, a high affinity, antagonistic, PD-L1 specific sdAb, for its ability to enhance DC mediated T-cell activation and benchmarked it against the use of the monoclonal antibodies [mAbs], MIH1, 29E.2A3 and avelumab. Similar to mAbs, sdAb K2 enhanced antigen-specific T-cell receptor signaling in PD-1 positive (PD-1pos) reporter cells activated by DCs. We further showed that the activation and function of antigen-specific CD8 positive (CD8pos) T cells, activated by DCs, was enhanced by inclusion of sdAb K2, but not mAbs. The failure of mAbs to enhance T-cell activation might be explained by their low efficacy to bind PD-L1 on DCs when compared to binding of PD-L1 on non-immune cells, whereas sdAb K2 shows high binding to PD-L1 on immune as well as non-immune cells. These data provide a rationale for the inclusion of sdAb K2 in DC-based immunotherapy strategies.

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Faculty Opinions recommendation of Crystal structure of a shark single-domain antibody V region in complex with lysozyme.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1024018.285841 ◽

2005 ◽

Author(s):

Christopher Garcia

Keyword(s):

Crystal Structure ◽

Single Domain ◽

Single Domain Antibody ◽

Domain Antibody ◽

V Region

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CAR T cells targeting CD13 controllably induce eradication of acute myeloid leukemia with a single domain antibody switch

Leukemia ◽

10.1038/s41375-021-01208-2 ◽

2021 ◽

Author(s):

Xin He ◽

Zijie Feng ◽

Jian Ma ◽

Xuyao Zhang ◽

Sunbin Ling ◽

...

Keyword(s):

T Cells ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Single Domain ◽

Single Domain Antibody ◽

Car T Cells ◽

Domain Antibody ◽

Car T ◽

Acute Myeloid

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Production, characterization and in-vitro applications of single-domain antibody against thyroglobulin selected from novel T7 phage display library

Journal of Immunological Methods ◽

10.1016/j.jim.2021.112990 ◽

2021 ◽

Vol 492 ◽

pp. 112990

Author(s):

Jothivel Kumarasamy ◽

Samar Kumar Ghorui ◽

Chandrakala Gholve ◽

Bharti Jain ◽

Yogesh Dhekale ◽

...

Keyword(s):

Phage Display ◽

Phage Display Library ◽

Single Domain ◽

Single Domain Antibody ◽

Domain Antibody ◽

T7 Phage Display ◽

T7 Phage

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A Single-Domain Antibody-Based Anti-PSMA Recombinant Immunotoxin Exhibits Specificity and Efficacy for Prostate Cancer Therapy

International Journal of Molecular Sciences ◽

10.3390/ijms22115501 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5501

Author(s):

Yutong Xing ◽

Keyuan Xu ◽

Shixiong Li ◽

Li Cao ◽

Yue Nan ◽

...

Keyword(s):

Prostate Cancer ◽

Animal Studies ◽

Single Domain ◽

Soluble Form ◽

Therapeutic Window ◽

Single Domain Antibody ◽

Pseudomonas Exotoxin A ◽

Simple Strategy ◽

Domain Antibody ◽

Recombinant Immunotoxin

Prostate cancer (PCa) is the second most common cancer in men, causing more than 300,000 deaths every year worldwide. Due to their superior cell-killing ability and the relative simplicity of their preparation, immunotoxin molecules have great potential in the clinical treatment of cancer, and several such molecules have been approved for clinical application. In this study, we adopted a relatively simple strategy based on a single-domain antibody (sdAb) and an improved Pseudomonas exotoxin A (PE) toxin (PE24X7) to prepare a safer immunotoxin against prostate-specific membrane antigen (PSMA) for PCa treatment. The designed anti-PSMA immunotoxin, JVM-PE24X7, was conveniently prepared in its soluble form in an Escherichia coli (E. coli) system, avoiding the complex renaturation process needed for immunotoxin preparation by the conventional strategy. The product was very stable and showed a very strong ability to bind the PSMA receptor. Cytotoxicity assays showed that this molecule at a very low concentration could kill PSMA-positive PCa cells, with an EC50 value (concentration at which the cell viability decreased by 50%) of 15.3 pM against PSMA-positive LNCaP cells. Moreover, this molecule showed very good killing selectivity between PSMA-positive and PSMA-negative cells, with a selection ratio of more than 300-fold. Animal studies showed that this molecule at a very low dosage (5 × 0.5 mg/kg once every three days) completely inhibited the growth of PCa tumors, and the maximum tolerable dose (MTD) was more than 15 mg/kg, indicating its very potent tumor-treatment ability and a wide therapeutic window. Use of the new PE toxin, PE24X7, as the effector moiety significantly reduced off-target toxicity and improved the therapeutic window of the immunotoxin. The above results demonstrate that the designed anti-PSMA immunotoxin, JVM-PE24X7, has good application value for the treatment of PCa.

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