IgG Format Research Articles

Fully human single-domain antibody targeting a highly conserved cryptic epitope on the Nipah virus G protein

Nipah virus infection, one of the top priority diseases recognized by the World Health Organization, underscores the urgent need to develop effective countermeasures against potential epidemics and pandemics. Here, we identify a fully human single-domain antibody that targets a highly conserved cryptic epitope situated at the dimeric interface of the Nipah virus G protein (receptor binding protein, RBP), as elucidated through structures by high-resolution cryo-electron microscopy (cryo-EM). This unique binding mode disrupts the tetramerization of the G protein, consequently obstructing the activation of the F protein and inhibiting viral membrane fusion. Furthermore, our investigations reveal that this compact antibody displays enhanced permeability across the blood-brain barrier (BBB) and demonstrates superior efficacy in eliminating pseudovirus within the brain in a murine model of Nipah virus infection, particularly compared to the well-characterized antibody m102.4 in an IgG1 format. Consequently, this single-domain antibody holds promise as a therapeutic candidate to prevent Nipah virus infections and has potential implications for vaccine development.

Remodeling of anti-tumor immunity with antibodies targeting a p53 mutant

Backgroundp53, the most frequently mutated gene in cancer, lacks effective targeted drugs.MethodsWe developed monoclonal antibodies (mAbs) that target a p53 hotspot mutation E285K without cross-reactivity with wild-type p53. They were delivered using lipid nanoparticles (LNPs) that encapsulate DNA plasmids. Western blot, BLI, flow cytometry, single-cell sequencing (scRNA-seq), and other methods were employed to assess the function of mAbs in vitro and in vivo.ResultsThese LNP-pE285K-mAbs in the IgG1 format exhibited a robust anti-tumor effect, facilitating the infiltration of immune cells, including CD8+ T, B, and NK cells. scRNA-seq revealed that IgG1 reduces immune inhibitory signaling, increases MHC signaling from B cells to CD8+ T cells, and enriches anti-tumor T cell and B cell receptor profiles. The E285K-mAbs were also produced in the dimeric IgA (dIgA) format, whose anti-tumor activity depended on the polymeric immunoglobulin receptor (PIGR), a membrane Ig receptor, whereas that of IgG1 relied on TRIM21, an intracellular IgG receptor.ConclusionsTargeting specific mutant epitopes using DNA-encoded and LNP-delivered mAbs represents a potential precision medicine strategy against p53 mutants in TRIM21- or PIGR-positive cancers.

Anti-CAMP1 IgG promotes macrophage phagocytosis of Cutibacterium acnes type II

Among 5 types of the Christie-Atkins-Munch-Petersen factor (CAMP) of Cutibacterium acnes, CAMP1 is highly expressed in phylotype II as well as IB, and thought to be a virulence factor of opportunistic but fatal blood, soft tissue, and implant-related infections. The target of a human single-chain variable antibody fragment (scFv), recently isolated from a phage display library, has been identified as CAMP1 of phylotype II, using immunoprecipitation followed by mass spectrometry, phage display peptide biopanning, 3D-modelling, and ELISA. The IgG1 format of the antibody could enhance phagocytosis of C. acnes DMST 14916 by THP-1 human monocytes. Our results suggest that the antibody-dependent phagocytosis process is mediated by the caveolae membrane system and involves the induction of IL-1β. This is the first report on the study of a human antibody against CAMP1 of C. acnes phylotype II, of which a potential use as therapeutic antibody against virulence C. acnes infection is postulated.

Half-life extension of single-domain antibody-drug conjugates by albumin binding moiety enhances antitumor efficacy.

Single-domain antibody-drug conjugates (sdADCs) have been proven to have deeper solid tumor penetration and intratumor accumulation capabilities due to their smaller size compared with traditional IgG format ADCs. However, one of the key challenges for improving clinical outcomes of sdADCs is their abbreviated in vivo half-life. In this study, we innovatively fused an antihuman serum albumin (αHSA) nanobody to a sdADCs targeting oncofetal antigen 5T4, conferring serum albumin binding to enhance the pharmacokinetic profiles of sdADCs. The fusion protein was conjugated with monomethyl auristatin E (MMAE) at s224c site mutation. The conjugate exhibited potent cytotoxicity against various tumor cells. Compared with the nonalbumin-binding counterparts, the conjugate exhibited a 10-fold extended half-life in wild-type mice and fivefold prolonged serum half-life in BxPC-3 xenograft tumor models as well as enhanced tumor accumulation and retention in mice. Consequently, n501-αHSA-MMAE showed potent antitumor effects, which were comparable to n501-MMAE in pancreatic cancer BxPC-3 xenograft tumor models; however, in human ovarian teratoma PA-1 xenograft tumor models, n501-αHSA-MMAE significantly improved antitumor efficacy. Moreover, the conjugate showed mitigated hepatotoxicity. In summary, our results suggested that fusion to albumin-binding moiety as a viable strategy can enhance the therapeutic potential of sdADCs through optimized pharmacokinetics.

Development of a Human B7-H3-Specific Antibody with Activity against Colorectal Cancer Cells through a Synthetic Nanobody Library.

Nanobodies have emerged as promising tools in biomedicine due to their single-chain structure and inherent stability. They generally have convex paratopes, which potentially prefer different epitope sites in an antigen compared to traditional antibodies. In this study, a synthetic phage display nanobody library was constructed and used to identify nanobodies targeting a tumor-associated antigen, the human B7-H3 protein. Combining next-generation sequencing and single-clone validation, two nanobodies were identified to specifically bind B7-H3 with medium nanomolar affinities. Further characterization revealed that these two clones targeted a different epitope compared to known B7-H3-specific antibodies, which have been explored in clinical trials. Furthermore, one of the clones, dubbed as A6, exhibited potent antibody-dependent cell-mediated cytotoxicity (ADCC) against a colorectal cancer cell line with an EC50 of 0.67 nM, upon conversion to an Fc-enhanced IgG format. These findings underscore a cost-effective strategy that bypasses the lengthy immunization process, offering potential rapid access to nanobodies targeting unexplored antigenic sites.

Abstract 6365: The bispecific antibody KA-3008, targeting both EGFR and B7H3, increases internalization and minimizes on-target, off-tumor toxicity

Abstract EGFR and B7H3 are highly expressed in various solid tumors, as well as in different normal tissues. Targeting EGFR or B7H3 alone with inhibitory monoclonal antibodies or antibody-drug conjugates (ADCs) may result in on-target, off-tumor toxicity. In this study, we developed a bispecific antibody (BsAb) named KA-3008, targeting both EGFR and B7H3 using our common light chain antibody discovery platform. KA-3008, in IgG1 format, features a regular antibody structure with an identical light chain, developed through knob-into-hole technology. Compared to its parent antibodies, its affinities for both EGFR and B7H3 decrease by more than ten times. It binds to cell lines expressing EGFR or B7H3 alone with an EC50 of more than 10nM, while it binds to cell lines expressing both EGFR and B7H3 with an EC50 of less than 1nM. KA-3008 also blocks the binding of EGF to EGFR and increases internalization when binding to both EGFR and B7H3 compared to binding to EGFR or B7H3 alone. In human tumor mouse models, KA-3008 effectively suppresses the growth of NCI-H1568 tumors expressing both EGFR and B7H3, but does not affect the growth of MS751 tumors that only highly express EGFR with low expression of B7H3. Additionally, KA-3008 has a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of this BsAb with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature, and KA-3008 shows neither aggregation nor degradation. In conclusion, the BsAb KA-3008, developed with our common light chain antibody discovery platform, is stable and holds potential for the development of ADCs targeting both EGFR and B7H3. Citation Format: Guojin Wu, Li Ding, Hao Peng, Feng Hao, Feng He, Jinying Ning. The bispecific antibody KA-3008, targeting both EGFR and B7H3, increases internalization and minimizes on-target, off-tumor toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6365.

Abstract 6362: The bispecific antibody KA-3002, targeting PSMA and 4-1BB, specifically enhances T cell activity within prostate tumors

Abstract Cancer immunotherapy with 4-1BB agonists has faced limitations in further clinical development due to dose-limiting toxicity. PSMA, highly expressed in normal prostate tissue and prostate cancer, is a clinically validated target for prostate cancer treatment. In this study, we developed a bispecific antibody (BsAb), KA-3002, targeting PSMA and human 4-1BB, with the aim of restricting 4-1BB stimulation to the interior of tumors. KA-3002 was developed based on our nanobody antibody discovery platform. KA-3002, in IgG1 format, features mutations in the Fc domain to eliminate ADCC, ADCP, and CDC activity. It contains two identical nanobodies at the C-terminal against 4-1BB to stimulate 4-1BB signaling in T cells and binds to PSMA with two Fabs at the N-terminal. KA-3002 exhibits high avidity binding to prostate tumor cells expressing PSMA (EC50<1nM) and also binds to 4-1BB expressed on 293T cells and activated human T cells. In the presence of a low concentration of CD3 antibody to stimulate T cell activation, co-culture of tumor cells expressing PSMA with primary T cells isolated from human PBMC enhances T cell activation and proliferation. In PBMC humanized immunodeficient mouse tumor models, KA-3002 effectively suppresses the growth of 22Rv1 tumors, which highly express PSMA. The antibody also demonstrates a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of this antibody with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature. KA-3002 shows neither aggregation nor degradation. In conclusion, the BsAb KA-3002, developed with our nanobody antibody discovery platform, emerges as a promising pre-clinical candidate drug for the treatment of prostate cancer. Citation Format: Guojin Wu, Jiabei Liang, Hao Peng, Feng Hao, Tongtong Liu, Jinying Ning. The bispecific antibody KA-3002, targeting PSMA and 4-1BB, specifically enhances T cell activity within prostate tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6362.

Abstract 2380: The bispecific antibody KA-3004, targeting PD-L1 and 4-1BB, is designed to enhance anti-tumor activity

Abstract Checkpoint inhibitors (CPI) have transformed the treatment landscape for advanced solid tumors; however, a majority of cancers still do not respond to immune checkpoint therapy. In this study, we developed a bispecific antibody (BsAb) named KA-3004, targeting PD-L1 and human 4-1BB, with the aim of enhancing the functionality and survival of stimulated CD8+ T cells in the tumor microenvironment. This antibody was designed using our nanobody antibody discovery platform. KA-3004, in IgG1 format, incorporates mutations in the Fc domain to eliminate ADCC, ADCP, and CDC activity. It features two identical nanobodies at the C-terminal against 4-1BB to stimulate 4-1BB signaling in T cells and binds to PD-L1 with two Fabs at the N-terminal. KA-3004 binds to PD-L1 with high affinity, blocking the interaction of PD-1 and PD-L1. It also binds to 4-1BB expressed on 293T cells and activated human T cells. In the presence of a low concentration of CD3 antibody to stimulate T cell activation, co-culture of tumor cells expressing PD-L1 with primary T cells isolated from human PBMC enhances T cell activation and proliferation. In PBMC humanized immunodeficient mouse tumor models, KA-3004 effectively suppresses the growth of NCI-H292 tumors expressing PD-L1. Additionally, KA-3004 has a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of this antibody with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature, and KA-3004 shows neither aggregation nor degradation. In conclusion, the BsAb KA-3004, developed with our nanobody antibody discovery platform, stands out as a promising pre-clinical candidate drug for the treatment of solid cancers. Citation Format: Jiabei Liang, Zhengcheng Guo, Hao Peng, Feng Hao, Tongtong Liu, Jinying Ning, Guojin Wu. The bispecific antibody KA-3004, targeting PD-L1 and 4-1BB, is designed to enhance anti-tumor activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2380.

Abstract 6366: The triple-specific antibody KA-3009 against EGFR, B7H3, and 4-1BB specifically enhances T cell activity within the tumor

Abstract Cancer immunotherapy with 4-1BB agonists faces limited further clinical development due to dose-limiting toxicity. Moreover, EGFR and B7H3 are highly expressed in various solid tumors, as well as in different normal tissues. In this study, we developed a trispecific antibody, KA-3009, targeting EGFR, B7-H3, and human 4-1BB, with the aim of restricting 4-1BB stimulation within tumors. KA-3009 was developed based on our common light chain bispecific antibody discovery platform and nanobody antibody discovery platform using knob-into-hole technology. It is in IgG1 format with mutations in the Fc domain to eliminate ADCC, ADCP, and CDC activity. Featuring two identical nanobodies at the C-terminal against 4-1BB, KA-3009 binds to EGFR and B7H3 respectively with two Fabs at the N-terminal, sharing an identical light chain. KA-3009 exhibits low avidity binding to tumor cells expressing only EGFR or B7H3, while binding to tumor cells co-overexpressing EGFR and B7H3 with increased avidity by more than ten times. Additionally, KA-3009 binds to 4-1BB expressed on 293T cells and activated human T cells. In the presence of a low concentration of CD3 antibody to stimulate T cell activation, co-culture of tumor cells co-expressing EGFR and B7H3 with primary T cells isolated from human PBMC enhances T cell activation and proliferation. In PBMC humanized immunodeficient mouse tumor models, KA-3009 effectively suppresses the growth of NCI-H1568 tumors expressing both EGFR and B7H3 but does not affect the growth of MS751 and NCI-H661 tumors, which only express EGFR or B7H3, respectively. Moreover, KA-3009 has a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of this antibody with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature, and KA-3009 shows neither aggregation nor degradation. In conclusion, the triple-specific antibody KA-3009, developed with our common light chain antibody discovery platform and nanobody antibody discovery platform, is a promising pre-clinical candidate drug for the treatment of different solid cancers that co-overexpress EGFR and B7H3. Citation Format: Guojin Wu, Tongtong Liu, Jiabei Liang, Hao Peng, Feng Hao, Jinying Ning. The triple-specific antibody KA-3009 against EGFR, B7H3, and 4-1BB specifically enhances T cell activity within the tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6366.

Abstract 2378: The triple-specific antibody KA-3003, targeting PSMA, CD28, and 4-1BB, is developed for the treatment of prostate cancer by enhancing T cell activity within the tumor

Abstract Immunotherapy, revolutionizing the treatment of advanced solid tumors by blocking PD1 signaling, has encountered a challenge in prostate cancer, exhibiting a low response ratio to anti-PD-1 therapy. Furthermore, cancer immunotherapy using 4-1BB agonists faces limited clinical development due to dose-limiting toxicity. Here, we developed a tri-specific antibody, KA-3003, targeting PSMA, CD28, and 4-1BB, with the goal of enhancing T cell activation in the tumor microenvironment. This antibody was created using our common light chain bispecific antibody discovery platform and nanobody antibody discovery platform with knob-into-hole technology. KA-3003, in IgG1 format, features mutations in the Fc domain to eliminate ADCC, ADCP, and CDC activity. It contains two identical nanobodies at the C-terminal against 4-1BB, while binding to PSMA and CD28 with two Fabs at the N-terminal, sharing an identical light chain. KA-3003 exhibits high affinity for PSMA and relatively lower affinity for CD28 and CD137. In the presence of a low concentration of CD3 antibody to stimulate T cell activation, co-culture of tumor cells expressing PSMA with primary T cells isolated from human PBMC enhances T cell activation and proliferation. In PBMC humanized immunodeficient mouse tumor models, KA-3003 effectively suppresses the growth of 22Rv1 tumors with or without a PD1 antagonist antibody. Additionally, KA-3003 has a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of this antibody with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature. KA-3003 shows neither aggregation nor degradation. In conclusion, the tri-specific antibody KA-3003, developed with our common light chain antibody discovery platform, stands out as a promising pre-clinical candidate drug for the treatment of prostate cancer. Citation Format: Guojin Wu, Zhengcheng Guo, Hao Peng, Feng Hao, Tongtong Liu, Jinying Ning. The triple-specific antibody KA-3003, targeting PSMA, CD28, and 4-1BB, is developed for the treatment of prostate cancer by enhancing T cell activity within the tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2378.

Abstract 6361: KY-HC-mouse: A low-cost and rapid nanobody discovery platform

Abstract Nanobodies, primarily derived from camelid animals, have gained prominence in antibody-drug development due to their small molecular weight and ease of modification. However, the high cost associated with camelid animals for nanobody discovery led us to develop a strain of heavy-chain mice known as KY-HC-mouse. This genetically modified mouse expresses IgG without the CH1 domain, resulting in the production of nanobodies in IgG format. Utilizing hybridoma techniques, we developed a variety of nanobodies against multiple targets, such as PSMA, CD38, PD-L1, CD28, and 4-1BB, from KY-HC-mouse. These nanobodies all demonstrate high affinity, with KD ranging from 0.01 nM to 10 nM. We also selected antagonist nanobodies that block the interaction of PD1 and PDL1, as well as agonist nanobodies that stimulate 4-1BB signaling in T cells. After humanization, most nanobodies have a half-life of more than five days in the blood of both mice and monkeys. Subjected to various treatments, such as high concentration, low pH, repeated freezing and thawing, and high temperature, most humanized nanobodies show neither aggregation nor degradation, suggesting good developability of these nanobodies. Finally, we have developed multiple bispecific antibodies (BsAbs) targeting both PDL1 and 4-1BB, PSMA and 4-1BB, or B7H3 and 4-1BB. These BsAbs exhibit good developability and efficacy. In conclusion, our KY-HC-mouse is a powerful nanobody discovery platform. Citation Format: Guojin Wu, Feng Hao, Feng He, Hao Peng, Yi Gu, Jinying Ning. KY-HC-mouse: A low-cost and rapid nanobody discovery platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6361.

Abstract 2379: The bispecific antibody KA-3007 against B7H3 and CD28 enhances T cell activation in solid tumors

Abstract Immunotherapy, revolutionizing the treatment of advanced solid tumors by blocking PD1 signaling, faces challenges as most cancers remain unresponsive to anti-PD-1 therapy. CD28, a key immune co-stimulatory receptor on T cells, often lacks ligands expressed on tumor cells. B7H3 is highly expressed in various solid tumors. In this study, we developed a bispecific antibody (BsAb) named KA-3007, targeting B7H3 and human CD28 to activate T cells in the tumor microenvironment. KA-3007, featuring an identical light chain, was developed using our common light chain bispecific antibody discovery platform with knob-into-hole technology. This BsAb is in regular IgG1 format with mutations in the Fc domain to eliminate ADCC, ADCP, and CDC activity. Its two Fabs bind to B7H3 with high affinity and CD28 with relatively low affinity. Co-culturing T cells with tumor cells expressing B7H3 enhances T cell activation. In PBMC humanized immunodeficient mouse tumor models, KA-3007 effectively suppresses the growth of NCI-H292 tumors, with or without a PD1 antagonist antibody. Furthermore, this antibody exhibits a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of KA-3007 with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature, and it shows neither aggregation nor degradation. In conclusion, the BsAb KA-3007, developed with our common light chain antibody discovery platform, emerges as a promising pre-clinical candidate drug for the treatment of solid cancers. Citation Format: Guojin Wu, Zhengcheng Guo, Hao Peng, Feng Hao, Feng He, Jinying Ning. The bispecific antibody KA-3007 against B7H3 and CD28 enhances T cell activation in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2379.

Abstract 2381: The bispecific antibody KA-3001, targeting PSMA and CD28, specifically enhances T cell activation within prostate tumors

Abstract Immunotherapy, which involves blocking PD-1 signaling, has revolutionized the treatment paradigm for advanced solid tumors. However, prostate cancer exhibits a low response ratio to anti-PD-1 therapy. In this study, we have developed a bispecific antibody (BsAb), KA-3001, targeting PSMA and human CD28, aiming to enhance T cell activation in the tumor microenvironment. KA-3001, in a regular IgG1 format, features an identical light chain and was designed using our common light chain bispecific antibody discovery platform with knob-into-hole technology. Mutations in the Fc domain were introduced to eliminate ADCC, ADCP, and CDC activity. KA-3001's two Fabs demonstrate high affinity for PSMA and relatively low affinity for CD28. In comparison to REGN5678, KA-3001 exhibits significantly stronger binding to PSMA-expressing prostate tumor cells, along with relatively lower CD28 activation, minimizing toxicity while maintaining anti-tumor efficacy. In PBMC humanized immunodeficient mouse tumor models, KA-3001 effectively suppresses the growth of 22Rv1 tumors with or without PD-1 antagonist antibody. Furthermore, KA-3001 has a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of this antibody through various treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature. The BsAb demonstrates neither aggregation nor degradation. In conclusion, the BsAb KA-3001, developed using our common light chain antibody discovery platform, stands out as a promising pre-clinical candidate drug for the treatment of prostate cancer. Citation Format: Jiabei Liang, Chen Su, Hao Peng, Feng Hao, Tongtong Liu, Jinying Ning, Guojin Wu. The bispecific antibody KA-3001, targeting PSMA and CD28, specifically enhances T cell activation within prostate tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2381.

Structure and function of therapeutic antibodies approved by the US FDA in 2023.

In calendar year 2023, the United States Food and Drug Administration (US FDA) approved a total of 55 new molecular entities, of which 12 were in the class of therapeutic antibodies. Besides antibody protein drugs, the US FDA also approved another five non-antibody protein drugs, making the broader class of protein drugs about 31% of the total approved drugs. Among the 12 therapeutic antibodies approved by the US FDA, 8 were relatively standard IgG formats, 3 were bivalent, bispecific antibodies and 1 was a trivalent, bispecific antibody. In 2023, no new antibody-drug conjugates, immunocytokines or chimeric antigen receptor-T cells were approved. Of the approved antibodies, two targeted programmed cell death receptor-1 (PD-1) for orphan indications, two targeted CD20 for diffuse large B cell lymphoma, two targeted different receptors (B-cell maturation antigen [BCMA] and G-coupled protein receptor class C, group 5, member D [GPRC5D]) for treatment of multiple myeloma, and one each that targeted amyloid-β protofibrils for Alzheimer's disease, neonatal Fc receptor alpha-chain for myasthenia gravis, complement factor C5 for CD55 deficiency with hyper-activation of complement, angiopathic thrombosis and severe protein-losing enteropathy disease, interleukin (IL)-23p19 for severely active ulcerative colitis, IL-17A-F for plaque psoriasis and respiratory syncytial virus (RSV)-F protein for season-long RSV prophylaxis in infants.

Bovine ultralong CDR-H3 derived knob paratopes elicit potent TNF-α neutralization and enable the generation of novel adalimumab-based antibody architectures with augmented features.

In this work we have generated cattle-derived chimeric ultralong CDR-H3 antibodies targeting tumor necrosis factor α (TNF-α) via immunization and yeast surface display. We identified one particular ultralong CDR-H3 paratope that potently neutralized TNF-α. Interestingly, grafting of the knob architecture onto a peripheral loop of the CH3 domain of the Fc part of an IgG1 resulted in the generation of a TNF-α neutralizing Fc (Fcknob) that did not show any potency loss compared with the parental chimeric IgG format. Eventually, grafting this knob onto the CH3 region of adalimumab enabled the engineering of a novel TNF-α targeting antibody architecture displaying augmented TNF-α inhibition.

I-shaped antibody engineering enables conformational tuning of biotherapeutic receptor agonists

The ability to leverage antibodies to agonize disease relevant biological pathways has tremendous potential for clinical investigation. Yet while antibodies have been successful as antagonists, immune mediators, and targeting agents, they are not readily effective at recapitulating the biology of natural ligands. Among the important determinants of antibody agonist activity is the geometry of target receptor engagement. Here, we describe an engineering approach inspired by a naturally occurring Fab-Fab homotypic interaction that constrains IgG in a unique i-shaped conformation. i-shaped antibody (iAb) engineering enables potent intrinsic agonism of five tumor necrosis factor receptor superfamily (TNFRSF) targets. When applied to bispecific antibodies against the heterodimeric IL-2 receptor pair, constrained bispecific IgG formats recapitulate IL-2 agonist activity. iAb engineering provides a tool to tune agonist antibody function and this work provides a framework for the development of intrinsic antibody agonists with the potential for generalization across broad receptor classes.

Antibody sequence-based prediction of pH gradient elution in multimodal chromatography

Multimodal chromatography has emerged as a promising technique for antibody purification, owing to its capacity to selectively capture and separate target molecules. However, the optimization of chromatography parameters remains a challenge due to the intricate nature of protein-ligand interactions. To tackle this issue, efficient predictive tools are essential for the development and optimization of multimodal chromatography processes. In this study, we introduce a methodology that predicts the elution behavior of antibodies in multimodal chromatography based on their amino acid sequences. We analyzed a total of 64 full-length antibodies, including IgG1, IgG4, and IgG-like multispecific formats, which were eluted using linear pH gradients from pH 9.0 to 4.0 on the anionic mixed-mode resin Capto adhere. Homology models were constructed, and 1312 antibody-specific physicochemical descriptors were calculated for each molecule. Our analysis identified six key structural features of the multimodal antibody interaction, which were correlated with the elution behavior, emphasizing the antibody variable region. The results show that our methodology can predict pH gradient elution for a diverse range of antibodies and antibody formats, with a test set R² of 0.898. The developed model can inform process development by predicting initial conditions for multimodal elution, thereby reducing trial and error during process optimization. Furthermore, the model holds the potential to enable an in silico manufacturability assessment by screening target antibodies that adhere to standardized purification conditions. In conclusion, this study highlights the feasibility of using structure-based prediction to enhance antibody purification in the biopharmaceutical industry. This approach can lead to more efficient and cost-effective process development while increasing process understanding.

Chimeric antibody targeting unique epitope on onco-mucin16 reduces tumor burden in pancreatic and lung malignancies

Aberrantly expressed onco-mucin 16 (MUC16) and its post-cleavage generated surface tethered carboxy-terminal (MUC16-Cter) domain are strongly associated with poor prognosis and lethality of pancreatic (PC) and non-small cell lung cancer (NSCLC). To date, most anti-MUC16 antibodies are directed towards the extracellular domain of MUC16 (CA125), which is usually cleaved and shed in the circulation hence obscuring antibody accessibility to the cancer cells. Herein, we establish the utility of targeting a post-cleavage generated, surface-tethered oncogenic MUC16 carboxy-terminal (MUC16-Cter) domain by using a novel chimeric antibody in human IgG1 format, ch5E6, whose epitope expression directly correlates with disease severity in both cancers. ch5E6 binds and interferes with MUC16-associated oncogenesis, suppresses the downstream signaling pFAK(Y397)/p-p70S6K(T389)/N-cadherin axis and exert antiproliferative effects in cancer cells, 3D organoids, and tumor xenografts of both PC and NSCLC. The robust clinical correlations observed between MUC16 and N-cadherin in patient tumors and metastatic samples imply ch5E6 potential in targeting a complex and significantly occurring phenomenon of epithelial to mesenchymal transition (EMT) associated with disease aggressiveness. Our study supports evaluating ch5E6 with standard-of-care drugs, to potentially augment treatment outcomes in malignancies inflicted with MUC16-associated poor prognosis.

Antibody aggregation can lead to reduced Protein A binding capacity and low step yield

Protein A affinity chromatography has been widely used for antibody capture and initial purification. In general, the yield of this step is relatively high (i.e., >90%). However, recently while purifying a bispecific antibody (bsAb) in appended IgG format, the Protein A capture step experienced low yield (i.e., ∼80%). It was found that the target bsAb started appearing in flow-through at a relatively low load density, suggesting that a portion of the expressed bsAb has compromised Protein A binding capability. Further studies indicated that the bsAb in flow-through was mainly in aggregate form. In addition, normal Protein A step yield was restored when the column was loaded with bsAb monomer. Thus, all the evidence pointed to the fact that aggregate with compromised binding capacity was the cause of low Protein A step yield in this case.

A fully human connective tissue growth factor blocking monoclonal antibody ameliorates experimental rheumatoid arthritis through inhibiting angiogenesis

BackgroundConnective tissue growth factor (CTGF) plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA) by facilitating angiogenesis and is a promising therapeutic target for RA treatment. Herein, we generated a fully human CTGF blocking monoclonal antibody (mAb) through phage display technology.ResultsA single-chain fragment variable (scFv) with a high affinity to human CTGF was isolated through screening a fully human phage display library. We carried out affinity maturation to elevate its affinity for CTGF and reconstructed it into a full-length IgG1 format for further optimization. Surface plasmon resonance (SPR) data showed that full-length antibody IgG mut-B2 bound to CTGF with a dissociation constant (KD) as low as 0.782 nM. In the collagen-induced arthritis (CIA) mice, IgG mut-B2 alleviated arthritis and decreased the level of pro-inflammatory cytokines in a dose-dependent manner. Furthermore, we confirmed that the TSP-1 domain of CTGF is essential for the interaction. Additionally, the results of Transwell assays, tube formation experiments, and chorioallantoic membrane (CAM) assays showed that IgG mut-B2 could effectively inhibit angiogenesis.ConclusionThe fully human mAb that antagonizes CTGF could effectively alleviate arthritis in CIA mice, and its mechanism is tightly associated with the TSP-1 domain of CTGF.