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Most read from mAbs, May-June 2019

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The Antibody Society is pleased  to be affiliated with mAbs, a multi-disciplinary journal dedicated to advancing the art and science of antibody research and development. We hope you enjoy these summaries based on the abstracts of the most read papers published in a recent issue.

All the articles are open access; PDFs can be freely downloaded by following the links below.

Issue 11.4 (May-June 2019)

Combining the best of two worlds: highly flexible chimeric antigen receptor adaptor molecules (CAR-adaptors) for the recruitment of chimeric antigen receptor T cells.

In this review, Darowski et al. summarize emerging approaches that aim to further evolve CAR-T cell therapy based on combinations of so-called universal or modular CAR-(modCAR-)T cells, and their respective adaptor molecules (CAR-adaptors), which mediate the crosslinking between target and effector cells. The activity of such modCAR-T cells is entirely dependent on binding of the respective CAR-adaptor to both a tumor antigen and to the CAR-expressing T cell. Contrary to conventional CAR-T cells, where the immunological synapse is established by direct interaction of CAR and membrane-bound target, modCAR-T cells provide a highly flexible and customizable development of the CAR-T cell concept and offer an additional possibility to control T cell activity.

Efficient tumor killing and minimal cytokine release with novel T-cell agonist bispecific antibodies.

Using a sequence-based discovery platform, Trinklein et al. identified new anti-CD3 antibodies from humanized rats that bind to multiple epitopes and elicit varying levels of T-cell activation. In T-BsAb format, 12 different anti-CD3 arms induce equivalent levels of tumor cell lysis by primary T-cells, but potency varies by a thousand-fold. The lead CD3-targeting arm stimulates very low levels of cytokine release, but drives robust tumor antigen-specific killing in vitro and in a mouse xenograft model. This new CD3-targeting antibody underpins a next-generation T-BsAb platform in which potent cytotoxicity is uncoupled from high levels of cytokine release, which may lead to a wider therapeutic window in the clinic.

Sym021, a promising anti-PD1 clinical candidate antibody derived from a new chicken antibody discovery platform.

In this study by Gjetting et al., the Symplex antibody discovery platform was adapted to chicken immunoglobulin genes and combined with high-throughput humanization of antibody frameworks by “mass complementarity-determining region grafting”. Wild type chickens were immunized with an immune checkpoint inhibitor programmed cell death 1 (PD1) antigen, and a repertoire of 144 antibodies was generated. The PD1 antibody repertoire was successfully humanized, and the authors found that most humanized antibodies retained affinity largely similar to that of the parental chicken antibodies. The lead antibody Sym021 blocked PD-L1 and PD-L2 ligand binding, resulting in elevated T-cell cytokine production in vitro. Detailed epitope mapping showed that the epitope recognized by Sym021 was unique compared to the clinically approved PD1 antibodies pembrolizumab and nivolumab. Moreover, Sym021 bound human PD1 with a stronger affinity (30 pM) compared to nivolumab and pembrolizumab, while also cross-reacting with cynomolgus and mouse PD1. This enabled direct testing of Sym021 in the syngeneic mouse in vivo cancer models and evaluation of preclinical toxicology in cynomolgus monkeys. Preclinical in vivo evaluation in various murine and human tumor models demonstrated a pronounced anti-tumor effect of Sym021, supporting its current evaluation in a Phase 1 clinical trial.

Most read from mAbs, April 2019

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The Antibody Society is pleased and proud to be affiliated with mAbs, a multi-disciplinary journal dedicated to advancing the art and science of antibody research and development. We hope you enjoy these summaries based on the abstracts of the most read papers published in a recent issue. All the articles are open access; PDFs can be freely downloaded by following the links below.

Issue 11.3 (April 2019)

CH2 domain orientation of human immunoglobulin G in solution: Structural comparison of glycosylated and aglycosylated Fc regions using small-angle X-ray scattering

Yageta et al examined the small-angle X-ray scattering (SAXS) profile of the glycosylated Fc region (gFc) and aglycosylated Fc region (aFc) in solution to determine if removal of the N-linked glycan alters the CH2 domain orientation in the Fc region. For both gFc and aFc, the best-fitted SAXS profiles corresponded to ones calculated based on the crystal structure of gFc that formed a “semi-closed” CH2 domain orientation. Collectively, the data indicated that the removal of the N-linked glycan only negligibly affected the CH2 domain orientation in solution. Their findings will guide the development of methodology for the production of highly refined functional Fc variants.

Charge variants characterization and release assay development for co-formulated antibodies as a combination therapy

Characterization of co-formulated biologics can be challenging due to the high degree of similarity in the physicochemical properties of co-formulated proteins, especially at different concentrations of individual components. In this new report, Cao et al present the results of a deamidation study of one monoclonal antibody component (mAb-B) in co-formulated combination antibodies (referred to as COMBO) that contain various ratios of mAb-A and mAb-B. A single deamidation site in the complementarity-determining region of mAb-B was identified as a critical quality attribute (CQA) due to its impact on biological activity. A conventional charge-based method of monitoring mAb-B deamidation presented specificity and robustness challenges, especially when mAb-B was a minor component in the COMBO, making it unsuitable for lot release and stability testing. The authors developed and qualified a new, quality-control-friendly, single quadrupole Dalton mass detector (QDa)–based method to monitor site-specific deamidation. Their approach can be also used as a multi-attribute method for monitoring other quality attributes in COMBO. This analytical paradigm is applicable to the identification of CQAs in combination therapeutic molecules, and to the subsequent development of a highly specific, highly sensitive, and sufficiently robust method for routine monitoring CQAs for lot release test and during stability studies.

Capture and display of antibodies secreted by hybridoma cells enables fluorescent on-cell screening

Puligedda et. al describe a system in which hybridomas specifically capture and display the mAbs they secrete. Using On-Cell mAb Screening (OCMS™), monoclonal antibodies (mAbs) displayed on the cell surface can be rapidly assayed for expression level and binding specificity using fluorescent antigens with high-content (image-based) methods or flow cytometry. OCMS™ demonstrated specific mAb binding to poliovirus and rabies virus by forming a cell surface IgG “cap”, as a universal assay for anti-viral mAbs. The authors produced and characterized OCMS™-enabled hybridomas secreting mAbs that neutralize poliovirus and used fluorescence microscopy to identify and clone a human mAb specific for the human N-methyl-D-aspartate receptor. They also used OCMS™ to assess expression and antigen binding of a recombinant mAb produced in 293T cells.

Physicochemical and functional assessments demonstrating analytical similarity between rituximab biosimilar HLX01 and the MabThera®

As discussed by Xu et al, development of bio-therapeutics has exhibited exponential growth in China over the past decade. However, no biosimilar drug has been approved in China (CN) due to the lack of a national biosimilar regulatory guidance. HLX01, a rituximab biosimilar developed in China under European Medicines Agency biosimilar guidelines and requirements, was the first such drug submitted for regulatory review in China, and it is expected to receive approval there as a biosimilar product. To demonstrate the analytical similarities of HLX01, CN-rituximab (sourced in China but manufactured in Europe) and EU-rituximab (sourced and manufactured in Europe), an extensive 3-way physicochemical and functional similarity assessment using a series of orthogonal and state-of-the-art techniques was conducted, following the similarity requirement guidelines recently published by China’s Center for Drug Evaluation. The results of the similarity study showed an identical protein amino acid sequence and highly similar primary structures between HLX01 and the reference product (RP) MabThera®, along with high similarities in higher order structures, potency, integrity, purity and impurity profiles, biological and immunological binding functions, as well as degradation behaviors under stress conditions. In addition, HLX01 presented slightly lower aggregates and better photostability compared with the RP. Despite slight changes in relative abundance of glycan moieties and heavy chain C-terminal lysine modification, no differences in biological activities and immunological properties were observed between the RP and HLX01. In conclusion, HLX01 is highly similar to CN- and EU-sourced RP in terms of physicochemical properties and biological activities, suggesting similar product quality, efficacy, and safety. The regulatory requirements interpreted and applied towards the HLX01 marketing application sets a precedent for analytical similarity assessment of biosimilar products in China.

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Most read from mAbs, Feb/March 2019

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The Antibody Society is pleased and proud to be affiliated with mAbs, a multi-disciplinary journal dedicated to advancing the art and science of antibody research and development. We hope you enjoy these summaries based on the abstracts of the most read papers published in a recent issue. All the articles are open access; PDFs can be freely downloaded by following the links below.

Issue 11.2 (February/March 2019)

Antibodies to watch in 2019.
For the past 10 years, the annual ‘Antibodies to watch’ articles have provided updates on key events in the late-stage development of antibody therapeutics, such as first regulatory review or approval, that occurred in the year before publication or were anticipated to occur during the year of publication. To commemorate the 10th anniversary of the article series and to celebrate the 2018 Nobel Prizes in Chemistry and in Physiology or Medicine, which were given for work that is highly relevant to antibody therapeutics research and development, Kaplon and Reichert expanded the scope of the data presented to include an overview of all commercial clinical development of antibody therapeutics and approval success rates for this class of molecules. The data indicate that:
1) antibody therapeutics are entering clinical study, and being approved, in record numbers;
2) the commercial pipeline is robust, with over 570 antibody therapeutics at various clinical phases, including 62 in late-stage clinical studies; and
3) Phase 1 to approval success rates are favorable, ranging from 17–25%, depending on the therapeutic area (cancer vs. non-cancer).

Ion channels as therapeutic antibody targets.
In this review, Hutchings et al evaluate the technical challenges of raising antibodies to membrane-spanning proteins together with enabling technologies that may facilitate the discovery of antibody therapeutics to ion channels. They also discuss the potential targeting opportunities in the anti-ion channel antibody landscape, along with a number of case studies where functional antibodies that target ion channels have been reported. Antibodies currently in development and progressing towards the clinic are highlighted.

Influence of N-glycosylation on effector functions and thermal stability of glycoengineered IgG1 monoclonal antibody with homogeneous glycoforms.
The separation of various glycoforms to investigate the biological and functional relevance of glycosylation is a major challenge, and the individual contributions of each glycoform is usually not considered when evaluating mAbs with highly heterogeneous distributions. In this study, Wada et al used chemoenzymatic glycoengineering incorporating an endo-β-N-acetylglucosaminidase (ENGase) EndoS2 and its mutant with transglycosylation activity to generate mAb glycoforms with highly homogeneous and well-defined N-glycans to better understand and precisely evaluate the effect of each N-glycan structure on Fc effector functions and protein stability. They demonstrated that the core fucosylation, non-reducing terminal galactosylation, sialylation, and mannosylation of IgG1 mAb N-glycans impact not only on FcγRIIIa binding, antibody-dependent cell-mediated cytotoxicity, and C1q binding, but also FcRn binding, thermal stability and propensity for protein aggregation.

Co-engaging CD47 and CD19 with a bispecific antibody abrogates B-cell receptor/CD19 association leading to impaired B-cell proliferation.
In this report, Hatterer et al describes the generation of a CD47xCD19 bispecific antibody (biAb) to target and deplete B cells via multiple antibody-mediated mechanisms. Interestingly, the biAb, constructed of a CD19 binding arm and a CD47 binding arm, inhibited BCR-mediated B-cell proliferation with an effect even more potent than a CD19 monoclonal antibody (mAb). The inhibitory effect of the biAb was not attributable to CD47 binding because a monovalent or bivalent anti-CD47 mAb had no effect on B cell proliferation. Fluorescence resonance energy transfer analysis demonstrated that co-engaging CD19 and CD47 prevented CD19 clustering and its migration to BCR clusters, while only engaging CD19 (with a mAb) showed no impact on either CD19 clustering or migration. The lack of association between CD19 and the BCR resulted in decreased phosphorylation of CD19 upon BCR activation. Furthermore, the biAb differentially modulated BCR-induced gene expression compared to a CD19 mAb. Taken together, this unexpected role of CD47xCD19 co-ligation in inhibiting B cell proliferation illuminates a novel approach in which two B cell surface molecules can be tethered, to one another in order, which may provide a therapeutic benefit in settings of autoimmunity and B cell malignancies.

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Grad/PostDoc Poster Awards presented at Antibody Engineering &Therapeutics

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Congratulations to our 2018 Graduate Student and Post-doctoral Poster Award winners! An award ceremony was held on December 12th at the Society’s annual meeting, Antibody Engineering &Therapeutics, to recognize the recipients. The winners were:

Junpeng Qi (Postdoctoral Associate, The Scripps Research Institute). Poster title: Potent and selective antitumor activity of a T cell-engaging bispecific antibody targeting a membrane-proximal epitope of ROR1.

Pietro Sormanni (Borysiewicz Biomedical Sciences Fellow (postdoctoral), University of Cambridge). Poster title: Third generation antibody discovery: In silico rational design.

Madeleine Jennewein (Ph.D. candidate, Harvard University). Poster title: Trans-placental antibody transfer selects for highly functional antibodies.


Junpeng Qi – Scripps Research Institute (The Rader Lab)

“I would to thank The Antibody Society for giving me this award. It is a great opportunity, especially for a young scientist, to get the latest progress in antibody engineering and therapeutics, and to be connected with the excellent scientists in the antibody field. From this impressive annual meeting I learned that we can do amazing science with antibodies and develop fantastic antibody therapeutics benefiting patients as well.”

Pietro Sormanni – University of Cambridge (The Vendruscolo Lab)

“I am immensely grateful to The Antibody Society for selecting my application, and even more for organizing this award. This award has given me the opportunity to attend this terrific meeting, to learn about world-class research in both industry and academia, and more importantly to share and discuss my own work with leading scientists from across the world. I would like to stress the importance of the existence of awards such as this, and I call for the Society and the sponsors of the meeting to make available more of these awards and travel grants to early career researchers. Because at the end of the day, the growing community of postdoctoral researchers and graduate students is the engine that powers biomedical research, certainly in academia, and increasingly also in industry. And these travel grants provide us with the unique opportunity to get out of the lab, come to these meetings and greatly expand our research horizons, and generate new ideas. So I hope to see a bit more space dedicated to early career researchers in future editions of this meeting, thank you all for your attention, and again to The Antibody Society for this award.”

Madeleine F Jennewein – Harvard University (The Alter Lab)

Madeleine Jennewein was unexpectedly unable to join us at the meeting in San Diego, but we thank her for her participation and wish her the best with her work.

The Antibody Society at Antibody Engineering & Therapeutics 2018

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The Antibody Society held its 2018 annual meeting at Antibody Engineering & Therapeutics in San Diego on December 9-13. It was a a great opportunity for the board members and volunteers to meet our society members and provide updates on Society initiatives.

Informative keynote addresses were given by Prof. Andreas Plückthun (University of Zurich), Prof. David Baker (University of Washington), Prof. Rachael Clark (Harvard Medical School) and Dr. Badrul Chowdhury (Medimmune).

One of the highlights of the conference was the Antibodies to Watch in 2019 presentation by Dr. Janice Reichert (Executive Director of TAbS and Editor-in-Chief of mAbs).


The ‘Antibodies to watch in 2019’ paper is currently online in the accepted (manuscript) form. Society members will be informed when the final article, which will be open access, is available.

The Antibody Society booth at Antibody Engineering &Therapeutics