A Modeling and Experimental Investigation of the Effects of Antigen Density, Binding Affinity, and Antigen Expression Ratio on Bispecific Antibody Binding to Cell Surface Targets

Rhoden, John J.; Dyas, Gregory L.; Wroblewski, Victor J.

doi:10.1074/jbc.m116.714287

Cited by 50 publications

(58 citation statements)

References 34 publications

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“…While structural modeling suggests that simultaneous engagement of two epitopes on the same toxin molecule by a single antibody is unlikely, it is possible that the presence of a second epitope nearby makes it easier for a bivalent construct to rebind the same toxin, essentially "wobbling" between the two epitopes. Avidity effects of multivalent and bispecific formats have been modeled (51) and have been proposed as a way to drive higher-affinity and higher-specificity binding of targets with multiple epitopes. Alternatively, bridging of two toxin molecules by one monoclonal antibody can allow bivalent binding of a second antibody to a different epitope, which has been proposed as a mechanism for synergy in the neutralization of anthrax toxin (52).…”

Section: Discussionmentioning

confidence: 99%

Synergistic Neutralization of Pertussis Toxin by a Bispecific Antibody In Vitro and In Vivo

Wagner

Wang

Bui

et al. 2016

Clin Vaccine Immunol

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Bispecific antibodies are a rapidly growing class of therapeutic molecules, originally developed for the treatment of cancer but recently explored for the treatment of autoimmune and infectious diseases. Bordetella pertussis is a reemerging pathogen, and several of the key symptoms of infection are caused by the pertussis toxin (PTx). Two humanized antibodies, hu1B7 and hu11E6, bind distinct epitopes on PTx and, when coadministered, mitigate disease severity in murine and baboon models of infection. Here we describe the generation of a bispecific human IgG1 molecule combining the hu1B7 and hu11E6 binding sites via a knobs-in-holes design. The bispecific antibody showed binding activity equivalent to that of the antibody mixture in a competition enzyme-linked immunosorbent assay (ELISA). A CHO cell neutralization assay provided preliminary evidence for synergy between the two antibodies, while a murine model of PTx-induced leukocytosis definitively showed synergistic neutralization. Notably, the bispecific antibody retained the synergy observed for the antibody mixture, supporting the conclusion that synergy is due to simultaneous blockade of both the catalytic and receptor binding activities of pertussis toxin. These data suggest that a hu1B7/hu11E6 bispecific antibody is a viable alternative to an antibody mixture for pertussis treatment. Despite vaccination, pertussis infection continues to cause ϳ195,000 deaths worldwide, primarily of infants (1). Of the estimated 16 million cases of pertussis each year, ϳ95% occur in the developing world. Even in developed countries, the disease incidence has increased dramatically over the last decade, reaching prevaccination levels in some countries (2, 3). This rise has been attributed to shortcomings of the current acellular vaccine (4) as well as pathogen adaptation (5). In both cases, high levels of circulating disease place young infants at risk, as this population is the most susceptible to severe disease. An antibody therapeutic could be used to treat seriously ill infants in the developing world and to prevent disease in high-risk areas.Pertussis toxin (PTx) is one of several virulence factors secreted by the Gram-negative bacterium Bordetella pertussis. PTx is directly responsible for suppression of the innate immune system (6) and for systemic leukocytosis, which is the key clinical indicator of severe disease and appears to be directly responsible for pulmonary hypertension and organ failure (7). In addition, low titers of PTx-neutralizing antibodies correlate with susceptibility to clinical infection (8). We previously developed a binary mixture of two humanized anti-pertussis toxin antibodies which was able to mitigate whooping cough in mouse and baboon models of infection (9). The antibody hu11E6 blocks binding of the toxin to host cells, while the antibody hu1B7 interferes with the catalytic pathway. At a dose selected to demonstrate efficacy but not synergy, the individual antibodies and the mixture were able to completely suppress leukocytosis in a murine ...

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Section: Discussionmentioning

confidence: 99%

Synergistic Neutralization of Pertussis Toxin by a Bispecific Antibody In Vitro and In Vivo

Wagner

Wang

Bui

et al. 2016

Clin Vaccine Immunol

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“…Further challenges are posed by unknown numbers and distributions of receptors on cell surfaces, as well as the lack of structural information on many of them . Improving our understanding of the numerous factors that have a role in tumor targeting requires the development of both theoretical and experimental models that can guide the design of tumor‐targeting antibodies and antibody mimetics for optimal affinity and efficacy …”

Section: Introductionmentioning

confidence: 99%

Synthetic Cancer‐Targeting Innate Immune Stimulators Give Insights into Avidity Effects

Conibear

Pötgens²,

Thewes

et al. 2018

ChemBioChem

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Multispecific and multivalent antibodies are seen as promising cancer therapeutics, and numerous antibody fragments and derivatives have been developed to exploit avidity effects that result in increased selectivity. Most of these multispecific and multivalent antibody strategies make use of recombinant expression of antigen-binding modules. In contrast, chemical synthesis and chemoselective ligations can be used to generate a variety of molecules with different numbers and combinations of binding moieties in a modular and homogeneous fashion. In this study we synthesized a series of targeted immune system engagers (ISErs) by using solid-phase peptide synthesis and chemoselective ligations. To explore avidity effects, we constructed molecules bearing different numbers and combinations of two "binder" peptides that target ephrin A2 and integrin α receptors and an "effector" peptide that binds to formyl peptide receptors and stimulates an immune response. We investigated various strategies for generating multivalent and multispecific targeted innate immune stimulators and studied their activities in terms of binding to cancer cells and stimulation of immune cells. This study gives insights into the influence that multivalency and receptor density have on avidity effects and is useful for the design of potential anticancer therapeutics.

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“…In the future, the model and its approximation can be extended with (i) TC effects on target cells, (ii) T cell rebound phenomena, and (iii) integration of local geometrical structures on the cell surface for the cross‐linking binding reactions . Inclusion of geometrical structures leads to mathematical models of the form Eqs.…”

Section: Discussionmentioning

confidence: 99%

“…Binding kinetics of the BsAb [12][13][14][15][16] are presented in Figure 1a. It is assumed that free BsAb concentration C binds to two targets (e.g., receptors) R A and R B to form BCs, RC A and RC B .…”

Section: Theoretical (Model Structure and Equations)mentioning

confidence: 99%

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Target‐Mediated Drug Disposition Model for Bispecific Antibodies: Properties, Approximation, and Optimal Dosing Strategy

Schropp

Khot

Shah

et al. 2019

CPT Pharmacom & Syst Pharma

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Bispecific antibodies (BsAbs) bind to two different targets, and create two binary and one ternary complex ( TC ). These molecules have shown promise as immuno‐oncology drugs, and the TC is considered the pharmacologically active species that drives their pharmacodynamic effect. Here, we have presented a general target‐mediated drug disposition (TMDD) model for these BsAbs, which bind to two different targets on different cell membranes. The model includes four different binding events for BsAbs, turnover of the targets, and internalization of the complexes. In addition, a quasi‐equilibrium (QE) approximation with decreased number of binding parameters and, if necessary, reduced internalization parameters is presented. The model is further used to investigate the kinetics of BsAb and TC concentrations. Our analysis shows that larger doses of BsAbs may delay the build‐up of the TC . Consequently, a method to compute the optimal dosing strategy of BsAbs, which will immediately create and maintain maximal possible TC concentration, is presented.

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A Modeling and Experimental Investigation of the Effects of Antigen Density, Binding Affinity, and Antigen Expression Ratio on Bispecific Antibody Binding to Cell Surface Targets

Cited by 50 publications

References 34 publications

Synergistic Neutralization of Pertussis Toxin by a Bispecific Antibody In Vitro and In Vivo

Synergistic Neutralization of Pertussis Toxin by a Bispecific Antibody In Vitro and In Vivo

Synthetic Cancer‐Targeting Innate Immune Stimulators Give Insights into Avidity Effects

Target‐Mediated Drug Disposition Model for Bispecific Antibodies: Properties, Approximation, and Optimal Dosing Strategy

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