Enhancement of Immune Effector Functions by Modulating IgG’s Intrinsic Affinity for Target Antigen

Mazor, Yariv; Yang, Chunshu; Borrok, M. Jack; Ayriss, Joanne; Aherne, Karen; Wu, Herren; Dall’Acqua, William F.

doi:10.1371/journal.pone.0157788

Cited by 32 publications

(48 citation statements)

References 46 publications

(45 reference statements)

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“…To determine how the intrinsic binding affinity of the anti-EGFR arm regulates target selectivity, we constructed an array of affinity-reduced variants of the GA201 mAb by employing alanine mutagenesis to exposed residues in complementarity-determining region (CDR)H3 and L329. The variable domains of three variants exhibiting a ~10–250-fold reduction in affinity compared with the parental sequence were paired with the trastuzumab arm and converted into a DuetMab format.…”

Section: Resultsmentioning

confidence: 99%

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Enhanced tumor-targeting selectivity by modulating bispecific antibody binding affinity and format valence

Mazor¹,

Sachsenmeier

Yang³

et al. 2017

Sci Rep

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103

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Bispecific antibodies are considered attractive bio-therapeutic agents owing to their ability to target two distinct disease mediators. Cross-arm avidity targeting of antigen double-positive cancer cells over single-positive normal tissue is believed to enhance the therapeutic efficacy, restrict major escape mechanisms and increase tumor-targeting selectivity, leading to reduced systemic toxicity and improved therapeutic index. However, the interplay of factors regulating target selectivity is not well understood and often overlooked when developing clinically relevant bispecific therapeutics. We show in vivo that dual targeting alone is not sufficient to endow selective tumor-targeting, and report the pivotal roles played by the affinity of the individual arms, overall avidity and format valence. Specifically, a series of monovalent and bivalent bispecific IgGs composed of the anti-HER2 trastuzumab moiety paired with affinity-modulated VH and VL regions of the anti-EGFR GA201 mAb were tested for selective targeting and eradication of double-positive human NCI-H358 non-small cell lung cancer target tumors over single-positive, non-target NCI-H358-HER2 CRISPR knock out tumors in nude mice bearing dual-flank tumor xenografts. Affinity-reduced monovalent bispecific variants, but not their bivalent bispecific counterparts, mediated a greater degree of tumor targeting selectivity, while the overall efficacy against the targeted tumor was not substantially affected.

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Section: Resultsmentioning

confidence: 99%

“…Alanine mutagenesis of targeted residues in CDRH3 and L3 of the anti-EGFR GA201 mAb was performed by site-directed mutagenesis using standard PCR techniques essentially as described29. For production as human IgG1, V H and V L DNA segments were cloned into an Orip/EBNA-1-based episomal mammalian expression plasmid, pOE as described51.…”

Section: Methodsmentioning

confidence: 99%

Enhanced tumor-targeting selectivity by modulating bispecific antibody binding affinity and format valence

Mazor¹,

Sachsenmeier

Yang³

et al. 2017

Sci Rep

Self Cite

103

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“…This has been hypothesized to result from the increased off-rates with lower affinity Fab-antigen interactions, leading to more monovalent Fab-antigen interactions and increased potential for dense IgG opsonization (1 Fc domain per 1 bound Fab domain). In contrast, higher affinity IgGs are more likely to form bivalent interactions with antigen (1 Fc domain per 2 bound Fab domains), limiting the potential for dense IgG binding (117). ADCC mediated by broadly reactive anti-HA mAbs may also be supported through increased affinity between target and effector cell due to broadly neutralizing mAb Fc-FcγRIIIa engagement in conjunction with binding by the viral HA to sialic acids on the effector cell (118).…”

Section: Signaling and Function Of Anti-tumor Antibodiesmentioning

confidence: 99%

Signaling by Antibodies: Recent Progress

Bournazos

Wang²,

Dahan³

et al. 2017

Annu. Rev. Immunol.

176

184

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IgG antibodies mediate a diversity of immune functions by coupling of antigen specificity through the Fab domain to signal transduction via Fc-Fc receptor interactions. Indeed, balanced IgG signaling through Type I and Type II Fc receptors is required for the control of pro-inflammatory, anti-inflammatory, and immunomodulatory processes. In this review, we discuss the mechanisms that govern IgG-Fc receptor interactions, highlighting the diversity of Fc receptor-mediated effector functions that regulate immunity and inflammation, as well as determine susceptibility to infection and autoimmunity, and responsiveness to antibody-based therapeutics, and vaccine responses.

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“…We recently reported that the intrinsic affinity of antibody to the target antigen directly influenced the extent and efficiency of ADCC. 39 More specifically, using an array of affinity-modulated anti-CD4, epidermal growth factor receptor (EGFR), and human epidermal growth factor receptor 2 (HER2) model mAbs, we have shown that at saturating antibody concentrations, IgG variants with moderate intrinsic affinities (dissociation constant [K D ]~10-150 nM), similar to those generated by the primary humoral immune response, exhibited ADCC that was superior to that of their affinity-improved counterparts (K D ≤1 nM). We further demonstrated that reformatting these high-affinity bivalent IgGs into monovalent formats resulted in substantial augmentation of ADCC.…”

Section: Introductionmentioning

confidence: 99%

“…We further demonstrated that reformatting these high-affinity bivalent IgGs into monovalent formats resulted in substantial augmentation of ADCC. 39 We speculated that IgG antibodies with faster off-rates are likely to dissociate each binding arm more rapidly, resulting in a higher propensity of monovalent engagement with the target cell. This binding mode promotes enhanced opsonization of the target cell, leading to improved recruitment of effector cells.…”

Section: Introductionmentioning

confidence: 99%

Regulation of antibody-mediated complement-dependent cytotoxicity by modulating the intrinsic affinity and binding valency of IgG for target antigen

Wang

Yang

Jin

et al. 2019

mAbs

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Complement-dependent cytotoxicity (CDC) is a potent effector mechanism, engaging both innate and adaptive immunity. Although strategies to improve the CDC activity of antibody therapeutics have primarily focused on enhancing the interaction between the antibody crystallizable fragment (Fc) and the first subcomponent of the C1 complement complex (C1q), the relative importance of intrinsic affinity and binding valency of an antibody to the target antigen is poorly understood. Here we show that antibody binding affinity to a cell surface target antigen evidently affects the extent and efficacy of antibody-mediated complement activation. We further report the fundamental role of antibody binding valency in the capacity to recruit C1q and regulate CDC. More specifically, an array of affinity-modulated variants and functionally monovalent bispecific derivatives of high-affinity anti-epidermal growth factor receptor (EGFR) and anti-human epidermal growth factor receptor 2 (HER2) therapeutic immunoglobulin Gs (IgGs), previously reported to be deficient in mediating complement activation, were tested for their ability to bind C1q by biolayer interferometry using antigen-loaded biosensors and to exert CDC against a panel of EGFR and HER2 tumor cells of various histological origins. Significantly, affinity-reduced variants or monovalent derivatives, but not their high-affinity bivalent IgG counterparts, induced near-complete cell cytotoxicity in tumor cell lines that had formerly been shown to be resistant to complement-mediated attack. Our findings suggest that monovalent target engagement may contribute to an optimal geometrical positioning of the antibody Fc to engage C1q and deploy the complement pathway.

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Enhancement of Immune Effector Functions by Modulating IgG’s Intrinsic Affinity for Target Antigen

Cited by 32 publications

References 46 publications

Enhanced tumor-targeting selectivity by modulating bispecific antibody binding affinity and format valence

Enhanced tumor-targeting selectivity by modulating bispecific antibody binding affinity and format valence

Signaling by Antibodies: Recent Progress

Regulation of antibody-mediated complement-dependent cytotoxicity by modulating the intrinsic affinity and binding valency of IgG for target antigen

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