Independence of the binding of domain‐specific ligands to Fab and Fc suggests that antigen‐induced effects in IgG antibodies are not allosteric

Wright, Joel E.; Engel, Jürgen

doi:10.1016/0014-5793(78)80302-0

Cited by 15 publications

(3 citation statements)

References 18 publications

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“…in the late 1970s used spectroscopy to address this possibility, but generated negative findings: no mutual structural changes could be detected using protein A (C H 2-C H 3 specific) as the probe indicating no allosteric transmission to the Fc region. 32 On the other hand, almost 3 decades later a similar study by Oda et al. using label-free surface plasmon resonance (SPR) biosensor technique showed that the binding to either protein A or protein G (C H 1 specific) in several mAbs was inhibited in the presence of increasing antigen concentrations.…”

Section: Cooperative Mechanisms In Antibody Functionmentioning

confidence: 99%

IgG cooperativity – Is there allostery? Implications for antibody functions and therapeutic antibody development

Yang

Kroe‐Barrett

Singh

et al. 2017

mAbs

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A central dogma in immunology is that an antibody's in vivo functionality is mediated by 2 independent events: antigen binding by the variable (V) region, followed by effector activation by the constant (C) region. However, this view has recently been challenged by reports suggesting allostery exists between the 2 regions, triggered by conformational changes or configurational differences. The possibility of allosteric signals propagating through the IgG domains complicates our understanding of the antibody structure-function relationship, and challenges the current subclass selection process in therapeutic antibody design. Here we review the types of cooperativity in IgG molecules by examining evidence for and against allosteric cooperativity in both Fab and Fc domains and the characteristics of associative cooperativity in effector system activation. We investigate the origin and the mechanism of allostery with an emphasis on the C-region-mediated effects on both V and C region interactions, and discuss its implications in biological functions. While available research does not support the existence of antigen-induced conformational allosteric cooperativity in IgGs, there is substantial evidence for configurational allostery due to glycosylation and sequence variations.

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Section: Cooperative Mechanisms In Antibody Functionmentioning

confidence: 99%

IgG cooperativity – Is there allostery? Implications for antibody functions and therapeutic antibody development

Yang

Kroe‐Barrett

Singh

et al. 2017

mAbs

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“…This aggregative model for the mode of antibody action is a tenable alternative to a putative allosteric model (Metzger, 1974(Metzger, , 1978. Experiments have indicated (a) that neither hapten nor antigen binding alters the conformation of the hinge peptides of IgG (Wright et a!., 1978a), (b) that the interactions of Faband Fc-specific ligand with antibody are independent (Wright et al, 1978b), and (c) that the interheavy-chain and heavy-light-chain disulphide bonds are not indispensable for complement fixation (Wright, 1978). Such observations favour a passive, albeit specific, role for antigen in an aggregative model of antibody function.…”

mentioning

confidence: 99%

Dimeric, trimeric and tetrameric complexes of immunoglobulin G fix complement

Wright¹,

Tschopp²,

Jaton³

et al. 1980

Biochemical Journal

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The binding of pure dimers, trimers and tetramers of randomly cross-linked non-immune rabbit immunoglobulin G to the first component and subcomponent of the complement system, C1 and C1q respectively, was studied. These oligomers possessed open linear structures. All three oligomers fixed complement with decreasing affinity in the order: tetramer, trimer, dimer. Complement fixation by dimeric immunoglobulin exhibited the strongest concentration-dependence. No clear distinction between a non-co-operative and a co-operative binding mechanism could be achieved, although the steepness of the complement-fixation curves for dimers and trimers was better reflected by the co-operative mechanism. Intrinsic binding constants were about 10(6)M-1 for dimers, 10(7)M-1 for trimers and 3 X 10(9)M-1 for tetramers, assuming non-co-operative binding. The data are consistent with a maximum valency of complement component C1 for immunoglobulin G protomers in the range 6-18. The binding of dimers to purified complement subcomponent C1q was demonstrated by sedimentation-velocity ultracentrifugation. Mild reduction of the complexes by dithioerythritol caused the immunoglobulin to revert to the monomeric state (S20,w = 6.2-6.5S) with concomitant loss of complement-fixing ability.

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“…Long-range conformational interactions between the various domains of monoclonal antibodies (mAbs), particularly the variable (V) and constant (C) domains, has been a hotly debated topic since the 1970s. − Although numerous studies have suggested a functional allosteric link between antigen binding in the V domains of the antigen-binding fragment (Fab) and C domain function in the fragment crystallizable (Fc) region (reviewed in ref ), the prevailing hypothesis is that the Fab and Fc domains are functionally independent, , supported by the perceived difficulty of transmitting allosteric conformational changes via the highly flexible hinge connecting the two regions …”

mentioning

confidence: 99%

Long-Range Conformational Changes in Monoclonal Antibodies Revealed Using FPOP-LC-MS/MS

et al. 2019

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Differences in conformational dynamics between two full-length monoclonal antibodies have been probed in detail using Fast Photochemical Oxidation of Proteins (FPOP) followed by proteolysis and LC-ESI-MS/MS analyses. FPOP uses hydroxyl radical labeling to probe the surface-accessible regions of proteins and has the advantage that the resulting covalent modifications are irreversible, thus permitting optimal downstream analysis. Despite the two monoclonal antibodies (mAbs) differing by only three amino acids in the heavy chain complementarity determining regions (CDRs), one mAb, MEDI1912-WFL, has been shown to undergo reversible self-association at high concentrations and exhibited poor pharmacokinetic properties in vivo, properties which are markedly improved in the variant, MEDI1912-STT. Identifying the differences in oxidative labeling between the two antibodies at residue level revealed long-range effects which provide a key insight into their conformational differences. Specifically, the amino acid mutations in the CDR region of the heavy chain resulted in significantly different labeling patterns at the interfaces of the CL–CH1 and CH1–CH2 domains, with the nonaggregating variant undergoing up to four times more labeling in this region than the aggregation prone variant, thus suggesting a change in the structure and orientation of the CL–CH1 interface. The wealth of FPOP and LC-MS data obtained enabled the study of the LC elution properties of FPOP-oxidized peptides. Some oxidized amino acids, specifically histidine and lysine, were noted to have unique effects on the retention time of the peptide, offering the promise of using such an analysis as an aid to MS/MS in assigning oxidation sites.

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Independence of the binding of domain‐specific ligands to Fab and Fc suggests that antigen‐induced effects in IgG antibodies are not allosteric

Cited by 15 publications

References 18 publications

IgG cooperativity – Is there allostery? Implications for antibody functions and therapeutic antibody development

IgG cooperativity – Is there allostery? Implications for antibody functions and therapeutic antibody development

Dimeric, trimeric and tetrameric complexes of immunoglobulin G fix complement

Long-Range Conformational Changes in Monoclonal Antibodies Revealed Using FPOP-LC-MS/MS

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