scholarly journals Allosteric Effects between the Antibody Constant and Variable Regions: A Study of IgA Fc Mutations on Antigen Binding

2018 ◽  
Author(s):  
Chinh Tran-To Su ◽  
Wai-Heng Lua ◽  
Wei-Li Ling ◽  
Samuel Ken-En Gan
Keyword(s):  
Small Molecules ◽  
Cell Activity ◽  
Systemic Circulation ◽  
Antigen Binding ◽  
Constant Region ◽  
Variable Regions ◽  
Functional Regions ◽  
Igg Isotypes ◽  
Iga Antibody ◽  
Conventional Idea

Therapeutics antibodies have increasingly shifted the paradigm of disease treatments, from small molecules to biologics, especially in cancer therapy. Despite the increasing number of antibody candidates, much remains unknown about the antibody and how its various regions interact. In fact, the constant region can govern effects that might be useful in reducing the unwanted consequences resulted from systemic circulation. For this reason, apart from the commonly used IgG isotypes, IgA antibodies are promising therapeutics drugs, given its localized mucosal effects. While the antibody Fc effector cell activity has been well explored, recent research has shown evidences that the constant region of the antibody can also influence antigen binding, challenging the conventional idea of region-specific antibody functions. To further investigate this, we analyzed the IgA antibody constant and its allosteric effects onto the antigen binding regions, using recombinant Pertuzumab IgA1 and IgA2 variants. We found mutations in the C-region to reduce Her2 binding, and our computational structural analysis showed that such allosteric communications were highly dependent on the antibody hinge, providing the evidence to consider antibodies as a whole protein rather than a sum of functional regions.

scholarly journals The constant region affects antigen binding of antibodies to DNA by altering secondary structure

2013 ◽  
Vol 56 (1-2) ◽  
pp. 28-37 ◽  
Author(s):  
Yumin Xia ◽  
Alena Janda ◽  
Ertan Eryilmaz ◽  
Arturo Casadevall ◽  
Chaim Putterman
Keyword(s):  
Secondary Structure ◽  
Antigen Binding ◽  
Constant Region ◽  
Antibodies To Dna

scholarly journals The Activation-induced Deaminase Functions in a Postcleavage Step of the Somatic Hypermutation Process

2002 ◽  
Vol 195 (9) ◽  
pp. 1193-1198 ◽  
Author(s):  
F. Nina Papavasiliou ◽  
David G. Schatz
Keyword(s):  
Somatic Hypermutation ◽  
Cytidine Deaminase ◽  
Point Mutations ◽  
Dna Lesions ◽  
Dominant Negative ◽  
Constant Region ◽  
Region Gene ◽  
Variable Regions ◽  
Class Switch ◽  
Activation Induced Deaminase

Activation of B cells by antigen fuels two distinct molecular modifications of immunoglobulin (Ig) genes. Class-switch recombination (CSR) replaces the Igμ heavy chain constant region with a downstream constant region gene, thereby altering the effector function of the resulting antibodies. Somatic hypermutation (SHM) introduces point mutations into the variable regions of Ig genes, thereby changing the affinity of antibody for antigen. Mechanistic overlap between the two reactions has been suggested by the finding that both require the activation-induced cytidine deaminase (AID). It has been proposed that AID initiates both CSR and SHM by activating a common nuclease. Here we provide evidence that cells lacking AID, or expressing a dominant negative form of the protein, are still able to incur DNA lesions in SHM target sequences. The results indicate that an intact cytidine deaminase motif is required for AID function, and that AID acts downstream of the initial DNA lesions in SHM.

scholarly journals Molecular characterization of antibodies bearing Id-460. II. Molecular basis for Id-460 expression.

1985 ◽  
Vol 162 (5) ◽  
pp. 1494-1511 ◽  
Author(s):  
E A Dzierzak ◽  
P Brodeur ◽  
T Marion ◽  
C A Janeway ◽  
A Bothwell
Keyword(s):  
Molecular Basis ◽  
Molecular Genetic ◽  
Gene Segment ◽  
Binding Specificity ◽  
Antigen Binding ◽  
Measurable Effect ◽  
Variable Regions ◽  
Genetic Level

Id-460+ immunoglobulins can be induced in vivo by immunization with dinitrophenyl (DNP) or P. pneumotropica and form two nonoverlapping groups of antibodies with respect to antigen binding specificity. In this study, using Id-460+ antibodies of differing antigen binding specificities, we compared on the molecular genetic level the five gene segment combinations (VH, DH, JH, VL, and JL) that encode the variable regions of these idiotype-positive immunoglobulins. The Id-460 determinant appears to be a conformational or combinatorial determinant encoded by VH460 and VK1 crosshybridizing genes. DH, JH, and JK gene segments appear to have no measurable effect upon expression of Id-460. Finally, antigen binding specificity does not appear to simply localize to any particular gene segment but may in part be the result of somatic mutation and/or VDJH junctional sequences, whose length correlates roughly with antigen binding specificity.

scholarly journals Kappa-on-Heavy (KoH) bodies are a distinct class of fully-human antibody-like therapeutic agents with antigen-binding properties

2019 ◽  
Vol 117 (1) ◽  
pp. 292-299 ◽  
Author(s):  
Lynn E. Macdonald ◽  
Karoline A. Meagher ◽  
Matthew C. Franklin ◽  
Natasha Levenkova ◽  
Johanna Hansen ◽  
...  
Keyword(s):  
Small Molecules ◽  
Binding Pocket ◽  
Human Antibody ◽  
Antigen Binding ◽  
Wild Type ◽  
Antigen Binding Site ◽  
Binding Properties ◽  
Variable Domains ◽  
Constant Domains ◽  
Ig Heavy Chain

We describe a Kappa-on-Heavy (KoH) mouse that produces a class of highly diverse, fully human, antibody-like agents. This mouse was made by replacing the germline variable sequences of both the Ig heavy-chain (IgH) and Ig kappa (IgK) loci with the human IgK germline variable sequences, producing antibody-like molecules with an antigen binding site made up of 2 kappa variable domains. These molecules, named KoH bodies, structurally mimic naturally existing Bence-Jones light-chain dimers in their variable domains and remain wild-type in their antibody constant domains. Unlike artificially diversified, nonimmunoglobulin alternative scaffolds (e.g., DARPins), KoH bodies consist of a configuration of normal Ig scaffolds that undergo natural diversification in B cells. Monoclonal KoH bodies have properties similar to those of conventional antibodies but exhibit an enhanced ability to bind small molecules such as the endogenous cardiotonic steroid marinobufagenin (MBG) and nicotine. A comparison of crystal structures of MBG bound to a KoH Fab versus a conventional Fab showed that the KoH body has a much deeper binding pocket, allowing MBG to be held 4 Å further down into the combining site between the 2 variable domains.

scholarly journals Global structures of IgG isotypes expressing identical variable regions

2013 ◽  
Vol 56 (4) ◽  
pp. 588-598 ◽  
Author(s):  
Ertan Eryilmaz ◽  
Alena Janda ◽  
Jungwook Kim ◽  
Radames J.B. Cordero ◽  
David Cowburn ◽  
...  
Keyword(s):  
Variable Regions ◽  
Igg Isotypes

scholarly journals Inhibition of T-antigen-binding cells by idiotypic antisera.

1977 ◽  
Vol 146 (3) ◽  
pp. 766-778 ◽  
Author(s):  
C A Prange ◽  
J Fiedler ◽  
D E Nitecki ◽  
C J Bellone
Keyword(s):  
T Cells ◽  
Lymph Node ◽  
Guinea Pig ◽  
T Cell Receptors ◽  
Binding Assay ◽  
T Antigen ◽  
Antigen Binding ◽  
Variable Regions ◽  
Heterologous System ◽  
Lymph Node Cells

Shared idiotypy between B- and T-cell receptors specific for the antigen L-tyrosine-p-azophenyltrimethylammonium [tyr(TMA)] was studied in an antigen-binding assay using idiotypic antisera. These idiotypic reagents were prepared by inoculation of rabbits with purified anti-tyr(TMA) antibody raised in strain 13 guinea pigs. The antisera blocked 78-83% of the antigen-binding T cells (T-ABC) and 50-55% of the antigen-binding B cells (B-ABC) from tyr(TMA)-immune strain 13 and outbred lymph node cells (LNC). An excess of normal guinea pig Ig in the ABC assay did not affect the ability of the idiotypic antisera to block T- and B-ABC. Nylon wool-passed tyr(TMA)-immune LNC were trypsin treated resulting in a 75% loss of T-ABC. The trypsin-treated population was then cultured for 16 h which resulted in a return of T-ABC to 92% of pretrypsin values. 77% of these regenerated T-ABC could be blocked with idiotypic antisera. Specificity of the idiotypic antisera was tested in L-tyrosine-p-azobenzenearsonate-immune guinea pig LNC. Neither T- nor B-ABC were blocked in this heterologous system. Further blocking experiments were performed to characterize the nature of the T-ABC receptor. A variety of anti-Ig reagents, some of which block B-ABC, do not inhibit T-ABC suggesting that variable regions on T cells are not linked to Ig Constant regions.

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