Antigen binding regions

Ab2 S Anti-idiotype antibody which binds to the antigen binding region Ab3 Anti-anti-idiotype antibody Abcc Antibody dependent cellular cytotoxicity... 

Figure 20.9 Polysaccharide groups on antibody molecules may be oxidized with periodate to create aldehydes. Modification with biotin-hydrazide results in hydrazone linkages. The sites of modification using this technique often are away from the antibody-antigen binding regions, thus preserving antibody activity.

Humanized Antibodies To further improve the avidity and reduce antigenicity, only the specific antigen-binding region is derived from mouse, while the remainder of the antibody is constructed using human proteins. These are the humanized antibodies and include the breast cancer targeting MAb called Herceptin (see Case Study 4). 

Fig. 2. Structure of the antibody Fab fusion protein expressed from the vector in Fig. 1 The antigen-binding region is formed by the VH and VL domains, the foreign protein (FP) fused to the truncated hinge region (H1) may be a toxin or prodrug activating enzyme.

Fig. 11.9. Result of randomization on part of the antigen-binding region of an Fd fragment (PDB file laqk, chain H).

Tig. 11.10. Z-score distribution for two randomized regions of an Fd fragment (PDB file laqk, chain H). White bars residues 100, 104—106 (part of antigen binding region), black bars residues 153, 180, 182, 184 (in loop of C-terminal half of the chain). The arrow marks the z-score of tire wild type. 

After penetrating into cells, these autoantibodies may localize within the cytoplasm or the nucleus, or recycle back to the cell membrane (R6). How do the antibodies localize to the nucleus Conformational analysis of the antibodies indicates that their antigen-binding regions share a tertiary structure resembling nuclear localization sequences (F6). 

Each end of Y is called the Fab (fragment, antigen binding) region... 

Figure 7-5 a Structure of Immunoglobulin G (IgG), showing antigen-binding regions and key elements of the molecule. 

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