Antibody

From Proteopedia

Revision as of 10:00, 9 February 2014

spinqualitylabelsall models Glycosylated human Igg with heavy chains (red and light red), light chains (aqua and green) (PDB code 1hzh) Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image Antibodies, also known as Immunoglobulins (Ig) are gamma globulin proteins, primarily found in the blood of vertebrates. These glycoproteins serve as a critical component of the immune system when the host fails to activate alternative compliment pathways or phagocytic cells in response to invading microorganisms or other antigens. The incredible specificity with which immunoglobulins bind to an antigen is based upon structural complementarity between the antigen and antibody and . It is this specificity that has made a critical component in laboratory and medical research. See more in IgA, Monoclonal Antibody. For Anti-HIV Fab see Human Fab PG16. Contents 1 Cellular Basis of Antibody Production 2 Structure of the Immunoglobulin 2.1 Heavy Chain 2.2 Light Chain 2.3 The Regions: Fab, Fv, CDR, and Fc. 2.3.1 Variable Regions 2.3.2 Constant Regions 2.4 Antibody Diversity 3 Antibody Applications Production of Antibodies by Plasma Cells Cellular Basis of Antibody Production When a foreign antigen binds to a B-lymphocyte (B-cell), it activates the B-cell, and upon stimulation by helper T-cells, undergoes clonal proliferation and B-cell maturation into antibody forming plasma cells. Each plasma cell is programmed to make an antibody of a single specificity, which it releases into the blood. [1] Once in the blood, antibodies aid the humoral immune system in three predominant ways: They coat foreign pathogens preventing them from entering healthy cells or disrupting antigen function; they coat pathogens, stimulating their removal via opsonization by phagocytes; and they trigger destruction of pathogens by stimulating the complement pathway or by Antibody Dependent Cell-mediated Cytotoxicity, among other immune responses. [2] [3] All of these functions rely heavily on accurate antigen binding and communication with other immune effector cells. The amazing specificity antibodies operate with is made possible by the physical structure of the antibody, which appears simplistic, but contains several levels of additional complexity. Structure of the Immunoglobulin (1igt). The basic functional unit of an antibody is an immunoglobulin monomer, but antibodies secreted from plasma cells are typically dimeric with occasional higher order structures. Typical secreted antibodies have a basic four-peptide structure of two identical and two identical joined together by interchain , forming a “Y” shaped molecule. The disulfide bonds are positioned within a flexible region called the , which seperates the lobes of the antibody from one another and provides ample flexibility to bind antigens effectively. [1] Each domain (2 heavy and 2 light) contain between 70-110 amino acids and are classified into different categories according to size and function. [4] Both domains, heavy and light, contain variable and constant regions that are crucial to antibody function. [5] Heavy Chain There are five types of immunoglobulin heavy chains, in mammals, α, δ, ε, γ, and μ, and give rise to the five unique classes or isotypes of antibodies, IgA, IgD, IgE, IgG, and IgM, which differ in size and composition. Each has a and . The constant region is identical in all antibodies of the same isotype, but differ in antibodies of different isotypes; i.e. all IgA have the same sequence in their heavy chain constant region, but these constant regions differ between IgA and IgD, etc. [6] The α, δ, and γ heavy chains have a constant region composed of while heavy chains ε and μ contain four. The variable region of the heavy chain in antibodies is different for all antibodies created by different B-cells. [7] Typical Structure of an Antibody Light Chain Every antibody contains two that are identical to each other. There are two types of immunoglobulin light chains in mammals, labeled lambda and kappa, with only one represented in each antibody. Each light chain has one followed by one , with a total length of about 215 amino acids. [1] The Regions: Fab, Fv, CDR, and Fc. The immunoglobulin can be broken down into regions, each serving a different purpose: Variable Regions The (Fragment, Antigen Binding region) is composed of one constant and one variable domain from each heavy and light chain of the antibody. It is the part of the antibody that gives it its famous “Y” shape.[8] Held within the Fab region is the variable domain, also known as the Fv region.[9] Within the Fv region lie positioned at one end of the variable domain where they form parts of the Beta-turn loops and are clustered close to each other in space. The clustering of the hypervariable loops at the tips of the variable regions where the antigen-binding site is located makes them perfect candidates for antigen recognition. [1]The sequence heterogeneity of the three heavy and three light chain hypervariable loops creates significant antigen specificity diversity through variations in the binding surface nature and shape. Each hypervariable region can be viewed as an independent structure contributing to the complementarity of the biding site and antigen and is often referred to as a complementarity determining region (CDR). [10] Constant Regions The remaining part of the antibody, namely the , does not play a role in binding the antigen, but rather is responsible for modulating the immune systems response to the formation of an antibody-antigen complex. The Fragment Crystallizable (Fc) region is composed of two heavy chain constant regions that are isotype specific. [11] Antibodies are glycoproteins because of at conserved positions in their Fc regions. This glycosylation is a critical component determing the rate of antibody clearance form the body.[12] Once an antibody binds to an antigen, the Fc region binds to Fc receptors, among other proteins, to mediate a host of different physiological responses ranging from oposonization, to degranulation of mast cells, to the release of cytokines and cytotoxic molecules, etc. resulting in the destruction of the pathogen. [13] Depending on the class of antibody, as dictated by the identity of the Fc region, the antibody half-life and distribution throughout the body varies. Further, since Fc receptors are antibody isotype specific, the type of immune response is dependent on the type of Fc region on the immunoglobulin, allowing for different immune responses to the same pathogen if necessary.[14] See table for brief characterization of Immunoglobulin isotypes: Immunoglobulin Classes and Function Class Function and Oligomeric State[1] IgG Dimeric - The most abundant Ig in the extravascular fluids. Neutralizes toxins and combats microorganisms by activating the compliment system and facilitating the binding of phagocytic cells. IgA Dimeric - Is the major Ig in seromucous secretions, where it serves to defend the external body surfaces. IgM Pentameric – It is an intravascular antibody and is produced very early in the immune response. Due to it high oligomeric state, it is extremely effective as a bacterial agglutinator and mediator of complement-dependent cytolysis, making it a powerful first-line defense against bacterial pathogens. IgD Dimeric - It is present on the lymphocyte and functions together with IgM as the antigen receptor on naïve B-cells. IgE It binds to mast cells and upon contact with antigen, leads to local recruitment of antimicrobial agents via degranulation of the mast cell and release of inflammatory mediators. IgE is important for certain kinds of parasitic infections and is responsible for the symptoms of atopic allergies like eczema and asthma. A model of the IgG molecule is present in the figure which indicates the spatial disposition and interaction of the domains in IgG. As Dr. Ivan Roitt writes in Essential Immunolgy, “To enable the Fab arms to have the freedom to move and twist so that they can align their hypervariable regions with the antigenic sites on large immobile carriers, and to permit the Fc structures to adjust spatially in order to trigger their effector functions, it is desirable for IgG to have a high degree of flexibility. And it has just that. Structural analysis shows that the Fab can ‘elbow-bend’ at its V-C junction and twist about the hinge, which itself can more properly be described as a loose thether, allowing the Fab and the Fc to drift relative to each other with remarkable suppleness. It could be said that movements like that make it a very sexy molecule!” [1] Image of V(D)J Recombination (2osl). Antibody Diversity Considering the nearly infinite number of possible antigens that can invade the body, the immune system had to develop a method for accurately targeting each one of these compounds, ranging from small molecules, to stray proteins, to viruses capable of infecting cells. The antibody was the immune systems response to this problem. It has been estimated that humans generate about 10^10 different antigens, each capable of binding a unique epitope of an antigen. Since antibodies are proteins, and proteins are controlled by the genes from which they are transcribed, a clever system of gene shuffling and manipulations developed to enable the immune system to create a huge repertoire of antibodies from a limited number of genes. [15] The variable region of each immunoglobulin chain is encoded in several pieces known as gene segments. For heavy chains, these segments are called the variable (V), diversity (D), and joining (J) segments. (Only V and J exist for light chains) 50 V segments, 25 D segments, and 6 J segments exist and are randomly arranged and rearranged in the genome in a process called V(D)J recombination. Each B-cell is programmed to produce antibodies of a single V(D)J recombination order. Additional diversity is created by the proteins RAG-1 and RAG-2 which introduce the double stranded breaks between V, D, and J segments to allow recombination. At this stage, nucleotides can either be deleted or inserted between adjoining segments before being ligated together. [1] This dramatically increases antibody diversity. Further diversity is created during B-cell proliferation when the variable chains undergo a high rate of point mutations in a process called somatic hypermutation, creating daughter cells of the original B-cell that are slightly different. The antibodies which bind the antigen with the highest affinity are selected for in a process called affinity maturation. [16][17] Isotype switching is also possible after activation of the B-cell by a mechanism called “class switch recombination” allowing different immunological responses to the same antigen bound by the same variable regions.[18] Through this clever system, tens of billions of different glycoprotein antibodies can be created from less than 100 genes, allowing antibodies to bind with exquisite precision. The discovery of antobdy diversity generation won Susumu Tonegawa the Nobel Prize in Medicine in 1987. Direct Immuno fluorescence Antibody labeling Antibody Applications Detection of particular antibodies is very common in medical diagnostic testing. Numerous biochemical assays exist to detect whether antibodies for specific antigens are present in the blood or other bodily fluids such as antibodies against Lyme disease or HIV, etc. Another common medical test involving antibodies is blood type detection in which an individual’s blood is screened against anti-A and anti-B antibodies to determine the identity of that individual’s blood antigen type. [19] Antibodies are also extremely powerful tools in the laboratory setting where they are commonly used in Western Blot to detect specific proteins in a sample [20]; flow cytometry, to differentiate cell types by their protein expression profiles; immunoprecipitation, to separate proteins from other compounds in a lysate and for cellular labeling. Numerous other examples exist. [21] The last two decades have seen a dramatic increase in antibody based technologies both for the lab and medicine thanks to the invention of the monoclonal antiboy, a discovery that won Niels K. Jerne, Georges J.F. Köhler, César Milstein the Nobel Prize in Medicine in 1984. See: Monoclonal Antibody for additional information.

3D Structures of the Immunoglobulin

Updated on 09-February-2014

Humanized mouse antibody (hmFab) is a modified mFab which resembles more hFab.

Fab

7fab, 1mco, 3na9, 3lrs, 3mme, 3hi5, 1vge, 3nfs, 1ad0, 3w9d, 4nm4, 8fab, 1opg, 4fnl, 4fqh, 1om3, 1aqk, 2hff, 2agj, 3hc0, 3g6a, 3dgg, 3dif, 1b2w, 3eyo, 3eyq, 2aj3, 3fzu, 3aaz, 3gje - hFab - human
3naa, 3nab, 3nac, 3ncj, 3o2v, 3hc3, 3hc4 - hFab (mutant)
3i75, 1nqb, 1f4w, 1aif, 1ghf, 2z91, 1ind, 3bkc, 3bkm, 1iy0, 3pp3, 3pp4, 3okm, 6fab, 2hkh]], 1ay1, 1nbv, 1qbm, 1bbd, 1dsf, 1gpo, 1mnu, 1igf, 1for, 1k6q, 1bz7, 1dqd, 2ipt, 2iq9, 2iqa, 2w60, 2w9d, 3iu4, 1q9k, 1q9l, 1q9o, 2z4q, 1cl7, 1n4x, 1cr9, 1r24, 1gig, 1uyw, 1cgs, 2cgr, 1q0x, 1ibg, 3eo0, 2op4, 2q76, 2ojz, 2g60, 2dbl, 1dbj, 1dbk, 1dbm, 1dba, 1mrc, 2gcy, 1flr, 1uz6, 1rfd, 1t2q, 1ggb, 1ggc, 1bm3, 2eh7, 2fat, 3cfc, 1fl3, 3cfe, 4j1u, 4gq9, 3qg7, 3rvt, 3s62, 4gay - mFab – mouse
3eot, 2d03, 3esv, 3et9 – mFab (mutant)
3iy2, 3iy3, 3iy4, 3iy5, [[3iy26], 3iy7 - mFab – Cryo EM
1jpt, 3mxv, 2o5x, 1ucb, 1bbj, 1t04, 2fgw, 1fvd, 1fve - hmFab
1cqk – mFab MAK33 CH3 domain
3mj8, 3r06 – AhFab – Armenian hamster
3iy1, 1zan – rFab – rat
4k3e, 4k3d – bFab – bovine
4b41, 1shm, 2xa3 – LgFab – Lama glama
1f2x – cFab – camel

Anti-HIV Fab

1rz7, 1rz8, 1rzf, 1rzg, 1rzi, 3mlj, 3mug, 3juy, 3qeh, 3ttn, rpi, 3tnm, 4fz8, 4f58, 4f57, 4f5a - hFab
3nz8, 3o6k, 3ntc, 3qeg – mFab

Fab: small molecule complex

3o2w - hFab 1e9 (mutant) + transition state analog
3ra7 – mFab + digoxigenin – mouse
3okd, 3oke, 3okk, 3okl, 3okn, 3oko, 3hzk, 3hzm, 3hzv, 3hzy, 3pho, 3phq, 3hns, 3hnt, 3hnv - mFab + liposaccharide
3oau – hFab 2g12 (mutant) + mannose
1ikf – hFab R45 + cyclosporin
3oay, 3oaz, 3ob0, 1zls, 1zlu, 1zlv, 1zlw - hFab 2g12 + glycan
2jb5, 2jb6 - hFab/mFab + hapten
1ine, 1ub5, 1ub6 - mFab + hapten
3ls4 – mFab + tetrahydrocannabinol
1mfc, 1mfd, 1mfe, 4hgw – mFab + polysaccharide
1op3, 1op5 - hFab + polysaccharide
3eyv - hFab/mFab 13G5 (mutant) + hapten
2ntf - mFab RS2-1G9 + lactone analog
1riu, 1riv, 1qyg, 1q72 - mFab + cocaine derivative
1ynk, 1ynl, 1etz – mFab + sweetener
1yef – mFab D2.3 + substrate analog
1yeg - mFab D2.3 + product
1p7k – mFab + HEPES
1q0y – mFab 9B1 + morphine
1q9q, 1q9r, 1q9t, 1q9v, 1q9w, 1f4x, 1f4y, 1mfa, 1mfb - mFab + carbohydrate
1mex – mFab 29G12 + benzoic acid derivative
1mrd, 1mre, 1mrf – mFab JEL103 + nucleotide
1dbb – mFab DB3 + progesterone
1igj - mFab 26-10 + digoxin
4fab – mFab 4-4-20 + fluorescin
1dl7 - mFab MCPC603 + phosphocholine
3cfb, 3cfd, 2g2r – mFab + stilbene hapten
1i3u, 1i3v - LgFab + hapten

Fab: peptide complex

3e8u - mFab + BNP peptide
2a6d, 2a6i, 2a6j, 2a6k - mFab + peptide
2a6d, 2a6i, 2a6j, 2a6k - mFab + peptide
3hr5 – mFab + M1prime peptide
3eys, 3eyu - mFab + amyloid-β-related peptide
3ggw – mFab + carbohydrate-mimetic peptide
3cxd, 3dsf – mFab + osteopontin peptide
2zpk – mFab + proteinase-activated receptor peptide
3ifl, 3ifn, 3ifo, 3ifp - mFab + amyloid peptide
3h0t - hFab + hepcidin peptide
1sm3 - hFab SM3 + peptide
3eyf – hFab + cytomegalovirus peptide
2hfg, 2h9g – hFab + TNF receptor peptide
3csy - hFab + Ebola envelope glycoprotein peptide
2eh8 - mFab + PRES1 peptide
2brr – mFab + outer membrane protein peptide
1xgy – mFab + rhodopsin peptide
1pz5 – mFab SYA/J6 + peptide
1a3r – mFab + rhinovirus capsid peptide
1cu4 - mFab + prion protein peptide
1fpt – mFab + poliovirus peptide
1jp5 – mFab + HIV-1 protease peptide
1mvu – mFab + glycoprotein
2ap2 – mFab + glycoprotein peptide + C-myc peptide
1jp5 – mFab + HIV-1 protease peptide
1mvu – mFab + glycoprotein
2ap2 – mFab + glycoprotein peptide + C-myc peptide
2hh0 – hFab/mFab + prion protein peptide
1frg, 1him, 1hin, 1ifh - mFab + hemagglutinin peptide
1tet – mFab + cholera toxin peptide
1i8i, 1i8k – mFab + EGFR peptide
1i8k – mFab + EGFR peptide
1i8i, 1i8k – mFab + EGFR peptide
1i8k – mFab + EGFR peptide
4gag, 4gaj – mFab + genome polyprotein peptide
3bky – hFab/mFab + CD20 peptide
4hs8 – hFab + hepatitis virus peptide

Anti-HIV Fab: peptide complex

3egs, 3drt, 3drq, 3dro, 2fx7, 2fx8, 2fx9, 2cmr, 1tzg, 1tjg, 3mnw, 3moa, 3mob, 3mod, 1tjh, 1tji, 1u8h, 1u8i, 1u8j, 1u8k, 1u8l, 1u8m, 1u8n, 1u8o, 1u8p, 1u8q, 1u91, 1u92, 1u93, 1u95, 2f5b - hFab anti-HIV + gp41 peptide
3ghb, 3ghe, 3c2a - hFab anti-HIV + envelope glycoprotein peptide
3go1 - hFab anti-HIV + envelope glycoprotein gp160 peptide
3fn0, 2oqj - hFab + peptide
2b0s, 2b1a, 2b1h, 3se8, 3se9, 4jkp, 4jpv, 4jb9 - hFab anti-HIV + glycoprotein gp120 peptide
1nak, 2f58, 3f58, 1f58, 1acy, 1qnz - mFab anti-HIV + glycoprotein gp120 peptide
1ai1, 1ggi – mFab anti-HIV + V3 peptide
3o6l, 3o6m - mFab 11H6H1 anti-HIV + Tat peptide
1svz - mFab anti-HIV + HIV-2 protease peptide

Fab: protein complex

3raj – mFab HB7 + CD38
3o0r – mFab + nitric oxide reductase
3mac, 3ma9 – hFab 8062 anti-HIV + transmembrane glycoprotein
3pnw – hFab + Tudor domain-containing protein 3
3h42 - hFab LDLR + proprotein convertase subtilisin/kexin
3nh7 – hFab ABD1556 + bone morphogenetic protein receptor
3hi6 – hFab AL-57 + integrin
2vxs - hFab + interleukin
3b2u, 3b2v – hFab IMC-11F8 + EGFR
2r0k, 2r0l – hFab + HGFA
3ld8, 3ldb – AhFab + bifunctional arginine demethylase
3be1, 3n85, 1n8z - hFab + ERBB-2
3kr3 – hFab + IGF-II
3g6d – hFab CNTO607 + IL-13
3idx, 3idy, 2ny7, 4jpw, 4lsp, 4lsq, 4lsr, 4lss, 4lst, 4lsu, 4lsv - hFab + gp120 core
2x7l – Fab anti-HIV + HIV REV
3gbm, 3gbn, 3lzf, 3fku, 3sdy, 3ztj, 3ztn, 4fp8, 4fqi, 4fqj, 4fqk, 4fql, 4fqr, 4fqv, 4fqy, 4gxu, 4nm8- hFab + hemagglutinin
3g6j – hFab + complement C3
2vxq – hFab + pollen allergen PHL
1fsk - mFab + pollen allergen
2wub, 3k2u – hFab 40 + hepatocyte growth factor activator
3grw - hFab + fibroblast growth factor receptor
3bdy, 2qr0, 2fjg, 2fjh, 1cz8 – hFab + VEGF
1tzh, 1tzi - mFab + VEGF
3bqu – hFab 2F5 anti-HIV + mFab 3H6
1adq – hFab IGM + igG1 Fc
3dvg, 3dvn – hFab igG1 + ubiquitin
3bn9 – hFab E2 + membrane-type serine protease
2jix – hFab ABT-007 + erythropoietin receptor
1za3 - hFab YSD1 + TNF receptor
3l95 – Fab + NRR1
1uj3, 4dtg – hFab + tissue factor
3lev – hFab 2F5 + RNA polymerase sigma factor
3ru8 – hFab B12 + epitope scaffold 2BODX43
3skj – hFab + ephrin receptor
3sob – hFab + LPR6
3vg9 – hFab + adenosine receptor
3vga – hFab + adenosine receptor (mutant)
2qqk, 2qql, 2qqn – hFab + neuropilin
2vyr – hFab + MDM4
4c2i – hFab + dengue virus envelope protein
4dag – hFab + metapneumovirus glycoprotein F0
1jps - hmFab D3H44 + tissue factor
1ahw - mFab 5G9+ tissue factor
1eo8, 1ken, 4mhh, 4mhj - mFab + hemagglutinin
2w9e, 1tpx, 1tqb, 1tqc – mFAB + major prion protein
2oz4 – mFab + intercellular adhesion molecule
3eo1 - mFab GC-1008 + transforming growth factor β-3
2dtg – mFab 83 + insulin receptor
1egj – mFab + cytokine receptor
2bdn – mFab + cytokine A2
1jrh – mFab + interferon-γ receptor
1ob1 – mFab + major merozoite surface protein
1qfw – mFab + gonadotropin
4cad – mFab + RCE1
4m48 – mFab + dopamine transporter
1yjd – mFab 5.11A1 + CD28
1sy6 – mFab OKT3 + CD3
4k4m, 4k2u – mFab + erythrocyte binding antigen
1afv – mFab anti-HIV + capsid protein C
2b2x – rFab AQC2 + integrin
2r56 – bFab igE + β-lactoglobulin
1bzq, 2p42, 2p43, 2p44, 2p45, 2p46, 2p47, 2p48, 2p49, 2p4a – bFab Cab-Rn05 + RNase
2r9h – mFab + exchange transporter ClCA
1nca, 1ncb, 1ncc, 1ncd – mFab + neuraminidase
1rjl – mFab + outer surface protein
1mhh – mFab + protein L (mutant)
1pg7 – mFab 6A6 + hmFab D3H44
1pkq – hFab/mFab 8-18C5 + myelin glycoprotein
2jel – mFab JEL42 + histidine-containing protein
1nsn – mFab N10 + nuclease
1rvf – mFab 17-IA + intact rhinovirus
3j3o, 3j3p- mFab + poliovirus proteins – cryoEM
1nfd – mFab H57 + T-cell receptor
1igc – mFab MOPC21 + streptococcal protein G
1iai – mFab idiotipic + mFab anti-idiotypic
2r8s – mFab + RNA
2fr4, 1xf2, 1xf3, 1xf4, 1i8m, 1cbv – mFab + DNA
1mhp, 3q3g, 3qa3 – mFab + integrin
3ab0 – mFab + BCLA protein
3etb – mFab M18 (mutant) + anthrax-protective antigen
3f5w, 3pjs, 3efd, 3eff, 2hjf, 2w0f, 4msw – mFab + KcsA K+ channel
3stl, 3stz, 4i9w - mFab + KcsA K+ channel (mutant)
1kb5 – mFab + T-cell receptor
4i18 – mFab + pro-lactin receptor
1uwx – mFab + protein G prime
4ckd – mFab + β-galactosidase
3fmg – mFab + glycoprotein VP7
3ve0 - mFab + Ebola envelope glycoprotein
3k7u, 3k80 – LgFab + MP18 RNA editing protein – Lama glama
3mj9 – AhFab HL4E10 + JAML
3r08 - AhFab 2C11 + CD3ε
4hti – rFab + TNF ligand
1g6v – bFab + carbonic anhydrase
4hgk – Fab + albumin – shark
4ej1, 4eiz, 4eig – LgFab + DHFR
3k81, 3stb, 4dk3, 4dk6, 4dka – LgFab + RNA editing complex protein
3p0g, 4lde, 4ldl, 4ldo – LgFab + adrenergic receptor
1jto, 1jtp, 1jtt, 1ri8, 1xfp, 1zmy, 1zv5, 1zvh – cFab + lysozyme
2x89 – cFab + β-2-microglobulin
4i0c – cFab + lysozyme
4ht1 – Fab + TNF ligand 12 – rabbit

Fab: protein ternary complex

3ixx, 3ixy - mFab E53 + envelope glycoprotein + West Nile virus peptide
1g9m, 1g9n, 1gc1, 2i5y, 2i60, 2nxy, 2nxz, 2ny0, 2ny1, 2ny2, 2ny3, 2ny4, 2ny5, 2ny6, 3jwd, 3jwo - hFab + envelope glycoprotein gp120 + CD4
2wuc - hFab 40 + hepatocyte growth factor activator + inhibitor
3lqa, 2qad - hFab anti-HIV + CD4 + gp160
3d85 - hFab 7G10 + IL-12 + IL-23
3bt2 – hFab anti-UPAR + urokinase-type plasminogen activator + vitronectin
3gjf, 3hae – hFab + β-2-microglobulin + MHC antigen + NYESO peptide
3gb7, 2p7t, 2h8p, 2hfe, 2atk - mFab + KcsA K+ channel + ion
3or6, 3or7, 3ogc, 3fb7, 3f7v, 3f7y, 3fb5, 3fb6, 3fb8, 3iga, 2itc, 2itd, 2nlj, 2bob, 2boc, 1s5h, 1r3i, 1r3j, 1r3k, 1r3l, 1k4c, 1k4d, 3hpl - mFab + KcsA K+ channel (mutant) + ion
2fd6 – mFab ATN-615 + urokinase-type plasminogen activator + urokinase plasminogen receptor
1j5o – mFab + reverse transcriptase + DNA
1qkz – mFab + protein G prime + major outer membrane protein peptide
2ibz – mFab + cytochrome bc1 complex + stigmatellin
3v0a – LgFab + BONT/A1 + NTNH
3sn6 – LgFab + adrenergic receptor + guanine nucleotide-binding protein
4laj - LgFab + envelope glycoprotein gp120 + CD4

Full Immunoglobulin

1hzh - hFab IgG B12
1iga - hIgA1 - model

Fc Fragments

3dnk - hFc Igg1br /> 1qp1 – hFc BRE
3muh – hFc PG9
4bsv, 4bsw – hFc heterodimeric (mutant)
1f6a - hFc IgE + high-affinity receptor Fc (ε) RI (α)
1fp5 - hFc IgE C ε 3-C ε 4

Fv Fragments

3dur, 3dus, 3duu, 3dv4, 3dv6 – mFv + Ig-like protein
3h3b – mFv + ERBB2
3hb3 – mFv + cytochrome c oxidase subunit 1-β
1qle - mFv + cytochrome c oxidase
3ln9 – cFv B10
3tpk – cFv KW1
3zhd, 3zhk, 3zhl – hFv scaffold
1kxq – cFv + α-amylase
1mel, 1rjc, 1zvy – cFv + lysozyme

References

1. ↑ ^{1.0 1.1 1.2 1.3 1.4 1.5 1.6} Roit, I. M. Roit's Essential Immunology. Oxford: Blackwell Science Ltd., 1997.
2. ↑ Parker DC. T cell-dependent B cell activation. Annu Rev Immunol. 1993;11:331-60. PMID:8476565 doi:http://dx.doi.org/10.1146/annurev.iy.11.040193.001555
3. ↑ Rus H, Cudrici C, Niculescu F. The role of the complement system in innate immunity. Immunol Res. 2005;33(2):103-12. PMID:16234578 doi:10.1385/IR:33:2:103
4. ↑ Roux KH. Immunoglobulin structure and function as revealed by electron microscopy. Int Arch Allergy Immunol. 1999 Oct;120(2):85-99. PMID:10545762
5. ↑ Putnam FW, Liu YS, Low TL. Primary structure of a human IgA1 immunoglobulin. IV. Streptococcal IgA1 protease, digestion, Fab and Fc fragments, and the complete amino acid sequence of the alpha 1 heavy chain. J Biol Chem. 1979 Apr 25;254(8):2865-74. PMID:107164
6. ↑ Woof JM, Burton DR. Human antibody-Fc receptor interactions illuminated by crystal structures. Nat Rev Immunol. 2004 Feb;4(2):89-99. PMID:15040582 doi:10.1038/nri1266
7. ↑ Putnam FW, Liu YS, Low TL. Primary structure of a human IgA1 immunoglobulin. IV. Streptococcal IgA1 protease, digestion, Fab and Fc fragments, and the complete amino acid sequence of the alpha 1 heavy chain. J Biol Chem. 1979 Apr 25;254(8):2865-74. PMID:107164
8. ↑ Harris LJ, Larson SB, Hasel KW, McPherson A. Refined structure of an intact IgG2a monoclonal antibody. Biochemistry. 1997 Feb 18;36(7):1581-97. PMID:9048542 doi:http://dx.doi.org/10.1021/bi962514+
9. ↑ Hochman J, Inbar D, Givol D. An active antibody fragment (Fv) composed of the variable portions of heavy and light chains. Biochemistry. 1973 Mar 13;12(6):1130-5. PMID:4569769
10. ↑ Putnam FW, Liu YS, Low TL. Primary structure of a human IgA1 immunoglobulin. IV. Streptococcal IgA1 protease, digestion, Fab and Fc fragments, and the complete amino acid sequence of the alpha 1 heavy chain. J Biol Chem. 1979 Apr 25;254(8):2865-74. PMID:107164
11. ↑ Woof JM, Burton DR. Human antibody-Fc receptor interactions illuminated by crystal structures. Nat Rev Immunol. 2004 Feb;4(2):89-99. PMID:15040582 doi:10.1038/nri1266
12. ↑ Wright A, Morrison SL. Effect of glycosylation on antibody function: implications for genetic engineering. Trends Biotechnol. 1997 Jan;15(1):26-32. PMID:9032990 doi:10.1016/S0167-7799(96)10062-7
13. ↑ Heyman B. Complement and Fc-receptors in regulation of the antibody response. Immunol Lett. 1996 Dec;54(2-3):195-9. PMID:9052877
14. ↑ Ravetch JV, Bolland S. IgG Fc receptors. Annu Rev Immunol. 2001;19:275-90. PMID:11244038 doi:19/1/275
15. ↑ Fanning LJ, Connor AM, Wu GE. Development of the immunoglobulin repertoire. Clin Immunol Immunopathol. 1996 Apr;79(1):1-14. PMID:8612345
16. ↑ Diaz M, Casali P. Somatic immunoglobulin hypermutation. Curr Opin Immunol. 2002 Apr;14(2):235-40. PMID:11869898
17. ↑ Borghesi L, Milcarek C. From B cell to plasma cell: regulation of V(D)J recombination and antibody secretion. Immunol Res. 2006;36(1-3):27-32. PMID:17337763 doi:10.1385/IR:36:1:27
18. ↑ Durandy A. Activation-induced cytidine deaminase: a dual role in class-switch recombination and somatic hypermutation. Eur J Immunol. 2003 Aug;33(8):2069-73. PMID:12884279 doi:10.1002/eji.200324133
19. ↑ CHOWN B, LEWIS M, KAITA K. A new Kell blood-group phenotype. Nature. 1957 Oct 5;180(4588):711. PMID:13477267
20. ↑ Burnette WN. "Western blotting": electrophoretic transfer of proteins from sodium dodecyl sulfate--polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A. Anal Biochem. 1981 Apr;112(2):195-203. PMID:6266278
21. ↑ Brehm-Stecher BF, Johnson EA. Single-cell microbiology: tools, technologies, and applications. Microbiol Mol Biol Rev. 2004 Sep;68(3):538-59. PMID:15353569 doi:10.1128/MMBR.68.3.538-559.2004

Additional Pages

• IgA
• Epitopes
• Major Histocompatibility Complex Class I
• Monoclonal Antibody

See Also

• Variable Lymphocyte Receptors
• Antibody at High school teachers' resources, where you will find tutorials on antibody structure.
• Antibodies at Wikipedia.