Antibody interactions

Immunoaffinity chromatography utilizes the high specificity of antigen—antibody interactions to achieve a separation. The procedure typically involves the binding, to a soHd phase, of a mouse monoclonal antibody which reacts either directly with the protein to be purified or with a closely associated protein which itself binds the product protein. The former approach has been appHed in the preparation of Factor VIII (43) and Factor IX (61) concentrates. The latter method has been used in the preparation of Factor VIII (42) by immobilization of a monoclonal antibody to von WiHebrand factor [109319-16-6] (62), a protein to which Factor VIII binds noncovalenfly. Further purification is necessary downstream of the immunoaffinity step to remove... 

Fig. 9. Immunosensor approaches where A is the analyte, is the labeled analyte, and Y is the antibody, (a) Direct immunosensors where the actual antigen—antibody interaction is measured (b) indirect immunosensors 1 and 2 which utilize formats similar to competitive and displacement...

Affinity chromatography (12) has become an important tool in the isolation of purified fractions of such substances as enzymes. Advantage is taken of specific interactions such as antigen-antibody interactions. One substance of the pair (e.g. antigen) is bonded to a support. When a mixture is passed through the column, the specific interaction retains the corresponding antibody relative to other substances. A change of mobile phase conditions then elutes the pure antibody. This method has a real potential for analysis of specific proteins in body fluids. 

The SPOT-synthesis method also employs Fmoc chemistry but uses hydroxyl groups present on cellulose filter paper to derivatize and thereby immobilize (3-alanine groups onto the paper. After deprotection, the 13-alanine groups can be used as platforms for the synthesis of peptide arrays (Fig. 7.5) (Frank, 1992 Gausepohl et al., 1992). This method has been widely used for mapping antigen-antibody interactions as well as protein-DNA, protein-metal and other protein-protein interactions (Reineke et al., 2001). 

Liposome conjugates may be used in various immunoassay procedures. The lipid vesicle can provide a multivalent surface to accommodate numerous antigen-antibody interactions and thus increase the sensitivity of an assay. At the same time, it can function as a vessel to carry encapsulated detection components needed for the assay system. This type of enzyme-linked immunosorbent assay (ELISA) is called a liposome immunosorbent assay or LISA. One method of using liposomes in an immunoassay is to modify the surface so that it can interact to form biotin-avidin or biotin-streptavidin complexes. The avidin-biotin interaction can be used to increase detectability or sensitivity in immunoassay tests (Chapter 23) (Savage et al., 1992). 

Odorico, M., Teulon, J.-M., Bessou, T., Vidaud, C., Bellanger, L., Chen, S.-W., Qucmcncur, fi., Parot, P., and Pellequer, J.-L. (2007) Energy landscape of chelated uranyl Antibody interactions by dynamic force spectroscopy. Biophys. J. 93, 645-654. 

R.J. Pei, Z.L. Cheng, E.K. Wang, and X.R. Yang, Amplification of antigen-antibody interactions based on biotin labeled protein—streptavidin network complex using impedance spectroscopy. Biosens. Bioelectron. 16, 355—361 (2001). 

Two variations of the basic technique are isoelectric focusing and immuno-electrophoresis. The former offers improved resolution and sharper bands in the separation of weak acids, weak bases and ampholytes through the use of pH and density gradients superimposed along the potential gradient. The latter employs specific antigen-antibody interactions (Chapter 10) to visualize the separated components of serum samples. 

Ovary, Z., Immediate reactions in the skin of experimental animals provoked by antigen-antibody interactions, Progr. Allergy, 5, 460, 1958... 

Antibody interaction drug delivery, 9 64 Antibody purification, 14 145 Antibody recognition, recombinant phage screening by, 12 506-507 Anticakes, for sodium nitrite, 22 857 Anticaking agents, 12 31, 63... 

HAp coatings, 14 105 HapMap project, 20 839 Hapten-antibody interactions, 9 64 Haptic sensor, for skin conditions, 3 749 Harcros antifoam, commercial defoamer, 3 24 It... 

The nature of the antigenic determinant has been characterized in a male worker with occupational asthma from nickel [415, 416] the antibody recognized Ni2+ bound at the natural Cu2 + /Ni2+ transport site of human albumin. The interpretation was deduced from metal ion blocking experiments and from the good agreement obtained between the pH dependency of the formation of the Ni2 + -albumin complex and the antigen-antibody complex. It was suggested that the antibody interaction depended on a special structural feature of the interaction of Ni2 + with human serum albumin, and perhaps the ability to form an octahedral complex affords one explanation [417]. 

Antibody avidity is commonly applied to antigen-antibody interaction, where multiple, weak, noncovalent bonds form between antigen and antibody. Avidity is distinct from affinity, which is a term used to describe the strength of a single bond. As such, avidity is the combined synergistic strength of bond affinities rather than the sum of bonds. 

Still with an enzyme monolayer, the synthesis and current responses of a system that involves simultaneous attachment of the cosubstrate to the electrode coating are then described. The next step consists in constructing a multilayered coating constituted by successive layers of enzyme built thanks to antigen-antibody interactions. Sensing the diffusion of the cosubstrate through the film thus constructed provides evidence for spatial order and an estimate of the distances between layers. 

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