Antigenic systems

The fact that blood grouping and/or typing antigens exist has been known since Landsteiner discovered the ABO system around 1900 (1). Since then over 246 published antigens have been found however, only three of these antigenic systems, the ABO, MN and Rh, have received crime laboratory acceptance (2). Until several years ago most crime laboratories did only ABO groupings however, with the improvements of specific antisera and the increased sensitivity of detection techniques, the MN and Rh systems have also been adopted as reliable systems. 

The ABO, MN and Rh systems, unlikely many of the other antigenic systems, have useful population frequencies. For instance, the four groups belonging to the ABO system occur in... 

The immunoassay selected is based on a competitive fluorescence energy transfer mechanism. This type of assay is general and can be adapted to any antibody and antigen system. The competing reactions are given in equation (1) and (2) ... 

Several peptide dendrimers have been reported/ a major application of which is for the preparation of multiple antigen peptides (MAPs). For example, Tam used the poly (lysine) platform to prepare a MAP. These peptides are used to activate the immune system to produce large numbers of antipeptide antibodies, and their use avoids the immunogenicity and the other disadvantages associated with conventional antigenic systems. 

Table II Cross Reactivity Comparison for Various Analytes on Different Antisera/Coating Antigen Systems (NI refers to non inhibition of ELISA system by that analyte)...

Figure 7. A Comparison of competitive ELISAs for three substrates, all with 1,3-dinitro substituents, with antisera to lib from rabbit 1320 with 8c as die coating antigen (System D in Tablell).

S. Sensitivity of the Radioimmunoassay. This depends on two factors. First, the hormone must be labeled with suflScient radioactive nuclide to allow the counting of free and antibody bound hormone fractions to be statistically significant at the end of the incubation period. Second, provided that the protein can be labeled to a high enough specific activity, the sensitivity of the test will depend on the equilibrium constant of the antibody-antigen system in use. The higher the constant in favor of the complex formation, the more sensitive will be the assay. 

Accordingly, when the system is working optimally the amount of hemolysis is quantitatively and inversely proportional to the amount of antigen added to the system. The hemolysis can be read spectro-photometrically (B9, M12), or the red blood cells can be tagged with Cr, and the amount of lysis determined by counting the amount of Cr which becomes soluble after lysis has occurred (B12). Not all antigen-antibody reactions will fix complement e.g., horse antisera do not, nor do univalent antibody-antigen systems (A12). 

Temperature-jump relaxation and the stopped-flow methods are suitable to follow the concentration changes over extremely short time intervals. Such studies have indicated that immune reaction kinetics resemble other biological systems in which ligands are bound to proteins (Weber, 1975) in that the binding strength of small molecules is largely dictated by the constant. The association rate constants ka, are very similar for various antibody-antigen systems, i.e., for... 

This chapter recounts aspects of two antigen systems li and SSEA-1 (Le ), that are prototype carbohydrate differentiation antigens which have served to establish some... 

A 2C model antigen system [61] was used to evaluate the ability of microspheres to induce T-cell activation. The model antigen is a heat shock fusion protein containing a peptide epitope pi [62] (Fig. 6.9). A plasmid encoding the construct was used for encapsulation and vaccination. 

QUANTUM DOTS AS FLUORESCENT RESONANCE ENERGY TRANSFER DONORS IN ANTIBODY-ANTIGEN SYSTEM... 

Molecular recognition is central to how biological systems work, especially at the cellular level (example Fig. 1). The observation of the various systems where processes of recognition occur (enzyme substrate complexes, antibody-antigen systems, DNA replication, membrane receptors, and so on) has indicated a certain number of directions for the preparation of synthetic systems capable of molecular recognition. 

This lipid carrier is, therefore, identical with, or at least very similar to, the C55 lipid involved in the synthesis of D-mannan in Micrococcus lysodeikticus the latter lipid, also, has two internal, trans, double bonds. The former lipid behaves very similarly to the carrier lipid involved in O side-chain synthesis in Gram-negative bacteria, and can substitute for the latter lipid in the O antigen system. This result is not, however, a rigorous proof of identity, as the M. lysodeikticus system is known to be able to use ficaprenol phosphate as efficiently as undecaprenol phosphate. ... 

The function of the Se gene is a good example of at least one way by which the expression of glycosyltransferases can be modified, and there are indications of possibly similar mechanisms in some other antigen systems. Hence the synthesis of glycosyltransferases is not the only mechanism by which the assembly of oligosaccharides is regulated and, perhaps, it is not even the most important such mechanism. 

In addition to the A, B, H, Le and antigen systems described above and the M and N antigens discussed earlier, two other groups of antigens have been shown to have saccharide epitopes. 

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