Epitope selection

Fleckenstein B, Molberg O, Qiao SW, Schmid DG, von der Mulbe F, Elgstoen K, et al. Gliadin T cell epitope selection by tissue transglutaminase in celiac disease. Role of enzyme specificity and pH influence on the transamidation versus deamidation process. J Biol Chem 2002 277 34109-34116. 

While monoclonal antibodies are initially almost prohibitively expensive to produce, they offer very distinct advantages over polyclonal antisera for analytical applications. Of primary importance is the immortality of the hybridoma lines monoclonal Abs produced by this cell line will show relatively little batch-to-batch variation, and the repetitive use of animals for antibody production becomes unnecessary. In addition, the single-epitope selectivity of the monoclonal Ab tends to minimize cross-reactions, except with epitopes possessing very similar structural characteristics to the original antigen s epitope. 

Affinity values are experimentally determined by maintaining a constant total Ab concentration, and varying the H concentration. Quantitation of [H]free and [H]bound then allows the construction of a Scatchard plot, where [H]bound/ [H]free[Ab]totai is plotted against [H]bound/[Ab]total. The slope of this plot is the negative of the affinity, —K. Scatchard plots for monoclonal and polyclonal antibodies are shown in Figure 5.4. Note that polyclonal antibodies yield a curved Scatchard plot due to their range of epitope selectivities and affinities.8... 

Paramithiotis E, Pinard M, Lawton T et al (2003) A prion protein epitope selective for the pathologically misfolded conformation. Nat Med 9 893-899... 

S Schwarz, P Berger, G Wick. Epitope-selective, monoclonal-antibody-based im-munoradiometric assays of predictable specificity for different measurement of choriogonadotropin and its subunits. Clin Chem 31 1322, 1985. 

Recently, sequencing has found a very novel application in epitope selection by screening universal peptide libraries in a process called in vitro selection. These libraries are generated by the solid-phase peptide synthesis of peptides prepared in random fashion... 

Development of a peptide vaccine is derived from the identification of the immunodominant epitope of an antigen (141). A polypeptide based on the amino acid sequence of the epitope can then be synthesized. Preparation of a peptide vaccine has the advantage of allowing for large-scale production of a vaccine at relatively low cost. It also allows for selecting the appropriate T- or B-ceU epitopes to be included in the vaccine, which may be advantageous in some cases. Several vaccines based on peptide approaches, such as SPf66 (95) for malaria and an HIV-1 peptide (142) have been in clinical trials. No peptide vaccines are Hcensed as yet. 

Silva GA, Czeisler C, Niece KL et al (2004) Selective differentiation of neural progenitor cells by high-epitope density nanofibers. Science 303 1352-1355... 

The development of class-selective antibodies is another approach to multi-analyte analysis. The analyst may design haptens that will generate antibodies that recognize an epitope common to several compounds, as explained above for the analysis of pyrethroids by measuring PBA. Other examples of class-selective immunoassays that have been developed are mercapturates," glucuronides, pyrethroids, organophosphate insecticides, and benzoylphenylurea insecticides." ... 

Hjorth S, Thirstrup K, Gandy D et al. Analysis of selective binding epitopes for... 

Capture ELISA on selected oligomeric fractions of formalin-treated RNase A (see curves 3-7 in Fig. 15.9) also reveal that the plateau values increase with an increase in the number of cross-linked molecules in the fractions. This is due to an increasing proportion of bound epitopes per binding site or, in other words, epitope density on the surface. Thus, the nearly identical plateau values for the titration of native RNase A and formalin-treated unfractionated RNase A (curves 1 and 2 in Fig. 15.9) are fortuitous, being caused by the particular composition of oligomers present in the formalin-treated RNase A preparations that was analyzed. 

Two studies have involved the fusion of an antigen to P-glucuronidase (GUS). Gil et al. [61] fused GUS to the 2L21 protective epitope from canine parvovirus, and Dus Santos et al. [23] fused GUS to the protective epitope from FMDV. Transformants in both cases were selected on the basis of GUS activity, and both proved to be immunogenic. Mice immunized orally or parenterally with the GUS-FMDV epitope fusion were completely protected against challenge with the native virus. 

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