Creative BioMart offers a test service that can be used to evaluate the MHC binding properties of test peptides compared to control peptides. In this aspect of the MHC stability assessment, our test platform has the ability to customize control peptides, and also accepts evaluation services based on control peptides provided by customers. Competitive testing is also an aspect of immunogenicity assessment in therapeutic peptide development, which can help investigators select the nearest competitor. Competitive assays are more targeted as an extension of conventional MHC peptide binding and rate assays.

Competition Binding Assays

Competitive assays play an important role in antibody development and, to a certain extent, enable the evaluation of competitors. In some specific R&D projects, performers need to assess not only the MHC binding of the peptide, but also how the peptide or peptidomimetic competes with a known control peptide for binding. This competitive assessment can help you have a prior expectation of a peptide or protein. The abundance of a given pMHC complex on the cell surface depends in part on the affinity of the peptide for the MHC molecule and is further controlled by mechanisms of antigen processing and presentation. Peptides bound to MHC molecules are fragments resulting from proteasomal degradation of newly synthesized defective ribosomal products, short-lived proteins, or fully mature proteins that degrade naturally over time. Peptides enter the endoplasmic reticulum (ER) via transporters associated with antigen processing (TAP) and compete for binding to MHC molecules in the peptide-loading complex. The principle of the competitive assay is achieved by competitive binding with a labeled control peptide.

Fig.1 Peptide competition assay. (Chew S L et al., 2011)

Featured MHC/Peptide Competition Assay

Our service is designed to evaluate the binding of test peptides compared to control peptides by a variety of test methods, such as fluorescence resonance assays that measure peptide binding to soluble recombinant MHC molecules. Probe peptides known to have a high affinity for MHC are labeled with fluorescent dyes, and unlabeled target peptides are then incubated with probe peptides that compete for binding to MHC. The binding of the labeled probe peptide to MHCII was measured by fluorescence polarization (FP). Typically, a high baseline signal is generated in an immunoassay by binding a labeled control peptide to the MHC complex. As the peptide competes with the unlabeled competitor peptide, the signal decreases with the increasing concentration of the competitor peptide. Some typical tests that exist today are performed for HLA-DR typing, including HLA-DRB1*01:01, *03:01, *04:01, *04:05, *07:01, *09:01, *11:01, *15:01. Our testing service platform provides competitive binding assays for IC50 determination and helps researchers measure MHC peptide affinity. The relative binding affinity of competing peptides can be assessed by determining IC50 values and analyzing competition binding curves with this service.

Fig.2 Competitive binding testing services from Creative BioMart.

Advantages of Creative BioMart

• This service allows the selection of control peptides based on the assay target, or multiple test peptides for batch testing.
• Our tests are based on control peptides, and customers can choose to provide test peptides/compounds, or you can choose to commission us to customize test peptides.
• Our testing protocols can be individually tailored to the researcher's testing goals, such as varying concentration ranges to suit specific project goals.
• Our platform has powerful analytical testing capabilities, allowing you to analyze mixtures of test peptides as well as monodisperse peptides.

If you are interested in our services, please contact us for cooperation.

References

• Chew S L, Or M Y, Chang C X L, et al. Stability screening of arrays of major histocompatibility complexes on combinatorially encoded flow cytometry beads[J]. Journal of Biological Chemistry, 2011, 286(32): 28466-28475.
• Yin L, Stern L J. Measurement of peptide binding to MHC class II molecules by fluorescence polarization[J]. Current protocols in immunology, 2014, 106(1): 5.10. 1-5.10. 12.