HLA Competition Test Service

Identification of human leukocyte antigen (HLA)-restricted cytotoxic T lymphocyte (CTL) epitopes is important for understanding the immunity in viral or bacterial infections, autoimmune diseases, and cancer as well as for the development of defined vaccines. Creative Biolabs provides high-quality HLA competition assays to identify peptides binding to HLA molecules.

Background

The peptide-binding groove of HLA molecules contains highly polymorphic allele-specific pockets that accommodate side chains of the so-called anchor residues of the bound peptide. The HLA competition assay aims at identifying peptides that bind to a wide range of HLA molecules. The methods are capable of predicting the binding of any given peptide to any given HLA molecule.

HLA Class I Competition Assay

HLA class I competition assay can be used in a screening procedure for identifying peptides binding to HLA molecules. It includes a titration procedure for determining the affinity of the positive peptides from the screening. Creative Biolabs uses a conformation-dependent anti-HLA class I antibody, W6/32, as one tag and a biotinylated recombinant HLA class I molecule as the other tag, and a proximity-based signal is generated through the luminescent oxygen channeling immunoassay technology. Compared with an enzyme-linked immunosorbent assay (ELISA) -based peptide-HLA class I binding assay, this assay yields virtually identical affinity measurements, with lots of features, such as a broader dynamic range, better signal-to-background ratios, and a higher capacity.

HLA Class II Competition Assay

HLA class II competition assay may be used to measure the affinity of putative epitopes for multiple HLA alleles. Our assay employs highly-purified class II molecules. Based on a concentration peptide titration, this assay format is far superior in sensitivity and specificity compared to cell-based assay formats. A non-linear regression analysis will be performed and an IC₅₀ value will be calculated.

Workflow

Fig.1 Workflow of HLA class I competition assay.

Highlights

Our HLA competition assay can be adapted to accommodate a range of requirements:

• Control peptides can be chosen depending on the objective.
• The concentration range can be varied to suit the specific project.
• Mixtures of peptides, as well as mono-disperse peptides, can be tested.

As a reliable partner in HLA Testing, Creative Biolabs aspires to become the best solution provider for our clients. Except for HLA testing service, Creative Biolabs also provides a full range of HLA-related products. For more information, please send us an inquiry or contact us directly.

References

1. Steere, A.C.; et al. Antibiotic-refractory lyme arthritis is associated with HLA-DR molecules that bind a borrelia burgdorferi peptide. J Exp Med. 2006; 203(4): 961-971.
2. Harndahl, M.; et al. Peptide binding to HLA class I molecules: homogenous, high-throughput screening, and affinity assays. J Biomol Screen. 2009, 14(2): 173-80.
3. Kessler, J.H.; et al. Competition-based cellular peptide binding assays for 13 prevalent HLA class I alleles using fluorescein-labeled synthetic peptides. Hum Immunol. 2003, 64(2): 245-55.