In vitro MHC peptide-binding assays do what prediction tools can’t. They confirm the physical binding characteristics of actual peptides, based on their sequence.
ProImmune is the world leader in providing in vitro MHC peptide binding assays, offering the widest range of MHC alleles and assay options, from high throughput screening to in-depth competition assays between candidate peptides. Our specialist immunology advisory team can help you define your project needs and quickly tailor the most relevant assay solution.
Researchers at the US FDA and colleagues use ProImmune REVEAL to understand how immunogenicity of therapeutic Factor VIII protein varies between ethnic groups based on their HLA tissue-type (Pandey G.S. et al. PLOS Computational Biology May 2013, Vol. 9 (5) e1003066):
Figure 1: (A) Binding scores of FVIII wild type peptides. Binding scores in a REVEAL assay were measured for the synthetic wild type peptides depicted in bold in Table 1. Each row represents a peptide and each column a MHC-II allele. The peptides are grouped together based on the position in the FVIII gene where the haplotypes H2 to H6 occur. Overlapping peptides were used around the position of each ns-SNP. Positive-control (PC) peptides are known T-cell epitopes of FVIII and negative control (NC) peptides are from regions of the FVIII protein where no T-cell epitopes have been identified. The scale for the binding score is shown at the top of the figure; dark colors represent peptides that bind with high affinity to the MHC-II allele. (B) FVIII high affinity binders. Wild type peptides with binding score >15% are shown and considered potential T-cell epitopes for each of the six MHC-II alleles. (C) Binding promiscuity scores for the wild type FVIII peptides. The binding promiscuity score for each peptide, defined as the fraction of MHC-II variants the peptide binds with a score >15%, is shown.
ProImmune REVEAL® is widely applicable across many disease areas including all areas of cancer and infectious diseases. New CD4+ and CD8+ T cell epitopes identified with the help of this technology can be used to assess protein antigenicity or as core building blocks for vaccine development or as targets for new immunotherapy.
Figure 2. Example process flows for ProImmune REVEAL assays for class I and class II MHC.
Prof. Julio Delgado, University of Utah, USA “The advantage of ProImmune’s in vitro system is that we could characterize binding to each HLA molecule individually and not have to guess which of the ranIge of HLA molecules expressed by our patients was responsible for antigen presentation. “
“ProImmune accomplished in two months what would have taken three years in our laboratory”.
ProImmune REVAL® data is reported in our detailed reporting templates for this assay range. Reports present data from the particular assays selected.
Class I: H-2
Class I: Mamu
Class II: IA
Class II: HLA DP
Figure: ProImmune REVEAL® results showing the population impact of Class II HLA binding peptides representing part of the mouse variable region of Remicade® (Infliximab). Remicade, a highly successful drug for the treatment of inflammatory autoimmune diseases also shows high rates of incidence of immunogenicity. The high-throughput nature of ProImmune REVEAL® allows researchers to develop a comprehensive understanding of how entire domains of monoclonal antibodies or therapeutic proteins interact with HLA molecules from a global population group based on actual experimental binding studies.
Identification of the individual epitopes of a therapeutic protein or other protein of interest allows separation of the intellectual property (IP) of that protein from the IP around the method of delivery or its therapeutic use. During vaccine development, defining IP for specific epitopes increases the options for future changes in product design. If the IP for the specific antigens in a protein of interest is not secured, competitive organizations may have the opportunity to develop an obstructive patent position.
Q: What information is required to get a quote for a ProImmune REVEAL project?
A: Ideally we need to know the peptide sequences you are interested along with the MHC alleles you want us to screen. We can however provide outline quotes for you based on numbers of peptides and alleles only, which will be a good start for scoping your project.
Q: How long does this service take?
A: This will very much depend on the project scope, including the number and specification of the peptides used. Once we know your project objective we will always provide you with an estimated delivery time with our quotes.
Q: With all the available options, how do I decide which one is best for me?
A: Based on the understanding that we develop in discussing your requirement with you, we will be able to propose the most suitable project scope for you and discuss how this can fit your broader study objectives and other assay work.
Westrop, S.J. et al. (2009). “Novel approach to recognition of predicted HIV-1 Gag B*35:01-restricted CD8 T-cell epitopes by HLA-B*35:01+ patients: Confirmation by quantitative ELISpot analyses and characterisation using multimers.” J Immunol Methods. 341: 76-85. [PubMedID: 19056394]
Figure. Results of the MHC-peptide binding assay for controls and the 12 peptides that were considered potential epitopes; binding signal is shown as a percentage relative to the pass/fail control; peptide 8, HPVHAGPIA (red) was further validated by Pentamer staining.
Figure. Pro5® Pentamer staining of live lymphocytes gated on CD3+ cells; the left plot shows staining with an allele mismatched negative control Pentamer, the right plot shows staining with the HA9 (B*35:01/HPVHAGPIA) Pentamer. 0.39% of CD3+ live lymphocytes are CD8+/HA Pentamer+ with a background stain of 0.03%.
The author commented that this study “confirms the novel ProImmune technology as a useful and superior tool for revealing potential immunogenic epitopes”, and also highlighted the importance of validating results in parallel using functional assays, such as ELISpot and Pro5® Pentamer staining.
See how Baxter (now Baxalta) to have used ProImmune REVEAL® to understand the immunogenicity of human Factor VIII treatment:
Steinitz, K. et al . “CD4+ T-cell epitopes associated with antibody responses after intravenously and subcutaneously applied human FVIII in humanized hemophilic E17 HLA-DRB1*15:01 mice.” Blood (2012) [PubMedID:22394599]