What are peptide-ready MHCs (prMHC)?
Load custom peptides onto an MHC monomer or tetramer in-house with our stabilized, peptide-free MHCs
We have developed a portfolio of peptide-ready MHC (prMHC) proteins which are MHC monomers or tetramers stabilized without an antigenic peptide. These MHCs are 'peptide-ready' meaning they can be loaded with your custom neoantigen peptide in-house to generate a custom MHC monomer or tetramer.
Simple & Fast Peptide Loading
Peptide Loading Protocol:
Our prMHCs can be loaded in your laboratory with a quick 3-step loading protocol. The peptide is dissolved in DMSO or PBS, mixed with the prMHC at a molar ratio of 5:1 or 10:1, and then incubated for 5-10 minutes at room temperature.
Advantages:
- Quick loading time
- Easy-to-operate protocol
- High-throughput compatibility
- Does not use UV or peptide exchange technology
For a more detailed protocol or for scientific support for your application, please contact us.
Product Applications
High-Throughput Neoantigen Screening
For researchers to evaluate tumor-specific antigen candidates, they must assess the immunogenicity of the antigenic peptide. Not all MHC-presented peptides will elicit an immune response from the T cell receptor (TCR). The recognition of the MHC-peptide (pMHC) complex by the TCR must be tested. In silico models can be used to predict the immunogenicity of antigenic peptides, but actual TCR reactivity must be experimentally validated. To facilitate this work, KACTUS has introduced a catalog of peptide-ready MHCs. These peptide-receptor MHC molecules can serve as a ready-to-use loading system for creating MHC-peptide complexes with custom neoantigens. By mixing the peptide-ready MHC with a custom peptide, a custom MHC-peptide complex is generated. This aids neoantigen screening studies by providing a quick and easy way to generate custom MHC-peptide complexes in-house for in vitro screening assessment. The fast and simple peptide-loading protocol makes screening large numbers of peptide candidates more efficient than other peptide exchange MHC technologies.
Assess TCR-pMHC Affinity
The TCR-pMHC affinity can be assessed as a way to characterize TCR-pMHC specificity or T cell responses. This may be used in the development of Chimeric Antigen Receptor-T cell therapy (CAR-T therapy) or TCR therapy. By enabling rapid and quality generation of custom Class I MHC tetramers, our peptide-ready MHCs can be used to analyze TCR-pMHC affinities via ELISA or Surface Plasmon Resonance (SPR). These peptide-ready MHCs can be loaded with a custom peptide quickly at room temperature to generate an MHC-peptide tetramer complex. These molecules can be used to determine the binding affinity of TCR-pMHCs.
Detect Antigen-Specific T Cells
Our peptide-ready MHC tetramers can be used to detect antigen-specific T cells for research and immunotherapy development. By loading the peptide-ready MCHs with a specific peptide, researchers can generate a custom MHC-peptide tetramer. By using our fluorescently-labeled peptide-ready MHCs, the fluorescent MHC tetramer can be used in flow cytometry to selectively bind to T cell subpopulations. This allows for identification and quantification of antigen-specific T cells for novel or proprietary neoantigens. Sorting antigen-specific T cells is useful for assessing antigenic immune responses, developing targeted vaccines or immunotherapies, or acting as positive controls for cell therapy development.
Specific Application Scenarios:
Antigenic Peptide Screening
TCR-pMHC Affinity Assessment
MHC Binding Studies
TCR Epitope Analysis
TCR Screening or Antigen-Specific T Cell Sorting
Custom prMHC
KACTUS also offers custom expression of other MHC alleles including class II alleles and non-human species. To request a quote, submit our custom MHC form.
Product Validation Data
TCR Binding
Loaded Peptide-ready MHC
Human prMHC monomer (HLA-A*11:01), His-Avi Tag, with KRAS G12D peptide
ka (1/Ms): 1.07E+5
ks (1/s): 1.60E-3
KD (M): 1.49E-8
Single-Chain Trimer MHC
Human single chain trimer MHC monomer (KRAS G12D, HLA-A*11:01), His-Avi Tag
ka (1/Ms): 1.43E+5
ks (1/s): 1.29E-3
KD (M): 9.00E-9
No Peptide
Human prMHC monomer (HLA-A*11:01), His-Avi Tag, with no peptide added
No binding
Figure 1. Surface Plasmon Resonance (SPR) analysis of the interaction between KRAS-G12D specific TCR (JDIa41b1) and human MHC complexes. The analysis was performed using different monomers tagged with His-Avi. The loaded prMHC demonstrates equivalent binding performance as the single chain trimer MHC.
T Cell Sorting
Identifying antigen-specific T cells is crucial in immunotherapy development, infectious disease research, and autoimmune disease research. Our loaded peptide-ready MHC tetramers demonstrate good T cell sorting activity. After loading with a custom peptide, the generated MHC-peptide tetramers show high specificity and sensitivity in identifying antigen-specific T cells.
Figure 2. Flow cytometry analysis of Jurkat Cells with Human APC-equivalent prMHC Tetramer (HLA-A*02:01), His Tag. Results demonstrate specific binding of the MHC-peptide complex to the NY-ESO-1 specific TCR, with a significant increase in APC-positive cells in the presence of the MHC loaded with NY-ESO-1 peptide.
Batch Consistency
Our prMHCs demonstrate consistent activity across batches. This consistency is crucial for effective TCR assessment and is validated through our rigorous quality control testing. If you'd like to learn more about the quality, consistency, or stability of our prMHCs, please contact us.
HLA-A*02:01 Monomer
HLA-A*02:01 Tetramer
Figure 3. ELISA data showing the batch consistency of Human HLA-A02:01&B2M&NY-ESO-1 (SLLMWITQC), His Tag monomer and tetramer. For both the monomer and tetramer, the single chain trimer MHC-peptide complex was compared to three separate batches of peptide-ready MHC loaded with NY-ESO-1 peptide (SLLMWITQC). Results demonstrate high reproducibility across batches.
Available Products
LEARN MORE
Neoantigen peptides and their role in MHC/TCR interactions
Neoantigens are highly specific targets and ideal targets for immunotherapy. Degraded neoantigen peptides can bind with major histocompatibility complex (MHC) molecules, forming complexes that are subsequently transported to the cell surface. These complexes are recognized by T-cell receptor (TCR), triggering an immune response. MHC polypeptide complexes constitute a category of neoantigen targets, and their distinctive interaction with TCR holds immense importance in the advancement of neoantigen-based immunotherapies, including TCR-T cell therapy, antibody drugs, and tumor vaccines.
Identification of the affinity of peptide loaded MHC with TCR [1].
Frequently Asked Questions
About prMHCs
Peptide-ready MHCs (prMHC) is an MHC that doesn’t contain any pre-loaded peptide and can be loaded with custom peptides for TCR binding and cell staining.
A prMHC monomer consists of an α-chain and β-2 microglobulin. It is a single subunit of prMHC tetramer.
It is a prMHC monomer with biotin at the C-terminal Avi tag.
A fluorescent prMHC tetramer is a complex of four prMHC monomers with fluorophores conjugated to each monomer subunit of the prMHC complex.
Expression of prMHCs
Yes, KACTUS prMHCs are a propriety design based on our SAMS™ Protein Engineering Platform.
Yes, prMHC are a single-chain design of α-chain and β-2 microglobulin developed by our protein engineering team.
Yes, prMHCs are purified from HEK293 cells.
prMHCs are affinity-purified via His tag at the C-terminus with additional size exclusion chromatography steps.
No, prMHC tetramerize in vivo during expression in HEK293, a KACTUS propriety design.
Our products
KACTUS provides catalog and customized prMHC monomers, biotinylated monomers, and fluorescent tetramers.
We analyze prMHC products for molecular weight (Tris-Bis PAGE), purity (Tris-Bis PAGE & SEC-HPLC), endotoxin, and concentration. Our prMHC products have > 95% purity and < 1 EU/µg.
Yes, KACTUS provides custom prMHC-I and prMHC-II for all available MHC alleles. Contact us at sales@kactusbio.us to request a custom MHC.
prMHCs can be stored for at least 12 months at -80°C.
Fluorescent Labeling
We currently offer APC-equivalent, FITC-equivalent and PE conjugation for prMHC tetramers.
APC-equivalent is a 90 kDa protein, with excitation peak at 609 nm and emission peak at 643 nm.
No, APC-equivalent is an in vivo label, part of KACTUS proprietary single chain design for fluorescent prMHC tetramer.
Protocols & Applications
Yes, contact support@kactusbio.us for a protocol.
Yes, KACTUS prMHCs can be used for peptide screening.
Yes, contact support@kactusbio.us for a protocol.
Ordering Information
We have a catalog selection of prMHCs in-stock and available to ship. Contact orders@kactusbio.us to place an order using a PO or pay via credit card on our website. We also offer custom prMHCs by submitting this form or contacting sales@kactusbio.us.
To order a custom prMHC, please submit this form or contact sales@kactusbio.us.
For prMHC catalog products, visit the specific product page to view the lead time. For custom prMHC orders, the lead time is 6 to 8 weeks.
Customize your MHC
Our team can modify parameters on an existing MHC catalog product such as neoantigen peptide, biotinylation, and fluorescent-labeling. Alternatively, submit our custom MHC request form to order an entirely customized MHC construct. We'll work closely with you to make sure the product meets your unique specifications.
Custom MHC Services
Soluble TCR Expression
Custom expression of soluble TCR with TCR/MHC binding analysis via SPR.
MHC Monomers & Tetramers
Browse our catalog selection of peptide-MHC complexes.
HLA-G and LILRs
Learn more about our full portfolio of HLA-G and LILRA/LILRB proteins.
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Waltham, MA 02451
United States
Monomers & Tetramers Ready-to-Load: Peptide-ready MHCs