Custom MHC Expression Services
At KACTUS, we specialize in providing high-quality and reliable custom MHC class I and MHC class II complexes to meet your immune monitoring needs. With our extensive expertise in manufacturing MHC tetramers, monomers, and peptide-ready MHCs, we ensure that each product is tailored to your specific requirements.
We understand that accurate antigen presentation is fundamental in immunotherapy research. Our platform supports both Class I MHC and other species alleles and is compatible with T cell receptor detection workflows. Whether your study involves T cells, TCRs, or TCR-mimic antibodies, we offer flexible MHC configurations to support diverse experimental models.
Service Highlights
Monomers & Tetramers
Biotinylation & Fluorescence
Class I, and Other Species Alleles
Mammalian or E. coli Expression
6-8 Week Production
SPR Binding Analysis for validating cell surface proteins interaction with T cells
Custom MHC Expression Workflow

1. Project Outline
After you submit your request, we'll set up an initial discussion to see what specifications you're looking for and your applications.

2. MHC Expression
We use structural information and our expertise in MHC engineering to produce mammalian-expressed single-chain trimer MHCs or peptide-ready MHCs.

3. Quality Control
Your product will undergo purity and activity testing depending on the specifications outlined for your application. This may include HPLC, ELISA, or SPR testing services.

4. Delivery
We'll deliver the final protein construct and any requested quality data in 6-8 weeks.
Available Alleles
Human
HLA-A*01:01
HLA-A*02:01
HLA-A*02:03
HLA-A*02:06
HLA-A*03:01
HLA-A*11:01
HLA-A*24:02
HLA-A*26:01
HLA-A*31:01
HLA-A*33:03
HLA-A*68:01
HLA-B*15:01
HLA-B*27:05
HLA-B*57:01
HLA-C*03:04
HLA-C*07:02
HLA-E*01:03
HLA-G
Mouse
H-2K
Qa-1b
Other Alleles
For MHC Class II alleles, non-canonical alleles or alleles from other species, please submit our custom MHC request form and we will conduct a feasibility assessment for you.
Custom MHC Product Types

Monomers
Mammalian-expressed MHC-peptide complexes in natural conformation with biotinylation or fluorescent labeling

Tetramers
Four biotinylated MHC monomers bound to streptavidin for enhanced avidity to TCRs with biotinylation or fluorescent labeling

Peptide-ready MHC
Stabilized peptide-free MHC so you can load your own antigenic peptide in house

Chimeric MHCs
MHCs with the human α3 immunoglobulin-like domain replaced with the mouse α3 domain to reduce non-specific antibodies during immunization
Example Data
Chimeric MHCs
We have creatively engineered species-chimeric MHC-peptide complexes, using a special design to replace MHC α3 or β2M with the corresponding domains from other species. This approach leaves more immunogenicity to the antigenic peptide, increasing the production of effective antibodies, thereby optimizing the screening process and reducing the screening intensity. Our chimeric MHCs are expressed in mammalian cells to maintain their natural conformation and demonstrate good bioactivity.

Figure 1. ELISA verification demonstrates that the Chimeric HLA-A02:01(mα3)&mB2M&NY-ESO-1 (SLLMWITQC) Monomer can bind to the HLA-A02:01&B2M&NY-ESO-1 (SLLMWITQC) Antibody. The activity is comparable to that of the non-chimeric HLA-A*02:01&B2M&NY-ESO-1 (SLLMWITQC) Monomer.

Figure 2. ELISA validation shows that the Chimeric HLA-A02:01(mα3)&mB2M&GP100 (YLEPGPVTA) Monomer can bind to the GP100 TCR&Anti-CD3 Bispecific Fusion. Its activity is comparable to the non-chimeric HLA-A02:01&B2M&GP100 (YLEPGPVTA) Monomer and superior to that of the chimeric monomer without special design.
Peptide-ready MHC
The discovery and identification of new antigens is an important process in immunotherapy. A key step in this process is detecting binding affinities of antigenic peptides with MHCs and the reactivity to TCRs. We have engineered functional Peptide-ready MHCs (prMHCs), which stabilized, peptide-free MHC monomers or tetramers. These prMHCs are available catalog and custom in Class I and Class II alleles.
Figure 3. Flow cytometry analysis of PE-labeled HLA-A02:01&B2M tetramers binding to Jurkat cells. TCR knockout Jurkat cells showed no significant binding to the tetramers, regardless of peptide presence. In contrast, 1G4 TCR monoclonal Jurkat cells exhibited high specific binding when the tetramers were complexed with the NY-ESO-1 (SLLMWITQC) peptide, while low binding was observed with an irrelevant peptide. This indicates that the loaded prMHC tetramer has high binding affinity with the TCR-expressing cells.

Webinar: Engineering MHCs as Versatile Reagents
Discover more about our MHC engineering by listening to our Chief Technology Officer, ManHee Suh, as he explains the innovative design of our diverse MHC molecules. Learn how we integrate novel peptide-loading strategies to support antigen processing, cell mediated immunity, and T cell receptor engineering across research involving MHC class I complexes, MHC class II complexes, and custom peptide sequence validation.