MHC Complexes & Tetramers | Peptide-MHC Reagents

Detect and characterize antigen-specific T cells with our peptide-MHC (pMHC) complexes and MHC-β₂-microglobulin (B2M) monomers. MHC class I molecules present intracellularly processed peptide epitopes (8–11 amino acids) on the cell surface for surveillance by CD8⁺ cytotoxic T lymphocytes (CTLs). The trimolecular complex — MHC heavy chain (α1/α2 peptide-binding groove + α3 domain), β₂-microglobulin, and bound peptide — is the fundamental unit of adaptive cellular immunity. Soluble biotinylated pMHC monomers can be multimerized with streptavidin-fluorophore conjugates to form MHC tetramers, the gold-standard tool for enumerating antigen-specific CD8⁺ T cells by flow cytometry. Our reagents present defined peptide epitopes in the context of MHC class I, enabling TCR binding affinity measurement (SPR, BLI), antigen-specific CD8⁺ T cell enumeration and phenotyping, neoantigen validation for personalized cancer vaccines, immunotherapy immune monitoring (checkpoint inhibitor, CAR-T, TCR-T response tracking), and infectious disease T cell immunity profiling. Available alleles include HLA-A*02:01, HLA-A*01:01, HLA-A*24:02, HLA-B*07:02 (human) and H-2K^b, H-2D^b (mouse). RUO

Peptide-MHC Monomers Refolded MHC class I heavy chain + β₂M + peptide monomers, site-specifically biotinylated via BirA-tag for oriented streptavidin tetramerization. Use as building blocks for MHC tetramer assembly (with streptavidin-PE/APC), or directly in SPR/BLI for TCR binding kinetics (k_on/k_off/K_D) measurement.

Pre-Loaded Peptide Epitopes Available with clinically relevant peptide epitopes: viral (CMV pp65_495-503, EBV LMP2A, SARS-CoV-2 Spike/Nucleocapsid), tumor-associated (NY-ESO-1_157-165, MART-1_26-35, WT1_126-134), and model antigens (OVA SIINFEKL). Custom peptide loading available via AtaGenix CRO services.

Neoantigen & Immunotherapy Research Validate computationally predicted neoantigens by testing pMHC binding to patient-derived tumor-infiltrating lymphocytes (TILs). Quantify tumor-reactive CD8⁺ T cell frequencies before and after checkpoint inhibitor therapy, CAR-T infusion, or TCR-T adoptive cell transfer to assess immunotherapy-induced clonal expansion.

Multiple Allele Coverage Human HLA alleles covering >80% of global populations: HLA-A*02:01 (most frequent worldwide), HLA-A*24:02 (high frequency in East Asian populations), HLA-A*01:01, HLA-B*07:02. Mouse alleles H-2K^b and H-2D^b (C57BL/6 background) for preclinical syngeneic tumor and infection models.

Quality Controlled Each lot validated for proper refolding by SEC-HPLC (monodisperse peak), peptide occupancy confirmed by LC-MS/MS, and functional T cell staining verified by FC with peptide-specific T cell lines. Supplied lyophilized with detailed reconstitution and tetramer assembly protocols.

All products manufactured by AtaGenix Laboratories under ISO 9001 & ISO 13485 quality systems.

References

1. Altman JD, Moss PAH, Goulder PJR, et al. Phenotypic analysis of antigen-specific T lymphocytes. Science. 1996;274(5284):94-96. DOI

2. Davis MM, Altman JD, Newell EW. Interrogating the repertoire: broadening the scope of peptide-MHC multimer analysis. Nat Rev Immunol. 2011;11(8):551-558. DOI

3. Schumacher TN, Schreiber RD. Neoantigens in cancer immunotherapy. Science. 2015;348(6230):69-74. DOI

4. Hadrup SR, Bakker AH, Shu CJ, et al. Parallel detection of antigen-specific T-cell responses by multidimensional encoding of MHC multimers. Nat Methods. 2009;6(7):520-526. DOI