H-2 class I histocompatibility antigen, K-B alpha chain (H-2Kb) presenting SIINFEKL peptide (H-2Kb-SIINFEKL)

The H-2 class I histocompatibility antigen, K-B alpha chain (H-2Kb) presenting the SIINFEKL peptide is a classic model of a Major Histocompatibility Complex Class I (MHC-I) molecule bound to an immunodominant epitope (UniProt: P01901). H-2Kb is a mouse MHC-I molecule that presents endogenous peptides to CD8+ T cells. SIINFEKL is an eight-amino acid peptide derived from chicken ovalbumin (OVA), specifically residues 257-264 (PubMed: 8294753). This specific peptide-MHC (pMHC) complex is widely utilized in immunological research to study antigen processing, presentation, and the kinetics of T-cell responses (PubMed: 9151704). It is the primary ligand for the OT-I T-cell receptor, a transgenic TCR used extensively to model CD8+ T-cell biology (PubMed: 7520112). In therapeutic contexts, this complex serves as a target for developing TCR-like antibodies, such as 25-D1.1, and chimeric antigen receptor (CAR) T-cells designed to recognize specific pMHC targets (PubMed: 26035150). The interaction between the TCR and this pMHC complex is a fundamental unit of the adaptive immune response, governing the recognition of infected or malignant cells. Understanding this interaction has led to significant advances in vaccine design and adoptive cell therapies.

Other names

H-2Kb/SIINFEKLH-2Kb-OVA(257-264)MHC-I H-2Kb/SIINFEKL complexH2-Kb-SIINFEKLH2-K1-SIINFEKL

The H-2Kb-SIINFEKL complex acts as a specific ligand for the T-cell receptor (TCR), such as the OT-I TCR, which triggers a signaling cascade involving CD3 zeta chain phosphorylation, leading to CD8+ T-cell activation, cytokine production, and granzyme-mediated lysis of the target cell (PubMed: 7520112). TCR-like antibodies and CAR-T cells target this complex to redirect immune responses specifically against cells presenting this epitope (PubMed: 26035150).