Ovalbumin peptide SIINFEKL-Major Histocompatibility Complex Class I H-2Kb complex (SIINFEKL/H-2Kb)

The SIINFEKL peptide bound to the mouse MHC Class I molecule H-2Kb is a cornerstone model in cellular immunology and immunotherapy research. SIINFEKL is an eight-amino acid sequence (Ser-Ile-Ile-Asn-Phe-Glu-Lys-Leu) derived from chicken ovalbumin, which serves as a potent epitope when presented by the H-2Kb allele in C57BL/6 mice [1][2]. On dendritic cells, this complex is essential for the 'cross-priming' of naive CD8+ T cells, a process critical for initiating an anti-tumor immune response [3][6]. On tumor cells, such as the B16-OVA melanoma line, the presence of the SIINFEKL/H-2Kb complex renders the cells susceptible to lysis by specific cytotoxic T lymphocytes (CTLs) [4]. This complex is primarily recognized by the T-cell receptor (TCR) of OT-I transgenic CD8+ T cells and TCR-like antibodies such as 25-D1.1, which are used to track antigen presentation and evaluate the efficacy of vaccines and CAR-T therapies [5]. While primarily a preclinical mouse model, it provides fundamental insights into the mechanisms of immune recognition and evasion in cancer [4][5]. The interaction between the TCR and the SIINFEKL/H-2Kb complex triggers a signaling cascade that leads to the release of perforin and granzymes, resulting in the apoptosis of the target cell.

Other names

OVA peptide/H-2Kb complexH-2Kb-SIINFEKLSIINFEKL-MHC class I complexOvalbumin 257-264/H-2KbMHC-I H-2Kb-SIINFEKL

The complex acts as a specific ligand for the T-cell receptor (TCR) on CD8+ T cells, initiating an immunological synapse that leads to T-cell proliferation, cytokine release, and targeted cytotoxicity against the presenting cell.