Mouse MHC class I antigen H-2Kb (H-2Kb) presenting ovalbumin-derived peptide SIINFEKL (H-2Kb-SIINFEKL)

The H-2Kb presenting the SIINFEKL peptide is a prototypical peptide-major histocompatibility complex (pMHC) class I molecule used as a gold standard in cellular immunology research. H-2Kb is a mouse MHC class I molecule of the b haplotype (UniProt P01901), while SIINFEKL is an eight-amino acid immunodominant epitope derived from chicken ovalbumin (UniProt P00336). This complex is essential for the study of antigen processing, presentation, and the kinetics of T-cell receptor (TCR) binding. It is specifically recognized by the OT-I transgenic TCR, making it a vital tool for developing and testing T-cell-based therapies and TCR-mimetic antibodies (Porgador et al., 1997). In therapeutic development, it serves as a surrogate target to validate the specificity and efficacy of novel immunotherapies, such as chimeric antigen receptor (CAR) T cells or bispecific T-cell engagers (BiTEs) targeting pMHCs. Its biological role is to signal the presence of foreign or aberrant proteins to the adaptive immune system, thereby initiating a targeted cytotoxic response (Hogquist et al., 1994). The complex is often used to evaluate the potency of vaccines and the efficiency of antigen delivery systems in preclinical mouse models.

Other names

H-2Kb/SIINFEKL complexSIINFEKL-H-2KbOvalbumin peptide-MHC complexH2-K1/SIINFEKLOVA257-264/H-2Kb

The complex acts as a ligand for the T-cell receptor (TCR) on CD8+ T cells. Upon binding to a specific TCR, such as the OT-I TCR, it induces the clustering of TCR-CD3 complexes and subsequent phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs), leading to T-cell activation and cytotoxic activity (Hogquist et al., 1994; Murphy et al., Janeway's Immunobiology).