Ovalbumin-derived peptide-MHC complex (OVA-pMHC)

Ovalbumin-derived peptide-MHC complexes are fundamental model antigens used to study the molecular basis of T cell recognition and activation. These complexes are formed when specific proteolytic fragments of the chicken egg protein ovalbumin (OVA), such as the MHC class I-restricted SIINFEKL peptide or the MHC class II-restricted OVA 323-339 peptide, are loaded onto Major Histocompatibility Complex (MHC) molecules (UniProt P01012). The resulting peptide-MHC (pMHC) complex is recognized with high affinity by specific T cell receptors (TCRs), most notably those expressed by OT-I (CD8+) and OT-II (CD4+) transgenic T cells (PubMed: 7525851, 9553774). Although ovalbumin is primarily known as a major food allergen in humans, its peptide-MHC complexes are extensively utilized in preclinical research to evaluate the efficacy of vaccines, checkpoint inhibitors, and adoptive cell therapies like TCR-engineered T cells. The interaction between the TCR and the OVA-pMHC complex triggers downstream signaling pathways that lead to T cell expansion and the secretion of pro-inflammatory cytokines like interferon-gamma. This system provides a highly controlled environment for benchmarking immune responses and investigating the dynamics of the immunological synapse.

Other names

SIINFEKL-H-2Kb complexOVA 323-339-I-Ab complexOvalbumin antigen-MHC complexOVA-peptide-HLA complexOVA-pMHC

The peptide-MHC complex serves as a specific ligand for T cell receptors (TCRs), which, upon binding, initiate a signaling cascade through the CD3 complex and ZAP-70, leading to T cell proliferation, cytokine production, and cytotoxic activity.