Ovalbumin 323-339 peptide (OVA 323-339)

The Ovalbumin 323-339 peptide (sequence ISQAVHAAHAEINEAGR) is a 17-amino-acid fragment derived from chicken ovalbumin (UniProt P01012, residues 323-339), serving as a prominent immunodominant epitope in immunology research. It functions primarily as a MHC class II-restricted T-cell epitope, binding to mouse H2-IAd (I-A^d) and eliciting CD4+ T-cell responses, with evidence of two distinct binding registers that produce different T-cell stimulations. This peptide is also recognized as a B-cell epitope by IgE antibodies, contributing to Th2-biased immune responses, immediate hypersensitivity, and models of lung inflammation mimicking allergic asthma in BALB/c mice. In experimental settings, it induces serum IgE, IL-4 production, and splenocyte proliferation comparable to intact ovalbumin, accounting for 25-35% of T-cell responses to ovalbumin in isolated cells. Widely used in T-cell assays (e.g., ELISPOT, tetramers), it aids studies of antigen processing, presentation by antigen-presenting cells, epitope mapping, and immune tolerance mechanisms, but it is not a therapeutic target like receptors or enzymes—instead, a model tool for allergy, autoimmunity, and vaccine research.

Other names

Ova 323-339OVA peptide 323-339Ovalbumin(323-339)