Ovalbumin (OVA) is a phosphoglucoprotein with a molecular weight of 45 kDa, which is one of the most plentiful proteins (up to 54% w/w) and is deemed to be one of the major anaphylactogens. Its sequence (containing 385 amino acids) contains 6 cysteines. There is a disulfide bond between Cys73 and Cys120. Asn292 has glycosylation sites. Ser68 and Ser344 have two phosphorylation sites. Like many other sensitized proteins, OVA partly oppose the hydrolysis of pepsinum and trypsin, which may be conducive to its ability to sensibilization or induce anaphylactic reactions. OVA (323-339) peptide sequence is H-2b restricted OVA class II epitope. OVA peptide (257-264) is a class I (Kb) restrictive peptide epitope of OVA. OVA is an octamer peptide from ovalbumin presented by class I MHC molecule H-2Kb.