IgE reactivity to type I collagen and its subunits from tilapia (Tilapia zillii)

Acid-soluble collagen (ASC) was isolated from the skin of tilapia (Tilapia zillii) via acetic acid (HAc) extraction and NaCl precipitation. ASC from tilapia consists of α chains (α1 and α2), β chains and γ chains and is classified as type I collagen. A comparison of the properties of tilapia collagen and silver carp parvalbumin showed that tilapia collagen was less stable under heat treatment and more resistant to pepsin digestion. Both tilapia collagen and silver carp parvalbumin were degraded at pH 2.0 but stable at pH 3.0–11.0. Subunits α1 and α2 were further purified from tilapia collagen by carboxymethyl (CM) cellulose column chromatography with linear gradient elution and stepwise elution, respectively. Enzyme-linked immunosorbent assay (ELISA) and immunoblotting results demonstrated the specific IgE activity of different fish-allergenic patients’ sera towards the α1 and α2 chains of tilapia collagen. It can be inferred that tilapia collagen and its subunits are all potential allergens.