Expression and analysis of recombinant salmon parvalbumin, the major allergen in atlantic salmon (Salmo salar)

The parvalbumin from white muscle of Atlantic salmon was previously found t o be a major allergen, and designated Sal s1. Two distinct cDNAs, 14.1 and 24.1, which comprise the entire parvalbumin-encoding regions, were cloned, revealing transcripts from two different parvalbumin genes. In the present study, the protein-coding regions of these cDNAs were subcloned into an Esc herichia coli expression vector (pET-19b). Both proteins were expressed and the generated target proteins were localized in both soluble and insoluble fractions of the expression host. The recombinant products in the soluble fraction were purified using the His tag-purification system and analysed o n Western blots with anti-salmon parvalbumin polyclonal rabbit sera and ser a from patients allergic to fish. Both recombinant products (His(10)-14.1 a nd His(10)-24.1) reacted positively with salmon parvalbumin-specific immuno globlin G (IgG) from rabbits, and with specific immunoglobulin E (IgE) from the sera of six fish-allergic patients. The allergenicity of His(10)-14.1 was confirmed using enzyme-linked immunosorbent assay (ELISA). The 14.1 cDN A of salmon parvalbumin was shown to be the dominant type represented in a muscle cDNA library.