Background Although Japanese cedar (Cryptomeria japonica) pollinosis has developed into a health problem, few methods eradicate indoor allergens completely. In a recent study, however, the effectiveness of inactivation with sodium hypochlorite (NaOCl) treatment was revealed. Therefore, the present study aimed to elucidate the ability of chlorine bleach (NaOCl) to reduce the immunogenicity of the major allergenic protein of Japanese cedar (Cry j 1). Methods Sodium dodecyl sulfate polyacrylamide gel electrophoresis, Western blotting, enzyme-linked immunosorbant assay, and skin testing were carried out in 7 individuals. Results The allergenic protein was undetectable using sodium dodecyl sulfate polyacrylamide gel electrophoresis and silver staining at a sodium hypochlorite/allergenic protein molar ratio of 457. Western blotting with human sera showed the same dose-dependent efficacy. The immunogenicity of the purified protein and cedar pollen was also demonstrated on enzyme-linked immunosorbant assay to be reduced by sodium hypochlorite treatment in a dose- and time-dependent manner. Moreover, sodium hypochlorite-treatment inhibited the skin test response to the protein in all 7 individuals. Conclusions Hypochlorous acid generated by electrolysis is an effective method for significantly reducing the immunogenicity of Cry j 1.
