サケ頬Oncorhynchus masou masouのざ仙の陸封型（ヤマメ）と遡河型（サクラマス）のアレルゲンの比較解析

摘要

サケ類のアレルギー表示は遡河型のみが対象となっている．本研究では，サケ類Oncorhynchus masou masouの陸封型（ヤマメ）と遡河型（サクラマス）のアレルゲンを比較した。SDS-PAGE分析により，主要アレルゲンであるパルプアルブミンの含量はヤマメのほうが高いことが示唆され，ELISAによる定量（ヤマメ:1.8～7.8mg／g，サクラマス：0.28～0.52 mg/g）で裏づけられた．また，患者血清を用いたELISAでは，ヤマメ抽出液のほうが強いIgE反応性を示した．次に，ヤマメおよびサクラマスから，それぞれ3成分のパルプアルブミンをゲルろ過，逆相HPLCにより精製した．逆相HPLCにおける保持時間およびMALDI／TOF-MSにより測定した分子量から，両魚種は同じパルプアルブミンアイソフォームを含むと考えられた．以上の結果から，アレルゲン性はヤマメのほうがサクラマスより高いと推測された．%Although the difference in allergenicity between landlocked and anadromous salmon is little understood, only anadromous salmon are recommended to be labeled in the current allergen labeling system. This study was designed to examine the allergenic potency of landlocked species (yama-me) and anadromous species (sakuramasu) of masu salmon Oncorhynchus masou masou, with special reference to parvalbumin, a known major fish allergen. Analysis of the heated extracts by SDS-PAGE suggested that yamame contains parvalbumin in the muscle at considerably higher levels, as compared with sakuramasu. In accordance with this, the parvalbumin content in the muscle of yamame (1.8-7.8 mg/g), determined by visible-light ELISA, was significantly higher than that of sakuramasu (0.28-0.52 mg/g). Furthermore, fluorescence ELISA experiments showed that the heated extract from yamame reacts with serum from fish-allergic patients more strongly than that from sakuramasu. Three parvalbumin isoforms (PA-I, -II and -III) were individually purified from yamame and sakuramasu by gel filtration and reverse-phase HPLC. Based on the retention times in reverse-phase HPLC and the molecular weights estimated by MALDI/TOF-MS, PA-I, -II and -III from yamame were judged to be identical with PA-I, -II and -III from sakuramasu, respectively. Taken together, our data indicate that landlocked masu salmon (yamame) is more allergenic than anadromous salmon (sakuramasu).