麻痺性貝毒簡易検出キット(PSP-ELISA)を用いた貝毒モニタリングシステムの有効性

摘要

We investigated the applicability of enzyme-linked immunosorbent assay(PSP-ELISA)using a monoclonal antibody against paralytic shellfish toxins(PST)for screening oysters collected at several coastal areas in Kumamoto prefecture, Japan. Oysters collected between 2007 and 2010 were analyzed by PSP-ELISA. As an alternative calibrant, a naturally contaminated oyster extract was used to quantify toxins in the oyster samples. The toxicity of the calibrant oyster extract determined by the official testing method, mouse bioassay(MBA)， was 4 MU/g. Oyster samples collected over 3 years showed a similar toxin profile to the alternative standard, resulting in good agreement between the PSP-ELISA and the MBA. The PSP-ELISA method was better than the MBA in terms of sensitivity, indicating that it may be useful for earlier warning of contamination of oysters by PST in the distinct coastal areas. To use the PSP-ELISA as a screening method prior to MBA, we finally set a screening level at 2 MU/g PSP-ELISA for oyster monitoring in Kumamoto prefecture. We confirmed that there were on samples exceeding the quarantine level(4 MU/g)in MBA among samples quantified as below the screening level by the PSP-ELISA. It was concluded that the use of PSP-ELISA could reduce the numbers of animals needed for MBA testing.%麻痺性貝毒の規制値である4 MU/gに相当する毒力を持つマガキ(Crassostrea gigas)の抽出液を代替標準品として大阪府立公衆衛生研究所が開発した麻痺性貝毒簡易測定キット(PSP-ELISA)を使ったスクリーニング検査の有効性を検証した.2007〜2O10年に熊本県海域で採取したマガキ試料をPSP-ELISAで測定したところ，PSP-ELISAと公定法の結果は高い相関性を示し，規制値の半量であるマウス毒力2MU/g以下でも十分検出できるため,マガキ の毒化予察に十分役立つことが分かった.また，マガキ抽出液を蛍光化HPLCで分析したところ，監視期間中のマガキの毒組成は一定であった.以上の結果から，スクリーニング基準値を2MU/g(PSP-ELISA)と設定した.熊本県海域ではこの基準値であれば，規制値以上のマウス毒力を持つマガキを確実に検出できることから，本モニタリング法の有効性が明らかになつた.