著者

土谷 正和

出版者

一般社団法人 日本エンドトキシン・自然免疫研究会

雑誌

エンドトキシン・自然免疫研究 (ISSN:24341177)

巻号頁・発行日

vol.23, pp.43-46, 2020 (Released:2020-10-29)

参考文献数

13

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Limulus amebocyte lysate (LAL) is widely used for detection of endotoxin, one of the most potent pyrogen. Recent studies revealed the mechanism of activation of Factor C and Factor B, endotoxin binding proteins in LAL cascade. It is well known that Factor C is the first factor to bind endotoxin aggregates. The second coagulation factor, Factor B is important to achieve specificity of LAL to endotoxin because activated Factor C on endotoxin aggregates are essential for its activation. The endotoxin-specific signal is amplified after the Factor B activation in LAL. On the other hand, recombinant Factor C reagents rely on only the specificity of Factor C to endotoxin, and amplifies the trypsin-like activity of activated Factor C that may not be specific to endotoxin. This mechanism seems not to be as specific to endotoxin as LAL. More evaluation and improvement are necessary for recombinant reagents for endotoxin measurement as a safety test.

著者

土谷 正和

出版者

一般社団法人 日本エンドトキシン・自然免疫研究会

雑誌

エンドトキシン・自然免疫研究 (ISSN:24341177)

巻号頁・発行日

vol.21, pp.23-25, 2018 (Released:2018-11-22)

参考文献数

7

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Low Endotoxin Recovery (LER) is a phenomenon of endotoxin activity decrease in a matrix containing a chelating agent and a detergent, and is a controversial topic in the biopharmaceutical field. The mechanism of LER is not fully elucidated. When endotoxin in LER solutions was diluted with water, the activity was decreased. The activity was maintained for a long time at 4°C, and was recovered by magnesium dilution and direct addition to the Limulus amebocyte lysate (LAL). The size of endotoxin in LER solution was not changed after the activity was decreased. Considering these results, a new LER mechanism was proposed. A chelating agent removes divalent cations from the surface of endotoxin aggregates, and endotoxin molecules on the surface of the aggregates are replaced with detergent molecules. The reduction of the surface area of endotoxin aggregates causes decrease of the endotoxin activity to the LAL.

著者

藤原 博 石田 説而 島崎 義男 内藤 誠之郎 土谷 正和 松浦 脩治

出版者

公益社団法人 日本薬学会

雑誌

YAKUGAKU ZASSHI (ISSN:00316903)

巻号頁・発行日

vol.110, no.5, pp.332-340, 1990-05-25 (Released:2008-05-30)

参考文献数

17

被引用文献数

1 3

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The amounts of endotoxin in commercial blood products were measured by the turbidimetric kinetic Limulus test with an ordinary reagent (LAL-HS) and a new endotoxinspecific reagent (LAL-ES). LAL-ES contains a sufficient amount of a water-soluble (1→3)-β-D-glucan derivative as a blocker of the (1→3)-β-D-glucan-mediated coagulation pathway in the reaction of the Limulus amebocyte lysate. The amounts of endotoxin in alubumin and globulin products measured with LAL-ES agreed with pyrogenic activities in rabbits, but those measured with LAL-HS did not. Added endotoxin in the blood products was well recovered with LAL-ES, but that in some products was excessively recovered with LAL-HS. The amounts of endotoxin in diphtheria-pertussis-tetanus combined vaccines measured with LAL-HS and LAL-ES agreed with the pyrogenic activities in rabbits. The results suggested the existence of a false-positive substance like β-glucan in the blood products but not in the vaccine. LAL-ES is more suitable for the detection of endotoxin in blood products than LAL-HS.