以螢光抗體法檢測志賀氏桿菌之探討

STUDIES ON FLUORESCENT ANTIBODY METHOD FOR DETECTING SHIGELLA

經紫外線照射後發出螢光之化合物，通稱為螢光物質，依照免疫學原理，免疫球蛋白可與特異性抗原相結合，用螢光染料標示之免疫球蛋白仍保持其原來特異，尚可與其特異性抗原相結合，且在螢光顯微鏡下放出螢光而進行免疫螢光顯微鏡觀察，本技術稱為螢光抗體法（Fluorescent Antibody Technique） 簡稱FA。螢光抗體法之特點包括1.特異性（specificity）：帶螢光物質之抗體間有相當高特異性結合反應。2.快速性（rapidity）螢光染色過程及顯微鏡觀察只須數小時就可完成。3.靈敏性（sensitivity）：少量抗原與適量螢光抗體結合就可看到螢光。志賀氏桿菌通常與密集發生之桿菌性病疾有關，這種病症常會引起死亡，可疑的食品包括經手操作或較少經熱處理（minimum heat treatment）動物類來源之食品，且其pH值在5.5-6.5之間，食品中若含大腸桿菌群、大腸桿菌及沙門氏桿菌者亦可能污染志賀氏菌。

The purpose of this test is to evaluate the possibility of detecting Shigella in foods by indirect fluorescent antibody method. The results showed: (1) Sensitivity: a minimum of 105 Shigella per ml is needed. (2) Cross reaction: the Shigella conjugated antisera reacted with Salmonella and E. coli up to 66.7% and 46.7%, respectively. (3) Application of this method on food examination needs further study.