免疫层析试纸条检测轻度感染小鼠肉汁抗旋毛虫抗体的研究

Immunochromatographic strip for detection of anti-Trichinella antibodies in muscle juice of experimentally infected mice with low grade of infection

目的观察免疫层析试纸条对轻度感染小鼠肉汁中抗旋毛虫抗体的检测效果。方法以胶体金标SPA和旋毛虫肌幼虫ES抗原制备免疫层析试纸条。将70只雄性昆明小鼠随机分为7组（每组10只），每组分别经口感染30、25、20、15、10、5、3条旋毛虫幼虫，感染后6周用试纸条进行血清及肉汁抗体检测，并与ELISA、镜检法及消化法的检测结果进行比较。结果30、25、20、15、10条旋毛虫幼虫感染的小鼠，试纸条与ELISA的血清及肉汁抗体阳性率均为100（10／10）,镜检法与消化法的幼虫检出率均为100％（10／10）。5条旋毛虫感染的10只小鼠，镜检法和消化法的幼虫检出率分别为70％（7／10）和100％（10／10），消化法检查时10只小鼠的每克肌肉虫荷为0．88～3．14条幼虫（平均为1．58条），试纸条与ELISA检测时的血清及肉汁抗体阳性率均为100％（10／10）。3条旋毛虫感染的10只小鼠，4种方法检测时均为阴性。结果表明，试纸条检验肉类中旋毛虫的敏感性与ELISA和消化法相同，且明显高于镜检法（P〈0．05）。低剂量旋毛虫感染小鼠后6周的肉汁抗体水平与感染剂量呈正相关（P〈0．05），肉汁与血清抗体水平均具有相关性（P〈0．05）。结论每克小鼠肌肉仅含0．88条旋毛虫幼虫时也可被试纸条检出，试纸条可用于轻度感染肉类中旋毛虫检疫的初筛。

To observe the effect of the immunochromatographic strip for detection of anti-Trichinella antibodies in muscle juice of experimentally infected mice with low grade of infections, the strip was prepared by using SPA labeled with colloidal gold and T. spiralis muscle larval excretory-secretory （ES） antigens. Seventy male Kunming mice were randomly divided into 7 groups （10 mice per group）, each group was orally inoculated with 30,25,20,15,10,5 ,or 3 muscle larvae of T. spiralis, respectively. The anti-Trichinella antibodies in serum and muscle juice from the infected mice were assayed by the strip 6 weeks post-infection （wpi）. The results of strip were compared with those of ELISA, trichinelloscopy and digestion method. In the mice infected with30,25,20,15 and 10 larvae, the antibody positive rate of serum and muscle juice was 100 % （10/10） by strip and ELISA, the larvae were detected in 100 % （10/10） of muscle samples by trichinelloscopy and digestion method. In 10 mice infected with 5 larvae, the positive rate of trichinelloscopy and digestion method was 70 % （7/10）and 100 % （10/10）, respectively; the larvae were detected in 10 muscle samples with 0.88-3.14 larvae per gram （1pg） （mean 1.58 lpg）by digestion method, the antibody positive rate of serum and muscle juice was also 100% （10/10） by strip and ELISA. In 10 mice infected with 3 larvae, anti-Trichinella antibodies in serum and muscle juice were not detected by strip and ELISA and the larvae not found by both of trichinelloscopy and digestion method. The results showed the sensitivity of the strip for examination of T. spiralis in meat was the same as ELISA and digestion method, and obviously higher than trichinelloscopy（P〈0.05）. There was a posi- tive correlation between antibody level in muscle juice and infecting dose in mice infected with low dose 6 wpi（P〈0.05）, the antibody level in muscle juice showed also significant positive correlation with serum antibodies 6 wpi. In conclusion, the mouse muscle samples containing 0. 88 1pg could be detected by the immunochromatographic strip and the strip could be used as the preliminary screening test for inspection of meat with low grade of Trichinella infection.