Establishment Of Up-converting Phosphor Immunochromatography Strip For Rapid Test Trichinella Spiralis

Trichinellosis is a zoonosis caused by trichinella spiralis(T.spiralis)of the Trichinella genus and distributes worldwide.Pigs were the main host of T.spiralis.Human were infected by eating raw and uncooked pork.Trichinellosis is of great threat for public health in epidemic countries.The classical detection methods had showed strickly limitation for trichinellosis detection on site.So that exploration of efficient and sensitive detection method will reduce the test time and provide a powerful support for rapid test of pig trichinellosis on the siteThe study is to develop an up-converting phosphor-lateral flow(UPT-LF)assay for rapid test T.spiralis on site.The UPT-LF strip was prepared by indirect method,which through screening the antigen and detection mode,and optimizing the chromatographic conditions.The goat anti-pig IgG,was covalent coupled with up-converting phosphor(UCP)particles to capture pig′s IgG in serum samples.The protein of WM5 was expressed by the serine protease inhibitor gene(WM5)of T.spiralis larvae and used as capture antigen in the strip.2 mg/ml of the protein of WM5 and 0.5 mg/ml of rabbit anti-goat IgG were fixed on the test line(T)and control line(C)of the nitrocellulose membrane respectively.Hence,the UPT-LF strip was named Tsp-UPT-LF.The dilute fold of Serum(five-fold)and sample treating buffer(0.03 mol/L PB contained 0.5% NP-40,0.1 mol/L NaCl,1% BSA)was defined by optimized test.The cutoff value of Tsp-UPT-LF was defined as 0.099 by detection of 95 negative serum samples.Tsp-UPT-LF showed excellent specificity for pig serum infected with T.spiralis,Cysticercus or Clonorchis sinensis.273 pig serum samples were detected by Tsp-UPT-LF and ELISA respectively.The total coincidence rate of Tsp-UPT-LF and ELISA was 92.31%.Its Kappa value is 0.837.The results demonstrated the excellent consistency for the two methods.Positive results with 0.109 of T/C on the day 28,the max detection value with 0.207 of T/C on the day 122 and the descent value on the day 425 was detected in detection of pigs serum infected with 50,000 T.spiralis by Tsp-UPT-LF.The rate of positive results was 71.4% for anti-Trichinella IgG of pigs serum infected with 50,000 T.spiralis.The UPT-LF assay for rapid detection of pig T.spiralis had been established in the study.The method is simple and easy to be operated.Tsp-UPT-LF has showed excellent specificity and spent short time(the detection process is completed within 20 minutes)in tests of the study.The study will provide a reference method for the point-of-care testing(POCT)of pig trichinellosis and food safety guarantee.