| Summary: | 碩士 === 國立中興大學 === 獸醫病理學研究所 === 92 === In order to evaluate the possibility of lymphoproliferative assay and IL-2 bioassay applied in the surveillance of bovine tuberculosis in Taiwan. Two experiments was undertaken in 2002 and 2003 respectively. In the first experiment, samples were collected from the infected diary herds in central and southern Taiwan that included 52 ITT positive samples and 229 ITT negative samples. The dynamics of lymphoproliferative assay、dexamethasone（DEX） lymphocyte suppression test、interferon-gamma （IFN-γ）ELISA test and lymphoproliferative assay were also included. The results showed the lymphoproliferative activity of PBMC could last for 18 hours, and them significantly decayed at 24 hours after bleeding. To cultures with DEX administration shows a significant suppression on the lymphoproliferation with dose-dependent effect. Surveillance on 52 ITT positive samples and 229 ITT negative samples shows 51.9 % and 14.0 % positive respectively, for IFN-γ ELISA test. The detectable rates of 52 ITT positive samples assayed by lymphoprolifirative assay using, whole blood、2 x diluted、5 x diluted blood and PBMC, were 19.0 %、24.0 %、48.0 % and 71.0 % respectively. Meanwhile, the detectable rate of 229 ITT negative samples assayed by whole blood、5 x diluted and PBMC were 20.0 %、7.4 % and 25.0 % respectively.
There were 2 TB-contaminated diary farms assigned in the second experiment. The total collected samples of 240 were used in the comparison of the sensitivity of ITT、IFN-γELISA test、lymphoproliferative assay and IL-2 bioassay. The results showed 2.5 %、7.9 %、17.0 % and 16.3 % of positive reaction for ITT test、 lymphoproliferation of 5 ×diluted blood、PBMC and IFN-γ ELISA test respectively. If positive result of IL-2 bioassay was cut-off at mean ＋ 2SD, the detection rate was 26.2 %. Those results indicated that IL-2 bioassay is the most sensitive and ITT is less sensitive method for TB detection. Moreover, compared with ITT in the first experiment, the sensitivity and specificity of IFN-γ ELISA test were 75.0 % and 91.7 % respectively, and κ value was 0.63. The sensitivity and specificity of lymphoproliferative assay were 71.0 % and 80.0 % respectively, and κ value was 0.49. In the second experiment, compared with ITT, the sensitivity and specificity of IFN-γ ELISA test were 100.0 % and 85.9 % respectively, and κ value was 0.23. The sensitivity and specificity of lymphoproliferative assay were 100.0 % and 85.0 % respectively, and κ value was 0.22. The sensitivity and specificity for IL-2 bioassay were 100.0 % and 76.0 % respectively, and κ value was 0.13. Taken together, though ITT is one of the standard methods for TB detection in Taiwan, the less sensitivity and effect by physical and management stresses were particularly concerned. Therefore, besides IFN-γELISA test, lymphoproliferative assay is also suitable for TB compulsory method. Therefore, combined ITT and other methods, can be applied for TB detection to enhance the sensitivity in TB contaminated farms.
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