Comparative Studies on Serological Tests for Actinobacillus pleuropneumoniae Infection in Swine

돼지에서 Actinobacillus pleuropneumoniae의 혈청학적 진단법에 대한 비교연구

To establish an effective diagnostic measure for detection of the antibodies against Actinobacillus pleuropneumoniae, the methods for tube agglutination test (TAT), plate agglutination test (PAT), micro-agglutination test(MAT) and agar-gel immunodiffusion test(ID) were improved and standarized, and the comparative studies were carried out. The results obtained through the experiments were summarized as follows. 1. The rabbit hyperimmune sera to reference serotypes 1 to 6 were cross-tested with TAT, PAT, MAT and ID. In the homologous systems, the range of antibody titers in TAT was 80 to 640, showing the cross-reaction in serotypes 3, 4, 5 and 6. The range of antibody titers in PAT was 4 to 64, showing the cross-reaction in serotypes 3, 4, 5 and 6. In ID, the range of antigen titers was 8 to 32, and cross-reaction was observed in serotype 5. 2. The optimal concentration of antigen in PAT and MAT were 100mg /ml and 1.25mg /ml respectively. The most sensitive reaction in MAT was observed in 52$^{\circ}C$ for 18hrs. 3. In ID, the most promising antigen and the buffer for agar-gel were EDTA-treated antigen and 0.05M tris buffer (pH 7.2), respectively. 4. By the tests for 200 swine sera, it was found that the frequency of positive reaction were 203 in TAT, 240 in PAT and 163 in ID. 5. When compared the titers of TAT with those of MAT for 200 swine sera, MAT showed the higher titer than TAT being increased by relative correlation. Int was found that the titer for positive readings were 20 in TAT and 40 in MAT. 6. when compared the results of ID with those of TAT for 200 swine sera, all sera with TAT titer under 10 were negative in ID. Of the sera with TAT titer 20 and 40, 55.1% nd 91.8% were positive in ID, respectively. All sera with TAT titer above 80 were positive in ID. In comparison of ID and MAT, all sera with MAT titer under 20 were negative in ID. Of the sera with MAT titer 40 and 80, 24.7% and 93.9% were positive in ID, respectively. All sera with MAT titer over 160 showed positive in ID. 7. In conclusion, the established MAT showed high sensitivity but low specificity, wherease ID revealed low sensitivity but high specificity.