Comparison of three immunological methods in detection of Yersina pestis F1 antigen

Abstract

Objective To compare the effect of three methods in diagnosis of plague by detecting of Yersina pestis F1 antigen. Methods In natural foci of plague, wild animal samples, such as blood, liver, spleen,and lymphoid tissue were collected, and the three methods of enzyme linked immunosorbent assay （ELISA）,reverse indirect hemagglutination assay（RIHA） and gold-immunochromatography assay（GICA） were employed to detect F1 antigen of Yersina pestis. Results Total of 414 infused organ samples of natural death and captured wild animals in natural foci of plague were determined. Positive samples detected by GICA and ELISA were the same,the positive rates were 5.31%（22/414）, both positive and negative coincidence rates were consistently 100%. Only 18 samples were positive by retrial in 186 samples with more than 2 holes aggregation by preliminary examination of RIHA, with nonspecific agglutination rate of 40.6% （168/414） and positive rate of 4.35% （18/414）. The positive coincidence rate was 81.82% （18/22） between RIHA with GICA and ELISA, and negative coincidence rate was statistically significant（t = 4.379, P 〈 0.01）. Conclusions ELISA, RIHA and GICA can be used for early diagnosis of plague by detecting F1 antigen. The results of RIHA have quantitative significance, with higher non-specific agglutination rate, and heavy workload of re-examination; GICA and ELISA has the same specificity and sensitivity, but the results of GICA is only qualitative. ELISA excluded the defect of RIHA and GICA, and combines the advantages of both methods. Key words: Plague ; Immunity; Diagnostic techniques and procedures