Detection of F1 antibody levels in convalescent sera from plague patients with three assays

Objective To understand the duration of F1 antibodies in the sera from plague patients in convalescent period and the effectiveness of three detecting assays of indirect hemagglutination test(IHA), double-antigen sandwich enzyme-linked immunosorbent assay(DAgs-ELISA)and colloidal gold immunochromatography(GICA). Methods Twenty five serum samples from plague patients in convalescent period were detected with IHA, DAgs-ELISA and GICA, respectively. Results Among the 25 serum samples, 19, 21 and 18 were detected to be positive in IHA test, DAgs-ELISA and GICA, respectively. F1 antibody titers were 1∶80-1∶320 in 15 positive samples in IHA test, and 1∶640-1∶1280 in 10 positive samples in DAgs-ELISA. Conclusion F1 antibodies could be detected in convalescent sera in most plague patients by conducting three assays above mentioned, indicating they are sensitive and specific in plague detection.