Development and evaluation of an immunochromatographic strip for detection of Streptococcus suis type 2 antibody.
In this study, an immunochromatographic strip (ICS) was developed for the detection of antibody against Streptococcus suis serotype 2 (SS2). Colloidal gold particles labeled with staphylococcal protein A (SPA), which can bind to the F(C) fragment of mammalian immunoglobulin, were used as the detector reagent. The capsular polysaccharide (CPS) of SS2 and affinity-purified IgG from a healthy naive pig were immobilized on test and control regions of a nitrocellulose membrane, respectively. The ICS was used to 1) detect anti-CPS antibody in 14 sera taken from 4 SS2-infected pigs, 24 sera from pigs hyperimmunized with SS2, and 68 sera from pigs inoculated or infected with bacteria other than SS2; 2) determine anti-CPS antibody titers of 20 positive sera for comparison with enzyme-linked immunosorbent assay (ELISA); and 3) detect anti-CPS antibody in 226 clinical sera taken from diseased pigs also for comparison with ELISA. An ELISA used as a reference test determined the specificity and sensitivity of the ICS to be 97.1% and 86.3%, respectively. There was excellent agreement between the results obtained by ELISA and the ICS (kappa = 0.843). Additionally, there was strong agreement between the results of bacterial isolation from pig tonsils and ICS test (kappa = 0.658). Because it is rapid and easy to use, the test is suitable for the serological surveillance of SS2 at farms.
Yang
Junxing
J
Unit of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, PR China 430070.
Jin
Meilin
M
Chen
Jianfeng
J
Yang
Ying
Y
Zheng
Pei
P
Zhang
Anding
A
Song
Yunfeng
Y
Zhou
Hongbo
H
Chen
Huanchun
H
D000818:Animals; D000907:Antibodies, Bacterial / Q000302:isolation & purification*; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D011934:Reagent Strips; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology / Q000662:veterinary; D017011:Streptococcus suis / Q000276:immunology*; D013552:Swine / Q000276:immunology / Q000382:microbiology*; D013553:Swine Diseases / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology
D000907:Antibodies, Bacterial; D011934:Reagent Strips