Development of an immunochromatographic strip for the detection of antibodies against foot-and-mouth disease virus serotype O.
ABSTRACT An immunochromatographic strip was developed for the serological detection of type O foot-and-mouth disease (FMD) in swine. In the strip, the expressed protein of VP1, the main protective antigen of FMDV, labeled with colloidal gold was used as the detector, the staphylococcal protein A (SPA) and swine anti-foot-and-mouth disease virus (FMDV) antibody were blotted on the nitrocellulose membrane for the test and control lines, respectively. 296 swine serum samples were collected to evaluate the characteristics of the strip in comparison with existing commercial liquid-phage blocking ELISA (LPB ELISA) kit and peptide ELISA kit. The strip was shown to be of high specificity and sensitivity. Furthermore, the dipstick assay based on the strip is rapid (5 min) and easy to perform with no requirement of professional skills, reagents nor equipment. This suggests that the immunochromatographic strip is an acceptable alternative for use in clinical laboratories lacking specialized equipment and for field diagnosis.
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ABSTRACT: BACKGROUND: The incidence of PHE among pigs in many countries is on the rise, and it has caused great economic losses to the pig industry. Therefore, the development of a sensitive, specific, and easily-performed assay is crucial for the rapid detection and surveillance of PHE-CoV infection and transmission. RESULTS: An immunochromatographic strip was developed for the detection of PHE-CoV. The colloidal gold-labeled MAb 4D4 was used as the detection reagent, and the MAb 1E2 and goat anti-mouse IgG coated the strip's test and control lines, respectively. The immunochromatographic strip was capable of specifically detecting PHE-CoV with a HA unit of 2 within 10 min. Storage of the strips at room temperature for 6 months or at 4 [DEGREE SIGN]C for 12 months did not change their sensitivity or specificity. Using RT-PCR as a reference test, the relative specificity and sensitivity of the immunochromatographic strip were determined to be 100% and 97.78%, respectively. There was an excellent agreement between the results obtained by RT-PCR and the immunochromatographic strips (kappa = 0.976). Additionally, there was a strong agreement between the sandwich enzyme-linked immunosorbent assay (ELISA) and immunochromatographic strips (Kappa = 0.976). When the immunochromatographic strips were used for diagnosing PHE-CoV infection in the Jilin Province, the PHE-CoV-positive rate ranged from 61.54% in the Jilin district to 17.95% in the Songyuan district. CONCLUSIONS: Based on its high specificity, sensitivity, and stability, the immunochromatographic strip would be suitable for on-site detection of PHE-CoV for surveillance and epidemiological purposes.Virology Journal 08/2012; 9(1):172. · 2.09 Impact Factor
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ABSTRACT: The genes encoding the Erns and E2 antigen epitopes of classical swine fever virus (CSFV) were expressed as a chimeric protein in Escherichia coli BL21 by pET expression system. The antigenicity of the expressed protein CnC2 was identified by indirect enzyme-linked immunoabsorbant assay (ELISA) and immunoblot with anti-CSFV antibodies. Based on the CnC2 protein, an immunochromatographic strip was developed to evaluate the antibody titer of serum samples from swine vaccinated with CSFV vaccine rapidly. The chimeric protein used as a detector was labeled with colloidal gold. Staphylococcal protein A (SPA) and anti-CnC2 monoclonal antibodies (mAbs) were blotted onto the nitrocellulose membrane as the test and control lines, respectively. The strip assay could be performed within 5min, which did not require any special equipment or skills. Through testing sera against various strains of CSFV, the sensitivity of the strip was determined to be 97.0% (65/67) and the specificity was 100% (98/98). The strip results were consistent with those of the existing commercial ELISA kit, and their correlation coefficient was 0.935. In conclusion, the immunochromatographic strip was an acceptable method for surveying CSFV-antibody titers in pigs.Journal of virological methods 12/2011; 180(1-2):32-7. · 2.13 Impact Factor
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ABSTRACT: A pocket device for rapid combined test of biomedical samples is comprised of four parts: strip, strip attached column, sampling head and test tube. One to multiple strips are separately attached to the shallow groove on the surface of the strip attached column. The strip attached column is placed inside the test tube of the device. The sampling head is in front of the test tube. The sampling head has a slim tube type suction nozzle, which is capped with a rubber protection cap. The cavity of the sampling head is front-to-back filled with sample filter material and sample water absorbent material. The sealing cap at the end of the test tube is able to block the waste after testing to prevent leakage. During the sample testing, one removes the rubber protection cap of sampling head suction nozzle and dips the suction nozzle into the test sample. Each strip undergoes once sampling and is detected at the same background. In 3-5 minutes we can concurrently test several indexes of the sample in the transparent areas of test tube with naked eyes. This device has many advantages: small size, low cost, simple, safe and fast operation, and it can effectively prevent detection of cross-interference. Post-test waste is still enclosed in the test tube, which helps to prevent the spread of pathogens and iatrogenic infections, and to dispose waste for environmental protection.01/2010;