Improvement of indirect enzyme-linked immunosorbent assay for detection of Japanese encephalitis virus antibodies in swine sera

Japanese encephalitis (JE) is an important zoonosis caused by the mosquito-transmitted JE virus (JEV), which is a causative agent of reproductive failure in pregnant sows. Detection of JEV antibodies in swine is performed by hemagglutination inhibition (HI), virus neutralization (VN), and the plaque reduction neutralization test (PRNT). The most stringent PRNT is the 90% endpoint PRNT (PRNT₉₀). These conventional assays are difficult to carry out in diagnostic laboratories with insufficient instruments or cell culture systems. An alternative assay that is easily conducted and time efficient is required. In this study, we improved the indirect enzyme-linked immunosorbent assay (I-ELISA) with clarified antigen for the detection of JEV antibodies. The I-ELISA results obtained from 175 swine serum samples were compared with HI, VN, and PRNT₉₀ results. The sensitivity of I-ELISA was 91.8%, 95.0%, and 94.7% compared with HI, VN, and PRNT₉₀ results, respectively. The specificity of I-ELISA was 92.2%, 94.7%, and 94.7% compared with HI, VN, and PRNT₉₀ results, respectively. Moreover, the I-ELISA results were significantly correlated with the HI (r = 0.93), VN (r = 0.95), and PRNT₉₀ (r = 0.92) results. These results suggest that the improved I-ELISA is useful for serosurveillance of JEV in swine.

Production of a fragment of glycoprotein G of herpes simplex virus type 2 and evaluation of its diagnostic potential

<p><b>INTRODUCTION</b>Herpes simplex virus type 2 (HSV-2) is the most common cause of genital herpes. Glycoprotein G (gG) is a prototype antigen for type-specific serodiagnosis distinguishing between HSV type 1 (HSV-1) and HSV-2 infections. As immunological diagnosis kits for accurate differentiation between HSV-1 and HSV-2 antibodies can be expensive, there is a need to develop a convenient, sensitive, specific and cost-effective serodiagnostic kit.</p><p><b>METHODS</b>We successfully expressed a fragment of gG comprising residues 321-580 of HSV-2 with histidine tag (gG(321-580His)) in a Bac-to-Bac baculovirus expression system, which had an antigenicity similar to its native counterpart. An indirect enzyme-linked immunosorbent assay (ELISA) was developed using gG(321-580His) as the diagnostic antigen and evaluated by comparison with a commercial HerpeSelect 2 ELISA immunoglobulin G kit as reference.</p><p><b>RESULTS</b>In testing 318 field serum samples, the diagnostic relative sensitivity and specificity of the developed gG(321-580His)-ELISA test in qualitative comparison with the commercial kit were 93.81% and 96.74%, respectively, and the accuracy was 94.65%.</p><p><b>CONCLUSION</b>The study indicates that gG(321-580His) has a high diagnostic potential for HSV-2 virus serodiagnosis in humans.</p>

Serological prevalence of brucellosis of cattle in selected dairy farms in Bangladesh / 대한수의학회지

This study was conducted to investigate the status of brucellosis in dairy cattle from five selected dairy farms in the Mohammadpur Beribadh area of Bangladesh. A cross-sectional study was carried out from October 2010 to March 2011 in which a total of 334 serum samples from cattle in five herds were screened by the Rose-Bengal plate-agglutination test (RBPT) and the positives were confirmed using an indirect enzyme-linked immunosorbent assay (I-ELISA). A structured questionnaire was used to collect epidemiological information describing the animals. Overall, 4.20% of the animals were RBPT positive, while subsequent confirmatory tests with I-ELISA revealed that the overall animal-level prevalence derived from the samples was 1.20%. Additionally, the prevalence was relatively higher in females than in males. A significant association was found between abortion, age of the animals, and the occurrence of brucellosis (p < 0.05). Considering the overall low prevalence of brucellosis in the selected farms in the present study, a brucellosis eradication program for dairy farms using a test-and-slaughter policy would be possible.

Regulatory effects of hippocampus extracts on PI4-K activity / 基础医学与临床

Objective The hippocampus has been used in Chinese medicine for a long time.Although it has the anti-decrepitude,anti-fatigue and anti-tumor effect,the molecular mechanism is not yet known.PI4-K,the first protein kinase in the PI pathway,should be the target molecular for drug screening.Methods We prepared antigen protein IOV-PI4-K through inside-out ghost,then the antibody-antigen reaction between IOV-PI4-K and its antibody A6D was tested by ELISA.Results Two different function groups,which could increase or decrease the binding affinity of PI4-K to its antibody,were screened out from the extracts of hippocampus.This fact indicated that there might be two different components to up-regulate or down-regulate the activity of PI4-K respectively.Conclusion Derivatives of the components could be developed into anti-tumor or anti-decrepitude drugs.Meanwhile,a new way for performing drug screen through ELISA was established.