Preliminary study on the identification methods for encephalomyocarditis virus

Abstract

Objective To explore and develop methods for encephalomyocarditis virus (EMCV) identification.Methods According to the genetic sequence VR-129B of EMCV recorded in the GenBank,five gene fragments were selected to design primer sequence pairs.RNA was extracted to run RT-PCR,and then the products of amplification were identified by agarose gel electrophoresis.The results of DNA sequences were compared with the sequences in GenBank of the same EMCV strains.Antiserum was prepared based on the EMCV cultured in RK cells for establishing indirect immunofluorescence assay (IIFA) and neutralization test method,and verification for precision and specificity of the two methods were carried out after it.Antiserum that was prepared with GST-VP1 and GST-VP2 expressed in E.coli was reacted with the purified EMCV in Western blot test.Results By sequencing and comparing,the similarity of DNA fragments between the obtained and the GenBank recorded was reached 98％ to 100％.The antiserum of No.20100901 batch that was chosen as the first antibody at a dilution of 1 ∶ 160 to develop IIFA brought about a better specificity.The neutralization titers of 20100901 batch antiserum was 1 ∶ 30 211 measured by fixing virus and diluting serum method,which showed good specificity and precision.The results of the Western blot test showed two clear bands above and under 33×103 respectively,which matched the theoretical value.Conclusion The RT-PCR,indirect immunofluorescence,neutralization test and Western blot method for EMCV strains identification were established initially. Key words: Encephalomyocarditis virus; Indirect immunofluorescence assay; Neutralization test