Structural Gene Analysis Of Porcine Reproductive And Respiratory Syndrome Strain From Different Parts Of China And Studies On Regularity Of CD4 And CD8 Changes

Two strains of PRRSV were isolated from the swine infected with PRRSV in Shangdong province and Daqing Area, in order to clarify the source and genetic background of porcine reproductive and respiratory syndrome virus (PRRSV) from different parts of China, thus providing theoretic basis for the study of vaccine against it. the PRRSV was cultured on Mark-145 cells for 5~~6 passages. When the CPE was obvious, the virus was harvested and purified. The RNA of the whole virus was extracted. The target genes fragments representing structural genes ORF2~7 were acquired by PCR and then connected to the pMD-18T vector. The positive recombinant plasmids were acquired after transformed, then sequenced. The sequences of the strains were compared with those of CH-la strain. And the physical and chemical characteristics of the structural gnome were analyzed.Results: The structural genome of PRRSV prevalent in Shandong Province and Daqing District were 94~99% identity with those of CH-la strain, the identities of amino acid were also beyond 90%. These results further the proof that the PRRSV prevalent in China belongs to those of VR-2332. However, the proteins encoded by these structural genes show some difference, especially in the composition of amino acid.The dynamic changes of CD4 and CDS in the PBMC after challenged with PRRSV were measured by flow cytometry. The CD4* and CDS* T Lymphocytes in blood of porcine infected with PRRSV were marked by anti- CD4* and CDS* T Lymphocytes monoclonal antibodies, and then detected by flow cytometry. Results: The number of CD4* and CDS* T Lymphocytes decreased sharply from 3 DPI, and became lowest at 12 DPI, then began to increase slowly, the number of CD4+ T Lymphocytes increased to the level of pre-infection at 26 DPI, while the number of CDS* T Lymphocytes increased to the level of pre-infection at 19 DPI.