Study On The Mechanisms Of Different Disease-resistance Between Landrace And Tongcheng To HP-PRRSV&A PB Transposon-based Library Of Insertionally Mutated Marc145Cells

HP-PRRSV is one of the most economical and important disease in swine industry. There are different disease resistance among breeds,which is important for breeding of disease-resistance.We have found two breeds with different disease-resistance,Landrace (susceptible) and Tongcheng(resistant) in the early study. Thus, the present study was designed to compare different mechanisms of disease resistance between these breeds. Apoptotic rate, expression of CD169and CD169+macrophages were measured by flow cytometry between two breeds at different time intervals, furthermore, the transcriptional levels of apoptotic genes (P53、Bc12L1、Bax) and CD169were carried out by q-PCR.We also compared the CD169+macrophages in lung tissue between the two breeds through immunohistochemistry.Besides these, we constructed a mutant Marc145cells library with PiggyBac(PB) transposon, which helped in screening of PRRSV related genes. The main results in this study were listed as follows:1.There were no significant variations in apoptotic rates of porcine alveolar macrophage (PAMs) between two breeds, where an initial decrease, then a rise and then another decrease was observed in apoptotic levels. However, the apoptotic level at7dpi was significantly higher in Landrace compared with Tongcheng pig breeds.2.There was a significant dropping tendency of expression of P53gene in both breeds with enhancing the infection time,while the gene expression is no difference between the breeds.Before infection, the expressions of Bax and Bcl2Ll genes were significantly higher in Tongcheng than Landrace pigs,however, on3dpi, a non-significant difference was observed between breeds.,On5dpi,a lower Bax and Bcl2L1genes expressions was measured in Tongcheng.Bcl2L1gene showed significantly higher expression at7dpi in the Tongcheng breed, whereas, the Bax gene expression was almost non-significant between these two breeds in different time intervals.3. A higher transcriptional and translational expression of CD169gene was observed in Tongcheng PAMs compared with Landrace after different time interval of HP-PRRSV infection however,while the total expression of CD169were declined with time.4. The proportion of CD169+macrophages among the total cells of lungs decreased in both breeds, which came to the bottom on the3dpi. However, the figure of Tongcheng was higher than Landrace before infection. Besides, the number of the CD169+macrophages in the lung tissue is no difference in both breeds.5. Definite the optimal condition for the transposition of PiggyBac (pHi5) in the Marc-145, and obtain several Marc-145with PB inserting stably.