As the initial results of the study were negative, the work was discussed informally with several researchers in the field, including a group that has worked with the SCID mice model, in order to optimize our results. Directed to virologists, PRRSV researchers, vaccinologists, pathologists and students. and within undergraduate and graduate courses. DISSEMINATION: results of the work intended to be discussed and presented at local and national meetings including CRWAD, International PRRS Symposium etc. A joint proposal to the USDA's Scientific Cooperation Exchange Program was submitted. Dongsheng He, Associate Professor, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People's Republic of China. Started an initiative of cooperation in research on PRRSV with Dr. Raj Maganti, a post-doctoral fellow, was trained in virus assays used in the study and in IFN beta immunoassay and bioassays. Through this and other ongoing studies Dr. Christopher Overend for Doctoral degree in Pathobiology and Veterinary Science who has worked in the project.
Attendance to the International PRRS Symposia and the CRWAD meetings held in Chicago, Illinois. Progress 10/01/05 to 09/30/08 Outputs OUTPUTS: OUTPUTS: Project: Development and Characterization of Chimeric Swine/NOD-SCID Mice Model for Use in PRRSV Studies Outputs: participation in the NC229 meetings held in Chicago, Illinois. Antibodies specific for swine cell markers will be added to some wells to ascertain the blastogenic response due to swine cells. If feasible splenocytes will be tested for virus-specific blastogenic responses. Blood will be collected periodically by tail bleeding to test for specific anti-PRRS antibodies and measure cytokine responses. The swine cytokines and other adjuvants will be administered in soluble form or through DNA expression vectors. With conventional or recombinant vaccines. Additionally, swine/NOD-SCID mice will be used to test the effects of cytokines and other immune modulators on the responses induced by infection or immunization The animals will be euthanized 1-2 weeks post infection and subjected to necropsies and collection of tissues for hispathology, immunohistochemistry, flow cytometric analysis and virologic tests. The mice will be examined twice daily for effects of infection and will be bled 4, 7 to 10 days post-infection to test for viremia, specific swine a-PRRSV antibodies and cytokines. Two groups of NOD/SCID mice (n=5/each) that did not receive donor cells will also be infected by the IN or IP routes. Chimerized control mice (2 groups of 5 mice each) will receive media alone at the same volume and by the same routes (IN, IP) used for the test animals. Swine/NOD-SCID mice will be inoculated with PRRSV by intranasal (IN) (n=5) or intraperitoneal (IP) route (n=5) at 104-105 TCID50/mouse 1 to 3 weeks after receiving the donor swine cells. The mice will be necropsied and organs including spleen, liver, kidney, lung, heart, brain, thymus and intestine will be collected in either 10 % formalin or frozen at -80 C for histologic, immunochemical, flow cytometric and functional analysis. Three mice per group will be sacrificed at weekly intervals starting one week after cell transfer until the third week post-transfer and the last three animals in each group will be sacrificed 10-12 weeks post-transfer. Blood samples will be collected 7 and 14 days post-cell transfer for flow cytometric analysis of swine cells in circulation and swine immunoglobulins by sandwich ELISA. For this purpose swine mononuclear cells obtained from peripheral blood (PBMNC), lymph nodes, spleen or alveolar macrophages will be injected into groups of 12 NOD/SCID mice each either intravenously (IV) or in the peritoneal cavity (IP). Project Methods The present study will develop and characterize swine/NOD-SCID mice.
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