This report describes results obtained for the optimization of reagents to be used for the construction of the novel photoluminescence sensor device. PRRSV strain NADC-8 was purified and characterized by gel electrophoresis, Western blotting and ELISA. We found initially that the widely used monoclonal antibody for detecting PRRSV did not react in the Western blot format. This result is in agreement with a recently published paper by Dr. Plagemann from the University of Minnesota. This prompted us to search for different monoclonal antibodies for evaluation. Six monoclonal antibodies to the nucleocapsid protein of PRRSV were kindly provided by Dr. Ken Platt from the College of Veterinary Medicine, Iowa State University. All six monoclonal antibodies reacted with the PRRSV antigen in the Western blot format as well as in the ELISA format. To improve sensitivity of detection, we used a fluorescent labeled reagent to detect monoclonal antibody binding to the PRRSV nucleocapsid protein antigen. Newer fluorescent labels such as ruthenium have been evaluated for use with the OLED–based and fluorometry detection systems for the detection of for PRRSV. However, unanticipated problems were encountered using the new laser dye with the OLED sensor. Experiments to further optimize the OLED detection system for the detection of PRRSV protein antigens are on-going. An ELISA was developed using PRRSV protein antigens that distinguished sero-positive from sero-negative serum samples. The data suggest that a two-dilution endpoint ELISA could be used to detect PRRSV in serum samples. For more information please contact Louisa B. Tabatabai at