Fluorescent microsphere immunoassay (FMIA), also known as “Luminex,” allows for the detection of antibodies to multiple antigens in a single, small volume of sample, and can be adapted for use on non-serum samples, such as oral fluids. The detection of antibodies to multiple pathogens in the same sample is a powerful tool that allows analysis of polymicrobial infections, such as PCVAD and PRDC. The goal of this research is to develop an FMIA to test for antibodies to PRRSV, PCV2, SIV and M. hyo, in oral fluid and serum samples. The first step was the expression of several target antigens, including N protein from type 1 and type 2 PRRSV, NP and NS1 from swine influenza virus, CP(43-233) and CP(160-233) from PCV2. All recombinant proteins were expressed, purified and successfully conjugated to polystyrene beads. All viral targets showed reactivity with positive sera. Comparison with the commercial PRRSV ELISA test showed that the Luminex assay possessed increased sensitivity. Another result was the demonstration that the CP(160-233) antigen from PCV2 could be incorporated as a target to differentiate infected from vaccinated animals (DIVA). As part of a collaborative effort, reagents and protocols were distributed to other veterinary diagnostic labs. The next step is to test the implementation of the Luminex technology across the industry.
Contact information: Raymond (Bob) Rowland, [email protected], 785-532-4631
