Antigenic characteristics of glycosylated protein 3 of highly pathogenic porcine reproductive and respiratory syndrome virus

Highly pathogenic (HP)-porcine reproductive and respiratory syndrome virus (PRRSV) emerged in 2006 and has now become a global threat to pig farms. Despite extensive characterization of HP-PRRSV proteins by direct analysis and comparison with typical PRRSV, immune recognition remain poorly understood. Glycosylated protein 3 (GP3) has an important function in inducing protective immune response. To analyze the antigenic character of HP-PRRSV GP3, a total of 217 peptides were printed on a chip and used to react with HP-PRRSV specific serum. The reactions of these peptides to HP-PRRSV specific pig serum were scanned and quantified using the software PepSlide® Analyzer by fluorescence intensity. The intensity plots showed various reactions in different parts of GP3. The highest reaction intensity value reached 29,184.5 with the peptide sequence of CSENDHDELGFMVPP. Conversely, 88 peptides showed no reaction with 0 florescence intensity. A further analysis based on the result of the peptide microarray revealed an antigen reaction active region (AR) from Y51 to S106 in GP3. The AR had four parts of variation that may be a significant mutation of the typical PRRSV to HP-PRRSV. Acquired data may be useful for understanding HP-PRRSV variation and its GP3 immune recognition.