Recombinant antigen and method of making the same, isolated polynucleotide of porcine reproductive and respiratory syndrome virus (prrsv) and composition including the same

The present invention relates to a recombinant antigen and an isolated polynucleotide of porcine reproductive and respiratory syndrome virus (PRRSV), a composition including the same and a method of making the same. The recombinant antigen is a chimeric protein of PRRSV dual structural proteins and T-cell epitope. The polynucleotide encodes an amino acid sequence of the recombinant antigen. The recombinant protein expressed by the polynucleotide in an eukaryotic expression system can be beneficial for mass production and purification. An immunogenic composition including the recombinant antigen can promote pro-inflammatory M1-phenotype polarization of porcine alveolar macrophages (PAMs), reduce receptor CD163 expression that is mediated for viral entry and activate T helper (Th1) immune responses, thereby being applied to a vaccine composition against PRRSV.