PURPOSE: A method for preparing mutant PRRSV(porcine reproductive and respiratory syndrome virus) is provided to obtain the virus with enhanced immunogenicity by mutating GP5 gene of selected PRRSV strain.CONSTITUTION: A mutant PRRSV(porcine reproductive and respiratory syndrome virus) contains PRRSV GP5 mutant polypeptides with respect to GP5 protein of sequence number 1. A composition for enhancing immune response for a PRRSV antigen contains the mutant PRRSV. The composition additionally contains a therapeutically acceptable carrier. The carrier includes protein, a buffer solution, surfactant, polyethylene glycol polymer, or a combination thereof. The composition also contains an adjuvant. A method for enhancing immune response for a PRRSV antigen in a pig comprises a step of administering the composition to the pig by subcutaneous injection, intravenous injection, intradermal injection, parenteral injection, intramuscular injection, needle free injection, electroporation, oral delivery, endonasal delivery, oronasal delivery, or a combination thereof. A pharmaceutical composition for treating PRRSV infection contains the virus.COPYRIGHT KIPO 2013본 발명은 돼지 생식기 호흡기 증후군 바리러스(이하, ‘PRRSV’함)의 변형 바이러스를 생산에 관한 것으로, 더욱 상세하게는 국내에서 분리하여 선발된 PRRSV주의 GP5의 유전자를 변형시켜 그 면역원성을 높이는 방법과, 또한 그를 이용하여 한국형에 맞는 백신주를 제작하는 것이다.
