PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VACCINE, BASEDON ISOLATE JA-142

摘要

Substantially avirulent forms of atypical porcine reproductive and respirato ry syndrome (PRRS) virus and corresponding vaccines are provided which result from cell culture passaging of virulent forms of PRRS. The resultant avirule nt atypical PRRS virus is useful as a vaccine in that PRRS specific antibody response is elicited by inoculation of host animals, thereby conferring effective immunity against both previously known strains of PRRS virus and newly isolated atypical PRRS virus strains. The preferred passaging techniqu e ensures that the virus remains in a logarithmic growth phase substantially throughout the process, which minimizes the time required to achieve attenuation.