Fulton R W, Neill J D, Saliki J T, Landis C, Burge L J, Payton M E
Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078 USA.
U.S. Department of Agriculture, Agricultural Research Service, National Animal Diseases Center, Ames, IA 50010 USA.
Virus Res. 2017 May 2;235:77-81. doi: 10.1016/j.virusres.2017.04.009. Epub 2017 Apr 14.
This study investigated the genetic and antigenic characterization of parainfluenza-3 virus (PI3V) of cattle. Using molecular tests including real time PCR and viral genome sequencing, PI3V strains could be separated into PI3V types, including PI3V A, PI3V B, and PI3V C. Isolates from cattle with bovine respiratory disease clinical signs and commercial vaccines in the U.S. with MLV PI3V were typed using these molecular tests. All the MLV vaccine strains tested were PI3V A. In most cases PI3V field strains from calves receiving MLV vaccines were types heterologous to the vaccine type A. Also antigenic differences were noted as PI3V C strains had lower antibody levels than PI3V A in serums from cattle receiving MLV PI3V A vaccines. This study further demonstrates there is genetic variability of U.S. PI3V strains and also antigenic variability. In addition, isolates from cattle with BRD signs and receiving MLV vaccines may have heterologous types to the vaccines, and molecular tests should be performed to differentiate field from vaccine strains. Potentially the efficacy of current PI3V A vaccines should be evaluated with other types such a PI3V B and PI3V C.
本研究调查了牛副流感3型病毒（PI3V）的基因和抗原特性。通过实时PCR和病毒基因组测序等分子检测，PI3V毒株可分为PI3V A型、PI3V B型和PI3V C型。利用这些分子检测方法，对美国患有牛呼吸道疾病临床症状的牛所分离出的毒株以及含有PI3V减毒活疫苗的商业疫苗进行了分型。所有检测的减毒活疫苗毒株均为PI3V A型。在大多数情况下，接受减毒活疫苗的犊牛所感染的PI3V野生毒株与疫苗A类型不同源。此外，还发现了抗原差异，因为在接受PI3V A减毒活疫苗的牛血清中，PI3V C毒株的抗体水平低于PI3V A。本研究进一步证明美国PI3V毒株存在基因变异性和抗原变异性。此外，患有牛呼吸道疾病症状且接受减毒活疫苗的牛所分离出的毒株可能与疫苗不同源，应进行分子检测以区分野生毒株和疫苗毒株。目前PI3V A疫苗的效力可能需要用其他类型如PI3V B和PI3V C进行评估。
