im·mu·no·gen /ɪˈmjunəʤən, ˌʤɛn/
  免疫原
  im·mu·no·gen /ɪˈmjunəʤən, ˈɪmjənə, ˌʤɛn/ 名詞
  免疫源,致免源
  immunogen
       n : any substance or organism that provokes an immune response
           (produces immunity) when introduced into the body [syn: immunizing
           agent]