antigen

例句：

1. 1. The vaccine is designed to stimulate the body's immune system to recognize and attack the antigen.
   疫苗旨在刺激身体免疫系统识别并攻击抗原。
2. 2. Antibodies are proteins that help the immune system recognize and neutralize antigens.
   抗体是帮助免疫系统识别和中和抗原的蛋白质。
3. 3. The study of antigens has led to the development of many vaccines.
   对抗原的研究导致了许多疫苗的开发。