Vi antigen

例句：

1. 1.The study of viruses is crucial for understanding the causes of many diseases.
   研究病毒对于理解许多疾病的成因至关重要。
2. 2. Virus antigens are detected in the body's immune system to identify infections.
   通过检测体内的病毒抗原来识别感染。
3. 3. Researchers have developed a new vaccine that targets specific virus antigens.
   研究人员开发了一种针对特定病毒抗原的新疫苗。