1. Precipitinogen is an antigen that can cause precipitation reactions when combined with the corresponding antibody.
沉淀原是一种抗原，当与相应的抗体结合时可以引起沉淀反应。

2. The level of precipitinogen in the blood can be measured to determine if a person has been exposed to a specific antigen.
可以测量血液中的沉淀原水平来确定一个人是否接触过特定的抗原。