It changes or adapts in response to an insult or a threat.

它通过改变自身,以获得抗性来应对侵犯和威胁

耶鲁公开课 - 生物医学工程探索课程节选

Because it's working to defend us against many different kinds of potential assaults, the immune system has a diverse repertoire of responses that it uses in the face of these assaults.

免疫系统的工作就是抵御,不同种类的潜在威胁,免疫系统具备类型众多的免疫反应类型,以应对各种威胁

耶鲁公开课 - 生物医学工程探索课程节选