The immune system is considered deficient when it can no longer fulfill its role of fighting infection and disease.

当免疫系统不能抵抗感染和疾病时，即被认为免疫缺陷。

An autoimmune disease results when the body's system for fighting infection (the immune system) turns against a part of the body.

自体免疫疾病是因身体(免疫系统)对抗感染时转而攻击身体的某一部分而产生的。

White blood cells are key to fighting infection, but high levels can be a sign of inflammation, which is linked to coronary heart disease.

白血球是抵抗感染的关键因素，但高水准的白血球却是炎症的信号，会导致冠心病。

Although both cell types come from cells known as myeloid progenitors, each type relies on its own set of functionally active genes to carry out its particular role in fighting infection.

虽然这两种细胞都来源于髓样细胞祖先，但每一种细胞都依赖他们各自的一套功能基因的激活来实行他们的特殊功能，抵抗感染。

One of the most powerful approaches to fighting health care-related infection is also the simplest: health care providers need to clean their hands every time they see a patient.

防止医疗保健相关感染最有力的方法也是最简便的方法，即医疗保健提供者每次为患者看病时必须清洁双手。