下列有关免疫的叙述正确的是( )。
- A.人体的前两道防线不具有特异性
- B.抗体主要分布在血清中，所以人体被病菌侵染后只要注射血清就可以治疗疾病
- C.艾滋病病毒侵入人体后主要破坏B淋巴细胞，从而破坏人体的免疫系统
- D.吞噬细胞的吞噬作用没有特异性，因此只在非特异性免疫过程中起作用
正确答案及解析
正确答案
解析
人体的前两道防线是人生来就有的，不具有特异性；而第三道防线是出生后产生的，通常对特定的病原体或异物起作用，具有特异性，A正确。人体被病菌侵染后，注射的血清中的抗体对侵入细胞中的病菌无法起作用，B错误；艾滋病病毒侵入人体后主要破坏T淋巴细胞，C错误；吞噬细胞在特异性免疫中起重要作用，大多数病原体都要经过吞噬细胞的摄取、处理和呈递，D错误。
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