还有一种办法是分析被咬的动物——比如鸡或者猪——的血液中是否存在病原的抗体。

An alternative approach is to analyse blood samples from animals, such as chickens and pigs, for antibodies that signal the presence of pathogens.

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改为——问题是抗体能识别和做出反应的分子是像蛋白质这样的大分子，这也是细菌，病毒和其他致病原的特征。

The problem is that the molecules antibodies recognise and react to are the big ones, such as proteins, that are characteristic of bacteria, viruses and other infectious agents.

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这个机制也说明了为什么抗疟疾的基因在非洲人中普遍存在，他们住在那些带病原的蚊子肆虐的地方。但在欧洲和亚洲人中就没有这种基因。

The mechanism also explains why genetic resistance to malaria has spread among Africans — who live where disease-carrying mosquitoes are prevalent — but not among Europeans or Asians.

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So, there's no absolutes about this, this is a general response where all the features can be different with different pathogens.

这其中并没有明确的规律,免疫应答是普遍存在的,但针对不同的病原体的应答规律各不相同

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So, the antigen we're thinking about is a vaccine particularly designed to elicit immune response against a pathogen.

我们现在考虑的这种抗原,是一种特别设计的疫苗,它能够诱发免疫效应以消灭病原体

耶鲁公开课 - 生物医学工程探索课程节选

Generally, you think about the immune system protecting against different classes of pathogens and several classes of pathogens are shown on this table.

大体上,你们会认为免疫系统使,我们免受不同种类病原体的侵害,这个表格里介绍了几类病原体

耶鲁公开课 - 生物医学工程探索课程节选