Well,

那么
your innate immune system tries to get rid of them.

你的先天性免疫系统试着去清除细菌
The innate immune system composed of neutrophils and macrophages;

它由嗜中性粒细胞和巨噬细胞构成
these are cells that are crawling around your body all the time

这些细胞不断在周身蠕行
ready to eat bacteria.

准备吞噬细菌
When they do that they can actually engulf the bacteria

免疫细胞确实是将细菌整个吞进了肚内
in a process called phagocytosis

这一过程称为吞噬作用
and break them down into antigens.

并将细菌分解成小抗原
Then those antigens get expressed with MHC

这些抗原同MHC共表达
just like they did in all the other cells inside the host,

就如同抗原在其他宿主细胞中那样
but particular cells of the innate immune system

但先天免疫系统有一类特殊的免疫细胞
have a different kind of MHC called MHC2.

具有一种称为MHC2的不同MHC