帮我看一下这个英文句子的语法问题
Dr.Tonegawa won the Nobel Prize for discovering how the body can constatly change its genes to fashion a seeming unlimited number of antibodies ,each targeted specifically at an invading microbe or foreign.
其中each是用逗号连接的,不是连词也不是分号,不是说两个独立的句子一定要用分号,冒号,句号或者连词连接吗?还是说这两个句子是有省略了的连词呢?
那是不是分词可以放在句子末尾呢？each targeted specifically at an invading microbe or foreign.
这里充当的是什么成分？