摘要: The mammalian immune system is a complex network of many cell types and proteins that collectively coordinate protective response against foreign entities. can be divided into two broad categories: innate adaptive immunity. Adaptive immunity, which primarily mediated by T B lymphocytes, first arose in jawed vertebrates has several distinct features from the more ancient (Pancer Cooper 2006). While immunity characterized non-specific recognition conserved molecular patterns leading to rapid effector response, delayed required expansion lymphocytes bearing receptors specific for particular antigen. After primary small fraction activated remain as memory cells, respond subsequent encounters with same antigen robust manner.