Comparative immune systems in animals.
Animal immune systems can be classified into those of innate immunity and those of adaptive immunity. It is generally thought that the former are universal for all animals and depend on germline-encoded receptors that recognize highly conserved pathogen-associated molecular patterns (PAMPs), whereas the latter are vertebrate specific and are mediated primarily by lymphocytes bearing a unique antigen receptor. However, novel adaptive or adaptive-like immunities have been found in invertebrates and jawless vertebrates, and extraordinarily complex innate immunities, created through huge expansions of many innate gene families, have recently been found in the cephalochordate amphioxus and the echinoderm sea urchin. These studies not only inspire immunologists to seek novel immune mechanisms in invertebrates but also raise questions about the origin and evolution of vertebrate immunities.
State Key Laboratory of Biocontrol, National Engineering Center of South China Sea for Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, People's Republic of China; email: yuanshch@mail.sysu.edu.cn , zsutx2005@163.com , hshengf2@mail.sysu.edu.cn , lsschshw@mail.sysu.edu.cn , lssxal@mail.sysu.edu.cn.
Shaochun
S
Yuan
Xin
X
Tao
Shengfeng
S
Huang
Shangwu
S
Chen
Anlong
A
Xu
D000818:Animals; D005075:Biological Evolution; D005786:Gene Expression Regulation / Q000276:immunology; D007448:Invertebrates / Q000235:genetics* / Q000276:immunology*; D013045:Species Specificity; D014714:Vertebrates / Q000235:genetics* / Q000276:immunology*
amphioxus; diversity; evolution; expansion; immunity