Send to

Choose Destination
See comment in PubMed Commons below
Trends Immunol. 2004 Feb;25(2):105-11.

On the origins of the adaptive immune system: novel insights from invertebrates and cold-blooded vertebrates.

Author information

  • 1Department of Biosystems Science, School of Advanced Sciences, The Graduate University for Advanced Studies (Sokendai), Shonan Village, Hayama 240-0193, Japan.


When and how adaptive immunity emerged is one of the fundamental questions in immunology. Accumulated evidence suggests that the key components of adaptive immunity, rearranging receptor genes and the MHC, are unique to jawed vertebrates. Recent studies in protochordates, in particular, the draft genome sequence of the ascidian Ciona intestinalis, are providing important clues for understanding the origin of antigen receptors and the MHC. We discuss a group of newly identified protochordate genes along with some cold-blooded vertebrate genes, the ancestors of which might have provided key elements of antigen receptors. The organization of the proto-MHCs in protochordates provides convincing evidence that the MHC regions of jawed vertebrates emerged as a result of two rounds of chromosomal duplication.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk