Allorecognition in colonial tunicates: Protection against predatory cell lineages?

Brad G. Magor, Anthony De Tomaso, Baruch Rinkevich, Irving L. Weissman

Research output: Contribution to journalReview articlepeer-review


The MHC molecules have been historically perceived as transplantation antigens, though it is now recognized that their primary, if not sole, role is in eliminating parasites and in surveillance and clearance of aberrant self. Indeed, pregnancy in mammals would represent the closest to a natural transplantation process that occurs in vertebrates. However, among the immediate ancestors to the vertebrates, natural intraspecific allorecognition processes are common. Among members of the colonial tunicate Botryllus schlosseri, two individuals that share a single allele of the highly polymorphic fusibility/histocompatibility (Fu/HC) locus are able to fuse with one another. Could this Fu/HC be related to the MHC such that the MHC really did have its origins as a transplantation antigen? Presently we review the genetics and biology of natural transplantation processes in colonial tunicates, comparing it with allorecognition as mediated through the vertebrate T-cell receptor, killer cell inhibitory receptor/Ly49, and MHC. Experimental approaches to determining if the molecules regulating allorecognition in tunicates have any ancestral relationship to the vertebrate MHC are discussed, as is a genomic approach to isolating novel mediators of allorecognition. We also explore the biological basis for allorecognition in colonial tunicates and recent work that highlights the costs of not maintaining a system for allorecognition.

Original languageEnglish
Pages (from-to)69-79
Number of pages11
JournalImmunological Reviews
StatePublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


Dive into the research topics of 'Allorecognition in colonial tunicates: Protection against predatory cell lineages?'. Together they form a unique fingerprint.

Cite this