Interpopulational allogeneic reactions in the colonial protochordate Botryllus schlosseri

Baruch Rinkevich, Irving L. Weissman

Research output: Contribution to journalArticlepeer-review


Botryllus schlosseri is a cosmopolitan encrusting colonial tunicate which undergoes a natural transplantation reaction. When the growing edges of two colonies come into direct contact by interaction between their extracorporeal blood vessel termini, the ampullae, they either reject each other or fuse. This phenomenon is controlled by a single gene locus (Fu/HC) with multiple codominantly expressed alleles. Rejecting colonies share no alleles. Here we analyze allogeneic responses of Monterey (Mon), California, versus Woods Hole (WH), Massachusetts, colonies. Of 42 Mon × WH pairs tested, allogeneic rejection reactions occurred in all. Necrotic lesions (points of rejection, PORs) were produced and developed only by Woods Hole ampullae, either within the Woods Hole tunic, in the borderline between the paired colonies, or within the Monterey tunic. Four types of PORs were characterized. All types involved reactions of blood cells and vessels, including infiltration, hemorrhage formation, retraction and ampullae amputation. These findings were observed in single WH × Mon pairs, in multiple subclones of WH × Mon from two parental colonies (seven independent colony pairs were assayed), and on multiple repeats of interactions from pairs that had already undergone a rejection reaction. In all cases, the range of reaction types, the location of PORs, and the timing of the responses could be found in primary as well as repeat reactions.

Original languageEnglish
Pages (from-to)1265-1272
Number of pages8
JournalInternational Immunology
Issue number12
StatePublished - Dec 1991
Externally publishedYes

Bibliographical note

Funding Information:
The technical help of K. Ishizuka and K. Palmeri is greatly appreciated. This study was partly supported by a grant from the US - Israel Binational Science Foundation (BSF), by a grant from S. Pries, NAF/IOLR, and by USPHS grant CA 42551.


  • Histocompatibility
  • Rejection
  • Self - non-self recognition
  • Tunicata

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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