TY - JOUR
T1 - Allorecognition in colonial tunicates
T2 - Protection against predatory cell lineages?
AU - Magor, Brad G.
AU - De Tomaso, Anthony
AU - Rinkevich, Baruch
AU - Weissman, Irving L.
PY - 1999
Y1 - 1999
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0032923449&partnerID=8YFLogxK
U2 - 10.1111/j.1600-065X.1999.tb01383.x
DO - 10.1111/j.1600-065X.1999.tb01383.x
M3 - Review article
C2 - 10319252
AN - SCOPUS:0032923449
SN - 0105-2896
VL - 167
SP - 69
EP - 79
JO - Immunological Reviews
JF - Immunological Reviews
ER -