|Budget Amount *help
¥3,000,000 (Direct Cost : ¥3,000,000)
Fiscal Year 1998 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1997 : ¥2,000,000 (Direct Cost : ¥2,000,000)
1) Molecular cloning and structural analysis of ascidian complement components :
cDNA clones for complement component MASP and C3 were isolated from the liver library of Japanese ascidian, Halocynthia roretzi. The deduced primary structures of these component indicated that they are ascidian counterparts of vertebrate MASP and C3. Antibodies against ascidian C3 inhibited an opsonic activity of ascidian body fluid to enhance phagocytosis of yeast by ascidian coelomocytes. These results indicate that the multi-component, opsonic complement system has been established by the time of urochordates emergence, much earlier than adaptive immunity.
2) Linkage analysis of mammalian MHC-encoded genes in Xenopus and Medaka fish :
Most mammalian MHC-encoded genes tested linked to each other in Xenopus, indicating the conservation of this linkage group between amphibians and mammals. In contrast, MHC class I, II and III genes showed a dispersed distribution all over Medaka fish chromosomes, except for a close linkage among the class IA, LMP2, LMP7 and TAP2 genes. Thus the class IA and its antigen processing/transport genes seem to be the core part of the MHC, indicating that the original physiological meaning of the MHC was to establish the class I antigen presentation system.