1986 Fiscal Year Final Research Report Summary
Recognition mechanism of heterologous erythrocytes by the alternative pathway of complement.
| Project/Area Number |
59580109
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物質生物化学
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| Research Institution | Showa University |
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Principal Investigator |
TOMITA Motowo School of Pharmaceutical Sciences, Showa University,Professor, 薬学部, 教授 (30102370)
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| Project Period (FY) |
1984 – 1986
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| Keywords | Alternative pathway of complement / Erythrocyte membrane / Recognition of heterologous cells / C3 / DAF |
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| Research Abstract |
Activation of the alternative complement pathway is independent of antigen-antibody complex for formation of C3 convertase. The alternative pathway of various species differs in the specificity of their recognition function. Thus, human alternative pathway is activated by rabbit erythrocytes while rabbit alternative pathway is activated by human erythrocytes; it is evident that the alternative pathway is not activated by homologous erythrocytes. Therefore, components of the alternative pathway distinguish between homologous and heterologous erythrocytes. In this project, I tried to determine the components that play a role on the distinguishing process. All of the six components constituting the alternative pathway (C3, B, D, P, H and I factors)were purified from both of human and rabbit bloods. The reconstitution mixture were substituted with the corresponding rabbit components and the hemolytic activities of the substituted reconstitution mixtures were measured with rabbit and human erythrocytes. The results indicated that C3 was the major participant in the recognition process of heterologous erythrocytes.
Since some components on erythrocyte membranes should be also responsible for the recognition process exhibited by the alternative pathway, I tried to identify the component. The most likely candidate among erythrocyte membrane proteins seemed to be DAF ( decay-accelerating factor of C3, C5-convertases ). Human and rabbit DAF's were isolated from the corresponding erythrocyte membranes by the methods developed for this project. DAF thus purified showed higher affinity to homologous C3 than to heterologous C3; indicating that DAF is a participant in the recognition process.
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