Release of Leukotriene B4 from Sublethally Injured Oligodendrocytes by Terminal Complement Complexes

: In the present study, the interaction of the terminal complement complexes with Oligodendrocytes was investigated for observation of its effect on membrane lipid hydrolysis. [14C]Arachidonic acid was incorporated into the membrane lipids of cultured Oligodendrocytes before sensitization with anti-galactocerebroside antiserum. Cells were then exposed to excess C6-deficient rabbit serum reconstituted with limiting doses of C6 to form various numbers of C5b-9 complexes. Qualitative analysis of the supernatants by HPLC revealed the presence of compounds that coeluted with arachidonic acid and its oxygenated derivatives, prostaglandin E2, leukotrienes E4 and B4, and 15-hydroxyeicosatetraenoic acid. The kinetics of leukotriene B4 release by excess C5b-8 was quantitated by radioimmunoassay. Leukotriene B4 release approached a maximum around 30 min, and C6 dose-response studies performed at l h showed that maximal levels of leukotriene B4 were detected over a range of sublytic C5b-9 attack. Maximal release of leukotriene B4 was also achieved by C5b-8 without further enhancement by addition of lytic doses of C9. Results indicate that sublytic attack of Oligodendrocytes by complement induces release of lipid-derived inflammatory mediators.