The glycolipid composition of activated rat lymphocytes and lymphocyte supernates in experimental allergic encephalomyelitis

Abstract

In investigation of effector moieties involved in the induction of experimental allergic encephalomyelitis (EAE), we have previously reported that lymph node cells (LNC) from Lewis rats developing EAE release a factor into the supernatant medium that is capable of transferring histopathologic changes of EAE to recipient animals. This factor, termed EAE supernate transfer activity (EAE-STA), has been localized to the floating lipid-containing layer following incubation and centrifugation (at 4°C) of concentrated LNC suspensions. However, we found that EAE-STA transfer activity was destroyed by chloroform-methanol extraction. In further investigating the glycolipids present in EAE-STA, HPLC analyses were carried out on EAE-STA-containing LNC and LNC supernates and compared with control non-EAE-STA-containing preparations. LNC contained high levels of glucocerebroside and gangliosides, with intermediate levels of ceramide and asialo GMI. The components that appeared to be shed from LNC into the supernate, following a 1 h incubation, were glucocerebroside, ceramide dihexoside, and asialo GMI. However, few differences were observed in glycolipid composition between EAE-STA-containing LNC or supernates and control preparations. Therefore, these results argue that the critical determinant responsible for EAE-STA activity is other than a conventional lipid moiety, and that the lipids present possibly represent structural membrane components shed from the surface of incubated LNC.