Degradation of human myelin phospholipids by phospholipase-enriched culture media of pathogenic Naegleria fowleri.

Cell-free media from cultures of virulent Naegleria fowleri were tested for phospholipase activities and their ability to degrade phospholipids of human myelin. Virulent N. fowleri selectively released lipolytic enzymes into the media at various times during growth and hydrolyzed the phospholipids of human myelin, while media from virulent-attenuated and nonpathogenic Naegleria spp. were almost totally inactive. Hydrolysis of myelin phospholipid increased concomitantly with amebal growth, and the relative rate of breakdown at pH 7.5 was sphingomyelin greater than phosphatidylcholine greater than phosphatidylethanolamine. Elevated levels of lysophosphatidylcholine and lysophosphatidylethanolamine were also noted.