Preparation and partial characterisation of a multilamellar body fraction from Schistosoma mansoni

Multilaminate vesicles were purified, from homogenised whole Schistosoma mansoni adults, by differential density centrifugation on sucrose gradients, following methods previously employed for isolating multilamellar bodies (MLB) from mammalian lung. Morphometric analysis, on electron micrographs, of the pelleted fraction revealed that the pellet contained at least 56% MLB (by volume of solid material). An apparent projection core was described in both fixed MLB from our fraction and in unfixed MLB from a freeze thaw preparation of whole worms. The phospholipid-protein ratio of the MLB fraction was 1.6:1. The major phospholipid classes were separated and identified by quantitative, two dimensional, thin layer chromatography on silica gel. Phosphatidylcholine was the predominant phospholipid in the MLB fraction, comprising 57% of the total phospholipids. Phosphatidic acid phosphatase, previously reported from lung MLB but not schistosomes, was detected in the fraction. The high activity of this enzyme suggests a more active role for schistosome MLB than that of a mere reservoir of preformed membrane precursors.