The aim of this project is to characterize schistosome surface molecules relevant to immunity, to analyze the genome of the parasite in relation to specific biological properties of the organism and to clone important schistosome immunogens. A. Molecular biology of paramyosin. Paramyosin was shown to be encoded by an unusually large transcript. cDNA's comprising unsequenced portions of the molecule were isolated along with peptides in these same regions. B. Demonstration of lipid anchors on schistosomulum membrane proteins. Four major schistosomulum surface antigens of Mr 70K, 32k-38k and 18k were shown to be anchored in the tegument by phosphatidylinositol linkages and released in the form of membrane vesicles. C. Detection of host DAF on the schistosome membrane. Using specific antibodies, host decay accelerating factor (DAF) was identified in the membrane of schistosomes recovered from monkeys and guinea pigs.