title: Equilibrium in lung schistosomula sphingomyelin breakdown and biosynthesis allows very small molecules, but not antibody, to access proteins at the host-parasite interface.
abstract: The mechanism by which lung-stage schistosomula expose proteins at the host-parasite interface to nutrient, but not antibody, uptake has been obscure. We have found that Schistosoma mansoni and Schistosoma haematobium larvae emerging from host lung at a pH of around 7.5, and fixed with diluted formaldehyde (HCHO), readily bind specific antibodies in indirect membrane immunofluorescence. Data on inhibitors and activators of parasite tegument-bound, magnesium-dependent, neutral sphingomyelinase (nSMase), and sphingomyelin biosynthesis inhibitors revealed that equilibrium in schistosomular sphingomyelin breakdown and biosynthesis prevents antibody binding, yet permits access of small HO-CH2-OH polymers to interact with and cross-link proteins at the host-parasite interface, allowing for their serological visualization.
authors.affiliation: Zoology Department, Faculty of Science, Cairo University, Cairo 12613, Egypt. rashika@mailer.eun.eg
authors.forename: Rashika
authors.initials: R
authors.lastname: El Ridi
authors.forename: Hatem
authors.initials: H
authors.lastname: Tallima
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology*; D015153:Blotting, Western; D006224:Cricetinae; D003523:Cycloserine / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D019084:Fluorescent Antibody Technique, Indirect; D015801:Helminth Proteins / Q000378:metabolism*; D006790:Host-Parasite Interactions; D006863:Hydrogen-Ion Concentration; D007814:Larva / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D008168:Lung / Q000469:parasitology; D008297:Male; D008647:Mesocricetus; D051379:Mice; D008810:Mice, Inbred C57BL; D011090:Polyenes / Q000494:pharmacology; D053284:Polyunsaturated Alkamides; D012548:Schistosoma haematobium / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D012550:Schistosoma mansoni / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D012553:Schistosomiasis haematobia / Q000276:immunology / Q000469:parasitology; D012555:Schistosomiasis mansoni / Q000276:immunology / Q000469:parasitology; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors / Q000378:metabolism; D013109:Sphingomyelins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D000909:Antibodies, Helminth; D004791:Enzyme Inhibitors; D005229:Fatty Acids, Monounsaturated; D015801:Helminth Proteins; D011090:Polyenes; D053284:Polyunsaturated Alkamides; D013109:Sphingomyelins; D003523:Cycloserine; D013108:Sphingomyelin Phosphodiesterase; C054474:manumycin; C001996:thermozymocidin