Sphingomyelin inhibition of Ciona intestinalis (Tunicata) cytotoxic hemocytes assayed against sheep erythrocytes.
Hemocytes from the ascidian, Ciona intestinalis, are capable of lysing erythrocytes in vitro following cell membrane contact. With the aim of examining the mechanism of cytotoxicity, we performed inhibition experiments with lipid components of erythrocyte membranes. Cholesterol is not an inhibitor, whereas, among the phospholipids tested, (sphingomyelin, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine) sphingomyelin inhibits the hemolytic activity of hemocytes. However, thin layer chromatography showed that sphingomyelinase activity was not contained in the chloroform-methanol extracts from hemocyte debris. The inhibition capacity of the components ceramide and phosphorylcholine suggests that the entire sphingomyelin molecule is involved in binding cytolysins. The lysin-lipid interactions probably cause changes in erythrocyte membrane permeability, leading to lysis.
Parrinello
N
N
Institute of Zoology, University of Palermo, Italy.
Cammarata
M
M
Lipari
L
L
Arizza
V
V
D000818:Animals; D002457:Cell Extracts; D002462:Cell Membrane / Q000737:chemistry / Q000502:physiology; D002784:Cholesterol / Q000494:pharmacology; D002855:Chromatography, Thin Layer; D002938:Ciona intestinalis / Q000187:drug effects* / Q000276:immunology; D003470:Culture Media / Q000737:chemistry; D003601:Cytotoxicity Tests, Immunologic; D006434:Hemocytes / Q000187:drug effects*; D006460:Hemolysin Proteins / Q000502:physiology*; D006461:Hemolysis / Q000187:drug effects*; D008563:Membrane Lipids / Q000494:pharmacology*; D009994:Osmolar Concentration; D010743:Phospholipids / Q000494:pharmacology; D012756:Sheep / Q000097:blood; D013108:Sphingomyelin Phosphodiesterase / Q000032:analysis; D013109:Sphingomyelins / Q000494:pharmacology*
D002457:Cell Extracts; D003470:Culture Media; D006460:Hemolysin Proteins; D008563:Membrane Lipids; D010743:Phospholipids; D013109:Sphingomyelins; D002784:Cholesterol; D013108:Sphingomyelin Phosphodiesterase