Distinct restriction of complement- and cell-mediated lysis.
Complement- and cell-mediated killing utilize related effector proteins (C8/C9 and perforin, respectively), suggesting that proteins which protect cells against complement- and cell-mediated attack may also be similar. In homologous complement-mediated killing two protective proteins, which are anchored to the cell membrane by phosphatidylinositol glycan (PIG) tails, are known. To study whether similar PIG-tailed proteins protect against lymphocyte-mediated killing, nucleated cell lines with a mutation in the biosynthesis of the PIG anchor were used. It was found that PIG-tailed membrane proteins restrict homologous complement-mediated lysis but not three different types of cell-mediated killing or lysis by purified perforin. Furthermore, E from patients with an acquired defect in PIG tail biosynthesis did not differ from normal E in sensitivity to antibody-dependent cell-mediated cytotoxicity, in spite of their increased sensitivity to human C8 and C9.
Hollander
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N
Rorer Biotechnology Inc., King of Prussia, PA 19406.
Shin
M L
ML
Rosse
W F
WF
Springer
T A
TA
D000920:Antibody-Dependent Cell Cytotoxicity; D001798:Blood Proteins / Q000502:physiology; D018957:CD59 Antigens; D002352:Carrier Proteins; D002460:Cell Line; D002999:Clone Cells / Q000276:immunology; D003171:Complement Pathway, Classical; D003165:Complement System Proteins / Q000502:physiology*; D017261:Glycosylphosphatidylinositols; D006801:Humans; D007111:Immunity, Cellular; D009154:Mutation; D010716:Phosphatidylinositols / Q000502:physiology; D011134:Polysaccharides / Q000502:physiology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D001798:Blood Proteins; D018957:CD59 Antigens; D002352:Carrier Proteins; D017261:Glycosylphosphatidylinositols; D010716:Phosphatidylinositols; D011134:Polysaccharides; C051590:CD59 protein, human; D003165:Complement System Proteins