Selective lysis of early embryonic cells by the alternative pathway of complement--a possible mechanism for programmed cell death in embryogenesis.
Early embryonic cells and early mouse embryos were shown to activate the alternative pathway of complement, and to be highly sensitive to complement-mediated cytolysis (Kircheis et al, In Vivo 9: 85-98, 1995). Under further development embryonic cells become resistant. The induction of resistance to the alternative pathway of complement correlates with: a) altered splicing of Cr2-transcript and b) changes in the acidic glycolipids under differentiation. Early embryonic cells have low amounts of sialic acid-containing glycolipids or express mainly GM3. The induction of differentiation changes the glycolipid pattern leading to an increase in membrane-bound sialic acid. The importance of membrane-bound sialic acid in the restriction of complement activation is demonstrated by increased sensitivity to complement after pre-treatment of cells with neuraminidase. The results indicate that there is target-specific lysis of early embryonic cells by the alternative pathway of complement. Early embryonic cells activate the alternative pathway of complement by expressing activators and low levels of membrane-bound sialic acid. Induction of differentiation changes the glycolipid pattern, leading to an increase in membrane-bound sialic acid sufficient to restrict complement-activation on the cell surface.
Kircheis
R
R
Biotechnology Research Center, Teikyo University, Kawasaki, Japan.
Kircheis
L
L
Oshima
H
H
Kohchi
C
C
Soma
G
G
Mizuno
D
D
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002454:Cell Differentiation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003165:Complement System Proteins; D004622:Embryo, Mammalian / Q000502:physiology; D006017:Glycolipids / Q000378:metabolism; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009439:Neuraminidase / Q000378:metabolism; D014407:Tumor Cells, Cultured
D006017:Glycolipids; D003165:Complement System Proteins; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid