Protection of xenogeneic cells from human complement-mediated lysis by the expression of human DAF, CD59 and MCP.
CD59 and membrane cofactor protein (MCP, CD46) are widely expressed cell surface glycoproteins that protect host cells from the effect of homologous complement attack. cDNAs encoding human CD59 and MCP cloned from Chinese human embryo were separately transfected into NIH/3T3 cells resulting in the expression of human CD59 and MCP protein on the cell surface. The functional properties of expressed proteins were studied. When the transfected cells were exposed to human serum as a source of complement and naturally occurring anti-mouse antibody, they were resistant to human complement-mediated cell killing. However, the cells remained sensitive to rabbit and guinea pig complement. Human CD59 and MCP can only protect NIH/3T3 cells from human complement-mediated lysis. These results demonstrated that complement inhibitory activity of these proteins is species-selective. The cDNAs of CD59 and MCP were also separately transfected into the endothelial cells (ECs) of the pigs transgenic for the human DAF gene to investigate a putative synergistic action. The ECs expressing both DAF and MCP proteins or both DAF and CD59 proteins exhibited more protection against cytolysis by human serum compared to the cells with only DAF expressed alone.
Huang
J
J
College of Life Science, Wuhan University, Wuhan439972, PR China. jianhuangm@yahoo.com
Gou
D
D
Zhen
C
C
Jiang
D
D
Mao
X
X
Li
W
W
Chen
S
S
Cai
C
C
D016475:3T3 Cells; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D018958:CD55 Antigens / Q000235:genetics / Q000378:metabolism*; D018957:CD59 Antigens / Q000235:genetics / Q000378:metabolism*; D003169:Complement Inactivator Proteins / Q000502:physiology; D003165:Complement System Proteins / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006168:Guinea Pigs; D006801:Humans; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D010957:Plasmids / Q000235:genetics; D011817:Rabbits; D013045:Species Specificity; D013552:Swine; D014162:Transfection; D014183:Transplantation, Heterologous
D015703:Antigens, CD; C497857:CD46 protein, human; D018958:CD55 Antigens; D018957:CD59 Antigens; D003169:Complement Inactivator Proteins; C497859:Mcp protein, mouse; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins; D003165:Complement System Proteins