Effect of various forms of the C1 esterase inhibitor (C1-INH) and DAF on complement mediated xenogeneic cell lysis.
The purpose of the present study was to assess the effect of various forms of the surface-bound form of the C1 esterase inhibitor (C1-INH-PI) and decay accelerating factor (DAF) on xenogenic cells. cDNAs of various deletion mutants of the C1-INH-PI, such as delta-1-99 amino acid (AA), delta-108-183AA loop, delta-whole loop, delta-exon5, delta-exon6 + 7, and delta-exon5 + 6 + 7, and that of DAF, the delta-short consensus repeat (SCR) 1-DAF were established. While all deletion mutants of C1-INH-PI except the delta-1-99AA were expressed in the cytoplasm but not on the cell surface, the delta-1-99AA was clearly expressed on the xenogeneic cell surface. Amelioration of complement-mediated xenogeneic cell lysis by delta-1-99AA was next tested, and compared with delta-SCR1 DAF. Both molecules blocked human complement-mediated cell lysis by approximately 57 to 90 and 93 to 98%, respectively, in Chinese hamster ovarian tumor (CHO) cells and pig endothelial cells (PECs). The CHO cell transfectants were incubated with 20% normal human serum, and the amounts of C4 and C3 deposition on the cell surface were analysed by flow cytometry. The DAF transfectant showed a large amount of C4-deposition and much less C3-deposition than the controls (approximately 85% suppression), whereas the delta-1-99AA showed approximately a 40% suppression in both C4- and C3-deposition. Consequently, both the delta-1-99AA C1-INH-PI and delta-SCR1 DAF molecules are quite effective in down-regulating the xenogeneic cell lysis, but accomplished this in different manners.
Fukuta
Daisuke
D
Division of Organ Transplantation, Department of Regenerative Medicine, Osaka University Graduate School of Medicine, Osaka, Japan.
Miyagawa
Shuji
S
Yamada
Mako
M
Matsunami
Katsuyoshi
K
Kurihara
Takashi
T
Shirasu
Akio
A
Hattori
Hiroyuki
H
Shirakura
Ryota
R
D000818:Animals; D018958:CD55 Antigens / Q000235:genetics / Q000378:metabolism*; D016466:CHO Cells; D003167:Complement Activation / Q000276:immunology*; D003174:Complement C1 Inactivator Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003176:Complement C3 / Q000276:immunology / Q000378:metabolism; D003181:Complement C4 / Q000276:immunology / Q000378:metabolism; D006224:Cricetinae; D004727:Endothelium / Q000166:cytology; D015151:Immunoblotting; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D017434:Protein Structure, Tertiary; D013552:Swine; D014183:Transplantation, Heterologous / Q000276:immunology*
D018958:CD55 Antigens; D003174:Complement C1 Inactivator Proteins; D003176:Complement C3; D003181:Complement C4; D008565:Membrane Proteins