The C8-binding protein of human erythrocytes: interaction with the components of the complement-attack phase.
C8-binding protein is an intrinsic membrane protein of the human erythrocyte. It inhibits the complement (C5b-9)-mediated lysis in a species-restricting manner. In the present study we incorporated C8bp, isolated from human erythrocytes, into sheep erythrocytes (SRBC). SRBC, normally sensitive to lysis by human C5b-9, became insensitive to lysis. Furthermore, we found that C8bp is incorporated into the membrane-attack complex C5b-9, most probably by interacting with C8, since C8bp has an affinity for C8, particularly for the C8 alpha-gamma-subunit. Antibodies to C8bp react with the C8 alpha-subunits and with C9, pointing to the possibility of a partial homology between these proteins.
Schönermark
S
S
Institut für Immunologie, Universität Heidelberg, FRG.
Filsinger
S
S
Berger
B
B
Hänsch
G M
GM
D000818:Animals; D001798:Blood Proteins / Q000276:immunology / Q000378:metabolism*; D018957:CD59 Antigens; D002352:Carrier Proteins; D002462:Cell Membrane / Q000378:metabolism; D003185:Complement C8 / Q000378:metabolism; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000276:immunology* / Q000378:metabolism; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000276:immunology*; D006461:Hemolysis; D006801:Humans
D001798:Blood Proteins; D018957:CD59 Antigens; D002352:Carrier Proteins; D003185:Complement C8; D015938:Complement Membrane Attack Complex; C051590:CD59 protein, human; D003165:Complement System Proteins