Two distinct abnormalities in patients with C8 alpha-gamma deficiency. Low level of C8 beta chain and presence of dysfunctional C8 alpha-gamma subunit.
The sera from three C8 alpha-gamma deficient patients previously reported to have a selective C8 alpha-gamma defect were analyzed by SDS-PAGE and Western blot using two polyclonal antisera to C8 alpha-gamma and a monoclonal antibody to C8 alpha. All three sera exhibited C8 alpha-gamma bands that dissociated into alpha and gamma chains under reducing conditions. Quantitation of the alpha-gamma subunit in these sera by a sensitive ELISA revealed an amount approximately 1% of that found in normal human serum. A similar assay performed with a specific antiserum to C8 beta showed unexpectedly low levels of C8 beta in these sera, which were confirmed by hemolytic titration of C8 beta. The remarkable differences between C8 alpha-gamma and C8 beta in the C8 alpha-gamma deficient sera was that in spite of their comparable immunochemical levels, C8 beta still exhibited functional activity whereas C8 alpha-gamma was totally inactive. That the residual C8 alpha-gamma was inactive was also proved by its inability to show lytic bands in an overlay system after SDS-PAGE and subsequent removal of SDS. The implications of these findings for a novel concept of C8 deficiency are discussed.
Tedesco
F
F
Istituto di Patologia Generale, Università di Trieste, Italy.
Roncelli
L
L
Petersen
B H
BH
Agnello
V
V
Sodetz
J M
JM
D015153:Blotting, Western; D003185:Complement C8 / Q000032:analysis / Q000172:deficiency* / Q000648:ultrastructure; D004797:Enzyme-Linked Immunosorbent Assay; D006461:Hemolysis; D006801:Humans; D046911:Macromolecular Substances
D003185:Complement C8; D046911:Macromolecular Substances