Subtypes of the human complement component C3 revealed by isoelectric focusing in immobilized pH gradients

Abstract

AbstractThe phenotyping of the third component (C3) of human complement has been performed by isoelectric focusing in immobilized pH gradients followed by immunoblotting on nitrocellulose filter membrane. This powerful technique reveals variations of C3* and C3*F alleles not detected by agarose electrophoresis. The limits of the resolving power of isoelectric focusing in immobilized pH gradients for C3 analysis are shown to depend upon the high molecular weight of this protein. The notion of “suptypes” is discussed. Finally, the importance of subtyping for medical applications and for determination at the molecular level of interacting protein mechanisms is underlined.