Complement Genes on Chromosome 6

Abstract

The classical complement pathway comprises nine serum proteins that interact sequentially to form a series of activated complexes and effectors of the immune response. In man, a number of inherited deficiency states of particular complement components are associated with increased susceptibility to infection or lupus-like syndromes.¹ The activity and interactions of the complement proteins are conveniently analyzed by measurement of complement-mediated lysis of antibody-sensitized erythrocytes. For initiation of the sequence, C1 (an aggregate of three protein subunits) binds to the Fc domain of antigenbound IgG or IgM through the C1q subunit. The C1r subunit then converts the C1s subunit to . . .