Rabbit anti-Human C4c Complement polyclonal antibody for IHC. C4 plays a centralrole in the activation of the classical pathway of the complement system.Human complement component C4 is polymorphic at two loci, C4A and C4B. TheC4A alleles carry the Rodgers (Rg) while the C4B alleles carry the Chido (Ch)blood group antigens. C4 (either allele A or B) protein is expressed as asingle chain precursor which is proteolytically cleaved into a trimer ofalpha, beta, and gamma chains prior to secretion. The trimer provides asurface for interaction between the antigen-antibody complex and othercomplement components. During activation, the alpha chain is cleaved by C1into C4a and C4b, and C4b stays linked to the beta and gamma chains. Furtherdegradation of C4b by C1 into the inactive fragments C4c and C4d blocks thegeneration of C3 convertase.