Complement component C8 beta chain (C8B)

Complement component C8 beta chain (C8B) is one of three protein subunits (alpha, beta, and gamma) that make up complement component 8, an essential part of the membrane attack complex (MAC) in the complement system of the innate immune response[1][3][6]. C8B associates with C8A and C8G, inserting into pathogen membranes as part of the larger MAC assembly, which forms pores that disrupt target cell membranes and mediate lysis of bacteria and other foreign cells[1][3][6]. C8B is necessary for the proper assembly and function of MAC, and deficiencies or mutations in C8B result in immune dysfunction and increased risk of severe infections, particularly by Neisseria species causing meningitis[1][6]. C8B is primarily found in the extracellular space and operates as a secreted protein within the plasma[3][6]. It is not an enzyme, receptor, or transporter, but a structural and functional component of a protein attack complex that underlies innate immunity[1][3][6].

Other names

C82Complement component 8 subunit betaComplement component 8, beta polypeptideComplement component C8 beta chain isoform 1 preproproteinComplement component C8 beta chain isoform 2Complement component C8 beta chain isoform 3