Mouse Anti-Human C1QB polyclonal antibody for WB. This gene encodes a major constituent of the human complement subcomponent C1q. C1q associates with C1r and C1s in;order to yield the first component of the serum complement system. Deficiency of C1q has been associated with lupus;erythematosus and glomerulonephritis. C1q is composed of 18 polypeptide chains: six A-chains, six B-chains, and six;C-chains. Each chain contains a collagen-like region located near the N terminus and a C-terminal globular region. The;A-, B-, and C-chains are arranged in the order A-C-B on chromosome 1. This gene encodes the B-chain polypeptide of;human complement subcomponent C1q.