Nerve growth factor: activation of the classical complement pathway by specific substitution for component C1-.

The interaction of homogeneous preparations of mouse submandibular gland nerve growth factor (NGF) with the classical complement pathway was studied. NGF was found to be capable of carrying out the enzyme activities of the first component (C1-) of the classical complement pathway (i.e., the cleavage of zymogen C4 and C2). NGF would not substitute for any other classical pathway component, C2-C9. The C1(-)-like activity of NGF was inhibited by human C1- inactivator. This interaction of NGF with the complement system may account for the previously described ability of NGF to accelerate the rate of contraction of experimentally induced wounds.