May play a role in the innate immune response of the leech nervous system to bacterial invasion. The oxygen-binding site in each chain contains two iron atoms (By similarity). Expressed in the central nervous system. Detected in the pair of large glia within the ganglionic neuropile, in the six packet glia that surround neuronal somata in each central ganglion, and in the bilateral pair of glia that separate axonal fascicles in the interganglionic connective nerves (at protein level). Up-regulated after septic shoc. Belongs to the hemerythrin family.