Immune effector mechanisms play key roles in the progressive (secondary) neurodegenerative changes that follow spinal cord injury (SCI).In our recent paper (Brennan et al.,2015),we showed that the inflammatory response to SCI includes rapid and robust activation of the innate immune complement system,with tissue levels of complement component 5a (C5a-an activation product generated by the proteolysis of complement factor 5 (C5)) peaking 12 to 24 hours post-injury.