Figure 2.

Sources of complement proteins after SCI.

Different C activation products are present in the spinal cord parenchyma after injury from a direct leak through disrupted BSB (1), local production by infiltrating immune cells (2), or production by CNS-resident cells including predominantly microglia and astrocytes (3). Neuronal sources of C proteins are possible (dashed lines) based on other disease models but have not been demonstrated in SCI literature (4). Created with BioRender.com. BSB: Blood–spinal cord barrier; C: complement; CNS: central nervous system; SCI: spinal cord injury.