Soluble complement complex C5b-9 promotes microglia activation

• Soluble C5b-9 was assembled to treat microglia.
• Soluble C5b-9 could promote microglia activation.
• Soluble C5b-9 could upregulate costimulatory molecule expression and cytokine secretion.
• Soluble C5b-9 possessed immunoregulatory potential on microglia.

Soluble C5b-9 has been described as a pro-inflammatory mediator that triggers cell activation rather than inducing cell death. Microglia is the most important immune cell involved in inflammatory response in the CNS. Although microglia activation induced by various stimuli has been well characterized, the role of C5b-9 in microglia has not been well studied. In the current experiment, we utilized assembled functional C5b-9 to treat microglia and analyzed the function. We found that soluble C5b-9 could promote microglia activation by up-regulation of costimulatory molecules and increase cytokine secretion. Our results suggested that soluble C5b-9 possessed immunoregulatory potential on microglia.