C5 and Sepsis: While Toll-like receptor 2 (TLR2) is thought to be the major contributor to neonatal infection caused by Gram-positive bacteria, the observation that the CSF levels of C1r, C3, and C5 were rapidly increased in S. epidermidis infection-induced sepsis model in pigs (Muk et al., 2019) suggests that systemic infection may cause CNS injury via aberrant activation of the complement cascade.