On the other hand, the combined administration of KYT1 and KYT36 significantly increased the extracellular levels of IL-6 and TNF-α, but significantly decreased NO metabolites, after infection of microglia with P. gingivalis. It has been reported that the cooperative action of Rgp and Kgp is also involved in the proteolytic degradation of various cytokines including TFN-α35 and IL-636,37. Here, IL6 is linked to infection.