Yersinia rLcrV and rYopB inhibits the activation of murine peritoneal macrophages in vitro

Yersinia antigenic proteins LcrV and YopB are translocators of effector Yops in type III secretion system. Recently, we have reported that rLcrV and rYopB inhibit the production of TNF-α, IFN-γ, and IL-12 in murine peritoneal macrophages. It was also demonstrated that IL-10 and TLR2 signaling pathways and inhibition of MAPK cascade is involved in rLcrV- and rYopB-induced immunomodulation. In the present study, it is reported that rLcrV and rYopB inhibited the LPS-induced production of IL-1β in macrophages. Pretreatment of macrophages with rLcrV and rYopB also inhibited the LPS-induced transcription of IL-6 but not of GM-CSF. However, the transcription of chemokines like MCP-1, MIP-1α, MIP-1β, and RANTES were inhibited by rLcrV and rYopB. Both proteins also affected the cytoskeleton and lipid rafts in macrophages. It is further observed that IL-10 antibodies abrogated the rLcrV- and rYopB-induced inhibition of IL-1β production in LPS-treated macrophages. The data, therefore, suggests a possible role of IL-10 in rLcrV and rYopB mediated inhibition of LPS-induced production of IL-1β in macrophages.