Porin of Shigella dysenteriae activates mouse peritoneal macrophage through Toll-like receptors 2 and 6 to induce polarized type I response.

Porin of Shigella dysenteriae type 1 coexpressed Toll-like receptor (TLR) 2 and TLR6 on peritoneal cavity (PerC) macrophages (MPhi) of C57BL/6 mice implicating that both the TLRs are essential as a combinatorial repertoire to recognize the protein. Besides TLRs, mRNA for MyD88 and TRAF6, and nuclear translocation of NF-kappaB were enhanced that indicate their involvement in tandem in the activity of porin. The protein selectively up-regulated CD80 on the activated MPhi together with MHC class II molecule and CD40, and had no effect on CD86 expression. The porin-induced profile of MIP-1alpha, MIP-1beta and RANTES showed strong bias for chemokines correlated with M1 polarization. Intracellular expression and release of TNF-alpha and IL-12 in presence of porin was found to be TLR2 and NF-kappaB dependent. Induction of TNF-alpha and IL-12 along with the chemokine profile suggests type I polarization of the MPhi that would influence Th1-type response.