Antigenic relatedness defines Toll-like receptor 2 is crafted on ligand blueprint.

Toll-like receptors are located particularly on mammalian immune cells to recognize pathogen-associated molecules. Toll-like receptors are categorized on the basis of ligand specificity that includes Toll-like receptor 2 with affinity for bacterial porin, the major outer membrane protein. Here we show TLR2 antibody recognizes the monomer of porin, primarily a TLR2-ligand in Western blot, thus displaying relatedness of primary structures between the receptor and its ligand. Quantitative analysis revealed relatedness of the native porin molecule with TLR2 was as high as 71%, suggesting imprint of native porin trimer is mostly copied by the receptor crossing limits of primary structures. Flow cytometric analysis of TLR2 on HEK-293 cells shows the receptor and ligand also have common molecular patterns on surface, which is distinctively separate from regions assigned for putative TLR(*)ligand interaction. Molecular mimetic and specificity of TLR will caution investigators targeting TLR-ligands to develop adjuvants and vaccines.