TLR4 and infection: During infection when nuclear factor kappa B (NF-κB) pathway is activated by bacterial LPS binding Toll-like receptor 4 (TLR4) receptor, LL-37 peptide can selectively inhibit production of proinflammatory tumor necrosis factor (TNF) and reactive oxygen species (ROS) while at the same time stimulate IL-8 production in epithelial cells to attract immune cells (56).