Lipoteichoic Acid

**Semantic type:** Organic Chemical

**Definition:** A biologically active lipopolysaccharide-type component of the Gram-negative bacterial cell wall. Lipoteichoic acid (LTA) may bind to cell surfaces non-specifically, through interactions with phospholipids, or specifically, through interactions with CD14 or toll-like receptors (TLR), and then be internalized. Binding to TLR2 may activate the NFkappaB pathway, mitogen-activated protein kinase (MAPK) signaling pathways and phosphoinositide 3-kinase (PI3K) activity. This can result in increased expression of pro-inflammatory cytokines and both pro- and anti-apoptotic genes and may stimulate expression of the immunosuppressive receptor programmed cell death protein 1 (PD-1; PDCD1; CD279). Increased expression of PD-1 promotes binding to its ligands, programmed cell death-1 ligand 1 (PD-L1) or 2 (PD-L2), which stimulates production of the anti-inflammatory cytokine interleukin-10 (IL-10) and leads to inhibition of CD4-positive T-cell proliferation and activity. Additionally, LTA also may induce cancer cell proliferation in certain susceptible tumor cells while having an inhibitory effect on proliferation of other cancer cells. Lastly, LTA levels in patient samples may also be correlated with inflammatory damage during acute bacterial infections.

**Synonyms:** - (2s)-1-({3-O-[2-(Acetylamino)-4-Amino-2,4,6-Trideoxy-Beta-D-Galactopyranosyl]-Alpha-D-Glucopyranosyl}oxy)-3-(Heptanoyloxy)propan-2-Yl (7z)-Pentadec-7-Enoate - LTA - [(2S)-1-[(2S,3R,4S,5R,6R)-4-[(2S,3R,4S,5R,6R)-3-acetamido-5-amino-4-hydroxy-6-methyloxan-2-yl]oxy-3,5-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-3-heptanoyloxypropan-2-yl] (E)-pentadec-7-enoate