Table 4.
TLR4 expression across species.
| Organs | Human | Non-human primate | Mouse | Rat | Swine | Rabbit | Dog |
|---|---|---|---|---|---|---|---|
| PBL | +++ | +++ | +++ | ND | ND | ND | +++ |
| Myeloid subsets | +++ | +++ | +++ | ND | ND | ND | ND |
| Monocytes | +++ | ND | +++ | + | +/− | ND | ND |
| Macrophages | +++ | ND | +++ | ND | +/− | ND | ND |
| Granulocytes | +++ | ND | +++ | ND | ND | ND | ND |
| Dendritic cells | +++ | +/++ | ND | ND | |||
| Immature dendritic cells | + | + | + | ND | +++ | ND | ND |
| Mature dendritic cells | − | − | ND | ND | +++ | ND | ND |
| Plasmacytoid dendritic cells | − | − | + | + | ND | ND | ND |
| Lymphoid subsets | +/− | +/− | ++ | ND | ND | ND | ND |
| Adipocytes | ++ | ND | ND | ND | ND | ND | ND |
| Brain | + | ND | ND | + | + | ND | |
| Basilar artery | ND | ND | ND | ND | ND | + | ND |
| Hypothalamus | ND | ND | ND | ND | + | ND | ND |
| Hippocampus | ND | ND | ND | ND | + | ND | ND |
| Cortex | ND | ND | ND | ND | + | ND | ND |
| Cerebellum | ND | ND | ND | ND | + | ND | ND |
| Microglia | ++ | ND | ++ | ++ | ND | ND | ND |
| Astrocytes | + | ND | − | +/− | ND | ND | ND |
| Neurons | ND | ND | ND | +/− | ND | ND | ND |
| Oligodendrocytes | + | ND | − | − | ND | ND | ND |
| Cornea | ND | ND | ND | + | + | ND | + |
| Endothelium | |||||||
| Dermal microvessel endothelium | ++ | ND | ND | ND | ND | ND | ND |
| Umbilical vein endothelium | ++ | ND | ND | ND | ND | ND | ND |
| Lung endothelium | ND | ND | ND | ND | ND | ++ | ND |
| Brain endothelial cell line | ++ | ND | ND | ND | ND | ND | ND |
| Primary brain endothelial cells | ND | ND | ND | ++ | ND | ND | ND |
| Heart | + | ND | +++ | + | ND | + | ND |
| Intestine | |||||||
| Small Intestine | ++ | ND | ND | ND | +/++ | ND | ++ |
| Colon | ++ | ++ | ND | ND | ++ | ND | + |
| Jejunum | ND | ND | ND | ND | +/++ | ND | ND |
| Ileum | ++ | ++ | ND | ND | ++ | ND | ++ |
| Duodenum | ND | ND | ND | ND | ND | ND | ++ |
| Intestinal epithelial cell lines | ++ | ND | ND | ND | ND | ND | ND |
| Mesenteric lymph node | ND | ND | ND | ND | ND | ND | +++ |
| Kidney | + | ND | ++ | ND | + | ++ | +/− |
| Liver | + | ND | ++ | ND | + | + | + |
| Kupffer cells | ND | ND | ND | ND | + | ND | + |
| Hepatocytes | ND | ND | ND | ND | − | ND | − |
| Vascular endothelium | ND | ND | ND | ND | − | ND | − |
| Bile duct epithelium | ND | ND | ND | ND | + | ND | + |
| Lung | ++ | ND | +++ | ND | + | ++ | + |
| Macrophages | ND | ND | ND | ND | + | ++ | + |
| Epithelial cells | ND | ND | ND | ND | + | − | + |
| Lymph node | ND | ND | ND | ND | ++ | ND | ND |
| Ovary | ++ | ND | ND | ND | + | ND | ND |
| Pancreas | + | ND | + | ND | ND | ND | ND |
| Insulin-producing β-cells | + | ND | + | ND | ND | ND | ND |
| Glucagon-secreting α-cells | +/− | ND | ND | ND | ND | ND | ND |
| Placenta | ++ | ND | ND | ND | ND | ND | ND |
| Prostate | + | ND | ND | ND | ND | ND | ND |
| Skeletal muscle | − | ND | ND | ND | −/+ | ND | − |
| Skin | − | ND | ND | ND | − | ND | − |
| Smooth muscle | + | ND | ++ | ND | − | ND | − |
| Spleen | +++ | ND | +++ | ND | ++/+++ | ++ | ++ |
| Stomach | ND | ND | ND | ND | ND | ND | ++ |
| Testis | + | ND | ND | ND | ND | ND | ND |
| Tonsil | ND | ND | ND | ND | ++/+++ | ND | ND |
| Thymus | + | ND | ND | ND | ++ | +/− | ND |
Summary of TLR4 expression patterns in the human, non-human primate, mouse, rat, swine, rabbit, and dog to our knowledge (see text for references, ND, not described).