TREM-1

TREM1 (Triggering Receptor Expressed on Myeloid cells) is a type I transmembrane protein having a single Iglike domain. It associates with the adapter protein, DAP12, to deliver an activating signal. Several other TREM family members have been reported that are structurally similar but share less than 30% amino acid identity. TREM1 is expressed on blood neutrophils and a subset of monocytes, and expression is upregulated by bacterial LPS. Engagement of TREM1 with a monoclonal antibody leads to expression of IL8, MCP1, and TNFα suggesting that this receptor plays an important role in inflammatory responses. TREM1 is expressed at high levels on neutrophils of patients with microbial sepsis and in mice with LPS induced shock. Blockade of TREM1 with a TREM1/ Fc fusion protein protected mice against LPS induced shock.