What does Toll-like receptor 4 do?

What does Toll-like receptor 4 do?

Toll-like receptor 4 (TLR4) belongs to the family of pattern recognition receptors (PRRs). They are highly conserved receptors that recognize conserved pathogen-associated molecular patterns (PAMPs), thus representing the first line of defense against infections.

What happens when TLR4 is activated?

TLR4 is a transmembrane protein, member of the toll-like receptor family, which belongs to the pattern recognition receptor (PRR) family. Its activation leads to an intracellular signaling pathway NF-κB and inflammatory cytokine production which is responsible for activating the innate immune system.

What TLR does LPS stimulate?

TLR4 is the key receptor involved in LPS recognition and signal initiation. Up to now, the structures of six of the ten human TLRs in complex with their cognate ligands have been determined.

What are toll-like receptor agonists?

Toll-like receptor agonists used as single agents especially when applied locally can effectively eradicate tumors due to their potent stimulation of innate and adaptive immunity as well as their effects on the tumor microenvironment (Figure 2).

What expresses Toll-like receptor 4?

In the human central nervous system (CNS), TLR4 is expressed by two types of non-neuronal supportive cells: the CNS residential macrophages or microglia and the macroglial cells such as astrocytes (65).

What does TLR 5 do?

TLR5 is expressed on both immune and non-immune cells. TLR5 recognizes bacterial flagellin, a principal component of bacterial flagella and a virulence factor. The activation of this receptor mobilizes the nuclear factor NF-κB and stimulates tumor necrosis factor-alpha production.

Does LPS stimulate T?

Although LPS-induced proliferation of lymphoid cells is thought to be primarily restricted to B cells, there are a number of reports that LPS can stimulate T cells. Thus, it is well established that LPS can act as a powerful adjuvant for T cell responses to specific antigen (19–21).

What does LPS do to cells?

LPS stimulates cells through Toll-like receptor 4 (TLR4), causing the release of inflammatory cytokines and upregulation of costimulatory molecules on antigen presenting cells.

What is a TLR agonist?

Agonists that target toll-like receptors (TLR) are being used clinically either alone or in combination with tumor antigens and showing initial success both in terms of enhancing immune responses and eliciting anti-tumor activity.

Why is it called toll-like receptors?

Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. TLRs received their name from their similarity to the protein coded by the toll gene identified in Drosophila in 1985 by Christiane Nüsslein-Volhard and Eric Wieschaus.

How many TLR does a human have?

There are ten functional TLRs in human (TLR1–10) and twelve in mice (TLR1−9, 11−13). Various combinations of TLRs are expressed by different subsets of immune and non-immune cell types such as monocytes, macrophages, dendritic cells, neutrophils, B cells, T cells, fibroblasts, endothelial cells, and epithelial cells.