TLR

Done by Dr Anees AlsaadiNov . 2008

What are Toll-like receptors?

• Are receptors involved in the innate immune system .

• Recognize specific molecular patterns that are present in microbial components.

Stimulation of different TLRs

induces distinct patterns of gene

expression.

Activation of innate immunity

Instructs the development of antigen-specific

acquired immunity.

Discovery of TLR? • Named for their similarity to Toll, a receptor first

identified in the fruit fly Drosophila melanogaster.

• The first reported human Toll-like receptor was described by Nomura and colleagues in 1994.

• 1997, Charles Janeway and Ruslan Medzhitov showed that a Toll-like receptor now known as TLR4 could, induce the activation of an adaptive immune response.

Where are TLR receptors found?

• TLR family members are expressed by:– Neutrophils.– Macrophages.– Dendritic cells.– Dermal endothelial cells.– Mucosal epithelial cells. – TLR2 and TLR4 expressed on B and T cells.

Are they intracellular or extracellular?

• Most TLRs are on the cell surface except of TLR9, which is an intracellular

• In MQ TLR4 expressed on cell surface and is internalized following engagement of the ligand.

• In TLR4 epithelial cells it resides in the Golgi apparatus.

What are the structure of TLR ?

What are the functions of TLR receptors?

• Engagement of TLRs with their ligands leads to:– Pro-inflammatory cytokines,– Chemokines, – Effector molecules.

• TLR2 Staphylococcus aureus . Haemophilus

influenzae or with RSV persist longer in the lungs of TLR4-deficient mice .

What are the functions of TLR receptors?

What are the functions of TLR receptors?

How is the signaling in TLR ?

How is the signaling in TLR?

How is the signaling in TLR?

How is TLR being regulated?

Thank you