Question

How might a PRR such as TLR-2 play a role in maintaining tolerance to non-pathogenic gut bacteria? What role does TGF-Beta play?

Answer 1

TLR-2 is surface protein which is an Pathogens Recognition Receptor and get activated by detecting presence of molecule of pathogenic origin also called Pathogen Associated Molecular Pattern (PAMP) and activation of it cause immune activation and cause inflamation. It involves also induction of production of IL-15. These cause inflammation and immune activation. TGF-Beta (Transformation Growth Factor - Beta) is released by white blood cells and involved in a no. of immune processes. Generally TLR-2 remain supressed in absence of pathogenic bacteria and maintain tolerance in non-pathogenic-bacteria in gut by supression with the help of IL-10 from Treg cells or by molecule like Single Immunoglobulin IL-1 receptor related molecule which down regulate TLR-2 in absence of pathogenic bacteria.