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Toll Like Receptors And Their Therapeutic Potential

Cellular Basis Of Disease: Why has the discovery of Toll-like receptors revolutionised our understanding of how the innate immune system works, and what is the therapeutic potential?

The body has two immune systems: the innate immune system and the adaptive immune system.
Adaptive, or acquired, immunity refers to antigen-specific defence mechanisms that take several days to become protective and are designed to react with and remove a specific antigen. This is immunity develops throughout life.
Innate immunity refers to antigen-nonspecific defence mechanisms that a host uses immediately or within several hours after exposure to an antigen. This is the immunity that you are born with, and is the initial response by the body to eliminate microbes and prevent infection.
It is in the innate immune system that Toll-like receptors are important in helping our understanding.
The most important role of the innate immune system is to react rapidly to infectious agents with the initiation an inflammatory response, and to shape the subsequent adaptive immune responses.
There are currently two different models for immune system induction. The first model predicts the recognition of non-self determinants on pathogens, and the other, more controvertial, model predicts that there is recognition of damage or danger to self-tissues.
In the first model, pathogens are recognised by either specific or general components of their structure. A system referring to the patterns that are recognised are the pathogen associated molecular patterns (PAMPs) and the receptors recognising them are pattern recognition receptors (PRRs).
The second model, put forward by Matzinger, is that it is the danger itself that is sensed. It is argued that it is tissue damage or cellular debris from necrotic cells that sends the signal for the immune system to initiate a response. The presence of DNA or RNA, that shouldn't be outside of the cell, may cause an alarm signal. Heat shock proteins...