In an online report released today in Science, Baylor College of Medicine‘s Dr. David Corry and his colleagues compared a membrane bound protein, toll-like receptor 4 (TLR4), to a computer chip involved in controlling the immune system in allergic disease and asthma.
Early studies carried out where mice were given a cocktail of proteinases demonstrated that these enzymes induced an allergic disease response, similar to asthma. Studying the role of proteinases in allergy, Dr. Corry demonstrated that these proteinases break down fibrinogen into small fragments which in turn bind to TLR4. The binding of these fragments to TLR4 sends signals to activate both T and B-cells within the adaptive immune system to fight against infection from pathogenic organisms such as fungi.
In a further study, Dr. Corry subjected laboratory mice lacking TLR4 to a proteinase producing fungi as an environmental trigger for asthma. In this study, he demonstrated that although these mice did not mount a strong allergic response to this fungi or even other triggers, normal Th2 immunity was observed.
This study strengthens the proposed role of TLR4 in the triggering of allergic disorders and asthma. It appears that although asthma is a potentially life threatening disorder, TLR4, which acts as one of the body’s computer chip, has developed to react accordingly to survive infection from pathogenic fungi. Dr. Corry stresses “against the insidious onslaught of organisms such as fungi, which can kill if left unchecked, asthma can be a better alternative.”
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