Induced hypersensitive response

Pines defend themselves against bark beetles and fungal pathogens by both a preformed resin system and an induced hypersensitive response. In the latter, the infected area at the site of beetle/fungal attack initially becomes soaked with resin. A layer... 

El-Ghorr, A. A. and Norval, M., A monoclonal antibody to cis-urocanic acid prevents the UV-induced changes in Langerhans cells and DTH responses in mice, although not preventing dendritic cell accumulation in lymph nodes draining the site of irradiation and contact hypersensitivity responses, J. Invest. Dermatol. 105, 264-268, 1995. 

Hart, P. H.et al., Histamine involvement in UVB-and cis-urocanic acid-induced systemic suppression of contact hypersensitivity responses, Immunology 91, 601-608, 1997. 

Patterson, R. et al., Arsenic-induced alterations in the contact hypersensitivity response in Balb/c mice, Toxicol. Appl. Pharmacol., 198, 434, 2004. 

Xenobiotics can affect allergic disease in one of two ways. They can themselves act as antigens and elicit hypersensitivity responses, or they can enhance the development or expression of allergic responses to commonly encountered allergens, such as dust mite. Chemicals that act as allergens include certain proteins that can by themselves induce an immune response and low molecular weight chemicals (known as haptens) that are too small to induce a specific immune response but may react with a protein to induce an immune response that is then hapten specific. Haptens have been associated with both allergic contact dermatitis (ACD), sometimes called contact hypersensitivity... 

The next figure (Figure 10) demonstrates that the intercellular mycelium in the treated tissue advanced to the mesophyll cells where it elicited a hypersensitive response within colonized, as well as in adjacent cells. The fungicide treatment induced in the susceptible wheat variety a reaction (hypersensitivity) which resembled that of a highly resistant host plant after rust attack, as described earlier for powdery mildew and barley. 

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