HYPERSENSITIVITY
CLASSICAL ALTERNATE AND LECTIN PATHWAYS
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Type I
|
|
|
Type II
|
|
|
Type III
|
|
|
Type IV
|
Detailed explanation-1: -IgE molecules are bound to mast cells, which are found in loose connective tissue. When enough antigen has bound with the IgE antibodies, the mast cells release granules of histamine and heparin and produce other agents such as leukotrienes.
Detailed explanation-2: -Allergens (or antigens) are presented to T-cells by Antigen-presenting cells (APCs) during the sensitization phase of Type I hypersensitivity. T-cells then signal for stimulation of B-cells to produce IgE antibodies, which bind to the Fc receptors on mast cells and basophils.
Detailed explanation-3: -Mast cells are activated upon immunoglobulin E (IgE)-mediated antigen stimulation, and release a wide variety of mediators, including histamine to trigger inflammatory responses. The surface expression levels of Fc receptor I (FcRI), a high affinity receptor of IgE, were found to be positively regulated by IgE.