Type 1 Hypersensitivity

Initial Exposure “Basic” antigen, B-cell, T-cell interaction B-cells produce IgE IgE circulates through the blood and will attach to mast cells (and basophils)

Later Exposure Antigen in blood attaches to IgE molecules on mast cells and basophils Mast cells and basophils undergo “dengranulation” Release histamines, cytokines, interleukins and prostaglandins) These cause vasodilation, mucous secretion, itchiness, etc. All this is humoral response (antibody-mediated)

Later Exposure Bee stings, food allergies, etc.

Type 4 – Delay-type HS Cell-mediated (T-cells) T-helper cell ‘recongnizes’ antigen on MHC of macrophage Becomes activated and replicates Second exposure – T-helpers release cytokines that attract more macrophages and Killer T-cells Cytokines and macrophages also cause swelling Macrophages can cause tissue damage, lesions, etc.

Type 4 – Delay-type HS Poison Ivy, other skin-contact allergens Tuberculosis test

Allergy Treatments? Why antihistamines? What would an epipen do?

Your turn Obj 10 & 17 Ready… GO!