Immune System and Antigen Immediate Hypersensitivity
Hypersensitivity
■ Exaggerated responses by an individual to an antigen following a previous exposure
■ Ag-ab reaction – release large quantities of chemicals, enzyme, and cell stimulators that are damaging to the host.
■ Traditionally classified based on time after exposure to offending antigen ❑ Immediate hypersensitivity – Ab mediated ❑ Delayed hypersensitivity – Cell mediated
Types of Hypersensitivity Type I - ANAPHYLACTIC Type II - CYTOTOXIC Type III – IMMUNE MEDIATED Type IV – DELAYED
Type I Hypersensitivity (Anaphylaxis, Atopy or allergy)
■ Occurs in atopic persons in response to: ❑ Allergens, bee sting, venom, pollen,house mite, dust ❑ Administered/injected antigens such as anti-tetanic serum, penicillin, and other drugs ❑ Antibody involved: IgE
Examples: ❑ Anaphylaxis – IgE binds to surface of mast cells and basophils ■ Release of various mediators – produce vascular changes ■ Examples: ■ Causes bronchoconstriction, inability to breath ■ Maybe due to: injection of antitetanic horse serum, penicillin or bee sting.
■ Allergic asthma (Extrinsic asthma) ❑ Characterized by bronchospasm – difficulty of breathing ❑ Eosinophilia in blood and sputum ❑ Skin redness, sneezing, wheezing ❑ Maybe caused by: fungal spores, dust, animal danders
■ Localized reactions during Type I ❑ Occurs as an immediate response to mediators released from mast cells ■ Urticaria/Hives ■ Angioedema ❑ At site of exposure ❑ Bowel after ingestion of certain foods ■ Redness of skin, itching at site of introduction
■ Generalized reactions during Type I ❑ Produced by mediators such as cytokines and vasoactive
■ Exaggerated responses by an individual to an antigen following a previous exposure
■ Ag-ab reaction – release large quantities of chemicals, enzyme, and cell stimulators that are damaging to the host.
■ Traditionally classified based on time after exposure to offending antigen ❑ Immediate hypersensitivity – Ab mediated ❑ Delayed hypersensitivity – Cell mediated
Types of Hypersensitivity Type I - ANAPHYLACTIC Type II - CYTOTOXIC Type III – IMMUNE MEDIATED Type IV – DELAYED
Type I Hypersensitivity (Anaphylaxis, Atopy or allergy)
■ Occurs in atopic persons in response to: ❑ Allergens, bee sting, venom, pollen,house mite, dust ❑ Administered/injected antigens such as anti-tetanic serum, penicillin, and other drugs ❑ Antibody involved: IgE
Examples: ❑ Anaphylaxis – IgE binds to surface of mast cells and basophils ■ Release of various mediators – produce vascular changes ■ Examples: ■ Causes bronchoconstriction, inability to breath ■ Maybe due to: injection of antitetanic horse serum, penicillin or bee sting.
■ Allergic asthma (Extrinsic asthma) ❑ Characterized by bronchospasm – difficulty of breathing ❑ Eosinophilia in blood and sputum ❑ Skin redness, sneezing, wheezing ❑ Maybe caused by: fungal spores, dust, animal danders
■ Localized reactions during Type I ❑ Occurs as an immediate response to mediators released from mast cells ■ Urticaria/Hives ■ Angioedema ❑ At site of exposure ❑ Bowel after ingestion of certain foods ■ Redness of skin, itching at site of introduction
■ Generalized reactions during Type I ❑ Produced by mediators such as cytokines and vasoactive