Chapter 14 Flashcards
What is Atopy?
Genetic predisposition towards an allergy
Allergens?
Induce hypersensitivity
Type 1 hypersensitivity explained?
-Soluble antigen binding to IgE bound via Fc domain to FcERI receptor of the mast cell, causing antigen engulfment and further degradation
-Re-exposure causes immune response and inflammation
Immediate response
Type 2 hypersensitivity explained?
Small molecule covalently binding to cell surface, creating new epitotes
-B cells secrete IgG, which further activates complement causing inflammation and damage
Type 3 hypersensitivity explained?
soluble immune complex including IgG form deposits in blood stream and further activate complement
Type 4 hypersensitivity explained?
Delayed repsonse
-Antigen specific effector T cells which are activated by antigens
-Further activating macrophages for damage at infection point
Parasitic Reaction response?
@MALT
-Macrophages engulf antigen and present to TH2 cells
-TH2 cell activates B cell to create IgE by proliferating into plasma B cell
-IgE binds via Fc domain to FcERI receptor of mast/eosinophil/besophil cells
-For future exposure to allergen
-To not eliminate parasites but to lesson the load
What is IgE and its properties? including FceRI receptor?
Binds to FceRI receptor via Fc domain on Mast cells
FceRI is a tetramer that contains 1 alpha chain and 3 signalling chains (1 Beta and 2 gamma)
-These signalling chains are activated when antigen crosslinks IgE
-Can have different affinities at receptor with which ever cell bound
Where Parasitic infections are common, Mast cells tend to have higher levels of Anti-parasitic IgE
What are Mast cells?
-Contain histamine
-Bind IgE
-Maintain tissue integrity via cytokine release
-Secrete growth hormones
-In all tissues EXCEPT CNS + Retina, don’t want an allergic response in those areas
What are Eosinophils?
Small in number
-release toxic granules and free radicals when activated
-Mast cell degranulation tends to attract them to site of infection
What are Basophils?
Less in number
-Secrete histamine + IL (interleukins)
-Initiate TH2 response
Characteristics of proteins that distinguish allergic vs nonallergic
NOTHING
What’s the difference between type 1 + type 2 immunity
Type 1: directed by TH1 cells
Type 2: directed by TH2 cells
What is the PEFR?
Peak Expiratory Flow Rate
(max speed one can blow out are in single burst)
-why? allergen in inhaled which usually decreases patient lung capacity and breathing due to inflammation from mast cells secreting cytokines
Type 1 hypersensitivity Diagnosis?
-inject small samples for an immediate and delayed immune response
-Drawbacks include introduction to new allergies, anaphylaxis or a terrible delayed response
-ELISA assay using blood
-Drawbacks: more money with less sensitivity, also more time
IgE allergic reaction effects on various allergens?
Airborne allergens irritate the respiratory tract, by decreasing diameter, which increases mucous secretion
Food allergens irritate the digestive tract
Blood and connective tissue receive allergens a number of different ways: * Insect bites
* Wounds
* Absorption from gut and respiratory mucosa
-Increase blood flow and permeability for the immune response
Systemic Anaphylaxis? and cure?
Caused by allergens in blood, leading to circulatory collapse and airway contraction
Epinephrin is used to relax bronchial smooth muscles and restore tight junctions between cells, restoring BP and preventing fluid loss from blood
Type 1 Hypersensitivity Treatments?
Prevention: Behaviour and environmental modification that reduces allergen exposure
Pharmacology: use drugs that reduce impact of contact with allergen
Immunological: modlating antibody response for desensitization of IgE to IgG to occur
Treatment of Hypersensitivity Type 1 via Omalizumab?
uses humanized monoclonal anti-IgE antibodies to bind to IgE to allow less binding to FceRI on mast cells, reducing allergic response
-Cannot bind to IgE if its already bound to FceRI receptor
Treatment of Hypersensitivity Type 1 via Palforzia?
Using Oral immunotherapy by slowly introducing allergen to desensitize the individual
NOT A CURE
