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Immunology Final
Hypersensitivity, Lec 23
| Term | Definition |
|---|---|
| What is Hypersensitivity? | OVER REACTION of immune system to harmless antigens, resulting in inflammation, tissue damage, and clinical diseases. |
| Ags that induce allergic reactivity are called _____. | Allergens |
| What are the 4 types of allergic reactions? | Type 1 = mediated by IgE response (everything goes chronic) Type 2/3 = mediated by IgG/IgM response to cell-associated/soluble allergens Type 4 = mediated by cellular immune response (Th1 or CTL) |
| Type 1 hypersensitivity is related to immune response against _________. | parasite infection |
| Primary parasite (helminth) activates DC to stimulate ____ T cell response that produces ___, ___, ___, etc. | Th2, IL-4, IL-5, IL-13 |
| IgE binds to _____, _____, and _____ via high affinity _____. | mast cells, basophils, activated eosinophils, FceRI |
| Activated mast cells release _______ and ________. | Inflammatory mediators, cytokines and chemokines |
| Activated eosinophils secret ____ to kill parasite. | MBP (major basic protein) |
| _________ has the highest prevalence in humans, and is higher developed in places with lower rate of parasite infection. | Type 1 hypersensitivity |
| The _____ is the reduced risk of over-reacting to non-pathogenic allergens by early exposure to ____ (due to poor hygienic condition)which facilitates the development of ___ and ___ mediated regulatory T cells that controls both the __ and __ responses. | Hygiene Hypothesis, commensal bacteria, IL-10, TGF-B, Th1, Th2 |
| What is Atopy? | The predisposition to become hypersensitive to TYPE 1 ALLERGEN. |
| Atopic individuals have a tendency to mount _____ response to allergens, have higher ______ levels and blood ____ counts. | IgE, Serum IgE, Eosinophil |
| What two factors affect predisposition to TYPE 1 Hypersensitivity? | Genetic predisposition and Environment stimuli |
| ____ are low dose proteins that are carried in the environ. When on contact they become soluble and penetrate the epithelial layer (______) to enter sub-epithel spaces to be taken by ____ to stim a ____ response | Allergens, Protease activity, DC, Th2 |
| Allergens activate DCs to stimulate ______ which produces IL-4, 5, ___, and ___ to augment Th2 RESPONSE. | Th2 biased T cell response, IL-13, IL-19 |
| Th2 cells favor ___ switch (IL-4, 13 from T cells) in allergen-specific B cells. | IgE |
| Allergen-specific IgE bind to ____ on MAST CELLS (as their receptors are diff from T cell receptors). IgE can also bind to _____ and _____. | high affinity FceRI, Basophils, activated Eosinophils |
| Mast cell degranulation are a result of _____, where allergens cross-link IgE on Mast cells. Their mediators induce: Blood vessel dilation, ______, leukocyte recruitment, and enhancing functions of ______. | Re-exposure, smooth muscle contraction, effector cells |
| What are the two types of Mast Cells? | 1) Connective tissue mast cells and 2) Mucosal mast cells |
| What are the two types of Mediators of Mast Cells? | 1) Preformed mediators (Present in Mast cell granules) and 2) De novo synthesized mediators (secreted later) |
| What are the 3 major mediators in TYPE 1 Hypersensitivity? | Inflammation mediator, Chemokines, and Cytokines |
| What does Histamine, Leukotrienes, and Prostaglandins do in TYPE 1 Hypersensitivity? | They increase vascular permeability, smooth muscle contraction, and mucus secretion |
| What do the chemokines Eosinophile chemotactic factor and Neutrophil chemotactic factor do in TYPE 1 Hypersensitivity? | Recruit cells to tissues |
| What do IL-1/TNF-a and IL-4/IL-13 do as Cytokines in TYPE 1 Hypersensitivity? | IL-1/TNF-a activate endothelial cells, inflammatory response, and Anaphylaxis. IL-4/IL-13 enhance IgE response. |
| Upon re-exposure, what are the 2 phases of TYPE 1 Hypersensitivity? | The Immediate Phase and the Late-Phase Reaction. |
| Describe the Immediate Phase in TYPE 1 Hypersensitivity. | Lasts ~30 minutes, mediated by initial degranulation of Mast Cells. The HISTAMINE induces vascular permeability and smooth muscle contraction. WHEAL-FLARE rection (skin) and AIRWAY CONSTRICTION (airways) |
| Describe the Late-phase reaction in TYPE 1 Hypersensitivity. | Lasts ~6-8hrs. De Novo is synthesized by Inflammatory Mediators, Cytokines, and Chemokines by Mast Cells. Eosinophils and Neutrophils are recruited to tissues and their mediators. |
| What is another name for Systerm Allergic Reaction in Type 1 Hypersensitivity? | Anaphylaxis |
| In Anaphylaxis, _____ enters the blood circulation, and a reaction is mediated by ________ associated with blood vessels. Inc in vasc permeability means BLOOD PRESSURE DROP called _____. Smooth muscle contractions cause blocked airway passage = death | Allergens, Connective tissue mast cells, Anaphylactic shock |
| How do you treat Anaphylaxis? | With Epinepherin to reduce vasc permeability and relax muscle contraction |
| What are some features of Upper Resp allergic reactions of Type 1? | Allergic rhinitis (Hay Fever), Inc of vasc permeability, and Conjunctivitis |
| What are some features of Skin allergic reactions? | Urticaria (Hives) and Angioderma (tissue swelling) |
| What are some features of Gut allergic reactions? | Histamine effects on epithelia cells, blood vesels, and smooth muscles cause DIARRHEA and VOMITING. Can be transported via Blood Circulation to other sites like skin. |
| What is Allergic Asthma? | When the allergen enters the low respiratory tract |
| During the ____ in Allergic Asthma, activated mast cells recruit more Leukocytes such as ___, ___, and ____ cells which secrete inflammatory mediators. | Acute response, Eosinophil, Neutrophils, Th2 T cells |
| ______ is considered as Type 4 Hypersensitivity bc is is not chiefly mediated by ____ response. | Chronic Allergic Asthma, IgE |
| _____ factors can trigger an ASTHMA ATTACK which traps air in lungs, can cause death. | Environmental |
| What are two ways you can prevent allergic reactions? | Desensitation or Vaccination with allergic peptide of MHC Class 2 complex |
| In Desensitation, the patient is injected increasingly with allergens to induce ___ and ___ that produce ____ and ____ responses. IgG binds to inhibitory ___ on Mast Cells to inhibit their activation, even after IgE binds to FcERI. IgG4 outcompetes ___ | IgG4, Tred, IL-10, TGF-B, FcgammaR2B, IgE |
| How does vaccination with allergic peptide help prevent an allergic reaction? | It induces ANERGY in an allergic TH2 T cell |
| TYPE 2 Hypersensitivity is mediated by __ or ___ but not ___ to respond against ____ resulting in cell destruction. | IgM, IgG, IgE, Cell-surface components |
| In Type 2 Hypersensitivity, What are 3 mechanisms of Ab mediated cell destruction? | 1) Ab mediated activation of the complement system 2) Ab dependent cell-mediated cytotoxicity (ADCC) 3) Ab-Fc receptor enhanced phagocytosis |
| What causes Type 2 Hypersensitivity? | a mismatch ABO blood type during transfusion |
| What happens if there is an ABO mismatch during transfusion? | Complement mediated RBC Lysis, and excess Hgb in blood can damage kidneys and toxic levels of Bilirubin |
| In TYPE 2 Hypersensitivity, _____ can bind to RBCs to create a new epitope foreign to host immunse system. RBC is then phagocytosed by ___, presented to ___ cells, and B cells are also activated to produce the Ab ___. It then induces comp act causing ___ | Penicillin, Macrophages, Th2 T cells, IgG, HEMOLYTIC ANEMIA |
| What is the most common penicillin that induces allergic reactions? | Type 1 Hypersensitivity |
| What causes TYPE 3 Hypersensitivity? | when Immune Complexes are formed by IgG abs binding to soluble protein Ags, usu. cleared by MO's. Abnormal clearance is Type 3 Hypersensitivity. |
| How does Type 3 Hypersensitivity work? | 1) Immune complex deposits on small blood vessels activating complement 2) complements C3a, C5a, and the IC can activate mast cells (C3aR, C5aR, FcgammaR3) to induce inflammation 3) Plts activated to form blood clots causing vessel bursting (Hemorrhage) |
| In Type 3 Hypersensitivity, _____ occurs during horse serum or monoclonal Ab is injected as treatment of infectious disease, venom poisoning, or cancer. | Serum sickness |
| In Type 3 Hypersensitivity, ____ occurs due to long exposure to high does hay dust or mold spores. | Farmer's lung |
| TYPE 4 Hypersesitivity is mediated by ___ or ___ and requires _____ Ags to manifest the reaction. Th1 T cells secret cytokines and ___ to recruit MO's where they are activated at the site of infection to release ___, cause tissue damage,and stim ___ in BM | Th1, CD8 T cells, more, chemokines, inflammatory mediators, monocyte production |
| What are some examples of Type 4 Hypersensitivity? | Tuberculin skin test, Reaction to poison ivy, and Celiac disease |
| In ____, Gluten is modified by tissue _____ (changes glutamine to glutamate) and binds strongly to ____ or ____ to activate Th1 T cells. B cells can also generate ___ to tissue transglutaminase. | Celiac Disease, Transglutaminase, HLADQ2.5, HLADQ8, Auto-Abs |
Created by:
Hamncheese52
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