Chapter 14 Flashcards by Julia Gumirov

A predisposition to become IgE sensitized to environmental allergens is called….

atopy

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When antigens not on infectious agents elicit adaptive immune response, then this results in a disease condition, specifically hypersensitivity reactions known as __________ reactions

allergic

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What is a type 1 hypersensitivity reaction?

immediate type mediated by IgE antibodies w/ mast cell activation

(mast cells get activated by presence of IgE (can also have basophils and eosinophils respond on top of the mast cells)

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What is a type 2 hypersensitivity reaction?

driven by antigen specific IgG, effector bind complement (IgG kicks up immune response and complement system)

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What is a type 3 hypersensitivity reaction?

driven by antigen specific IgG, effector being FcR bearing cells

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What is a type 4 hypersensitivity reaction?

driven by cellular effectors including lymphocytes and myeloid cell types (cellular immunity w/ T cells)

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Type 1 hypersensitivity/IgE mediated reaction is an immediate hypersensitivity reaction caused by activation of mast cells and basophils by multivalent antigen bridging IgE bound to their cell surfaces. IgE is predominant in tissues where it is tightly bound to….

mast cells via Fc receptor

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In a type 1 hypersensitivity/IgE mediated reaction, when the antigen binds, it crosslinks the _____ receptors causing release of chemical mediators from mast cells. This leads to allergic disease. Symptoms vary based on route of entry of agent

IgE

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What is Der p 1?

respiratory allergen in house dust mites fecal pellet

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The enzyme Der p 1 cleaves occludin in tight junctions and enters the mucosa. Der p 1 is taken up by dendritic cells for antigen presentation and _____ priming. The DC primes T cell in the lymph node and TH2 cell induces B cell switch to ____ production. If pt sees Der p 1 again, then the plasma cell will travel back to mucosa and produces Der p 1 specific IgE antibodies. IgE binds to Fc receptor on mast cell and triggers mast cell degranulation. Mast cell granule contents cause allergic symptoms

TH2, IgE

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Der p 1 is a respiratory allergen in fecal pellet of house dust mites. In _______ individuals when they first see the antigen, DCs ingest it and go to the lymph node to present it to T helper cells

atopic

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Der p 1 is a respiratory allergen in fecal pellet of house dust mites. The immune response leading to IgE production is driven by 2 groups of signals. What are they?

1) differentiation of T helper cell into T helper 2 phenotype
2) TH2 cytokines are released and stimulate B cells to switch to production of IgE (to ensure that there is class switching in Ab production, CD40L on the T cell must bind to CD40 ligand on the B cell)

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Der p 1 is a respiratory allergen in fecal pellet of house dust mites. The IgE binds to Fc receptor in ______________ cells

resident submucosal mast

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define atopic individual

someone who is more sensitive to common triggers that can be breathed in or taken into system

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Sensitization involves class switching to _____ production on first contact w/ an allergen

IgE

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Sensitization involves class switching to IgE production on first contact w/ an allergen. IgE secreted by plasma cells binds to a high affinity Fc receptor on basophils. The activated basophils provide contact and secreted signals to ___ cells to stimulate IgE production

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Sensitization involves class switching to IgE production on first contact w/ an allergen. Once IgE is made, they bind to Fc receptors on basophils (allergen cross-links w/ Ab). Then the antigen binds to the Ab and the signal allows basophils to produce _________ and also release ______. These bind to a B cell and stimulate production of IgE and class switching to produce more IgE

CD40L (has a CD40/CD40L interaction), IL4

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Mast cells are releasing mediators and talking/calling basophils and eosinophils during allergic reactions to produce more Ab. The more Ab made= more ___________= more granule release

cross-linking

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Although many types of antigens cause allergic sensitization, _________ are common sensitizing antigens

proteases

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Usually, airborne allergens are small soluble proteins that are carried on dry particles like….

pollen

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Usually, airborne allergens are small soluble proteins that are carried on dry particles like pollen. When they contact mucus regions, the allergens are eluted from particles and diffuses into the mucosa which is then picked up with…..

DCs

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What 2 factors interact and may cause allergic disease?

environmental and genetic susceptibility

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Genome wide-associated studies show that there are over _____ genes associated w/ propensity for asthma and eczema

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Genome wide-associated studies show that there are over 40 genes associated w/ propensity for asthma and eczema. The genes are genes for cytokines that allow for mast cell proliferation and cytokines that allow for Ig class switching. This along w/ environmental factors become determinants in developing ________ diseases.

allergic

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What is the hygiene hypothesis?

exposure to some infections and common environmental microorganisms in infancy drives immune system towards non-atopic

Define atopy

predisposition to become IgE sensitized to environmental allergens

Mast cells line external mucosal surfaces. When activated, they induce inflammation by secreting ___________ and release cytokines. Mast cells also synthesize prostaglandins and leukotrienes from the plasma membrane

histamine

IgE mediated mast cell activation has a variety of responses and that depends on the dose of the antigen and the....

route of entry

Mast cells are derived from HSCs and mature locally residing near surfaces exposed to....

pathogens/allergens

Mast cells are derived from HSCs and mature locally residing near surfaces exposed to pathogens/allergens. Mast cells always express FC receptor and are activated when they....

cross link to IgE

What happens when there is mast cell activation and granule release in the GI tract?

What happens when there is mast cell activation and granule release in the eyes, nasal passages, and airways?

What happens when there is mast cell activation and granule release in the blood vessels?

Mast cells release enzymes and toxic mediators from granules. What is the specific toxic mediator that is released and what are its biological effects?

histamine -toxic to parasites -increase vascular permeability -cause smooth muscle contraction -anticoagulation

What specific cytokine did we talk about that is released by mast cells?

TNF alpha

What specific lipid mediators did we talk about that is released by mast cells?

prostaglandins and leukotrienes (part of the phospholipid bilayer)

Histamine has ____ GPCRs. Histamine acts on the receptor in blood vessels and causes immediate release in the blood flow and causes increased vessel permeability

Histamine leads to _______ and _____________

edema, inflammation

Histamine has 4 GPCRs. Histamine acts on the receptor in blood vessels and causes immediate release in the blood flow and causes increased vessel permeability. Histamine also activates neural receptors, which leads to....

sneezing and itching

leukocytes

Prostaglandins and leukotrienes (known as eicosanoids) are derived from membrane associated fatty acid arachidonic acid. It can be altered by _______________ via 2 pathways to produce either prostaglandin or leukotriene

phospholipase A2 (phospholipase A2 cleaves arachidonic acid and releases either prostaglandin or leukotriene depending on situation/what is needed)

Biologics is antibody therapy against....

IgE antibody

Prostaglandin D2 is made by mast cells and it is a big component of ___________ diseases

allergic

What is needed to sustain inflammatory response in tissues?

leukotrienes

What is used to prevent prostaglandin production?

NSAIDs like aspirin or ibuprofen (ensures that prostaglandins or leukotrienes do not get released)

NSAIDs act on ___________ that act on arachidonic acid to form the ring shape in prostaglandins

cyclooxygenases

What is the abbreviation for phospholipase A2?

PLA2

Phospholipase A2 (PLA2) is essential to inflammation and the immune response. Arachidonic acid is released from phospholipids by PLA2 and is further oxidized to prostaglandins or ______________ by the actions of COX or 5-LOX, respectfully

thromboxanes

Polymorphisms in the prostaglandin D2 gene has been linked to increased risk of developing....

asthma

What cells cause inflammation and tissue damage in allergic reactions?

eosinophils and basophils

Eosinophils and basophils cause inflammation and tissue damage in allergic reactions. This is because they release enzymes and toxic proteins from granules. What is the enzyme and toxin protein specifically?

enzyme= eosinophil collagenase (remodels connective tissue matrix, causes problems in tissues/cytoskeleton) toxic protein= major basic protein (talks between basophils, eosinophils, and mast cells)

Major basic protein forces degranulation from _______ cells

mast

Eosinophils and basophils are found in connective tissue underneath the gut, respiratory tract, and urogenital tract. When activated, they release toxic granules and free radicals which kill microbes but also affect our cells. Then they also synthesize ____________, ___________ and cytokines. This amplifies inflammatory response by activating epithelial cells and recruiting more leukocytes and eosinophils

prostaglandins, leukotrienes

Major basic protein causes degranulation of mast cells and.....

basophils

Activation of ___________ is tightly regulated

eosinophils

Eosinophils are found in the bone marrow and only a few are produced when there is no infection or immune stimulation. ______ cells get activated in the presence of an immune response and release cytokines such as _________ which will increase production of eosinophils and release them into circulation

Th2, GM-CSF

Eosinophil degranulation releases what?

major basic protein

If the allergen is introduced into bloodstream, then the connective tissue mast cells become activated and this results in widespread release of histamine. This will cause ______________ in extreme cases, or urticarial hives (rash) in mild cases.

anaphylaxis

If the allergen gets through the respiratory tract, then IgE mediated allergic reaction is called _________ _______ and results in the activation of mucosal mast cells

allergic rhinitis

If the allergen gets through the respiratory tract, then IgE mediated allergic reaction is called allergic rhinitis and results in the activation of mucosal mast cells. More serious is ________ ________. This occurs when submucosal mast cells are activated in the lower airways and quickly leads to bronchial constriction and secretion of mucus in the airways. The air gets trapped in the lungs and makes it difficult to breathe

allergic asthma

Allergen in the __________ and the _________ activates connective tissue mast cells

bloodstream, skin

Allergen in bloodstream activates connective tissue mast cells and __________ is released into the blood.

histamine

__________ allergens activate mucosal mast cells

inhaled

Inhaled allergens activate mucosal mast cells and cause increased mucus secretion and imitation leading to ________. If constriction reaches ________ airways, then this is considered asthma.

rhinitis, lower

Ingested allergen penetrates the gut epithelium and causes....

smooth muscle contraction (cramps)

Allergy to particular foods causes __________ reactions as well as symptoms limited to the gut

systemic

What are some risk factors for the development of food allergies?

1) immature mucosal immune system 2) early introduction of solid food 3) hereditary increase in mucosal permeability 4) IgA deficiency or delayed IgA production 5) inadequate colonization of the intestinal immune system by commensal flora 6) birth by C section (not exposed to as many pathogens) 7) genetically determined bias towards a Th2 environment 8) polymorphisms of Th2 cytokine or IgE receptor genes 9) impaired enteric NS 10) immune alterations (ex: low levels of TGF-beta) 11) GI infections

Adverse reactions to food are either: 1) 2) 3) 4) fill in blank

1) IgE mediated allergic reactions 2) non-IgE mediated food allergy (celiacs disease) 3) idiosyncrasies (unknown cause) 4) food intolerance (non-immune adverse reactions due to metabolic deficits)

IgE mediated allergies to food are in ____% of Americans and Europeans

1-4

Food allergens have high resistance to digestion by ______ in stomach and make their way to small intestine as intact allergen

pepsin

IgE-mediated allergic disease can be treated by inhibiting the effector pathways that lead to symptoms or by desensitization techniques that aim at restoring ___________ _____________ to the allergen

biological tolerance

What is the treatment for IgE mediated allergic reactions?

-antihistamines and beta agonists or immunosuppressive drugs like corticosteroids -treatment is palliative not curative -anaphylactic shock is treated w/ epinephrine (to bronchodilate and vasoconstrict), which stimulates reformation of endothelial tight junctions, promotes relaxation of smooth muscle in bronchials, and stimulates the heart -anti-IgE antibodies (ex: omalizumab downregulates (blocks binding onto receptor) Fc receptor production on mast cells which makes them less easily activated/accessible by antigens

Immediate hypersensitivity reactions involving IgG : Systemic disease caused by immune-complex formation can follow the administration of large quantities of poorly catabolized antigens. Immune complexes of antigen: antibody get deposited in tissue sites, blood vessel walls, ligate Fc receptors on leukocytes and lead to tissue injury Local hypersensitivity reaction is called....

arthus reaction

Deposition of immune complex in tissue leads to ______ inflammatory response called arthus reaction

local

Deposition of immune complex in tissue leads to local inflammatory response called arthus reaction. In people who have IgG against the antigen and the same antigen is injected into the skin, it forms an immune complex w/ IgG. This happens when theres is a low dose of antigen and the antigen complexes are formed close to the site of injection. They activate mast cells bearing the F c receptors, activate complement, and C5a sensitizes the mast cell to respond to the immune complexes. Inflammatory cells show up, blood vessels permeability increases, blood flows, and if all of this is severe then it can lead to....

tissue necrosis

Hypersensitivity reactions can be mediated by ______ cells and ____________ cells. Delayed hypersensitivity reactions take 3-5 days to develop.

TH1, CD8 cytotoxic T

What is an example of a delayed type antigen that is injected into the skin?

mantoux test (TB test)

In a contact delayed type antigen, it is absorbed into the skin and vesicles from. There is an accumulation of fluid and blisters at the level of the ____________ _____________ between the dermis and epidermis.

basement membrane

In gluten-sensitivity enteropathy, it is a delayed type antigen and is absorbed into the...

gut

What are the 3 syndromes based on route antigen and how it passes into body?

What are the 3 reaction stages of delayed type hypersensitivity reactions?

In delayed type hypersensitivity reactions, the antigen is processed by tissue macrophages and stimulates TH1 cells. What cytokines are released?

-chemokines -IFN-gamma -TNF alpha and LT -IL3 and GM-CSF

Chapter 14 Flashcards

(82 cards)