hypersensitivity Flashcards
Name some common substances that cause allergic rxn
- kiwi
- dust mite
- animal fur
- shellfish
- allergy
- pollens
- insulin
Which type(s) of hypersensitivity is/are mediated by IgG antibodies?
type II & III
Which type(s) of hypersensitivity is/are mediated by IgE antibodies?
type I
Which type(s) of hypersensitivity is/are mediated by T cells (CD4/CD8)?
type IV
Desc the diff types of hypersensitivity
Type I: immediate response aft a person has exposure to an antigen
Type II: dependent on antibody to destroy cells
Type III: mediated by immune complexes
Type IV: cell-mediated tissue injury
Effector mechanisms of the diff types of hypersensitivity
Type I: mast cell activation
Type II: complement, Fc receptor, phagocytes, NK cells
Type III: complement, phagocytes
Type IV:
- T helper type 1: macrophage activation
- Th2: IgE, eosinophil, mast cells
- CD8: cytotoxicity
In type I: the Th2 cells produce IL4. This drives the ______ to _____________________.
This drives the B cells to switch the class of the antibody from IgM to IgE.
In type I: the IgE binds to FCeRI on the mast cells and the mast cells are 1. ______ for subsequent exposure. The individual is 2. _______ to the antigen.
- primed
2. sensitized
In type I: on subsequent exposure, antigens bind to multiple IgE molecules on mast cells, 1. ______ the IgE molecules.
Within minutes, the cross-linking 2. _______ mast cells and triggers 3. ______.
- cross-linking
- activates
- degranulation
In type I: on subsequent exposure, the activated mast cells also release ______ 2-4hrs hours ltr.
cytokines
Type I hypersensitivity side effects include:
hay fever rhinitis
asthma
conjunctivitis
anaphylaxis
The IgE produced during type I hypersensitivity reactions is meant as immunity against _______
helminths
In type I early phase response, activated mast cells produce 1. _______ and 2. ______.
- ______ stimulates the blood vessels to become 3. _____. Thus, increased 4. _________
- ______ stimulates the 5. ____________ and cause 6. ___________, thus ______.
- histamines
- lipid mediators (eg. prostaglandin)
- leaky
- mucus secretion
- smooth muscle cells
- bronchoconstriction, thus SOB
In type I late response, activated mast cells produce 1. _______ , 2. ______ and 3.________.
- _______ and 2. ______. cause 4. _________.
- ________ start to 5. _____ tissues, causing tissue injury/damage.
- cytokines
- lipid mediators
- enzymes eg. tryptase
- inflammation
- degrade
Desc the 4 stages of anaphylaxis
1: generalised itching; urticaria
2: swelling away from the sting; incontinence
3: difficulty in breathing
4: drop in BP, loss of consciousness
Some symptoms after type I hypersensitivity Resp: GI: Cardio: Skin:
Resp:
- wheezing
- dypsnea
- hypoxia
- bronchoconstriction
- stridor
- sneezing
GI:
- nausea
- vomiting
- diarrhoea
- abdominal pain
Cardio:
- hypotension
- vasodilation
- tachycardia
Skin:
- flushing
- urticaria
- itch
- edema
Desc central tolerance and the 2 selections.
It is when self-reactive T cells undergo clonal deletion or differentiation into regulatory T cells
tve selection: targets desired cell population with an antibody specific to cell surf. make eg. CD4, CD8
-ve selection: only those that DONT react with their own antigens will be kept
In type II hypersensitivity: Myasthenia gravis— where auto-antibodies block 1. ____________, interfering with 2. _____________, leading to 3. _______.
- acetylcholine receptors
- neuro-muscular synapse functions
- muscle fatigue
In type II hypersensitivity: after macrophages are activated, they attack the muscle cells, and then the _______ is activated.
complement system
______ is a very important indicator of Systemic Lupus Erythematosus
anti-dsDNA
Diagnostic criteria for Systemic Lupus Erythematosus (4 or more)
- malar (butterfly) rash
- photosensitivity
- oral ulcers
- arthritis
- proteinuria
- seizures & psychosis
- thrombocytopenia, anemia
- anti-DNA
- antinuclear autoantibodies (ANA)
Pathogenic mechanisms. of antinuclear autoantibodies (ANA) for injury caused by anti-tissue antibody
- ANA exit blood into tissues & binds to cell debris
- antibody binds to Fc receptor
- neutrophils & macrophages are activated
- enzymes, ROI, etc damage tissue
Pathogenic mechanisms. of antinuclear autoantibodies (ANA) for injury caused by cell-mediated tissue injury
- immune complexes form in blood
- deposition on vessel walls
- neutrophils are activated
- enzymes, ROI, etc damage tissue
In type IV hypersensitivity: CD8 T cells destroy ________ in type I DM.
pancreatic beta cells
