Immunology II (11.30.17) Flashcards
Define sensitization
first exposure to antigen with immune response (antibody)
What is a type I hypersensitivity?
Allergy or anaphylaxis
Which hypersensitivity reactions are antibody mediated?
Type I, II, III
Which antibody is involved in Type I hypersensitivity?
IgE
Where does IgE bind?
Mast cells
What is the mechanism of type I hypersensitivity?
- First exposure causes IgE formation
- IgE binds to mast cells
- Antigen crosslinkes to 2 IgEs on surface of mast cell
- Degranulation
- Release of mediators
What is the time frame for Type 1 hypersensitivity?
minutes
Result of Type I hypersensitivity?
- increased vascular permeability
- Edema
- Smooth muscle contraction
What are the symptoms/clinical manifestations associated with Type 1 hypersensitivity?
- Edema
- erythema
- itching
- urticaria
- eczema
- rhinitis
- conjunctivitis
- asthma
During sensitization the APC picks up allergen and presents it to what type of cell?
T-helper 2 cell
What does the T-helper 2 cell do in regards to allergic response?
Th 2 cell helps a B cell become a plasma cell
What type of cell produces IgE?
plasma cells
What are the effects of histamine?
- vasodilation
- increased capillary permeability
- smooth muscle contraction
What is the effect of Slow-reacting substance of anaphylaxis (SRS-A) [leukotrienes]?
- increased vascular permeability
- smooth msucle contraction
What is the effect of Eosinophil chemotactic factor of anaphylaxis (ECF-A)?
- release histaminase
- release arylsulfatase
*these degrade histamine and SRS-A
What are the effect of prostaglandins and thromboxanes?
- Dilation and increased permeability of capillaries
- bronchoconstriction
- aggregate platelets
What is the effect of platelet-activating factor (PAF)?
- Bronchoconstriction
- hypotension
- vascular permeability
Which antibody is involved in Type II hypersensitivity reaction?
IgG
Name the steps in Type II hypersensitivity
- Antigen on the cell surface combine with IgG antibody
2. Complement-mediated lysis of the cells
What is the typical time of onset or a Type II hypersensitivity reaction (cytotoxic)
hours to days
Live attenuated vaccine
- weakened virus
- must be refrigerated
- not for immune compromised or pregnancy
Examples: measles, mumps, reubella, varicella, rotavirus, yellow fever
Inactivated vaccine
- don’t require refrigeration
- induce weaker immune response
- need multiple doses to sustain immunity
Examples: poliovirus, hepatitis A, Japanese encephalititis
Subunit vaccine
Use a component of the pathogen as vaccine to mimic exposure
-Weaker than live attenuated
Conjugate subunit vaccine
Technology binds polysaccharide from bacterial capsule to a carrie protein.
This antigen combo induces long-term protection
Ex. Hib, Pneumococcal, meningococcal
