chapter 15 Flashcards
(44 cards)
exaggerated immune response that causes damage to the individual
hypersensitivity
an exaggerated immune response mediated by antibody or antigen-antibody complex that manifest with minutes to hours after exposure to antigen
immediate hypersensitvity
A type sensitive response mediated TH cells, which release various cytokines and chemokines. The response generally occurs 2-3 days after TH cells interact with antigen
Delayed-type hypersensitivity (DTH)
-responsible for type I hypersensitivity
-allergies are initiated by an interaction between an _____ antibody and a multivalent antigen
IgE
How do Ige antibodies act?
-by cross-linking Fcε receptors on the surfaces of innate immune cells
-granule contents are released
A type I hypersensitivity reaction is induced by certain types of antigens referred to as ____________________.
allergens
What does it mean if someone has atopy?
they are predisposed to generate IgE antibodies against common environmental antigens
The high-affinity IgE receptor, FcεRI
-responsible for most allergy symptoms
-found on basophils and mast cells
The low-affinity IgE receptor, FcεRII
regulates production of IgE by B cells
Histamine:
-accounts for 10% of granule weight
-binds to one of four possible histamine receptors
induces contraction of intestinal and bronchial smooth muscles,
increased permeability of venules, and mucous secretion
H1 binding
increases vasopermeability and vasodilation, stimulates exocrine
glands, and increases stomach acid; also suppresses degranulation of mast cells/basophils in a negative feedback loop
H2 binding
Leukotrienes and prostaglandins:
-Secondary mediators―formed when membrane phospholipids are enzymatically cleaved
-more potent stimulators of vascular permeability and mucous secretion
–considered to be a major cause of asthma symptoms
stimulate TH2 responses to increase IgE production by B cells
IL-4 and IL-13
recruits and activates eosinophils
IL-5
may contribute to shock in systemic anaphylaxis
TNF-α
acts as a chemotactic factor, attracting other cells
IL-8
stimulates production and activation of more myeloid cells, including more granulocytes
GM-CSF
Type I early responses:
-occur within minutes of allergen exposure
-Mediated by mast cell granule contents
Type I late responses:
-occur hours later, a result of recruited cells
-Often inflammatory cell types such as neutrophils
Type I 3rd phase?
-starts three days after exposure, peaks at four days post-exposure
-Characterized by massive eosinophil infiltration
a serious allergic reaction that is rapid in onset and may cause death
Anaphylaxis
Systemic Anaphylaxis:
-a shock-like and often fatal state, the onset of which occurs within minutes.
-Venom from bee, wasp, hornet, and ant stings; drugs such as penicillin, insulin, and antitoxins; and seafood and nut.
-Epinephrine is the drug of choice
results from inhalation of common airborne allergen, such as
pollen
Allergic rhinitis (hay fever)
