Type 1 Hypersensitivity Flashcards
antigens that trigger type I hypersensitivity are called
allergens
A distinguishing feature of type I hypersensitivity is the _, usually minutes, between exposure to allergen and the onset of clinical symptoms.
short time lag
occurs when serum is transferred from an allergic individual to a non-allergic individual, and the second individual is challenged at a later time with the specific allergen.
passive cutaneous anaphylaxis
refers to an inherited tendency to develop classic allergic responses to naturally occurring inhaled or ingested allergens
Atopy
IgE is primarily synthesized by _ in the lymphoid tissue of the respiratory and gastrointestinal tracts, as well as the lymph nodes.
B cells and plasma cells
The regulation of IgE production appears to be a function of a _
subset of T cells called type 2 helper cells (Th2)
key immunologic components involved in type I hypersensitivity reactions are _, _, _, and _.
IgE antibody, mast cells, basophils, and eosinophils
when Th2 is predominant, production of several cytokines, including _ and _, is the result.
IL-4 and IL-13
Type I hypersensitivity occurs in two major phases:
sensitization and activation
the IgE antibody attaches to high-affinity receptors called _, which bind the fragment crystallizable (Fc) region of the epsilon-heavy chain.
FcεRI
principal effector cells of immediate hy- persensitivity
mast cells
The most abundant preformed mediator is _, which comprises approximately 10% of the total weight of the granules in mast cells.
histamine
skin, local swelling and redness, sometimes referred to as a _
wheal-and-flare reaction
These products are more potent than the primary mediators and are responsible for a late-phase allergic reaction that can be seen in some individuals 6 to 8 hours after exposure to the antigen
secondary mediators
