Lecture 14: Type 1 Hypersensitivity Reactions Flashcards
_____: adaptive immune responses that occur in exaggerated or inappropriate forms and result in disease
Hypersensitivity reactions
What is the pathologic immune mechanism associated with Type 1 Hypersensitivity reactions?
IgE antibody
What are the two primary mechanisms of tissue injury in Type 1 Hypersensitivity reactions?
1) Activation of mast cells, basophils, eosinophils + release of their mediators (histamine, arachidonic acid, cytokines)
2) Release of O2 and N2 radicals + proteases
What mechanisms of tissue injury are common to both Type II and Type III hypersensitivity reactions?
1) Activation of complement
2) Recruitment and activation of leukocytes (neutrophils, macrophages)
If a transfusion goes poorly, what type of hypersensitivity response will often occur?
Type 2
Auto-immunity, Arthus Reaction, or Serum Sickness are associated with which hypersensitivity?
Type 3
True or False: Type III hypersensitivity reactions are antibody mediated while Type II are immune complex mediated
False -
Type II reactions are: antibody mediated cytoxic/cytolytic reactions
Type III reactions are: immune complex-mediated
IgM or IgG antibodies against
tissue or cell surface antigen is seen in which hypersensitivity reaction?
Type II
Immune complexes of
circulating antigens and IgM or IgG antibodies are seen in which hypersensitivity reaction?
Type III
Which hypersensitivity reaction is T cell mediated?
Type IV
What are the two mechanisms of tissue injury used in Type IV hypersensitivity reactions?
1) Activated macrophages,
cytokines
2) Direct target cell lysis,
cytokines
Both CD4+ T cells (delayed type hypersensitivity) and CD8+ CTLs (T cell-mediated cytolysis) are present in which hypersensitivity reaction?
Type IV
Anaphylactic and allergic
reactions are associated with which type of hypersensitivity?
Type 1
There are often adverse responses mediated by___, which includes: allergies, asthma, and anaphylaxis
IgE
____: an antigen that stimulates IgE-mediated reactions (pollen, dust,
animal dander, etc.)
allergen
_____: an adverse response provoked by an allergen, mediated by
IgE, results in vasodilation and constriction of smooth muscles (including those of the bronchus), which can result in shock and death.
Anaphylaxis
____: susceptibility of certain individuals to natural sensitization by
environmental allergens, e.g., pollen, spores, foods
___: serum from a sensitized atopic individual that contains antibodies to an allergen
Atopy
Atopic serum
____: the process of inducing an immune response resulting in an
untoward (adverse) effect – for type I hypersensitivities it is the production
of IgE
Sensitization