Notes: Allergic Reaction

Question 0

Any substance the body recognizes as foreign and produces an immunological response against it, is defined as a(n):

Answer 0

Antigen (Ag)

Question 1

An allergic reaction is defined as an:

Answer 1

Abnormal antigen-antibody reaction

Question 2

Protein produced in response to the presence of an antigen?

Answer 2

Antibody (Ab)

Question 3

What is opsonization?

Answer 3

The formation of an Ag-Ab complex that enhances phagocytosis of the antigen by macrophages.

Question 4

What is the first exposure to an allergen (Ag) called?

Answer 4

Sensitizing Dose

Question 5

What happens during the sensitizing dose?

Answer 5

Plasma cells produce IgE, Immunoglobulin E, which attach to the surface of mast cells (500,00 IgE/ mast cell). This response takes approximately 10 days to occur, but the IgE stay attached to the mast cells for weeks, months and possibly years.

Question 6

Is there an allergic reaction during the sensitizing dose? Explain.

Answer 6

No Ag-Ab reaction (allergic reaction) because the antigen and antibody are not present at the same time.

Question 7

Explain what happens during the second exposure or eliciting dose to an allergen.

Answer 7

Allergen (Ag) binds to IgE forming Ag-Ab complexes on the surface of mast cells damaging their cell membrane. This increases the mast cells’s permeability to Ca2+. Increased Ca2+ Influx causes degranulation of mast cell and release of histamine, prostaglandins & kinins via exocytosis.