Module 2: Normal Leukocytes (Eosinophils and Basophils)

Question 1

Blood levels vs tissue levels

Answer 1

both cells are at normal levels in blood and high levels in tissue (esp. respiratory, GI and lower genitourinary tracts)

Question 2

eosinophil characteristics

Answer 2

rel 2-4%
similar in size to neutrophils, but with bilobed nuclei
numerous large, oval, membrane-bound, specific granules

Question 3

eosinophil granules

Answer 3

rich in major basic protein (preformed mediators like peroxidase, arylsulfatase B, histamines, catalase, lipidoxidase, lectin, phospholipase D)

Question 4

eosinophil membrane

Answer 4

large numbers of H1 and H2 histamine receptors and IgE receptors

Question 5

H1 and H2

Answer 5

both receive histamine as a messenger but meaning is conveyed differently
H1 produce the symptoms and activate a reaction
H2 act as negative feedback receptors and turn off allergic reaction

Question 6

Eosinophil function

Answer 6

release secondary granules to kill parasites

instantaneous hypersensitivity reactions in tissues

Question 7

Basophil characteristics

Answer 7

Rel 0-2%
consider blood basophils IMMATURE that transform into tissue basophils (mature form)
contain large, round/oval specific basophilic granules

Question 8

Basophil granules

Answer 8

contain sulphated glycosaminoglycans
histamine
some enzymes (trypsin and chymotrypsin)
eosinophil chemotactic factor (ECF-A) - specific tetra peptides which attract eosinophils

Question 9

basophil membrane

Answer 9

large numbers of IgE-Fc receptors

Question 10

basophil function

Answer 10

not fully understood
capable of ingesting foreign particles
produce heparin and histamine (to induce inflammation)

Question 11

how basophils and eosinophils work together

Answer 11

the presence of allergens may stimulate the production of IgE antibodies by plasma cells
Mast cells (baso) produce immediate hypersensitive reaction and symptoms of anaphylaxis
Eosinophils follow up and suppress everything

Question 12

helminth parasite infections

Answer 12

allergens secreted from parasite activate a sensitized (IgE coated) mast cell (results in hypersensitive reaction; release of histamine, heparin and ECF-A)
Eosinophils attracted by mast cell mediators and move into area
If parasite if coated with IgE (produced by lymphs activated by the presence of a parasite) then eosinophil will bind to membrane receptors for complement and IgE-Fc
Eosinophils release cytotoxic substances from granules onto surface of parasite