Module 2: Normal Leukocytes (Eosinophils and Basophils) Flashcards Preview

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Flashcards in Module 2: Normal Leukocytes (Eosinophils and Basophils) Deck (12):

Blood levels vs tissue levels

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


eosinophil characteristics

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


eosinophil granules

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


eosinophil membrane

large numbers of H1 and H2 histamine receptors and IgE receptors


H1 and H2

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


Eosinophil function

release secondary granules to kill parasites
instantaneous hypersensitivity reactions in tissues


Basophil characteristics

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


Basophil granules

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


basophil membrane

large numbers of IgE-Fc receptors


basophil function

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


how basophils and eosinophils work together

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


helminth parasite infections

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