Q.69 Which of the following molecule is NOT found in the Eosinophilic granule ?
1. Ribonucleases
2. Cytokines
3. Chemokines
4. Histamine
Eosinophil Granule Contents: Q.69 Molecule NOT Found Identified
Eosinophils store key proteins, enzymes, and signaling molecules in their granules for immune defense against parasites and allergens. Histamine stands out as absent from these structures, unlike the other options.
Correct Answer
Option 4: Histamine is NOT found in eosinophilic granules.
Option Explanations
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Option 1: Ribonucleases – Present: Eosinophil-derived neurotoxin (EDN) functions as a ribonuclease, stored in granule matrix alongside other toxic RNases.
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Option 2: Cytokines – Present: Granules contain preformed cytokines like IL-4, IL-5, IL-13, and GM-CSF for rapid Th2 immune responses.
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Option 3: Chemokines – Present: RANTES (CCL5) and eotaxin (CCL11) localize in crystalloid granules to recruit more eosinophils.
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Option 4: Histamine – Absent: Histamine resides in basophil and mast cell granules, not eosinophils; eosinophils instead release histaminase to degrade it.
Granule Composition Overview
Eosinophil specific granules feature a crystalloid core (major basic protein) and matrix with eosinophil peroxidase, cationic protein, and neurotoxin. These enable extracellular secretion during activation.
Exam Strategy
Distinguish cell-specific mediators: basophils/mast cells for histamine, eosinophils for RNases and granule cytokines. Link to allergy/parasite defense mechanisms.
