A 12-year-old boy returning from a rural endemic area has intestinal helminthic infection. Tissue section shows dense infiltration by granulocytes with bilobed nuclei and coarse eosinophilic granules. The cationic granule protein chiefly responsible for killing helminths in these cells is:

• A Lactoferrin
• B Defensin
• C Myeloperoxidase
• D Major basic protein ✓

Explanation

Eosinophil secondary granules contain major basic protein, a highly cationic polypeptide that is directly toxic to helminths and also triggers mast cell degranulation. Defensins and lactoferrin reside mainly in neutrophil granules, and myeloperoxidase belongs to the azurophilic granules of neutrophils. Recognizing the cell as the eosinophil and its signature granule protein is what the item tests.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.