A biopsy of a subcutaneous nodule in a patient with filarial infection shows a dense infiltrate containing numerous bilobed granulocytes whose specific granules contain a highly basic protein that is directly toxic to helminths. What is this granule constituent?

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

Explanation

Eosinophil granules contain major basic protein, a cationic protein that damages the tegument of helminths and is central to defense against parasites recruited by IgE and IL-5. Myeloperoxidase and defensins are constituents of neutrophil azurophilic granules used in bacterial killing, and lysozyme is found in both neutrophils and macrophages but has no special antihelminthic activity, which distinguishes these options from the eosinophil product.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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