In acute inflammation, margination of neutrophils is mediated initially by which selectin-ligand interaction?
- A LFA-1 (CD11a/CD18) on neutrophils binding ICAM-1 on endothelium — firm adhesion
- B P-selectin and E-selectin on endothelium binding PSGL-1 (sialyl-Lewis X) on neutrophils — rolling ✓
- C VCAM-1 on endothelium binding VLA-4 on neutrophils — transmigration
- D CD31 (PECAM-1) on both cells — diapedesis
Correct answer: B. P-selectin and E-selectin on endothelium binding PSGL-1 (sialyl-Lewis X) on neutrophils — rolling
Explanation
Rolling is the initial step of leukocyte extravasation, mediated by selectins: P-selectin (rapidly expressed from Weibel-Palade bodies) and E-selectin (induced over hours) on activated endothelium bind to sialyl-Lewis X (PSGL-1) on neutrophils. This tethers and rolls leukocytes along the endothelium. LFA-1/ICAM-1 mediates the subsequent firm adhesion step. PECAM-1 mediates transmigration through endothelial junctions.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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