During acute inflammation, neutrophils roll along the endothelium via selectin-mediated interactions. Which selectin on the endothelium binds sialyl-Lewis X on neutrophils during rolling?

• A Both P-selectin and E-selectin mediate rolling, but P-selectin acts first within minutes ✓
• B P-selectin — stored in Weibel-Palade bodies, rapidly expressed after histamine stimulus
• C E-selectin — synthesized de novo after NF-κB activation, expressed 4–6 hours after stimulus
• D L-selectin — constitutively expressed on all leukocytes, shed during activation

Explanation

Both P-selectin and E-selectin on endothelial cells bind sialyl-Lewis X on neutrophil surfaces to mediate rolling. P-selectin is preformed and stored in Weibel-Palade bodies, appearing on the surface within minutes of histamine or thrombin stimulation, making it the first responder. E-selectin requires new protein synthesis via NF-κB and takes 4–6 hours to appear. L-selectin is on leukocytes (not endothelium) and mediates leukocyte-to-lymph node homing.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.