A 19-year-old college student presents with acute bacterial meningitis. Vital signs show BP 118/76 mmHg, HR 102 bpm, RR 22/min, temperature 39.2°C, and SpO2 98% on room air. CSF analysis reveals elevated protein (180 mg/dL) and positive gram stain. He denies recent antibiotic use. Inflammatory cytokines from activated macrophages upregulate adhesion molecules on local endothelial cells, enabling neutrophils to roll along vessel walls before migrating into tissue. Which molecule mediates this rolling step?
- A)C3b binding to microbial surfaces
- B)PECAM 1 between endothelial cells and leukocytes
- C)CD40 ligand binding CD40 on macrophages
- D)Selectins on endothelium binding sialyl Lewis X on leukocytesGABARITO
- E)Integrins on neutrophils binding ICAM 1
Explicação
Leukocyte rolling is mediated by selectins, especially E selectin and P selectin on activated endothelium, interacting with sialyl Lewis X on leukocytes. This is the first adhesive step that slows leukocytes before firm adhesion and transmigration. Ver explicação completa e trilha adaptativa →