Which of the following pairs correctly matches an opsonin with its corresponding leukocyte receptor?
- A iC3b with CR1 (CD35)
- B IgG Fc portion with CD16 (Fc gamma RIII) ✓
- C Mannose-binding lectin with CD11c/CD18
- D C3b with CD89
Correct answer: B. IgG Fc portion with CD16 (Fc gamma RIII)
Explanation
The Fc portion of IgG bound to microbes engages Fc gamma receptors, chiefly CD16 (Fc gamma RIII) and CD32 (Fc gamma RII), on neutrophils and macrophages, triggering engulfment. iC3b is recognized by CR3 (CD11b/CD18) and CR4, not CR1, while C3b binds CR1. CD89 is the Fc alpha receptor for IgA. Receptor-ligand pairing in opsonization is a standard examination point.
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.