A 19-year-old college student has five days of fever, exudative tonsillitis, posterior cervical lymphadenopathy and splenomegaly. Peripheral smear shows lymphocytosis with atypical lymphocytes and the Monospot test is positive. Epstein-Barr virus attaches to and enters its target cell by binding which receptor?
- A CD4 molecule on helper T lymphocytes
- B CD21 (complement receptor 2) on B lymphocytes ✓
- C CCR5 chemokine receptor on macrophages
- D CD155 on motor neurons
Correct answer: B. CD21 (complement receptor 2) on B lymphocytes
Explanation
EBV uses gp350/gp220 envelope glycoprotein to bind CD21 (CR2), the complement C3d receptor expressed on mature B cells, making the B lymphocyte its site of latency and transformation. Atypical lymphocytes in infectious mononucleosis are reactive CD8+ cytotoxic T cells responding to infected B cells, not the infected population itself. CD4 with CCR5/CXCR4 is used by HIV, and CD155 (poliovirus receptor-related nectin) is used by HSV entry into neurons.
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.