A 19-year-old college student presents with two weeks of fever, sore throat, and marked cervical lymphadenopathy. Examination reveals splenomegaly. Peripheral smear shows atypical lymphocytes and the Paul-Bunnell test is positive. The causative virus infects which cell type via the CD21 receptor?
- A CD4+ T lymphocytes
- B B lymphocytes ✓
- C Macrophages
- D Dendritic cells
Correct answer: B. B lymphocytes
Explanation
Epstein-Barr virus binds CD21 (complement receptor type 2, also the C3d receptor), which is expressed on mature B lymphocytes, establishing latent infection there. The atypical lymphocytes seen on smear are reactive CD8+ cytotoxic T cells responding to infected B cells, which tempts students to pick CD4+ T cells or T cells generally, but the virus itself infects B cells only. Latency is maintained as episomal circular DNA with expression of LMP proteins.
Reference: Jawetz, Melnick and Adelberg's Medical Microbiology, 28th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.