Maraviroc is used in treatment-experienced HIV-1 patients after confirming viral tropism. Which statement about its mechanism is correct?
- A It allosterically alters the host CCR5 chemokine receptor so gp120 cannot engage it ✓
- B It binds gp41 and blocks six-helix bundle formation required for membrane fusion
- C It blocks the CXCR4 co-receptor on naive CD4+ T cells
- D It inhibits maturation of gag-pol polyprotein by binding the capsid spacer peptide
Correct answer: A. It allosterically alters the host CCR5 chemokine receptor so gp120 cannot engage it
Explanation
Maraviroc is a CCR5 antagonist acting on the host cell rather than the virus; it induces a conformational change in CCR5 that prevents recognition by gp120 of R5-tropic strains. Because it is ineffective against CXCR4-tropic or dual-tropic virus, tropism testing by genotypic assay is mandatory before use. Distractor B describes enfuvirtide, the gp41 fusion inhibitor, and D describes maturation inhibitors such as bevirimat-class compounds.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.