Which surface receptor molecule on human target cells is recognized and bound by the Human Immunodeficiency Virus (HIV) envelope glycoprotein gp120?
Answer and explanation
Correct answer: D. CD4 receptor present on helper T lymphocytes
- Step 1: HIV envelope glycoprotein gp120 binds to the primary cellular receptor CD4 on T helper cells, macrophages, and dendritic cells. Step 2. Subsequent interaction with chemokine coreceptors (CCR5 or CXCR4) triggers gp41-mediated viral envelope fusion. Answer: CD4 receptor present on helper T lymphocytes. Why not the others: CD8 identifies cytotoxic T cells; MHC class I presents endogenous antigens to CD8+ cells.
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