Final answer:
Macrophage-tropic HIV uses the 5) CCR5 co-receptor to bind to cells, which also presents a target for anti-HIV drug development. The CCR5-delta 32 mutation confers resistance to HIV infection by preventing the virus from binding effectively to this co-receptor.
Step-by-step explanation:
The student asked about the mechanism through which macrophage-tropic HIV binds to cells. Macrophage-tropic HIV uses a co-receptor, specifically 5) CCR5, to bind to cells in addition to the primary receptor CD4.
The other co-receptor mentioned, CXCR4, is typically used by T cell-tropic strains of HIV for entry into cells. The CCR5 co-receptor, which is normally involved in the immune response by binding to chemokines, presents an opportunity for developing anti-HIV drugs.
A notable mutation called CCR5-delta 32 can render individuals resistant to HIV infection as it produces a modified receptor that HIV cannot effectively bind to, preventing the virus from entering host cells.