Fig. 1.

Differences between the HIV-1 replication cycle in CD4⁺ T-cells and macrophages. (1) HIV-1 isolates show tropism in the two cell types with CCR5 primarily being utilized on macrophages and CXCR4 primarily used on CD4⁺ T-cells. Moreover, HIV-1 can alternatively enter macrophages via macropinocytosis. (2) Proteins like Vpr are essential components of the PIC in macrophages, which assist nuclear transport via an intact nuclear membrane (3), whereas in T-cells Vpr is dispensable for integration and the nuclear membrane has increased permeability. (4) A differential transcriptional programme is utilized in the two cell types with the factors like C/EBP and NFAT5 playing a crucial role in macrophages. (5) Viral assembly and budding in multi-vesicular bodies (MVBs) occurs in macrophages, but not in T-cells.