Figure 3.

HIV-1 spreads between macrophages through Siglec-1⁺ tunneling nanotubes (TNT). Primary human monocytes were differentiated for 3 days with supernatant from Mycobacterium tuberculosis-infected MDM, and then infected with HIV-1_NLAD8-VSVg. Representative immunofluorescence labeling showing HIV⁺-Siglec-1⁺ thick TNT (taken from [117] and used under CCBY 4.0). Staining shows extracellular Siglec-1 (top) intracellular HIV-1_Gag (middle), and cell plasma membrane stained with Wheat Germ Agglutinin (WGA, grey) with all 3 colors merged in the lower image. Scale bar: 10 μm.