FIGURE 4. HIV-infected T cells tether to other LN cells and form syncytia through Env, and migrate to distant tissues to disseminate infection.

a. Intravital micrographs from LNs of BLT mice injected 48 hours earlier with HIV-GFP (left) in one, and HIV-GFP ΔEnv (right) into the other footpad. b. Representative traces of infected T cells depicting instantaneous cell skeletal length (color-coded) and migratory velocity over time. Traces selected from 281 recorded in 14 movies/3 independent experiments. c. Mean cell skeletal length and arrest coefficient of individual cells infected with HIV-GFP or HIV-GFP ΔEnv. Data are pooled from six and eight recordings, respectively, from three independent experiments. d. Cell lengths of HIV-GFP-infected Tcm injected into NK cell-depleted, antibody-deficient D_HLMP2A mice, and of BLT LN cells infected in situ with HIV-GFP D368R or HIV-GFP. e. Recording of LN cells infected with HIV-nGFP. Bottom panels indicate border between cytoplasm and nuclei, based on a 80% of maximum fluorescence intensity (FI) threshold. f. Cell lengths of mono- and multinucleated, HIV-infected cells. g, h. Viremia in NSG BLT mice treated with FTY720 or vehicle starting at the day of s.c. HIV-infection via the cheek skin. g. Infection with HIV-GFP. h. Infection with clone SF162R3. FTY720 treatment was ended at day 56. i. Plasma viremia under FTY-treatment started four weeks after in i.p-infection, when virema had stabilized. One representative experiment of two is shown.