Electron Tomography of HIV-1 Infection in Gut-Associated Lymphoid Tissue
Figure 5
Intercalating infected cell with a budding profile contacting an adjacent cell.
(A) Tomographic slice (9 nm) from a six-frame montaged tomogram near the edge of a crypt in colon. The field contained two cells (N, nucleus) with an intercalating HIV-1–infected cell (presumably a dendritic cell; green outline). Four HIV-1 budding profiles were forming from the presumptive dendritic cell at different positions in the volume (magenta dots and black arrow). Dots indicate the approximate position of free mature virions at different positions in the volume (upper cell: light blue; lower cell magenta); the black arrow indicates a budding profile potentially involved in a virological synapse. (B) Eight tomographic slices (9 nm each) detailing the approach of the bud in panel A (black arrows) to the adjacent cell. Red arrowheads indicate the points of contact with the adjacent cell. (C) Immunolocalization of ICAM-1 near a presumptive virological synapse. A budding virion (arrow) is shown projecting from an infected cell and contacting the surface of an adjacent cell across an intercellular space (IS). The surfaces of both cells labeled for ICAM-1 (arrowheads). (D) Immunolocalization of LFA-1 near a presumptive forming virological synapse. The budding profile (arrow) extending from the infected cell was nearing the surface of the adjacent cell. LFA-1 (arrowheads) was present on the surface and proximal underlying compartments of the infected cell. Details of this interaction are shown in the latter part of Movie S1. Other examples of potential virological synapses are shown in Figure S6.