Electron microscopic evidence of colocalization of exogenous HIV-1 VLPs and endogenous mature virions within the VCC in HIV-1-infected MDMs.

(A) 400 ng of HIV-1 Gag-EGFP VLPs (ratio of WT:Gag-EGFP 1:1) were added to mature MDMs and allowed to internalize overnight prior to harvest and subsequent processing for transmission EM. (B) Enlargement of white dotted boxed area from (A). (C) NLUdel infected MDMs at day 10 post-infection displaying typical VCC morphology incorporating large amounts of mature HIV-1. (D) Enlargement of white dotted boxed area from (C). (E) MDMs were infected with NLUdel at a TCID50 of 2.0/cell. On day 9 post-infection, 400 ng of HIV-1 Gag-EGFP VLPs (ratio of WT:Gag-EGFP 3:1) were allowed to internalize overnight prior to harvest and processing. (F) Enlargement of white dotted boxed area from (E). (G-L) Same procedure as (E), except HIV-1 Gag-EGFP VLPs produced at a WT:Gag-EGFP ratio of 1:1 in order to simplify identification of exogenous VLPs. In each paired image, the enlarged section is indicated by a white broken line in the preceding image. Images were acquired on a 120 kV Hitachi H-7500 transmission electron microscope. Size bars = 500 nm.