FIG. 2.

Electron microscopy of HIV-1 infected CHO and MDTF derivatives. (Upper panels) (a) Ultrathin sections were processed by glutaraldehyde-osmium fixation and ERL embedding. Budding structures (a) and extracellular HIV-1 particles are present. (b and c) Immunoelectron microscopy with anti-CA antibody of HIV-1-infected CHO derivative shows labeled budding structures (b) and adjacent extracellular particles (c). Gold particles are scarce in the cytoplasm and nearly absent in the extracellular space. (d and e) Gold-labeled HIV-like particles in the ER cisternae. Some cytoplasmic vacuoles (V) were labeled (arrow), while adjacent vacuoles remained unlabeled (arrowhead). (Lower panels) (a) Ultrathin sections of infected, fixed, and embedded MDTF.CD4.R5.CyT cells at low magnification showed virus particles at the plasma membrane. Morphological alterations were not observed. (b) Higher magnification revealed mature extracellular HIV-1 particles adjacent to the plasma membrane. (c) The extracellular particles were immunolabeled.