Example of an autophagosome in an HIV-infected cell. Shown is a transmission electron micrograph of an HIV-1SF33-infected monocyte-derived macrophage (L Ackerman and MS Killian, unpublished data). At higher magnification, the HIV-1 particles (roughly 0.1 μm in diameter) are clearly visible within the autophagosomal structure (inset). Abbreviations: nucleus, N; autophagosome, AP; rough endoplasmic reticulum, RER. Arrows point to the multiple membranes surrounding the autophagosome.