Ultrastructural analysis of HIV-1 by electron microscopy

MT-2/IIIB cells were washed and cultured at 37°C in complete RPMI containing 0.25% dimethyl sulfoxide (DMSO), 15 nM GS-CA1 or 500 nM ATV. After a 4 day incubation, samples were pelleted, fixed in ice-cold 2% glutaraldehyde, 1% paraformaldehyde in 0.1 M sodium cacodylate buffer pH 7.4, post-fixed in 2% osmium tetroxide in the same buffer, en block stained in 2% aqueous uranyl acetate, dehydrated in acetone, and embedded in LX-112 resin. Samples were ultrathin sectioned and counterstained with 0.8% lead citrate. Grids were examined on a JEOL JEM-1230 transmission electron microscope and photographed with the Gatan Ultrascan 1000 digital camera.