FIG. 2.

Sucrose density-equilibrium gradient analysis of extracellular supernatants from HXB2NEO and H9(LVifSN) cell lines. Extracellular supernatants were pelleted through 20% sucrose and then subjected to sucrose density-equilibrium gradient centrifugation in 20 to 60% sucrose. Fractions were collected, with fraction 1 referring to the top of the gradient, as indicated; the protein profiles were analyzed by Western blotting. Supernatants from HXB2NEO H9 cells (A) and H9(LVifSN) (B) were stained with anti-HIV-1-positive serum (top panels) or anti-Vif serum (bottom panels). Gradient fraction densities are given for HXB2NEO (C) and H9(LVifSN) (D) supernatants.