FIG 4.

Fructose reduces the potency of GRFT and MAb 2G12 in a simulant of seminal plasma. (A) Effects of fructose on HIV-1 inhibition by lectins and MAbs. Infection by viruses containing strain 1053-07 or WEAU Envs was measured in DMEM, sSP(−Fr), or sSP containing 30 mM fructose using the protocol outlined in Fig. 3C. Infection was also measured in the presence of GRFT (60 nM), GNA (400 nM), MAb 2G12 (15 μg/ml), MAb PGT121 (3 μg/ml), or MAb b12 (10 μg/ml). Infection in the presence of each inhibitor is expressed as a percentage of the level of infection measured in the absence of inhibitors. Error bars, SEM. P values were determined by a two-tailed t test. *, P < 0.05; **, P < 0.005; ***, P < 0.0005. (B) Effects of fructose on inhibition of virus infection in sSP. (C) Effects of fructose on inhibition of virus infection in Tris-buffered saline (150 mM NaCl, 20 mM Tris base, pH 7.5). (D) Binding of antibodies to Envs in sSP. The indicated MAbs (all at 0.5 μg/ml) were suspended in sSP containing different concentrations of fructose, and the media were incubated with HOS cells that expressed 1053-07 or WEAU Envs. Values are expressed as a percentage of the level of binding in the absence of fructose. (E) GRFT binding to HIV-1 in sSP. The binding of His-tagged GRFT to virus particles that contained the indicated Envs was measured in the presence of different fructose concentrations and is expressed as a percentage of the level of binding in the absence of fructose. Error bars, SEM.