FIG. 6.
Infectious HHV-6 is required to suppress HIV replication in coinfected DC cultures. (A, C, and D) Purified DC were exposed overnight to HHV-6Z29 at a variety of MOIs (A) or at an MOI of 0.1 (C and D), washed, placed back into culture for 2 days, and exposed to HIVBaL at an MOI of 0.1 (arrows). (B) Purified DC were exposed overnight to HIVBaL at an MOI of 0.1, washed, placed back into culture for 2 days, and exposed to HHV-6Z29 at a variety of MOIs (arrows). (C) Some DC were exposed to HHV-6 that had been heat inactivated at 56°C for 30 min. (D) Some DC were exposed to HHV-6 that had been preincubated with different concentrations of neutralizing anti-HHV-6 MAbs for 1 h at 37°C. HHV-6 preincubated with nonneutralizing anti-HHV-6 MAbs suppressed HIV replication in coinfected DC cultures (results not shown). Culture supernatants were assessed for HIV-1 p24 content every other day by RIA. The results shown are representative of at least three separate experiments. (A and B): □, MOI = 0.1; ●, MOI = 0.01; ▵, MOI = 0.001; ▴, MOI = 0.0001; ○, HIV alone. (C) □, HIV alone; ▵, coinfection; ○, coinfection with heat-inactivated HHV-6. (D) □, HIV alone; ▵, coinfection; ●, coinfection with HHV-6 preincubated with 500 μg of the HHV-6 neutralizing MAb OHV3 per ml; ▴, coinfection with HHV-6 pre-incubated with 5 μg of OHV3 per ml; ■, coinfection with HHV-6 preincubated with 0.5 μg of OHV3 per ml.