FIG 6.

Maintenance of Tri Bam Env antigenicity on virions after prolonged incubation on ice. HEK 293T cells were transfected with the pNL4-3.Tri Bam infectious molecular clone. Seventy-two hours later, virus particles were purified, aliquoted and stored at −80°C. Pilot experiments found no detectable difference in the Env content or antigenicity of VLPs that were analyzed directly after production or were frozen at −80°C once. One −80°C aliquot was thawed and incubated on ice for 7 days (+Ice). At this time, a second aliquot was thawed to serve as a reference control (−Ice). Both samples were pelleted and washed to remove any shed gp120, after which the Env antigenicity on virus particles was analyzed as described in the Fig. 2C legend. The results are representative of those obtained in two independent experiments, with the means and standard deviations reported in the bar graphs on the right.