FIG 6.
Effect of gp41 ectodomain changes on cold inactivation of HIV-1. Recombinant HIV-1 expressing luciferase and bearing wild-type or mutant Envs from HIV-1HXBc2 were normalized by reverse transcriptase activity. Equal amounts of viruses were kept at −80°C (initially) or incubated on ice for the indicated times, as indicated in Materials and Methods, and used to infect Cf2Th-CD4 CXCR4 cells. The infectivity relative to that observed in the absence of incubation on ice is shown. Quadruplicate samples were analyzed; data shown are representative of those obtained in at least two independent experiments.