FIG 5.

DC-SIGN binding and transfer to target cells. Comparison of DC-SIGN capture (A) and DC-mediated transfer to TZM-bl cells (B) of Env-pseudotyped viruses derived from historical patients (HP; n = 11), intermediate patients (IP; n = 15), and contemporary patients (CP; n = 14). Raji/DC-SIGN or Raji cells (negative control) were pulsed with each virus, whose inputs were normalized by p24 content. Samples were washed extensively to remove cell-free virions and lysed, and cell-associated virus was assayed by p24 ELISA. Percentages of capture were calculated after subtracting nonspecific binding to Raji cells. For transfer experiments, virus-bound Raji/DC-SIGN or Raji cells were cocultured with TZM-bl cells. Forty-eight hours later, cells were lysed and luciferase activity was determined. Differences between viruses over calendar time were evaluated using a Jonckheere-Terpstra test. (C) Correlation between cell-free and DC-mediated infectivities.