FIG. 4.
IF-S inhibits DC-SIGN-dependent recognition of HIV-1. (A and B) Binding of gp120-Fc to K562 and K562-CD209 cells (A) or MDDCs (B) in the presence of S. cerevisiae mannan (Man), laminarin (Lam), IF-S, anti-DC-SIGN, or an irrelevant antibody, as determined by flow cytometry. The percentage of marker-positive cells (B) and the mean fluorescence intensity (MFI) (A and B) are indicated. (C) Binding of HIVNFN-SX to Raji and Raji DC-SIGN cells in the presence of DC-SIGN blocking agents, as determined by a p24gag ELISA. (D) HIVJRFL/NL43-Luc transmission from Raji DC-SIGN or Raji cells to Hut CCR5 target cells in the presence of DC-SIGN blocking agents. As a control of direct infection, pulsed Raji DC-SIGN cells were also cultured with Hut CXCR4 target cells. Dotted line, background levels of luciferase (RLU, relative light units) observed with nonpulsed Raji DC-SIGN cells.