Interaction between gp120 and mAbs to CD4, DC-SIGN, and MR.
(A) Inhibition of mAbs with increasing concentrations of gp120. MDDCs were incubated with increasing concentrations of b-gp120 under conditions outlined in Figure 1A. The availability of CD4 and CLR epitopes (those not blocked by gp120 binding) was detected by mAbs to CD4 (Leu3a), DC-SIGN (AZN-D2), and MR (clone 19) all at 1 μg/mL. For comparison, binding of b-gp120 alone at increasing concentrations is shown. Detection and incubation of bound b-gp120 was performed as outlined in Figure 1A. Percent binding of mAbs to DCs was calculated as per Figure 1 with positive and negative controls defined as follows. Positive controls were cells incubated with mAbs in the absence of gp120. Negative controls were cells incubated with the appropriate mAb isotype control (IgG1 for all 3 mAbs listed above). (B) Inhibition of gp120 binding to CLRs by mannan, DC-SIGN (AZN-D2), and MR (clone 19) mAbs at various concentrations of gp120. MDDCs were preincubated with mAbs as in Figure 2. After washing, b-gp120 was incubated with cells at concentrations ranging from 20 ng/mL to 5 μg/mL and detected as outlined in Figure 1A.
