Figure 4. Impact of lactose on RTB-B7’s recognition of ricin.

To examine the impact of lactose on the ability of antibody to recognize ricin, ELISA plates were coated with ricin overnight. Plates were then probed with lactose for 1-mixed lactose with serial diluted concentrations of (A) RTB-B7 and RTB-D8 or (B) RTB-D12 and TFTB-1. Plates were incubated with mixtures of lactose:Ab and developed as described in Materials and Methods. (C) In the competition ELISA, plates were coated with the indicated antibodies at a constant concentration (V_HHs at 10 µg/mL and TFTB-1 at 2 µg/mL) overnight. Serial dilutions of lactose (5 mg/mL) were incubated with biotinylated ricin before being applied to plates and developed. Binding was normalized to ricin bound to antibody in the absence of lactose. The data shown represent a single experiment in which each sample was done in triplicate and repeated at least twice. Data are expressed as the mean ± SD.