FIGURE 2.

CRP is the major serum protein binding to ES-62. A, other serum proteins do not inhibit CRP binding to ES-62. ES-62 (0.25 μg/ml) was coated onto microtiter plates, and CRP at indicated concentrations was added alone (□) or in the presence of two individual normal serum samples (■ and ▴). CRP binding was detected as for Fig. 1B. OD, optical density. B, CRP is the major protein pulled out of normal serum by ES-62 (lanes 1 and 2) or AGP-PCh (lanes 3 and 4) coupled to magnetic beads. Bound protein was eluted with EDTA (lanes 1 and 3) or by SDS-PAGE lysis buffer (lanes 2 and 4). SDS-PAGE gels were run and analyzed by Coomassie Blue staining (lanes 1–4). Gels were also immunoblotted, and CRP eluted from ES-62-coated beads was detected by Western blotting (lane 5), as was SAP to a lesser degree (lane 6).