Fig 1: Solid phase binding assay of leptin receptor to C-reactive protein (CRP). (A) Concentration dependence: different concentrations of monomeric CRP (mCRP) from serum (s-mCRP), recombinant CRP (R-mCRP), native serum CRP (n-CRP), and heat treated (h-mCRP) were coated on to 96-well micro titer plate incubated with leptin receptor (100 ng of Ob R) and the amount of Ob R bound was quantitated by ELISA using anti-Ob R antibody and HRP-conjugated secondary antibody as described in text. Values given are the average of 3–6 experiments done in duplicate ± SD. (B) Effect of different substances: mCRP (0.6 µg/ml) was coated on to 96-well micro titer plate and binding of leptin receptor in the presence of different cations (1 µM each of MnCl2, MgCl2, and CaCl2), or different amino acids (1 µM each of His, Tyr, Asp, and Glu) or in buffer pH 5.0 was assayed. Binding of leptin receptor to wells coated with BSA (100 µg/ml), lysozyme (100 µg/ml) native CRP (nCRP), or heat-treated CRP (0.6 µg/ml) was also analyzed. Results are expressed as percent of untreated mCRP control. Each value represents mean ± SD of three experiments.