C Reactive Protein (CRP) is an annular (ring-shaped), pentameric protein, a member of the pentraxin family of proteins. It is an acute-phase protein of hepatic origin that increases following interleukin-6 secretion by macrophages and T cells. Its physiological role is to bind to lysophosphatidylcholine expressed on the surface of dead or dying cells (and some types of bacteria) in order to activate the complement system via C1q. CRP is synthesized by the liver in response to factors released by macrophages and fat cells (adipocytes). Besides, Ribosomal Protein L23A (RPL23A) has been identified as an interactor of CRP, thus a binding ELISA assay was conducted to detect the interaction of recombinant human CRP and recombinant human RPL23A. Briefly, CRP were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100μL were then transferred to RPL23A-coated microtiter wells and incubated for 2h at 37℃. Wells were washed with PBST and incubated for 1h with anti-CRP pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50µL stop solution to the wells and read at 450nm immediately. The binding activity of CRP and RPL23A was shown in Figure 1, and this effect was in a dose dependent manner