Demonstration of calcium-induced conformational change(s) in C-reactive protein by using monoclonal antibodies

Mol Immunol. 1982 Sep;19(9):1159-65. doi: 10.1016/0161-5890(82)90326-1.


Three out of four anti-C-reactive protein monoclonal antibodies [HB3-2, (micro, k)], EA4-1 (gamma 2a, k) and FB2-1 (gamma 1, k) bind to C-reactive protein in the presence of 2.5 mM Ca2+ but not in the presence of 1.0 mM EDTA, indicating that the conformation of the antigenic determinant(s) recognized by these three antibodies is dependent upon Ca2+. This Ca2+-dependent binding can be inhibited by 1.0 mM phosphocholine, indicating that this antigenic determinant is at or near the phosphocholine-binding site of C-reactive protein. The binding of the fourth monoclonal antibody [HD2-4 (gamma 2-k)] is independent of the presence of Ca2+ and is not inhibited by phosphocholine. HB3-2 (micro, k) recognizes an antigenic determinant on the structurally related proteins, rabbit CRP and serum amyloid P.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Antibody Specificity
  • C-Reactive Protein* / immunology
  • Calcium / pharmacology*
  • Cross Reactions
  • Edetic Acid / pharmacology
  • Epitopes
  • Immunoglobulin G / immunology
  • Phosphorylcholine / pharmacology
  • Protein Conformation / drug effects


  • Antibodies, Monoclonal
  • Epitopes
  • Immunoglobulin G
  • Phosphorylcholine
  • C-Reactive Protein
  • Edetic Acid
  • Calcium