Human mannose-binding protein is identical to a component of Ra-reactive factor

Biochem Biophys Res Commun. 1992 Mar 16;183(2):645-51. doi: 10.1016/0006-291x(92)90531-o.


Human Ra-reactive factor (RaRF) and mannose-binding protein (MBP) were isolated from sera by utilizing their affinity to Ra chemotype Salmonella typhimurium and yeast mannan, respectively. A predominant polypeptide of human RaRF with an Mr of 32 kDa (P32) has the same mobility as human MBP on SDS-PAGE gels. A monoclonal antibody against P32 of human RaRF, 3E7, was found to react not only with P32 but also with human MBP, as assessed by immunoblotting. In addition, 3E7 blocked the complement-activating capacity of human MBP. The NH2-terminal amino acid sequence of P32 of human RaRF was determined and found to coincide with that of human MBP. Based on these results, it is clear that human MBP is identical to a component of RaRF.

MeSH terms

  • Antibodies, Monoclonal
  • Blood Proteins / chemistry*
  • Blood Proteins / immunology
  • Carrier Proteins / chemistry*
  • Carrier Proteins / immunology
  • Complement Activation
  • Humans
  • Mannose-Binding Lectin* / analogs & derivatives*
  • Mannose-Binding Lectins
  • Sequence Homology, Nucleic Acid


  • Antibodies, Monoclonal
  • Blood Proteins
  • Carrier Proteins
  • MBL2 protein, human
  • Mannose-Binding Lectin
  • Mannose-Binding Lectins