An ELISA for hCAP-18, the cathelicidin present in human neutrophils and plasma

J Immunol Methods. 1997 Aug 7;206(1-2):53-9. doi: 10.1016/s0022-1759(97)00084-7.


hCAP-18 is a newly described protein of human neutrophilic granulocytes which belongs to the cathelicidin family of antimicrobial proteins. Members of this protein family share a common N-terminal sequence followed by a highly diverse antimicrobial, cationic C-terminus. The present work describes the production of recombinant hCAP-18, the generation of antibodies to the protein and the development of an accurate, sensitive and specific ELISA for the detection of hCAP-18 in cells, plasma and urine with a detection limit of 0.084 ng/ml. The amount of hCAP-18 in neutrophils is 0.627 microgram protein per 10(6) cells. The plasma level is 1.18 micrograms/ml which is several fold higher than for other neutrophil specific granule proteins. hCAP-18 is present in plasma as high molecular weight complexes. In accordance with this, hCAP-18 is barely excreted in the urine. The bone marrow appears to be the major source of plasma hCAP-18. The high level of hCAP-18 in plasma may provide an important defense against microorganisms and endotoxins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Infective Agents / blood*
  • Anti-Infective Agents / chemistry
  • Anti-Infective Agents / immunology
  • Antibodies / chemistry
  • Antimicrobial Cationic Peptides*
  • Carrier Proteins / blood*
  • Carrier Proteins / chemistry
  • Carrier Proteins / immunology
  • Cathelicidins
  • Enzyme-Linked Immunosorbent Assay / methods*
  • Humans
  • Neutrophils / chemistry*
  • Plasma / chemistry*
  • Rabbits
  • Reproducibility of Results
  • Sensitivity and Specificity


  • Anti-Infective Agents
  • Antibodies
  • Antimicrobial Cationic Peptides
  • Carrier Proteins
  • Cathelicidins