Extracellular granzymes A and B in humans: detection of native species during CTL responses in vitro and in vivo

J Immunol. 1998 Apr 1;160(7):3610-6.


Activated CTLs and NK cells induce apoptosis via multiple mechanisms, including that termed granule exocytosis. The latter pathway consists of vectorial secretion of perforin and a family of granule-associated serine proteases (granzymes) to the target cell. To establish whether granzymes are released extracellularly during cytolytic reactions in vivo, ELISAs that measure the native enzymes were developed and were found to specifically detect granzyme A (GrA) and granzyme B (GrB) at picogram concentrations. Low levels of GrA and GrB were present in plasma of healthy individuals (GrA, 33.5 pg/ml (median); GrB, 11.5 pg/ml (median)), whereas significantly higher levels were present in patients with ongoing CTL response, i.e., patients suffering from infections by EBV or HIV type 1. Markedly elevated levels were also noted in synovial fluid of patients with active rheumatoid arthritis. The measurement of soluble granzymes should be useful to assess clinical disorders associated with activated CTL and NK cells. Furthermore, these results suggest that granzymes mediate biologic effects beyond their described role in apoptotic cell death.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / metabolism
  • Antibody Specificity
  • Arthritis, Rheumatoid / blood
  • Arthritis, Rheumatoid / enzymology
  • Cell Degranulation
  • Cells, Cultured
  • Enzyme-Linked Immunosorbent Assay / methods
  • Extracellular Space / enzymology*
  • Granzymes
  • HIV Infections / blood
  • HIV Infections / enzymology
  • HIV-1
  • Herpesvirus 4, Human
  • Humans
  • Infectious Mononucleosis / blood
  • Infectious Mononucleosis / enzymology
  • Injections, Subcutaneous
  • Longitudinal Studies
  • Mice
  • Mice, Inbred BALB C
  • Serine Endopeptidases / administration & dosage
  • Serine Endopeptidases / blood
  • Serine Endopeptidases / immunology*
  • Solubility
  • Synovial Fluid / enzymology
  • T-Lymphocytes, Cytotoxic / enzymology*
  • T-Lymphocytes, Cytotoxic / immunology
  • Tumor Cells, Cultured


  • Antibodies, Monoclonal
  • GZMB protein, human
  • Granzymes
  • Gzmb protein, mouse
  • Serine Endopeptidases
  • GZMA protein, human