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Type 1-prophospholipase A2 propeptide immunoreactivity is released from activated granulocytes
D Rae1, N Sumar, N Beechey-Newman
1Department of Surgery, St. George's Hospital Medical School, London, UK.
Clinical Biochemistry
|February 1, 1995
Summary
A new ELISA assay detects the release of type 1-phospholipase A2 propeptide (1-proPLA2) from activated granulocytes. This method specifically measures DSGISPR release, indicating granulocyte activation and potential relevance to acute lung injury.
Area of Science:
- Biochemistry
- Immunology
- Cell Biology
Background:
- Human type 1-phospholipase A2 (1-proPLA2) is synthesized as an inactive zymogen.
- Activation requires N-terminal cleavage, releasing the heptapeptide DSGISPR.
- A specific assay is needed to quantify this release.
Purpose of the Study:
- To develop a sensitive ELISA for measuring DSGISPR, the propeptide released from activated 1-proPLA2.
- To establish a method for assessing 1-proPLA2 precursor levels via trypsinization and subsequent DSGISPR assay.
Main Methods:
- Development of a solid-phase ELISA using antibodies against synthetic DSGISPR.
- Quantification of DSGISPR and its precursor in human blood cells.
- Stimulation of granulocytes with TNF-alpha and GM-CSF to induce release.
Main Results:
- The ELISA successfully detected DSGISPR and its 1-proPLA2 precursor in human granulocytes, but not in macrophages or lymphocytes.
- Cultured granulocytes rapidly released DSGISPR and precursor upon stimulation with TNF-alpha or GM-CSF.
- Chromatographic analysis confirmed the identity of the immunoreactive signal.
Conclusions:
- DSGISPR release is a specific marker of granulocyte activation.
- This assay has potential clinical relevance for understanding conditions like acute lung injury.