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Identification of hemolytic granules isolated from human myocardial cells
Y Kawamoto1, T Hanaichi, M Naito
1Department of Microbiology, Fujita-gakuen Health University School of Medicine, Aichi, Japan.
Abstract:
Human myocardial cells from fresh autopsy material contained granules which possessed hemolytic activity against guinea pig and rabbit erythrocytes. The hemolytic granules, which had a density of 1.02 and a diameter of 200-300 nm, were recovered as a microsome fraction from subcellular homogenates of human myocardial cells by differential centrifugation in 300 mM sucrose containing 0.1 mM PMSF and 10 mM EDTA. The membrane lesions caused by the granules were ring-like structures with an internal diameter of about 10-17 nm, analogous to that caused by perforin- and complement-induced lysis. However, the requirement for divalent cation differed from that for perforin-induced lysis, since the microsome-mediated lysis occurred in the presence of EDTA.
Insights
Human heart cells contain granules with hemolytic activity. These myocardial granules, isolated via centrifugation, create membrane lesions similar to perforin but function independently of divalent cations.
Area of Science:
- Cardiovascular Biology
- Cellular Biochemistry
- Immunology
Background:
- Human myocardial cells possess granules with hemolytic activity.
- These granules exhibit lytic effects on erythrocytes from guinea pigs and rabbits.
Purpose of the Study:
- To isolate and characterize hemolytic granules from human myocardial cells.
- To investigate the mechanism of granule-mediated membrane damage and its cation dependency.
Main Methods:
- Subcellular fractionation of human myocardial cells using differential centrifugation.
- Isolation of microsome fraction containing hemolytic granules.
- Analysis of granule size, density, and hemolytic activity.
- Characterization of membrane lesions and cation requirements.
Main Results:
- Hemolytic granules were isolated as a microsome fraction (density 1.02, diameter 200-300 nm).
- Granules induced ring-like membrane lesions (10-17 nm internal diameter), analogous to perforin and complement.
- Lysis occurred in the presence of EDTA, indicating no requirement for divalent cations, unlike perforin-induced lysis.
Conclusions:
- Human myocardial cells contain unique hemolytic granules.
- These granules induce cell lysis through a mechanism distinct from perforin, particularly regarding cation dependency.