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Human eosinophils express, relative to other circulating leukocytes, large amounts of secretory 14-kD phospholipase A2

Blom, M. LU ; Tool, A. T J ; Wever, P. C. ; Wolbink, G. J. ; Brouwer, M. C. LU ; Calafat, J. ; Egesten, A. LU ; Knol, E. F. ; Hack, C. E. and Roos, D. , et al. (1998) In Blood 91(8). p.3037-3043
Abstract

Human eosinophils perform several functions dependent on phospholipase A2 (PLA2) activity, most notably the synthesis of platelet-activating factor (PAF) and leukotriene C4 (LTC4). Several forms of PLA2 have been identified in mammalian cells. In the present study, the 14-kD, secretory form of PLA2 was detected in human eosinophils by immunocytochemical staining with the specific monoclonal antibody (MoAb) 4A1. In contrast, preparations of neutrophils, monocytes, lymphocytes, and basophils did not show detectable staining. With two MoAbs in a sandwich enzyme-linked immunosorbent assay (ELISA), large amounts of sPLA2 were detected in lysates of eosinophils, that... (More)

Human eosinophils perform several functions dependent on phospholipase A2 (PLA2) activity, most notably the synthesis of platelet-activating factor (PAF) and leukotriene C4 (LTC4). Several forms of PLA2 have been identified in mammalian cells. In the present study, the 14-kD, secretory form of PLA2 was detected in human eosinophils by immunocytochemical staining with the specific monoclonal antibody (MoAb) 4A1. In contrast, preparations of neutrophils, monocytes, lymphocytes, and basophils did not show detectable staining. With two MoAbs in a sandwich enzyme-linked immunosorbent assay (ELISA), large amounts of sPLA2 were detected in lysates of eosinophils, that were 20-fold to 100-fold higher than in the other circulating leukocytes (ie, neutrophils, basophils, monocytes, and lymphocytes). In addition, with a commercially available sPLA2 activity assay kit, we were able to show high activity of sPLA2 in human eosinophils relative to neutrophils. Investigations at the ultrastructural level showed that sPLA2 in eosinophils is mainly located in specific granules. Immunoelectron microscopy also visualized sPLA2 within phagosomes after addition of opsonized particles to the eosinophils. However, sPLA2 was not detected in the cell-free supernatants of activated eosinophils, in contrast to eosinophil-cationic protein (ECP), which colocalizes with sPLA2 in resting eosinophils. These findings warrant further studies into the role of sPLA2 in eosinophil function.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Blood
volume
91
issue
8
pages
7 pages
publisher
American Society of Hematology
external identifiers
  • scopus:0032522966
  • pmid:9531617
ISSN
1528-0020
language
English
LU publication?
yes
id
2789f764-afc8-4c30-aa12-3ec94fc4dcc0 (old id 1296527)
alternative location
http://bloodjournal.hematologylibrary.org/cgi/content/abstract/91/8/3037
date added to LUP
2016-04-01 12:04:45
date last changed
2024-12-04 02:16:10
@article{2789f764-afc8-4c30-aa12-3ec94fc4dcc0,
  abstract     = {{<p>Human eosinophils perform several functions dependent on phospholipase A<sub>2</sub> (PLA<sub>2</sub>) activity, most notably the synthesis of platelet-activating factor (PAF) and leukotriene C<sub>4</sub> (LTC<sub>4</sub>). Several forms of PLA<sub>2</sub> have been identified in mammalian cells. In the present study, the 14-kD, secretory form of PLA<sub>2</sub> was detected in human eosinophils by immunocytochemical staining with the specific monoclonal antibody (MoAb) 4A1. In contrast, preparations of neutrophils, monocytes, lymphocytes, and basophils did not show detectable staining. With two MoAbs in a sandwich enzyme-linked immunosorbent assay (ELISA), large amounts of sPLA<sub>2</sub> were detected in lysates of eosinophils, that were 20-fold to 100-fold higher than in the other circulating leukocytes (ie, neutrophils, basophils, monocytes, and lymphocytes). In addition, with a commercially available sPLA<sub>2</sub> activity assay kit, we were able to show high activity of sPLA<sub>2</sub> in human eosinophils relative to neutrophils. Investigations at the ultrastructural level showed that sPLA<sub>2</sub> in eosinophils is mainly located in specific granules. Immunoelectron microscopy also visualized sPLA<sub>2</sub> within phagosomes after addition of opsonized particles to the eosinophils. However, sPLA<sub>2</sub> was not detected in the cell-free supernatants of activated eosinophils, in contrast to eosinophil-cationic protein (ECP), which colocalizes with sPLA<sub>2</sub> in resting eosinophils. These findings warrant further studies into the role of sPLA<sub>2</sub> in eosinophil function.</p>}},
  author       = {{Blom, M. and Tool, A. T J and Wever, P. C. and Wolbink, G. J. and Brouwer, M. C. and Calafat, J. and Egesten, A. and Knol, E. F. and Hack, C. E. and Roos, D. and Verhoeven, A. J.}},
  issn         = {{1528-0020}},
  language     = {{eng}},
  month        = {{04}},
  number       = {{8}},
  pages        = {{3037--3043}},
  publisher    = {{American Society of Hematology}},
  series       = {{Blood}},
  title        = {{Human eosinophils express, relative to other circulating leukocytes, large amounts of secretory 14-kD phospholipase A2}},
  url          = {{http://bloodjournal.hematologylibrary.org/cgi/content/abstract/91/8/3037}},
  volume       = {{91}},
  year         = {{1998}},
}