Stimulation of Leukocyte Lysophospholipase Activity by Noninfectious Agents

Abstract

Mouse peritoneal leukocyte lysophospholipase (LPL) activity was studied to determine whether or not noninfectious agents cause increased enzyme activity and whether neutrophils have LPL activity. In the first study, mice infected with Ascaris suum, a known inducer of LPL activity, were given intraperitoneal injections of proteose peptone, thioglycolate, bovine albumin, paraffin, glycogen, or A. suum whole worm extract (WWE). Cell populations collected from mice injected with A. suum WWE, proteose peptone, thioglycolate, or bovine albumin contained increased numbers of neutrophils and eosinophils. These cell populations had increased LPL activity when treated, in vitro, with either A. suum WWE, zymosan-activated complement, or with the agent they were induced with. However, the LPL activity of the different cell populations did not respond to all treatments in the same way. In a second study, A. suum-infected or noninfected mice were given intraperitoneal injections of paraffin, thioglycolate, glycogen, or A. suum WWE. Enriched cell populations containing either lymphocytes or macrophages, from infected or noninfected mice, did not have increased LPL activity following in vitro stimulation with A. suum WWE, zymosan-activated complement, or with the agent they were induced with. Enriched neutrophil populations from infected or noninfected mice had increased LPL activity following in vitro treatment with A. suum WWE or zymosan-activated complement. Results demonstrate that the LPL activity of peritoneal leukocytes can be induced by noninfectious agents and that neutrophils have increased LPL activity following in vitro stimulation.

The substrate specificities of four different lysophospholipases as determined by a novel fluorescence assay

“…Lysophospholipids play an important role in the pathogenesis of a broad spectrum of diseases and have been associated with myocardial infarctions, infections, neoplasia and asthma [1][2][3][4][5][6]. Specific lysophospholipids can participate in the regulation of signal-transduction processes and biological events, including modulation of protein kinase C activity, ion fluxes, G-proteindependent signalling, mitogenic stimulation of cells and degranulation of mast cells [7][8][9][10][11][12][13][14][15].…”