A novel enzyme immunoassay for the determination of phosphatidylserine-specific phospholipase A(1) in human serum samples

Background: The bioactive lipid lysophosphatidylserine (LPS) is postulated to induce important biological responses and to be produced by phosphatidylserine-specific phospholipase A(1) (PS-PLA(1)). To evaluate the functional roles of LPS in vivo, a facile assay method for PS-PLA(1) has been awaited.

Methods: Recombinant human PS-PLA(1) was produced using a baculovirus system, and anti-human PS-PLA(1) monoclonal antibodies were generated. Two clones were then selected for a 2-site immunoassay. The resulting PS-PLA(1) assay reagent was applied to a commercial automated immunoassay analyzer.

Results: Satisfactory results were obtained for the within-run and between-run precision, interference, detection limit, and linearity of this PS-PLA(1) assay. The mean+/-SD of the serum PS-PLA(1) antigen concentration in the 191 healthy subjects was 33.8+/-16.6microg/l, and the central 95th percentile reference interval for the serum PS-PLA(1) antigen concentration was 13.8-74.1microg/l. The concentration was significantly (p<0.001) higher among men (13.8-80.6microg/l) than among women (12.1-68.8microg/l). We did not find a correlation between PS-PLA(1) and existing laboratory tests.

Conclusions: The present PS-PLA(1) assay method can be applied to clinical laboratory testing, and further studies are warranted to establish its clinical significance.