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The development of an assay for human neutrophit lipocalin (HNL) - to be used as a specific marker of neutrophil activity in vivo and vitro
Abstract
Human neutrophil lipocalin (HNL) is a newly discovered protein from human neutrophil secretory granules. A
double-antibody radioimmunoassay (RIA) was developed for the measurement of HNL in various body fluids and its
high specificity was confirmed by the absence of cross-reaction with other granulocyte granule proteins. The RIA
measures HNL within the range of 4-256/~g/1. The intra- and interassay coefficients of variation were less than 6%
and 10%, respectively. When HNL was added to serum samples full recovery was obtained. Sera and plasma from
100 apparently healthy individuals revealed a mean level of 78.40/~g/1 (range 37.95-190.87 tzg/1) in serum and a
mean level of 50.65 pg/l (range 30.51-105.8 /zg/l) in EDTA-plasma. The distribution of HNL after gel filtration
indicated that HNL exists mainly in two major forms, dimer and monomer. This, in addition to the excellent
recovery, suggests that these major forms of HNL do not bind to compounds in serum or plasma that would interfere
with the assay. The high specificity, sensitivity, reproducibility and accuracy of the present assay should facilitate the
measurement of HNL in blood and other body fluids. |
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