Quantification of human apolipoprotein A-IV by "sandwich"-type enzyme-linked immunosorbent assay.

Abstract

A specific and sensitive "sandwich"-type enzyme-linked immunosorbent assay (ELISA) has been developed for quantifying human apo A-IV. Using apo A-IV immunosorbent columns, we isolated monospecific anti-apo A-IV antibodies for coating the ELISA plates and for preparing peroxidase-antibody conjugate. The assay can detect as little as 0.20 ng of apo A-IV, with mean intra- and interassay CVs of 3.6% and 8.2%, respectively. The apoA-IV concentrations in normolipemic and hyperlipemic plasma were unaffected by either delipidation or treatment with detergents or urea. To validate the ELISA assay we compared it with an immunoelectrophoretic technique. ApoA-IV concentrations in plasma from normo- and dyslipemic subjects compared well by the two assays (r = 0.89). The mean apo A-IV concentration, measured by ELISA in plasma from 50 normolipemic subjects, was 143 (SD 52) mg/L; values for dyslipemic subjects were not significantly different. We also used this new assay to monitor apo A-IV profiles of normolipemic and hypertriglyceridemic plasma after chromatographic fractionation.

Apolipoprotein A-IV polymorphism in the Hungarian population: Gene frequencies, effect on lipid levels, and sequence of two new variants

“…Cholesterol and HDL-C were measured enzymatically with commercially available test kits (Boehringer Mannheim, Germany). The "sandwich"-type enzymelinked immunosorbent assay (ELISA) for quantification of apolipoprotein A-IV was performed as described by Rosseneu et al (1988). Plasma apolipoprotein A-I was meausred by radioimmunodiffusion (Sniderman et al, 1975).…”

Plasma apolipoprotein A‐IV metabolism in patients with chronic renal disease

“…Apolipoprotein A-IV concentrations in plasma and fractions thereof were determined by a recently described sandwich-type enzyme-linked immunosorbent assay (ELISA) [26]. Briefly, affinity-purified polyclonal rabbit antiserum to human apolipoprotein A-IV was used for coating microtitre plates and for preparing a peroxidase conjugate of this affinity-purified antibody according to Nakane [27].…”

“…Briefly, affinity-purified polyclonal rabbit antiserum to human apolipoprotein A-IV was used for coating microtitre plates and for preparing a peroxidase conjugate of this affinity-purified antibody according to Nakane [27]. Plasma with known content of apo A-IV (standardized with purified apolipoprotein A-IV after phenylalanine quantification by high pressure liquid chromatography [26]) was used as standard. The ELISA was performed as for other apolipoproteins with some modifications.…”

Tibolone lowers high density lipoprotein cholesterol by increasing hepatic lipase activity but does not impair cholesterol efflux

“…The interassay CV for these assays was below 7%. ApoA‐IV (Rosseneu et al ., 1988) and apoE (Huang et al ., 1996) were measured by enzyme‐linked immunoabsorbant assays. For the determination of apoE in HDL, apoB‐containing particles were precipitated with phosphotungstic acid/MgCl 2 (Roche diagnostics).…”