Quantitative measurement of lipoprotein particles containing both apolipoprotein AIV and apolipoprotein B in human plasma by a noncompetitive ELISA.
BACKGROUND
A reliable method for plasma would be useful to investigate the role of apolipoprotein (apo) AIV when associated with apo B-containing or triglyceride-rich lipoproteins.


METHODS
We used a sandwich ELISA to quantify lipoprotein B:AIV particles (Lp B:AIVf; lipoproteins containing at least apo B and apo AIV) in plasma. The method used microtiter plates coated with purified anti-apo B immunoglobulins that selectively retained apo B-containing particles. Lipoproteins containing both apo B and apo AIV were distinguished from those containing only apo B by use of a peroxidase-labeled anti-apo AIV antibody. These subspecies were revealed by ABTS reagent and further quantified by spectrophotometry. Results were expressed in mg/L apo AIV associated with apo B. This method was applied to samples with different cholesterol and triglyceride concentrations.


RESULTS
The developed sandwich ELISA method identified and quantified Lp B:AIVf in plasma samples. Within- and between-run CVs were approximately 10%, and analytical recoveries were 95-107%. Results were not significantly influenced by addition of triglycerides or by storage at -20 degrees C (up to 9 months). Under these conditions, plasma Lp B:AIVf concentrations were statistically higher in hypercholesterolemic and mixed hyperlipidemic individuals (53 +/- 13 mg/L; P <0.001 and 70 +/- 18 mg/L; P <0.001, respectively) than in normolipidemic individuals (43 +/- 12 mg/L). Lp B:AIVf concentration appeared to be well correlated with total cholesterol, triglycerides, LDL-cholesterol, and apo B. These results were in contrast to total apo AIV, which was not different between dyslipidemic and normolipidemic individuals.


CONCLUSIONS
The developed ELISA method for Lp B:AIVf in plasma combines specificity, reliability, and speed. The increase in Lp B:AIVf concentrations in various dyslipidemic states, together with a lack of change in total apo AIV concentrations, suggests a redistribution of apo AIV toward apo B-containing lipoproteins when these lipoproteins accumulate.
Ferrer
Fanny
F
INSERM U539, Centre de Recherche en Nutrition Humaine, CHU Hôtel Dieu, 44035 Nantes, France.
Bigot-Corbel
Edith
E
N'Guyen
Patrick
P
Krempf
Michel
M
Bard
Jean-Marie
JM
D001054:Apolipoproteins A / Q000097:blood*; D001055:Apolipoproteins B / Q000097:blood*; D002784:Cholesterol / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014280:Triglycerides / Q000097:blood
D001054:Apolipoproteins A; D001055:Apolipoproteins B; D014280:Triglycerides; C022205:apolipoprotein A-IV; D002784:Cholesterol