A sandwich enzyme-linked immunosorbent assay for human plasma apolipoprotein A-V concentration

Apolipoprotein A-V ( apoA-V) is a recently discovered apolipoprotein that appears to have a role in plasma triglyceride ( TG) transport. We have developed an ELISA for apoA-V using monoclonal antibodies that has a lower limit of detection of 0.3 ng/ml and linearity up to 20 ng/ml. The ELISA was then used to quantify plasma apoA-V in 196 healthy subjects and 106 patients with insulin-resistant diabetes mellitus. In the healthy subjects, total apoA-V concentration was 179.2 +/- 74.8 ng/ ml, and it was greater in females than in males ( P < 0.005). It was correlated positively with the plasma HDL cholesterol ( r = 0.32, P < 0.0001), apoA-I ( r = 0.27, P = 0.0001), and apoE ( r = 0.18, P = 0.011) concentrations and negatively with plasma TG concentration ( r = - 0.22, P = 0.021). In relation to single nucleotide polymorphism 3 ( - 1131C/T) of the apoA-V gene, apoA-V concentration was higher in the T/T type than in the C/C type ( P < 0.01). Plasma TG concentration was lower in the T/T type than in the C/C or C/T type (P < 0.05). ApoA-V concentration was lower in the diabetic patients (69.4 +/- 44.3 ng/ ml; P < 0.01) than in the healthy controls.