Journal of Lipid Research, Vol 26, 995-1001, Copyright © 1985 by Lipid Research, Inc.
Evaluation of the measurement of B protein of plasma low density lipoprotein by radial immunodiffusion
AJ Lutalo-Bosa, JL Adolphson and JJ Albers
Radial immunodiffusion (RID) has been used for determination of low density
lipoprotein (LDL) B protein in plasma. During measurement of B protein in
plasma and the d less than and d greater than 1.019 g/ml plasma fractions
by RID in 1.0%, 1.5%, 2.0%, and 2.5% agarose, the d less than 1.019 g/ml
lipoproteins diffuse in the agarose and produce precipitin rings. Among
normotriglyceridemic subjects, the B protein values in whole plasma
obtained by RID using 1.5 to 2.5% agarose were only slightly higher than
the values in the d greater than 1.019 g/ml fraction obtained by RID and
closely approximated the values obtained in the d greater than 1.019 g/ml
fraction by radioimmunoassay. However, among the hypertriglyceridemic
subjects, the RID measurement of B protein in plasma using 1.0 to 2.5%
agarose overestimated the LDL B protein levels in plasma. The RID procedure
at agarose concentrations of 1.5% to 2.5% can be used to estimate plasma
LDL B protein levels in normotriglyceridemic subjects. However, measurement
of LDL B protein by RID in plasma of hypertriglyceridemic subjects must be
interpreted with caution; the LDL B protein is overestimated by this
procedure because of the contribution by the d less than 1.019 g/ml
lipoproteins to the B protein value.