Determination of apolipoprotein B-48 in serum by a sandwich ELISA.
BACKGROUND
Apolipoprotein B-48 (apoB-48) is produced by the small intestine, as a part of chylomicrons (CMs), and appears to be a suitable marker for clinical studies of postprandial lipoproteins and related cardiovascular risk factors. We have developed an assay for routine analysis to quantify apoB-48 in serum or plasma.


METHODS
A microtiter plate was coated with monoclonal antibody (4C8) raised against apoB-48 C-terminal specific decapeptide. Serum samples were diluted 100-fold with 0.05 mol/l Tris-HCl buffer (with or without 0.1% Triton X-100). Appropriate calibration curves were obtained in the ELISA by using apoB-48 recombinant antigen.


RESULTS
No cross-reactivity (<0.001%) was found with apoB-100, as verified by ELISA and Western blot analyses. Intra- and inter-assay CVs were 4.8% and 5.4%, respectively. Recovery of added recombinant apoB-48 in serum was within 94-105%. The assay linearity was intact >5-fold dilution of serum by dilution buffer. ApoB-48 levels in healthy controls (n=18) at fasting were within the range of 2.69-6.56 microg/ml (mean+/-S.D.: 4.60+/-1.54 microg/ml). In healthy subjects, serum apoB-48 concentrations markedly increased in the postprandial state, in parallel with serum triglycerides.


CONCLUSIONS
This method for measuring apoB-48 using the monoclonal antibody 4C8 is simple, reliable and suitable for routine analyses.
Kinoshita
Makoto
M
Department of Internal Medicine, Teikyo University School of Medicine, Itabashi, Tokyo 173-8605 Japan. makkino@med.teikyo-u.ac.jp
Kojima
Masaaki
M
Matsushima
Teruhiko
T
Teramoto
Tamio
T
D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B / Q000097:blood*; D015153:Blotting, Western; D002138:Calibration; D002914:Chylomicrons / Q000378:metabolism; D003429:Cross Reactions; D003902:Detergents; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides / Q000097:blood; D012016:Reference Values
D000911:Antibodies, Monoclonal; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B; D002914:Chylomicrons; D003902:Detergents; D010455:Peptides