Exploring the complementary selectivity of immunocapture and MS detection for the differentiation between hCG isoforms in clinically relevant samples.
Whereas numerous immunoassays have been developed to ensure detection of the entire spectrum of isoforms displayed by the human chorionic gonadotropin (hCG) molecule, significant variation has been demonstrated in how these isoforms are recognized by the antibodies in different immunoassays. The aim of this study was to establish a method using the dual selectivity of the immunoextraction and the mass spectrometry detection for the differentiation between various hCG isoforms in clinically relevant samples. Immunoextraction of endogenous hCG isoforms using a monoclonal antibody (E27) on a 96-well microtitier plate, followed by in-well tryptic digestion, and SIM monitoring of the selected signature peptides, resulted in the qualitative differentiation between several hCG isoforms in serum or urine. We conclude that the orthogonal selectivity conferred by the combination of immunoaffinity extraction and LC-MS analysis offers valuable complementary information to the conventional immunoassays.
Lund
Hanne
H
Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Oslo, Norway.
Torsetnes
Silje Bøen
SB
Paus
Elisabeth
E
Nustad
Kjell
K
Reubsaet
Léon
L
Halvorsen
Trine Grønhaug
TG
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D015415:Biomarkers / Q000737:chemistry / Q000378:metabolism; D006063:Chorionic Gonadotropin / Q000097:blood / Q000737:chemistry* / Q000235:genetics / Q000652:urine; D002853:Chromatography, Liquid / Q000379:methods; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D013058:Mass Spectrometry / Q000379:methods*; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000235:genetics; D011247:Pregnancy; D020033:Protein Isoforms / Q000097:blood / Q000737:chemistry* / Q000235:genetics / Q000652:urine; D040901:Proteomics / Q000379:methods; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods
D000911:Antibodies, Monoclonal; D015415:Biomarkers; D006063:Chorionic Gonadotropin; D010455:Peptides; D020033:Protein Isoforms