Determination of hyperglycosylated human chorionic gonadotropin produced by malignant gestational trophoblastic neoplasias and male germ cell tumors using a lectin-based immunoassay and surface plasmon resonance

Abstract

The ability to reliably detect aberrant glycosylation of human chorionic gonadotropin (hCG) may have profound implications for the diagnosis and monitoring of malignant gestational trophoblastic neoplasia, germ cell tumors, other malignancies, and pregnancy complications. To become a clinically useful assay, however, this discrimination of glycoforms should be possible on minimally treated biological specimens. Towards this end, we have developed a lectin-based sandwich-type immunoassay to compare the glycosylation patterns of hCG among urine specimens from patients presenting with a normal pregnancy, invasive mole, choriocarcinoma, and male germ cell tumors using carbohydrate-free antibody fragments as capture reagents and a panel of eight lectins, five recognizing neutral sugars and three recognizing sialic acid. There was no significant difference in the binding of any of the lectins to hCG in the urine of women over the gestational range of 6 -38 weeks. Three lectins, however, exhibited differential binding to urinary hCG derived from these normal pregnant controls and that from patients with malignant forms of gestational trophoblastic disease and male germ cell tumors. Galanthus nivalis agglutinin and Maackia amurensis lectin, which bind terminal mannose and α(2-3)sialic acid, respectively, preferentially bound pregnancyderived hCG, whereas the lectin, wheat germ agglutinin, which binds sialic acid and β(1-4)Nacetylglucosamine, exhibited decreased binding to pregnancy-derived hCG compared to that from patients with male germ cell tumors and malignant gestational trophoblastic neoplasia. The differential binding observed with these three promising lectins is most encouraging and warrants further examination. The experimental paradigm also holds promise for the development of comparable assays for other glycosylated tumor markers.

Qualification and application of an ELISA for the determination of Tamm Horsfall Protein (THP) in human urine and its use for screening of Kidney Stone Disease

“…WGA is a type of lectin that is specific to the receptor of THP 15. WGA binds specifically to the di N-acetylglucosamine and sialic acid on the receptor of THP 15 but bind weakly to human chorionic gonadotropin that was excreted abundantly in urine of pregnant women 16. The captured THP was recognized by an anti-THP antibody and the Ab-Ag complexes were then recaptured by a secondary antibody tagged with horseradish peroxidase (HRP), the amount of THP was quantified based on the intensity of the color reaction developed between the HRP and its substrate.…”

Sensitive immunoassay of human chorionic gonadotrophin based on multi-walled carbon nanotube–chitosan matrix

“…The increased lever of HCG in serum and urine is associated with the prostate cancer, the trophoblastic cancer and many diseases related to pregnancy [2]. Thus, it is necessary to measure HCG in all modern immunological pregnancy tests and even early monitoring of trophoblastic diseases [3][4][5]. The amperometric immunosensors seem to be excellent candidates for the quantification of immunological moieties in clinical samples, which display a relatively low detection limit and high sensitivity, and employ the innate amplification properties of enzymes.…”

Lectinomics I. Relevance of exogenous plant lectins in biomedical diagnostics

“…In contrast, the WGA lectin (with sialic acid and β-D-GlcNAc specificity) exhibited decreased binding to pregnancy-derived hCG as compared to patients with male germ cell tumors and malignant gestational trophoblastic neoplasia. The differential binding among these three lectins is encouraging and warrants the development of comparable assays for other glycosylated tumor markers (Kelly et al 2007). …”

“…A lectin-based sandwich-type immunoassay was developed in order to compare the glycosylation patterns of human chorionic gonadotropin (hCG) hormone, and applied to urine specimens from patients presenting with normal pregnancy, invasive mole, choriocarcinoma, and male germ cell tumors (Kelly et al 2007). GNA and MAA lectins, specific for terminal mannose and α-2,3-sialic acid, respectively, preferentially bind pregnancy-derived hCG.…”