Usefulness of Immunoglobulin Fraction Precipitated with Polyethylene Glycol in Assay for TSH Receptor Antibodies using Chinese Hamster Overy Cells Expressing Human TSH Receptors.
- Author:
Won Bae KIM
;
Hyun Kyung CHUNG
;
Chang Soon KOH
;
Chang Hoon YIM
;
Do Joon PARK
;
Bo Yeon CHO
;
Hong Gyu LEE
- Publication Type:Original Article
- Keywords:
TSAb;
TSBAb;
hTSHR-transfected CHO cell;
PEG-precipitated immunoglobuhn
- MeSH:
Animals;
Antibodies*;
Asian Continental Ancestry Group*;
CHO Cells;
Cricetinae;
Cricetulus*;
Diagnosis;
Graves Disease;
Humans;
Humans*;
Immunoglobulin G;
Immunoglobulins*;
Myxedema;
Polyethylene Glycols*;
Polyethylene*;
Rats;
Receptors, Thyrotropin*;
Sensitivity and Specificity;
Thyroid Gland
- From:Journal of Korean Society of Endocrinology
1998;13(2):167-180
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Graves' disease and primary myxedema are thought to be caused by the action of TSH receptor autoantibodies(thyroid stimulating antibody; TSAb & thyroid stimulation blocking antibody; TSBAb). Thus, detection of these antibodies is crucial in diagnosis and in follow up of those patients. Recently, a sensitive method using human TSH receptor transfected Chinese Hamster Ovary(CHO) cells has been developed. However, the complexity of IgG purification procedure is considered as a limitation for its clinical application as a routine test. The aim of this study is to determine whether polyethylene glycol(PEG)-precipitated immunogiobuIin fraction could substitute for purified IgG. METHODS: We developed optimal conditions for TSAb and TSBAb assays using crude, PEG precipitated immunoglobulin fraction; and evaluated the correlation of TSAb and TSBAb activities between thase measured using crude immunoglobulin fraction and purified IgG to clarify the usefulness of PEG-precipitated immunoglobulin fraction. TSH receptor expressing wild type CHO cells were used in TSAb and CHO cells expressing chimeric TSH receptor(Mc2; 90-165 amino acid residues were substituted by those of rat LH/CG receptar) were used in TSBAb assay to minimize the possible disturbing effects of TSAb in serum. RESULTS: The optimal serum amount for TSAb and TSBAb assay using PEG-precipitated immunoglobulin fraction were 250mL serum equivalent/well and 50mL serum equivalent/well, respectively. The optimal incubation time for both assays were 2 homs, and aptimal ccrncentration of bTSH for TSBAb assay was 0.1U/L. TSAb activities measured with PEG-precipitated immunoglobulin were significantly correlated with those measured with purified IgG in 26 patients with Graves diseases(r=0.93, p<0.001). Although TSBAb activities measured using PEG-precipitated imrnunoglobulin were conelated with those measured using purified IgG in 20 patients with primary myxedema(r=0.86, p<0.001), the positive rate in TSBAb assay using PEG-precipitated immunoglobulin was lower than that of usmg purified IgG(20% v.s. 65%) because of negative conversion of TSBAb activities in samples with weakly positive TSBAb activities measured using purified IgG. CONCLUSION: PEG-precipitated immunoglobulin fraction could be used instead of purified IgG in TSAb assay using hTSHR-tranasfected wild type CHO cells with equal sensitivity and specificity. This simple and practical TSAb assay using PEG-precipitated immunoglobulin in hTSHR-transfected CHO cells would be useful in clinica1 practiee.
