Basic Science Investigation
Time-resolved fluorescence immunochromatographic assay for the detection of mycoplasma pneumoniae IgM and IgG
Zhang Yi, Zhou Bin, Zhang Jue, Yang Xue, Liu Jie, Hu Zhigang
Published 2022-04-25
Cite as Chin J Nucl Med Mol Imaging, 2022, 42(4): 226-230. DOI: 10.3760/cma.j.cn321828-20200818-00315
Abstract
ObjectiveTo establish time-resolved fluorescence immunochromatographic assay (TFICA) for rapid and quantitative detection of mycoplasma pneumoniae (MP) immunoglobulin (Ig)M and IgG.
MethodsBased on capillary effect and europium nanospheres, rapid TFICA for MP-IgM and IgG detections were developed with the optimized parameters (coupling rates of antigens or antibodies to microspheres, dilution of labeled nanospheres, fixture concentrations on test line and serum dilutions). The methodological performances were estimated such as sensitivity, specificity, stability. By testing 55 healthy control samples, the reference values of TFICA were obtained. The reliability was evaluated by Kappa test from detecting sera of 88 cases (33 patients and 55 healthy controls) using TFICA and commercial kits by chemiluminescence immunoassays (CLA).
ResultsAfter screening the assay conditions, the mass ratios of mouse anti-human IgG and MP antigen with nanospheres were 1∶20 and 1∶100 respectively; the work dilutions of nanobeads conjugated with anti-human IgG and MP antigen were 1∶200 and 1∶100 respectively; the spraying concentrations of MP antigen and goat anti-human IgM were 0.5 and 1.0 g/L on the test line respectively, and the working dilutions of serum sample were both 1∶300. In the MP-IgM and IgG detections, the linear working ranges were (0.78-70.00)×103 relative unit (RU)/L and (0.17-200.00)×103 RU/L, while the sensitivities of the assays were 0.78×103 and 0.17×103 RU/L, respectively. No cross reactions were found with antithyroid peroxidase antibody, anticardiolipin antibody or thyroglobulin antibody. In these MP-IgM and IgG assays, the relative standard deviations were 3.7%-14.8% and 2.9%-14.0%, the average reduction rates of fluorescence were 13.7% and 14.2% respectively after incubation at 37 ℃ for 5 d. The reference values of MP-IgM and IgG were 3.33×103 and 2.61×103 RU/L, while the Kappa values between TFICA and CLA were 0.79 and 0.76, respectively.
ConclusionTFICA is a simple, sensitive, specific and quantitative method for detecting MP-IgM and IgG antibodies, and may show great promise for future clinical use.
Key words:
Immunoglobulin M; Immunoglobulin G; Mycoplasma pneumoniae; Fluoroimmunoassay; Microspheres
Contributor Information
Zhang Yi
NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
Zhou Bin
NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
Zhang Jue
NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
Yang Xue
Department of Clinical Laboratory, Wuxi Children′s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, China
Liu Jie
Respiratory Department, Wuxi People′s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, China
Hu Zhigang
Department of Clinical Laboratory, Wuxi Children′s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, China
