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Gu Y, Guo Y, Deng Y, Song H, Nian R, Liu W. Development of a highly sensitive immunoassay based on pentameric nanobodies for carcinoembryonic antigen detection. Anal Chim Acta 2023; 1279:341840. [PMID: 37827654 DOI: 10.1016/j.aca.2023.341840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 09/21/2023] [Indexed: 10/14/2023]
Abstract
BACKGROUND Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM-5) is a well-characterized biomarker for the clinical diagnosis of various cancers. Nanobodies, considered the smallest antibody fragments with intact antigen-binding capacity, have gained significant attention in disease diagnosis and therapy. Due to their peculiar properties, nanobodies have become promising alternative diagnostic reagents in immunoassay. However, nanobodies-based immunoassay is still hindered by small molecular size and low antigen capture efficacy. Therefore, there is a pressing need to develop novel nanobody-based immunoassays with superior performance. RESULTS A novel pentameric nanobodies-based immunoassay (PNIA) was developed with enhanced sensitivity and specificity for CEACAM-5 detection. The binding epitopes of three anti-CEACAM-5 nanobodies (Nb1, Nb2 and Nb3) were analyzed. To enhance the capture and detection efficacy of CEACAM-5 in the immunoassay, we engineered bispecific nanobodies (Nb1-Nb2-rFc) as the capture antibody, and developed the FITC-labeled pentameric nanobodies (Nb3-VT1B) as the detection antibody. The binding affinities of Nb1-Nb2-rFc (1.746 × 10-10) and Nb3-VT1B (1.279 × 10-11) were significantly higher than those of unmodified nanobodies (Nb1-rFc, 4.063 × 10-9; Nb2-rFc, 2.136 × 10-8; Nb3, 3.357 × 10-9). The PNIA showed a linear range of 0.625-160 ng mL-1 with a correlation coefficient R2 of 0.9985, and a limit of detection of 0.52 ng mL-1, which was 24-fold lower than the immunoassay using monomeric nanobody. The PNIA was validated with the spiked human serum. The average recoveries ranged from 91.8% to 102% and the coefficients of variation ranged from 0.026% to 0.082%. SIGNIFICANCE AND NOVELTY The advantages of nanobodies offer a promising alternative to conventional antibodies in disease diagnosis. The novel PNIA demonstrated superior sensitivity and high specificity for the detection of CEACAM-5 antigen. This bispecific or multivalent nanobody design will provide some new insights into the design of immunoassays for clinical diagnosis.
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Affiliation(s)
- Yi Gu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189, Songling Road, Qingdao, 266101, China; University of Chinese Academy of Sciences, No 19(A), Yuquan Road, Beijing, 100049, China
| | - Yang Guo
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189, Songling Road, Qingdao, 266101, China; University of Chinese Academy of Sciences, No 19(A), Yuquan Road, Beijing, 100049, China
| | - Yang Deng
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189, Songling Road, Qingdao, 266101, China; University of Chinese Academy of Sciences, No 19(A), Yuquan Road, Beijing, 100049, China
| | - Haipeng Song
- Shenzhen Innova Nanobodi Co., Ltd, No. 1301 Guanguang Road, Shenzhen, 518110, China
| | - Rui Nian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189, Songling Road, Qingdao, 266101, China; Shandong Energy Institute, No. 189, Songling Road, Qingdao, 266101, China; Qingdao New Energy Shandong Laboratory, No. 189, Songling Road, Qingdao, 266101, China.
| | - Wenshuai Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189, Songling Road, Qingdao, 266101, China; Shandong Energy Institute, No. 189, Songling Road, Qingdao, 266101, China; Qingdao New Energy Shandong Laboratory, No. 189, Songling Road, Qingdao, 266101, China.
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Wu Y, Sun NN, Dang EL, Jin L, Liu ZF, Zhang W, Yang LT, Wang G. Anti-collagen XVII single-chain Fv antibody blocks the autoimmune reaction mediated by pathogenic autoantibodies in bullous pemphigoid. J Dermatol Sci 2013; 72:25-31. [PMID: 23827201 DOI: 10.1016/j.jdermsci.2013.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 04/22/2013] [Accepted: 05/01/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Pathogenic autoantibodies in bullous pemphigoid (BP) recognize the non-collagenous 16A domain (NC16A) of collagen XVII (COL17), a hemidesmosomal component at the skin membrane. This immune inflammation involves activation of the complement cascade via the classical pathway. With similar antigen binding activity, Fab and single-chain variable fragments (scFv) of pathogenic anti-COL17 antibodies can interfere with COL17 binding of autoantibodies, blocking subsequent complement activation and granulocyte activation. OBJECTIVE To characterize the biological functions of human anti-COL17 scFv antibody. METHODS We constructed scFv antibodies against the corresponding antigen from parental Fab by expression in Escherichia coli. IgG autoantibodies against COL17 were purified by affinity chromatography from serum of BP patients. The inhibitory effects of anti-COL17 scFv on binding of BP autoantibodies to the NC16A domain of human COL17 antigen were observed by inhibition ELISA, immunofluorescence, and inhibition of complement activation. Reactive oxygen production assay and BP cryosection model were performed to assess the inhibitory effect of scFv on granulocyte activation and then the dermal-epidermal separation. RESULTS ELISA and Western blot showed specific binding of scFv to COL17. We found that anti-COL17 scFv can inhibit the binding of intact IgG purified from BP parents to the corresponding COL17 antigen and then subsequent C1q and C3 activation and granulocyte activation in vitro. Most importantly, we confirmed that recombinant scFv can inhibit BP-IgG induced dermal-epidermal separation by BP cryosection model. CONCLUSION The anti-COL17 scFv antibody can inhibit the binding of BP-IgG autoantibodies to COL17, thereby affecting subsequent complement activation and granulocyte activation in vitro. Our results suggest that blocking pathogenic epitopes using engineered scFv is an efficient BP therapy.
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Affiliation(s)
- Yan Wu
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, 127 Changlexi Road, Xi'an 710032, China
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