Journal Article Epublish
PubMed: 40463384 DOI: 10.3389/fimmu.2025.1571418
Exploring the standardized detection and sampling methods of human nasal SARS-CoV-2 RBD IgA.
Front Immunol 16:1571418
Authors: Xuanxuan Zhang, Jizong Jia, Chaoying Hu, Yulong Fu, Guanxing Liu, Yajing Li, Qian He, Fan Gao, Na Li, Lina Wang, Jianping Chu, Henggang Xu, Zhihao Fu, Hui Zhao, Zhenglun Liang, Jingxin Li, Miao Xu, Qunying Mao
Affiliations
- State Key Laboratory of Drug Regulatory Science, Evaluation of Biological Products, Key Laboratory of Research on Quality and Standardization of Biotech Products, Institute of Biological Products, National Institutes for Food and Drug Control, Beijing, China. Research Units of Innovative Vaccine Quality Evaluation and Standardization, Chinese Academy of Medical Sciences, Beijing, China.
- Beijing Wantai Biological Pharmacy Enterprise Co. Ltd, Beijing, China.
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, China.
- Changchun Institute of Biological Products Co. Ltd. Changchun, China.
- Shanghai Institute of Biological Products Co. Ltd. Shanghai, China.
- Beijing Minhai Biotechnology Co. Ltd. Beijing, China.
- Jiangsu Provincial Centre for Disease Control and Prevention, Public Health Research Institute of Jiangsu Province, Nanjing, Jiangsu, China.
Abstract
Introduction
Vaccines capable of effectively inducing mucosal immunity, particularly specific IgA antibodies, represent an ideal strategy for preventing infections and the transmission of pathogens such as SARS-CoV-2 and influenza viruses that rapidly replicate in the upper respiratory tract and cause clinical symptoms. However, a lack of standardized nasal antibody detection and sampling methods has hindered cross-study comparability and vaccine development.
Methods
This study uses SARS-CoV-2 as a model pathogen to standardize nasal antibody detection methods and sampling methods. Following the scientific guidelines (Q14 and Q2(R2)) for analytical procedure development and validation released by the International Council for Harmonization (ICH), an ELISA for nasal SARS-CoV-2 WT-RBD specific IgA detection was established and validated. To compare the sampling methods, nasal samples were collected from five groups using three commonly used nasal sampling methods (M1: nasopharyngeal swab; M2: nasal swab; M3: expanding sponge method). The total IgA and SARS-CoV-2 WT-RBD IgA in clinical samples were detected.
Results
The first validated ELISA for nasal SARS-CoV-2 WT-RBD specific IgA detection was established through analytical target profiling (ATP), risk assessment, and design of experiment optimization. Systematic validation demonstrated exclusive specificity for the target antigen, with intermediate precision of <17% and relative bias of <±4%, meeting ATP requirements. Analysis of 154 clinical samples demonstrated strong concordance between the novel method and electrochemiluminescence assays, with a concordance correlation coefficient of 0.87 for quantitative results and a kappa coefficient of 0.85 for results above and below the dilution-adjusted limit of quantification (LOQ). Applying this novel method, a clinical comparison revealed that M3 achieved superior performance in terms of the single-day detection rate (above dilution-adjusted LOQ 95.5%), 5-day consecutive detection rate (above dilution-adjusted LOQ 88.9%), and median SARS-CoV-2 WT-RBD IgA concentration (171.2 U/mL), significantly outperforming M1 (68.8%; 48.7%; 28.7 U/mL, p<0.0001) and M2 (88.3%; 77.3%; 93.7 U/mL, p<0.05).
Conclusion
This study has established the first standardized nasal detection system. The system can be adapted with appropriate modifications for the clinical evaluation of other respiratory mucosal vaccines, thereby advancing the development of mucosal vaccines.
MeSH
Sars-Cov-2, Vaccines, Signs And Symptoms, Immunoglobulin A, Immune System Diseases, Severe Acute Respiratory Syndrome-Related Coronavirus