A time-resolved fluoroimmunoassay to assay the rabies virus glycoprotein: application for estimation of human rabies vaccine potency

Guanfeng Lin,Junyu Liang,Qiaoting Deng,Yingsong Wu,Shaolang Chen,Tiancai Liu,Rongliang Liang,Xinxin Guo,Baihong Chen,Zhenhua Chen,Hui Zhao

doi:10.1038/s41598-017-07687-7

Abstract

Replacement of the in vivo rabies vaccine potency test (NIH test) by in vitro methods had been discussed by several researcher including WHO expert working groups. In this paper, a time-resolved fluoroimmunoassay (TRFIA) for the assay of rabies virus glycoprotein in rabies vaccine was first established to estimate the rabies vaccine potency by using specific monoclonal antibody that only recognized the native, trimeric and immunogenic form of rabies virus glycoprotein. Potency of the rabies virus glycoprotein was assayed with satisfactory performance under optimal conditions, and the method demonstrated satisfactory results when applied in practical samples. The correlation coefficient of potency values obtained from the present TRFIA and ELISA was 0.912, and 0.903 for those from the present TRFIA and NIH test. These preliminary results confirmed that this TRFIA can replace ELISA with higher performance, and could be a promising replacement of the NIH test. Based upon these results, the present TRFIA seemed to be a convenient tool for evaluating rabies vaccine potency and its products at different stages accordingly.

Highlights

Replacement of the in vivo rabies vaccine potency test (NIH test) by in vitro methods had been discussed by several researcher including WHO expert working groups
Signal saturation appeared when the dose exceeded 1 000 international units per milliliter (IU/ml) for the present method. This means that when the dose exceeds 1000 IU/ml, the relationship between concentration and fluorescence signal no longer meet the linear relationship of the fitting equation
Conventional fluorescent labeling has a limited success in assay of analyte because of its high background, short decay time and broad spectrum, which make it difficult to be a qualified labeling for excellent quantitative analytical technique

Summary

Introduction

Replacement of the in vivo rabies vaccine potency test (NIH test) by in vitro methods had been discussed by several researcher including WHO expert working groups. These preliminary results confirmed that this TRFIA can replace ELISA with higher performance, and could be a promising replacement of the NIH test Based upon these results, the present TRFIA seemed to be a convenient tool for evaluating rabies vaccine potency and its products at different stages . The replacement of the NIH test for rabies vaccine evaluation by in vitro methods had been discussed in several research and by WHO expert working groups[8]. Using specific MAbs that only recognized the native, trimeric and immunogenic form of rabies virus glycoprotein prevented detection of non-immunogenic, soluble glycoprotein in vaccines, we first designed a novel TRFIA which was designed to estimate the potency of human rabies vaccines by assaying glycoprotein in rabies vaccines, and may have utility in replacement of the NIH test. This study involved measurement of parameters, such as sensitivity, precision, recovery, linearity and feasibility

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Conclusion