# A Monoclonal Antibody-Based Indirect Competitive ELISA for Detecting Goose Astrovirus Antibodies

## TL;DR

A new ELISA test using monoclonal antibodies was developed to detect goose astrovirus antibodies, aiding in disease surveillance and vaccine development.

## Contribution

Development of a monoclonal antibody-based ic-ELISA for rapid and accurate detection of goose astrovirus antibodies.

## Key findings

- A monoclonal antibody (3G11) with strong immunoreactivity against GoAstV VP27 was generated and validated.
- The optimized ic-ELISA showed high sensitivity, specificity, and reproducibility for GoAstV antibody detection.
- A 11.7% seropositivity rate was observed in goose serum samples from Shandong province.

## Abstract

China is the world’s leading producer of geese, accounting for over 70% of global goose production. With the rapid expansion of the goose industry, the control of viral diseases has become increasingly challenging, particularly in the case of goose astrovirus (GoAstV). While vaccines against GoAstV remain in the experimental stage, comprehensive epidemiological surveillance and evaluation of immune protection are essential. In this study, we generated a monoclonal antibody (mAb) targeting VP27 using GoAstV particles to obtain antibodies with neutralizing potential. Utilizing this mAb, we established an indirect competitive ELISA (ic-ELISA) for the rapid and accurate diagnosis of GoAstV infection in goose flocks. This study provides valuable tools and insights to support future vaccine development against GoAstV.

Goose astrovirus (GoAstV) infection has become prevalent in major goose-producing regions, causing substantial economic losses to the industry. In this study, an indirect competitive ELISA (ic-ELISA) was developed based on a monoclonal antibody (mAb) targeting the GoAstV VP27 protein. The recombinant VP27 protein was expressed in E. coli and purified, followed by the generation of murine mAbs using the purified antigen. Through screening with GoAstV particles, mAb 3G11 exhibited strong immunoreactivity, which was further confirmed by Western blot and immunofluorescence assay (IFA). The ic-ELISA conditions were optimized as follows: GoAstV particle coating concentration of 104 TCID50 per well, 3G11 mAb dilution of 1:8000, and incubation times of 120 min for coating, 60 min for serum samples, and 60 min for mAb binding. The assay exhibited satisfactory performance in terms of sensitivity, specificity, and reproducibility. Using this method, serum samples collected from major goose farming areas in Shandong province were tested and showed an overall seropositivity rate of 11.7%. This study provided a reliable serological tool for detecting GoAstV-specific antibodies and would support future vaccine evaluation efforts.