# Expression of BVDV E2 protein in CHO-S cells and development of an indirect ELISA for serological detection

## TL;DR

This study developed a highly sensitive and specific ELISA test using a recombinant BVDV E2 protein to detect antibodies in cattle for better disease monitoring and vaccine evaluation.

## Contribution

A novel indirect ELISA using CHO-S-expressed BVDV E2 protein for improved serological detection of BVDV in cattle.

## Key findings

- The rE2-iELISA showed exclusive specificity for BVDV-1 and BVDV-2 with high sensitivity.
- The assay demonstrated 94.8% concordance with the IDEXX ELISA and low coefficient of variation (<5%).
- ROC analysis yielded an AUC of 0.998, indicating excellent diagnostic performance.

## Abstract

Bovine viral diarrhea virus (BVDV) causes ongoing economic losses to the livestock industry. Monitoring antibodies via enzyme-linked immunosorbent assay (ELISA) is a key tool for ensuring the eradication of BVDV from cattle herds. We developed an indirect ELISA (rE2-iELISA) using CHO-S-expressed recombinant E2 protein, the major immunogenic glycoprotein mediating viral attachment and immune evasion. Optimized assay conditions included: 0.4 μg/well antigen coating, 5% BSA blocking, 1:100 serum dilution, and 1:5000 secondary antibody dilution. The assay demonstrated exclusive specificity for BVDV-1 and BVDV-2 with detection sensitivity to 1:1,500 serum dilution. Validation revealed exceptional diagnostic performance: ROC analysis showed 0.998 AUC (cutoff=0.125), 94.8% concordance with IDEXX ELISA, and the intra- and inter-batch coefficient of variation are both less than 5%. The experimental results indicate that the indirect ELISA detection method based on BVDV rE2 exhibits good sensitivity, specificity, and stability. And a stable serological tool for BVDV surveillance and vaccine efficacy evaluation in cattle populations.