# Two proteins, one goal: ELISAs based on p32 and L1R for LSDV antibodies detection

## TL;DR

This study develops two ELISA tests using LSDV proteins p32 and L1R to detect antibodies, offering a scalable and cost-effective tool for monitoring the virus in livestock.

## Contribution

The study introduces and validates two novel recombinant LSDV antigens (p32 and L1R) for use in ELISAs, supporting improved serological surveillance.

## Key findings

- Both p32 and L1R-based ELISAs showed high immunoreactivity and strong agreement with the virus neutralization test.
- The antigens are suitable for serological assays, and a multi-target ELISA approach could enhance diagnostic sensitivity.
- These assays may improve large-scale, cost-effective surveillance of LSDV in endemic and at-risk regions.

## Abstract

Lumpy skin disease virus (LSDV), a member of the Capripoxvirus genus, poses a significant threat to livestock health and productivity in both endemic and newly affected regions. The disease is primarily transmitted by blood-feeding insects, leading to fever, cutaneous nodules, lymphadenopathy, and substantial economic losses. While vaccination remains the cornerstone of control efforts, effective surveillance—especially in high-risk areas—relies on robust and scalable diagnostic tools. Although the virus neutralization test is considered the reference standard among serological assays for detecting neutralising antibodies, it is labor-intensive and requires high-containment laboratories.

In this study, we produced and evaluated two recombinant LSDV antigens: ORF074 (p32), a well-known immunodominant protein, and ORF060 (homologous to the Vaccinia virus L1R), a myristoylated membrane protein identified as a promising immunogenic target. Both proteins were expressed in E. coli. Recombinant p32 was purified under native conditions, whereas recombinant L1R required denaturation and refolding. The antigens were used to develop two indirect ELISAs, and were evaluated using sera from experimentally infected cattle, as well as both vaccinated and infected field samples from Albania and Serbia.

Both assays demonstrated high immunoreactivity and strong concordance with the VNT. These results support the suitability of both antigens for use in serological assays and suggest that a combined, multi-target ELISA approach could enhance diagnostic sensitivity. Once validated for routine use, these novel tools may significantly improve large-scale, cost-effective serological surveillance of LSDV in endemic and at-risk regions.