Development of high-titer polyclonal antisera targeting a local bovine viral diarrhea virus-1a strain: A preliminary study from Indonesia.

Background and Aim: Bovine viral diarrhea virus (BVDV) is an economically significant pathogen of cattle, causing reproductive disorders, immunosuppression, and production losses worldwide. In Indonesia, BVDV-1a is among the most prevalent subgenotypes; however, field diagnosis still relies heavily on imported kits developed using non-local strains, which can lead to potential gaps in sensitivity and specificity. Locally tailored immunological reagents could enhance diagnostic accuracy and support future control strategies. This study aimed to produce and characterize polyclonal antisera against a local BVDV-1a isolate from Indonesia. Materials and Methods: Four New Zealand white rabbits were immunized with inactivated BVDV-1a antigen propagated in Madin-Darby bovine kidney (MDBK) cells. Booster immunizations were administered on days 14 and 28. Ten days after the final booster, sera were collected, pooled, and purified using ammonium sulfate precipitation and dialysis. Purified antisera were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Antibody titers were assessed using indirect enzyme-linked immunosorbent assay (ELISA), and specificity was validated by immunoperoxidase monolayer assay (IPMA) in infected MDBK cells. Results: The purification process yielded polyclonal antisera with a protein concentration of 40.33 mg/mL. SDS-PAGE revealed characteristic bands at approximately 53, 75, and 100 kDa, consistent with immunoglobulin components. Indirect ELISA showed strong antibody titers, with positive reactivity sustained up to 1:100. IPMA confirmed specific recognition of BVDV antigens, as infected MDBK cells exhibited distinct cytoplasmic staining, whereas uninfected controls remained negative. Conclusion: This preliminary study successfully generated high-titer polyclonal antisera against a local Indonesian BVDV-1a strain. The antibodies demonstrated robust reactivity and specificity, highlighting their potential utility as foundational reagents for developing regionally relevant diagnostic assays. While limited by a small sample size and pooled sera, these findings represent an important first step toward establishing locally adapted immunodiagnostic resources for BVDV. The development of local diagnostic tools not only strengthens veterinary disease surveillance but also safeguards livestock-dependent livelihoods, enhances food security, and reduces reliance on imported kits. Improved BVDV control in cattle contributes to One Health by minimizing economic losses, ensuring the safety of animal-derived food products, and reducing the risk of viral persistence in mixed livestock populations.