Generation of Monoclonal Antibodies Specific to Tilapia Lake Virus for Immunoassay-Based Detection in Tilapia

The global tilapia farming industry faces a significant threat from a widespread pandemic caused by tilapia lake virus (TiLV), which can cause mortality rates of up to 90% within 14 days in infected fish. This study describes the generation, evaluation and comparison of monoclonal antibodies (Mabs) with molecular techniques for TiLV detection. The antigen was produced as a recombinant protein using a bacterial expression system, specifically targeting segment 8 of the TiLV genome. Four Mabs successfully detected TiLV-infected tilapia samples using dot blotting and Western blotting assays, with detection limits of 0.78 ng/spot for each Mab. Notably, a combination of Mabs enhanced detection sensitivity fourfold and exhibited no cross-reactivity with bacterial and viral pathogens in tilapia. Furthermore, two Mabs effectively localised TiLV within infected tilapia tissue via immunohistochemistry. Although immunoassay-based techniques demonstrated high specificity, their sensitivity was approximately thirtyfold lower than that of semi-nested RT-PCR. Nonetheless, the Mabs accurately detected TiLV in all 20 confirmed positive samples via dot blotting and offer advantages in terms of reduced processing time and cost per reaction. These Mabs will contribute to future efforts aimed at preventing and controlling the spread of tilapia lake virus disease in aquaculture by facilitating the rapid identification and diagnosis of TiLV-infected fish.