IV Jornadas Latinoamericanas de Bacteriófagos

Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals that causes severe economic losses worldwide. In Argentina, serotypes A, O, and C have historically circulated, with A24 being of major local epidemiological relevance and widely used as a reference strain for standardizing serological assays; its antigenic variability makes it an appropriate model for studying immune recognition and improving diagnostic sensitivity. In this context, phage display technology constitutes a robust strategy for identifying specific recombinant antibodies against FMDV, establishing a platform that can be extended to other serotypes of epidemiological importance.
A library of recombinant bovine antibodies against foot-and-mouth disease virus (FMDV) was successfully constructed using a phage display system, based on RNA extracted from prescapular lymph nodes of cattle previously vaccinated with a tetravalent vaccine. The present study focused on the detection and selection of recombinant single-chain variable fragment (scFv) antibodies specific to FMDV serotype A24.
Three consecutive rounds of biopanning were performed against purified A24 viral antigen to enrich specific binders. Enrichment process was monitored by polyclonal phage ELISA after each round and subsequently by monoclonal phage ELISA to identify individual positive clones. Phagemid DNA from selected clones was isolated using a commercial purification kit, and the presence of scFv inserts was confirmed by PCR. Inserts were subjected to automated sequencing using BI 3730 system. Nucleotide sequences were assembled and translated using BioEdit v7.2.5 software.
As a result, 18 recombinant scFv antibodies were selected, and their specificity toward FMDV serotype A24 was confirmed by ELISA. These scFv antibodies represent a valuable repertoire with potential application in the development of serotype-specific diagnostic tools and in FMDV antigenic characterization studies.
Future work will focus on the functional characterization of the selected scFv antibodies, including evaluation of their cross-reactivity with other FMDV serotypes, supporting improved detection and surveillance strategies.