Faculty of Veterinary Medicine, Urmia University Veterinary Research Forum 2008-8140 Articles in Press 2026 07 28 Assessment of humoral Immune Responses Induced by a specific Synthetic Epitope Derived from Foot-and-Mouth Disease Virus Serotype O in Rabbits 738169 10.30466/vrf.2025.2064473.4806 EN Mohammad Mehdi Ranjbar Razi vaccine ans Sera research institute 0000-0001-8611-5762 Soodeh Enayati Department of Microbiology , Ka. C. , Islamic Azad University , Karaj , Iran Naser Harzandi Department of Microbiology , Ka. C. , Islamic Azad University , Karaj , Iran Homayoon Mahravani Behbahani Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education, and Extension Organization (AREEO), Karaj, Iran Maryam Rahimi Department of Microbiology, Karaj branch, Islamic azad university, Karaj, Iran Journal Article 2025 06 30 Foot-and-mouth disease virus (FMDV) continues to pose a major threat to the livestock industry worldwide due to its high transmissibility and substantial economic consequences. For diagnostic and vaccinal purposes, necessitate the exploration of novel immunogenic targets is pivotal. Here, antigenic determinant (an epitope) sequence comprising core of 12 amino acids from VP1 protein of foot-and-mouth disease virus (FMDV) was designed by immuno informatics. To improve the physio-chemical and stability characteristics of the final peptide, additional residues were incorporated until it resulted in the synthesis of a 23-amino acid peptide (VARTLPTSFNYGAIKATRVTDEC, 2.5 Kda and PI 8.17). After chemical synthetizing with 95 % purity, the peptide was conjugated to bovine serum albumin (BSA) via EDC/NHS cross linker (Peptide: EDC: Sulfo-NHS: BSA (carrier protein): 10:40:50:1 in MES buffer (50 Mm)) and formulated with an aluminum hydroxide adjuvant. Twelve male New Zealand White rabbits were randomly assigned into three groups and main group received the peptide-BSA conjugate. Sera were direct to Dot blot, double immunodiffusion (DID) and serum neutralization (SN) tests, and also indirect peptide ELISA. The synthetic peptide elicited strong antibody response by primary positive results in dot blot and DID test (positive in 1:4 serum dilution) as well as it showed cross-reactivity with whole antigen. Although only low SN titers (1:8) were observed. Moreover, the peptide ELISA confirmed specific antibody responses against O serotype (OD of 2.4 at day 55 in 1/10 dilutions). Altogether, rationally designed epitope are promising regimes for the future development of FMDV novel diagnostic tools and vaccine cocktails.