Assessment of humoral Immune Responses Induced by a specific Synthetic Epitope Derived from Foot-and-Mouth Disease Virus Serotype O in Rabbits
Articles in Press, Accepted Manuscript, Available Online from 28 July 2026
Mohammad mehdi Ranjbar, Soodeh Enayati, Naser Harzandi, Homayoon Mahravani behbahani, Maryam Rahimi
Abstract 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.