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.
Development of solid phase competitive enzyme-linked immunosorbent assay to detect foot-and-mouth disease virus A serotype specific antibodies based on immunoglobulin Y antibody
Volume 16, Issue 5, May 2025, Pages 285-292
Zahra Ivani, Behzad Hemati, Naser Harzandi, Seyed Mahmoud Azimi, Mohammad mehdi Ranjbar
Abstract The aim of this study was to using purified chicken antibody (IgY) for developing solid phase competitive (SPC) enzyme-linked immunosorbent assay (ELISA) to detect the foot-and-mouth disease virus (FMDV) A serotype. After immunization of chickens, polyclonal immunoglobulin (IgY) antibodies were extracted and purified from egg yolk and yield was about 5.00 mg mL-1 of yolk as well as near 0.40 mg mL-1 of specific IgY antibody against FMDV serotype A. Also, optimized sucrose density gradient method produced 228 µg mL-1 whole virus which is much higher than that of the conventional method of sucrose density gradient method. The optimum concentration of purified capture IgY and bind type A antigen were 0.50 µg and 0.10 µg per well, respectively. The OD values < 0.70 were considered positive, and values ≥ 0.70 were negative for in-house kit base on standard controls. Statistical analysis base on 80 serum samples showed the 96.66% sensitivity, 100% specificity, 100% positive predictive value, 90.90% negative predictive value, 97.50% accuracy, and 98.33% reliability for serum samples for two commercial and in-house kits. The SPCE developed based on IgY antibody is a suitable alternative for the detection of antibodies after vaccination against type A FMDV with high sensitivity and specificity. The present research demonstrated the possibility of commercial development of the SPCE kit using IgY antibodies for the detection of FMDV antibodies in serum samples with adequate sensitivity and accuracy.