Designing a polytopic complex vaccine candidate against Gallibacterium anatis: an In-silico study

Document Type: Original Articles

Authors

1 Department of Avian Bacterial Diseases, Razi Vaccine and Serum Research Institute, Agricultural Research, Education, and Extension Organization, Karaj, Iran

2 Department of Animal Viral Diseases, Razi Vaccine and Serum Research Institute, Agricultural Research, Education, and Extension Organization, Karaj, Iran

3 Department of Cellular Molecular Sciences, Faculty of Life Sciences, Kharazmi University, Karaj, Iran

4 R & D, Tose Kosar Group, Tehran, Iran

Abstract

The haemolytic biovar of Gallibacterium anatis (G. anatis) is responsible for urogenital, gastrointestinal, and respiratory diseases in chickens. There are numerous reports on the resistance of G. anatis to antibiotics and recurrence of the disease, which raise concerns about antimicrobial treatment efficiency. Vaccination has been considered as the most feasible procedure of prevention in high risk farms. Subunit vaccines containing immunogenic components can have practical protective value in preventive measures regarding the infection. The present study aimed to introduce a polytopic vaccine candidate based on epitope detection. All registered sequences of four immunogenic proteins, includig Flfa, GTxA, Gab_1309, and Gab_2348 were retrieved and directed for variational analysis. A vaccine isolate was selected for each protein and tested for B-cell epitope mapping using different tools. Furthermore, consensus selected immunogenic regions with special patterns fused together by flexible linkers were integrated into two constructs and checked for the best status of proteasomal cleavage sites, as well as hydropathy plot. Moreover, back translations, along with codon optimization were performed, and then some tags were added to the constructs. The selected consensus B-cell immunogenic epitopes were for 12656: AA114-181, 7990: AA114-181, Avicor: AA42-77, 134-197, and IPDH: 61-155 for Flfa protein, AA185-235, AA372-457, and AA807-941 for GtxA-N, AA260-305, AA340-400, and AA110-146 for Gab-1309, and AA125-AA175 for Gab-2348. Two suitable patterns of attachment were selected from the different fusion patterns of epitopes in B-cell polytopic vaccinal constructs. Finally, the examination of these constructs showed their effect and efficacy for immune system stimulation. Based on bioinformatics results, these immunogens could be utilized as potential candidates to develop polytopic protective vaccines and design diagnostic kits.

Keywords

Main Subjects


Article Title [French]

Conception du Candidat Vaccin Polytopique Complexe contre Gallibacterium Anatis: Une Étude in silico"

Abstract [French]

Le biovar hémolytique de Gallibacterium anatis (G. anatis) est responsable de maladies urogénitales, gastro-intestinales et respiratoires chez les poulets. De nombreux rapports sur la résistance de G. anatis aux antibiotiques et sur la récurrence de la maladie soulèvent des préoccupations quant à l'efficacité du traitement antimicrobien. La vaccination a été considérée comme la procédure de prévention la plus réalisable dans les exploitations à haut risque. Les vaccins sous-unitaires contenant des composants immunogènes peuvent avoir une valeur protectrice pratique dans les mesures préventives relatives à l'infection. Cetteétude visait à présenter un nouveau candidat vaccin polytopique basé sur la détection d'épitopes. Toutes les séquences enregistrées pour lesquatre protéines immunogènes Flfa, GTxA, Gab_1309 et Gab_2348 ont été extraites et utilisées pour une analyse variationnelle. Des souches vaccinales ont été sélectionnées pour chaque protéine et analysées pour la cartographie des épitopes de la céllule B en utilisant différents outils. En outre, des régions immunogènes sélectionnées par consensus avec des motifs spéciaux fusionnés par des lieurs flexibles ont été intégrées dans deux constructions et vérifiées pour les meilleurs statuts des sites de clivage protéasomal, ainsi que du tracé d'hydropathie. De plus, descontres traductions, ainsi que l'optimisation des codons, ont été effectuées, puis des tags ont été ajoutés aux constructions. Les épitopes immunogènes consensus à cellules B sélectionnés étaient pour 12656: AA114-181, 7990: AA114-181, Avicor: AA42-77, 134-197 et IPDH: 61-155 ; pour la protéine Flfa, AA185-235, AA372-457. et AA807-941 ; pour GtxA-N, AA260-305, AA340-400 et AA110-146 ; enfinpour Gab-1309 et AA125-AA175 pour Gab-2348. Deux modèles d'attachement appropriés ont été sélectionnés parmi les différents modèles de fusion d'épitopes dans des constructions vaccinales polytopiques à cellules B. Enfin, l'examen de ces constructions a démontré leur effet et leur efficacité pour la stimulation du système immunitaire. Sur la base des résultats bioinformatiques, ces immunogènes pourraient être utilisés comme candidats potentiels pour développer des vaccins protecteurs polytopiques et concevoir des kits de diagnostic.

Keywords [French]

  • Gallibacterium anatis
  • Vaccin
  • Polytopique
  • In-silico
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