Prediction of antigenic epitopes for coat protein of Potato virus Y, Egypt

Seham Abdel-Shafi,Ghaly Mohamed Farouk,Mohamed Taha ,Khalid A El-Dougdoug

doi:10.21608/nrmj.2019.30610

Abstract

Isolated Potato virus Y Egypt (PVY- EG) obtained from naturally infected potato plants in El-Sharkia, Egypt, was identified by biological, molecular and serological assays. The aims of this study were to predict the antigenic determinants (epitopes) of the isolated PVY using immunoinformatics; to prepare antibodies then apply them for PVY screening in potato plants in the field, as well as comparison with antibodies against coat protein. The amino acid sequence of PVY isolate was expected by DNAStar protean system; in which four parameters for epitope prediction including antigenicity, surface probability, hydrophobicity and secondary structure were used. These models were applied to PVY as a case study to predict immunogenic peptides for antibodies production. The most hydrophilic regions of PVY-coat protein (PVY- CP) were; 36-40, 46-47, 67-74, 96-98, 130-133, 164-166 and 198-200, which showed high hydrophobicity of this protein. This indicated that this protein was one of the best candidates to be immunogenic, and capable of producing antibodies that cross react with PVY. The peptide was chemically synthesized and injected into a rabbit. Obtained antibodies were evaluated using Double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), and Immune Dot-Blot assay. These antibodies positively reacted against PVY infected potato tissues.

Highlights

Potato virus Y (PVY) is the type-species of genus Potyvirus, which is a member of Potyviridae family (Pringle, 1999; Abdel-Shafi et al, 2017; Dupuis; 2017; Gibbs et al, 2017)
This scale puts a positive score for the non-polar residues, and negative score for polar residues of a given protein. From these data; we assayed the hydrophilic regions of PVY-CP as they were supposed to be antigenic in nature, and more exposed to the surface of the protein
Results of Dot blot immunoassay (DBIA) and Tissue printing immunoassays (TPIA) assays presented in Table (6), Fig. (5) revealed that the ten plant species showed different PVY symptoms; gave positive reactions with different degrees on using PVY polyclonal antibody, PVY isolate and the predicted epitope

Summary

Introduction

Potato virus Y (PVY) is the type-species of genus Potyvirus, which is a member of Potyviridae family (Pringle, 1999; Abdel-Shafi et al, 2017; Dupuis; 2017; Gibbs et al, 2017). This genus of Potyvirus forms one of the largest and most economically important groups of plant viruses. PVY is a flexuous; helical, rod-shaped virus of approximately 700 nm length, 12 nm in diameter, and 3.4 nm helical pitches It has a single stranded positive sense RNA genome of approximately 10 kb length; encapsidated by about 2000 copies of a single coat protein of approximately 30 KD size. During the infection process; this RNA is translated into a large precursor polyprotein; that is cleaved co- and post-translationally into 10 mature proteins (Riechmann et al, 1992; Han et al, 2017).

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