title: The carboxy-terminal half of nonstructural protein 3A is not essential for foot-and-mouth disease virus replication in cultured cell lines.
abstract: In foot-and-mouth disease (FMD)-endemic parts of the globe, control is mainly implemented by preventive vaccination with an inactivated purified vaccine. ELISAs detecting antibodies to the viral nonstructural proteins (NSP) distinguish FMD virus (FMDV)-infected animals in the vaccinated population (DIVA). However, residual NSPs present in the vaccines are suspected to be a cause of occasional false positive results, and therefore, an epitope-deleted negative marker vaccine strategy is considered a more logical option. In this study, employing a serotype Asia 1 FMDV infectious cDNA clone, it is demonstrated that while large deletions differing in size and location in the carboxy-terminal half of 3A downstream of the putative hydrophobic membrane-binding domain (deletion of residues 86-110, 101-149, 81-149 and 81-153) are tolerated by the virus without affecting its infectivity in cultured cell lines, deletions in the amino-terminal half (residues 5-54, 21-50, 21-80, 55-80 and 5-149) containing the dimerization and the transmembrane domains are deleterious to its multiplication. Most importantly, the virus could dispense with the entire carboxy-terminal half of 3A (residues 81-153) including the residues involved in the formation of the 3A-3B1 cleavage junction. The rescue of a replication-competent FMDV variant carrying the largest deletion ever in 3A (residues 81-153) and the fact that the deleted region contains a series of linear B-cell epitopes inspired us to devise an indirect ELISA based on a recombinant 3A carboxy-terminal fragment and to evaluate its potential to serve as a companion diagnostic assay for differential serosurveillance if the 3A-truncated virus is used as a marker vaccine.
authors.affiliation: ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, 263 138, Uttarakhand, India.
authors.forename: Mrutyunjay
authors.initials: M
authors.lastname: Behura
authors.affiliation: ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, 263 138, Uttarakhand, India. jajati1@gmail.com.
authors.forename: Jajati K
authors.initials: JK
authors.lastname: Mohapatra
authors.affiliation: ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, 263 138, Uttarakhand, India.
authors.forename: Laxmi K
authors.initials: LK
authors.lastname: Pandey
authors.affiliation: ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, 263 138, Uttarakhand, India.
authors.forename: Biswajit
authors.initials: B
authors.lastname: Das
authors.affiliation: ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, 263 138, Uttarakhand, India.
authors.forename: Mukesh
authors.initials: M
authors.lastname: Bhatt
authors.affiliation: ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, 263 138, Uttarakhand, India.
authors.forename: Saravanan
authors.initials: S
authors.lastname: Subramaniam
authors.affiliation: ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, 263 138, Uttarakhand, India.
authors.forename: Bramhadev
authors.initials: B
authors.lastname: Pattnaik
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002417:Cattle; D002418:Cattle Diseases / Q000821:virology; D002460:Cell Line; D003001:Cloning, Molecular; D006224:Cricetinae; D004797:Enzyme-Linked Immunosorbent Assay; D005536:Foot-and-Mouth Disease / Q000821:virology; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D013552:Swine; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000502:physiology*; D014779:Virus Replication / Q000502:physiology*
chemical_list: D017361:Viral Nonstructural Proteins