MUTANTS OF THE VIRUS OF THE INFECTIONAL DISEASE OF THE BURSAS (IBDV) ADAPTED BY GENETIC ENGINEERING FOR CELL CULTURE.

摘要

A method for the preparation of an infectious mutant of IBDV capable of replicating in a culture of CEF cells comprising the steps of: (i) separately preparing a DNA construct containing cDNA of genomic segments A and B of an IBDV that does not is able to replicate in a culture of CEF cells, (ii) introduce a mutation in: to one or both codons for amino acid residues 253 and 284 of the VP2 gene of Variant-E or Classical strains of IBDV, or in b the codon for amino acid residue 284 of the VP2 gene of a GLS strain of IBDV, in the cDNA comprising segment A, such that the codons for amino acid residues 253 and 284 of the mutated VP2 gene encode a residue of histidine and a threonine residue, respectively, in the case of IBDV Variant-E or Classic strains, or in such a way that the codon for amino acid residue 284 of the mutated VP2 gene encodes a threonine residue in the case of a strain GLS of the IBDV, ( iii) allow the cDNA RNA transcripts comprising segment A and segment B to initiate replication of the IBDV mutant in host cells in a culture medium, and (iv) isolate the IBDV mutant from the culture.