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Differentiation of infectious bursal disease virus strains at a genomic level

Authors :: Zdenko Biđin
Ivana Lojkić
Magdalena Grce
Stanislav Čajavec
Biserka Pokrić
Source :: Veterinarski arhiv, Volume 71, Issue 6
Publication Year :: 2001
Publisher :: Faculty of Veterinary Medicine University of Zagreb, 2001.
Abstract: Reverse transcription-polymerase chain reaction (RT-PCR) followed by restriction fragment-length polymorphism (RFLP) analysis was tested in order to determine its accuracy and sensitivity for differentiation of infectious bursal disease virus (IBDV) strains. Two commercial vaccine strains and two Croatian field isolates were analysed. RT-PCR assay was used for amplification of a variable part of VP2 gene (422 bp) encoding for major neutralizing epitopes. Amplified VP2 fragments were further characterized by RFLP analysis using the SacI and TaqI restriction endonucleases. Both field isolates showed RFLP pattern similar to highly virulent European and Asian strains. Both vaccine strains had RFLP profiles different from that of the field isolates. Vaccinal strain 2512 had RFLP pattern similar to mild vaccinal strain pbg-98, and strain VMG-91 was similar to other classical vaccinal strains of intermediate pathogenicity.<br />Procijenjena je točnost i osjetljivost metode temeljene na razlici dužina restrikcijskih odsječaka DNA (RFLP, restriction fragment lenght polymorphism) za razlikovanje sojeva virusa zarazne bolesti burze (VZBB). Lančanom reakcijom polimerazom (PCR, polymerase chain reaction) uz prethodnu reverznu transkripciju (RT, reverse transcription) umnožen je dio promjenljivog dijela VP2 gena koji kodira glavne virusne neutralizacijske epitope. Nastali produkti veličine 422 parova baza (bp, base pair) pocijepani su restrikcijskim endonukleazama SacI i TaqI. Restrikcijski profili nastali enzimskim cijepanjem uspoređeni su s podatcima navedenim u banci gena. Metoda je testirana na dva komercijalna cjepiva proizvedena u Hrvatskoj (Gumbokal® SPF, soj 2512 i Gumbokal® IM SPF, soj VMG 91) te dva hrvatska terenska izolata VZBB (IBDV/96/01 i IBDV/ 97/02). Oba su terenska izolata pokazala RFLP profil jednak vrlo virulentnim europskim i azijskim sojevima VZBB. Oba cijepna soja imala su različit RFLP profil od terenskih izolata. Cijepni soj 2512 ima RFLP profil jednak blagim cijepnim sojem pbg-98, a VMG 91 je sličan poznatim intermedijarnim sojevima VZBB.