The Production of Recombinant African Swine Fever Virus Lv17/WB/Rie1 Strains and Their In Vitro and In Vivo Characterizations

• Published in: Vaccines (Basel) Vol. 11; no. 12; p. 1860
• Main Authors: Petrini, Stefano, Righi, Cecilia, Mészáros, István, D'Errico, Federica, Tamás, Vivien, Pela, Michela, Olasz, Ferenc, Gallardo, Carmina, Fernandez-Pinero, Jovita, Göltl, Eszter, Magyar, Tibor, Feliziani, Francesco, Zádori, Zoltán
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.12.2023; MDPI
• Subjects: African swine fever; Antibiotics; ASFV; Causes of; Cell culture; Dilution; DNA viruses; Epidemics; Experiments; Genetic aspects; Genetic recombination; Genetically modified organisms; Genomes; Hogs; Homologous recombination; Homology; illegitimate recombination; Infections; live-attenuated vaccine; pigs; Prevention; Proteins; Strains (organisms); Vaccines; Viral vaccines; Virus research; Viruses; Italy; United States > US; pigs; African swine fever; homologous recombination; ASFV; live-attenuated vaccine; illegitimate recombination
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines11121860

Lv17/WB/Rie1-Δ24 was produced via illegitimate recombination mediated by low-dilution serial passage in the Cos7 cell line and isolated on PAM cell culture. The virus contains a huge ~26.4 Kb deletion in the left end of its genome. Lv17/WB/Rie1-ΔCD-ΔGL was generated via homologous recombination, crossing two ASFV strains (Lv17/WB/Rie1-ΔCD and Lv17/WB/Rie1-ΔGL containing eGFP and mCherry markers) during PAM co-infection. The presence of unique parental markers in the Lv17/WB/Rie1-ΔCD-ΔGL genome indicates at least two recombination events during the crossing, suggesting that homologous recombination is a relatively frequent event in the ASFV genome during replication in PAM. Pigs infected with Lv17/WB/Rie1-Δ24 and Lv17/WB/Rie1/ΔCD-ΔGL strains have shown mild clinical signs despite that ASFV could not be detected in their sera until a challenge infection with the Armenia/07 ASFV strain. The two viruses were not able to induce protective immunity in pigs against a virulent Armenia/07 challenge.