A Polyuridine Insertion in the 3′ Untranslated Region of Classical Swine Fever Virus Activates Immunity and Reduces Viral Virulence in Piglets
Bohórquez, José Alejandro
Low-virulence classical swine fever virus (CSFV) strains make CSF eradication particularly difficult. Few data are available on the molecular determinants of CSFV virulence. The aim of the present study was to assess a possible role for CSFV virulence of a unique, uninterrupted 36-uridine (poly-U) sequence found in the 3' untranslated region (3' UTR) of the low-virulence CSFV isolate Pinar de Rio (PdR). To this end, a pair of cDNA-derived viruses based on the PdR backbone were generated, one carrying the long poly-U insertion in the 3' UTR (vPdR-36U) and the other harboring the standard 5 uridines at this position (vPdR-5U). Two groups of 20 5-day-old piglets were infected with vPdR-36U and vPdR-5U. Ten contact piglets were added to each group. Disease progression, virus replication, and immune responses were monitored for 5 weeks. The vPdR-5U virus was significantly more virulent than the vPdR-36U virus, with more severe disease, higher mortality, and significantly higher viral loads in serum and body secretions, despite similar replication characteristics in cell culture. The two viruses were transmitted to all contact piglets. Ninety percent of the piglets infected with vPdR-36U seroconverted, while only one vPdR-5U-infected piglet developed antibodies. The vPdR-5U-infected piglets showed only transient alpha interferon (IFN-α) responses in serum after 1 week of infection, while the vPdR-36U-infected piglets showed sustained IFN-α levels during the first 2 weeks. Taken together, these data show that the 3' UTR poly-U insertion acquired by the PdR isolate reduces viral virulence and activates the innate and humoral immune responses without affecting viral transmission.
619 - Veterinària
American Society for Microbiology
Is part of
Journal of Virology
Wang, Miaomiao, Matthias Liniger, Sara Muñoz-González, José Alejandro Bohórquez, Yoandry Hinojosa, Markus Gerber, Sergio López-Soria, Rosa Rosell, Nicolas Ruggli, and Llilianne Ganges. 2020. "A Polyuridine Insertion In The 3′ Untranslated Region Of Classical Swine Fever Virus Activates Immunity And Reduces Viral Virulence In Piglets". Journal Of Virology 94 (2). doi:10.1128/jvi.01214-19.
Grant agreement number
MINECO/Programa estatal de I+D+I orientada a los retos de la sociedad/RTI2018-100887-B-100/ES/Descifrando nuevos factores virales y del hospedador involucrados en el desarrollo de la peste porcina clásica: implicaciones para el control de la enfermedad/
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