Postnatal Persistent Infection with Classical Swine Fever Virus and Its Immunological Implications

Muñoz-González, Sara; Ruggli, Nicolas; Rosell, Rosa; Pérez, Lester Josué; Frías-Leuporeau, Maria Teresa; Fraile, Lorenzo; Montoya, Maria; Cordoba, Lorena; Domingo, Mariano; Ehrensperger, Felix; Summerfield, Artur; Ganges, Llilianne

Compared to the adaptive immune response, the innate immune response to the virus, as measured by type I IFN-α in the serum, was not impaired in the persistently infected piglets. At seven days post-infection, when the viral loads were similar in all of the piglets, the IFN-α levels were comparable in the pigs that had seroconverted and in the persistently infected piglets (Fig 5) . Similarly, serum IFN-α levels were measured in Cat01 virus-infected 10-week-old immunocompetent pigs in a separate study [32] . Surprisingly, the persistently infected piglets inoculated with the PR strain had overall significantly higher serum IFN-α levels than the Cat01-infected pigs, although their virus load was lower. This situation was different from acute CSFV infections, in which the serum IFN-α levels were consistently higher with higher virus titres in the circulation [58, 59] . Additionally, it was recently demonstrated that E rns impaired pDC-mediated IFN-α secretion in response to CSFV infection [60] . Different efficiencies of the E rns of PR versus Cat01 in terms of pDC inhibition might account for the discrepancy observed here.