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

The data suggested that immunosuppression occurred at a certain point in the adaptive immune response. Therefore, we wondered whether myeloid bone marrow cells were affected by viral persistence. The fate and infection of the myeloid BMHCs were determined at necropsy in 6-week-old (i) non-infected piglets, (ii) seropositive piglets infected with the PR virus (pigs 1 19 and 23) . The percentages of myeloid (CD172a + , CD163 + ) cells were clearly increased in both the PR and Cat01 virus-infected piglets (Fig 6) . In contrast, the increases in SLAII + and CD172a + /SLAII + cells were more prominent in the immunocompetent piglets infected with the PR strain. Consistent with viral persistence, the percentage of CSFV-positive BMHCs overall was three times higher in the pigs infected with Cat01, compared with the PR virus-infected piglets that had seroconverted to the infection (Fig 6A and 6B ). Accordingly, a higher percentage of immature granulocytes (6D10 + ) and CSFV + /6D10 + cells was found in the BMHCs from the Cat01 virus-infected piglets (Fig 6C and 6D ). This finding was confirmed by qRT-PCR with 6D10 + sorted cells (Fig 6E) .