Replication characteristics of eight virulent and two attenuated genotype 1 and 2 porcine reproductive and respiratory syndrome virus (PRRSV) strains in nasal mucosa explants

Review on the transmission porcine reproductive and respiratory syndrome virus between pigs and farms and impact on vaccination

“…Increased replication efficiency and higher viral titres in serum were also observed for the highly pathogenic HuN4 [57] and Lena [52] strains, although in these cases the viral shedding was not assessed. Moreover, in several studies by Frydas et al [53, 54, 58] it was shown, at least for genotype 1, that different isolates replicate to a different extent in the nasal mucosa, and this may have an influence on the formation of aerosols. Collectively, these data suggest that pigs infected with highly virulent strains could shed higher amounts of virus than pigs infected with low virulent strains, and that the replication in nasal mucosa varies between isolates.…”

Molecular cloning of porcine Siglec-3, Siglec-5 and Siglec-10, and identification of Siglec-10 as an alternative receptor for porcine reproductive and respiratory syndrome virus (PRRSV)

“…PK-15 cells were transiently transfected with a pCD163-encoding vector in combination with a Siglec-1, Siglec-3, Siglec-5, Siglec-10 or control vector, and 48 h after transfection the cells were treated or not treated with sialidase for 1 h and inoculated with PRRSV LV or MN-184 for 1 h. Twenty-four hours post-infection, the cells were fixed and stained for infection and expression of the different Siglecs and CD163. (a) Immunofluorescence staining of infected cells with mAb 13E2 (against PRRSV nucleocapsid protein; green) [ 26, 43 ] and Hoechst 33 342 (nuclei; blue). The absolute number of infected cells for each condition was determined and displayed in the images as the mean ± SEM of three independent experiments.…”

“…After transfection, cells were treated or mock-treated with sialidase and then inoculated with the PRRSV type 1 LV strain and the PRRSV type 2 MN-184 strain. As it has previously been shown that MN-184 shows a higher cell tropism for Sn - cells [ 26 ], the MN-184 strain was selected for the present study. The results showed that in addition to Siglec-1, Siglec-10 significantly increases the infection for both virus strains, although to a greater extent for MN-184.…”

“…Both Siglec-1 and Siglec-10 were able to improve the infection rate and virus production to almost the same level, regardless of sialidase treatment. It has been stated that the LV strain has a strict cell tropism for Sn + macrophages [ 14, 29 ], whereas MN-184 and some other type 2 PRRSV strains are able to infect Sn − cells [ 26 ]. In addition to Sn, these viruses most likely use another binding and entry receptor.…”

“…PRRS virions were visualized via the nucleocapsid protein specific mAb 13E2 [ 26, 43 ] and a secondary conjugate. For detection of the V5-tag, a mouse monoclonal antibody (GenScript; A00641) and a goat anti-mouse IgG horseradish peroxidase (HRP)-labelled secondary antibody (Dako; P0447) were used, or a directly labelled mAb conjugated with FITC (Invitrogen; R963-25), was used.…”