Phenotypic characterization of a highly pathogenic Italian porcine reproductive and respiratory syndrome virus (PRRSV) type 1 subtype 1 isolate in experimentally infected pigs

Canelli, Elena; Catella, Alessia; Borghetti, Paolo; Ferrari, Luca; Ogno, Giulia; Angelis, Elena De; Corradi, A.; Passeri, Benedetta; Bertani, Valeria; Sandri, Giampietro; Bonilauri, Paolo; Leung, Frederick Chi-Ching; Guazzetti, Stefano; Martelli, Paolo

doi:10.1016/j.vetmic.2017.09.002

Cited by 47 publications

(53 citation statements)

References 52 publications

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“…The limited PRRSV pathology can be explained by the clean study conditions limiting the risk of secondary infections. Despite some studies which report pig deaths in PRRSV infection studies [30,31], the mild pathology is also consistent with several PRRSV studies performed under ABSL-2 conditions [32,33,34,35]. Overall, the PRRSV-2 infection and clinical pathology data are consistent with the PRRSV vaccination and infection trials described in the literature.…”

Section: Discussionsupporting

confidence: 87%

The T-Cell Response to Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)

Kick

Amaral

Cortes

et al. 2019

Viruses

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Porcine reproductive and respiratory syndrome virus (PRRSV) continues to cause severe reproductive and respiratory pathologies resulting in immense monetary and welfare costs for the swine industry. The vaccines against PRRSV are available; but they struggle with providing protection against the plethora of heterologous PRRSV strains. To improve PRRSV vaccine development, the aim of this study was to provide an in-depth analysis of the crucial heterologous T-cell response to type-2 PRRSV. Following PRRSV modified live virus (MLV) vaccination or infection using one high- or one low-pathogenic PRRSV-strain, this nine-week study evaluated the T-cell response to different PRRSV strains. Our results demonstrate an important role for T cells in this homo- and heterologous response. Specifically, the T-helper cells were the main responders during viremia. Their peak response at 28 dpi correlated with a reduction in viremia, and their homing receptor expression indicated the additional importance for the anti-PRRSV response in the lymphatic and lung tissue. The cytotoxic T lymphocyte (CTL) response was the strongest at the site of infection—the lung and bronchoalveolar lavage. The TCR-γδ T cells were the main responders post viremia and PRRSV induced their expression of the lymph node homing the chemokine receptor, CCR7: This indicates a crucial role for TCR-γδ T cells in the anti-PRRSV response in the lymphatic system.

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Section: Discussionsupporting

confidence: 87%

The T-Cell Response to Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)

Kick

Amaral

Cortes

et al. 2019

Viruses

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“…PRRSV plays a pivotal role in PRDC, modulating the host immune response and favouring secondary bacterial infections (Gómez-Laguna et al, 2013;Van Gucht et al, 2004). Virulent PRRSV-1 strains cause more severe clinical signs, higher mortality rates as well as marked lung injury with a higher incidence of bronchopneumonia as opposed to low virulent strains (Amarilla et al, 2015;Canelli et al, 2017;Frydas et al, 2013;Gómez-Laguna et al, 2010;Morgan et al, 2013;Renson et al, 2017;Rodríguez-Gómez et al, 2019;Stadejek et al, 2017;Weesendorp et al, 2013). Accordingly, we hypothesise that severe pulmonary lesions observed along infection with virulent PRRSV-1 strains might be associated with a higher decrease in the amount of PAMs as well as an imbalance between anti-and pro-inflammatory responses with different molecules potentially involved in this process.…”

Section: Discussionmentioning

confidence: 99%

Activation of pro- and anti-inflammatory responses in lung tissue injury during the acute phase of PRRSV-1 infection with the virulent strain Lena

Sánchez‐Carvajal

Rodríguez-Gómez

Ruedas‐Torres

et al. 2020

Veterinary Microbiology

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Porcine reproductive and respiratory syndrome virus (PRRSV) plays a key role in porcine respiratory disease complex modulating the host immune response and favouring secondary bacterial infections. Pulmonary alveolar macrophages (PAMs) are the main cells supporting PRRSV replication, with CD163 as the essential receptor for viral infection. Although interstitial pneumonia is by far the representative lung lesion, suppurative bronchopneumonia is described for PRRSV virulent strains. This research explores the role of several immune markers potentially involved in the regulation of the inflammatory response and sensitisation of lung to secondary bacterial infections by PRRSV-1 strains of different virulence. Conventional pigs were intranasally inoculated with the virulent subtype 3 Lena strain or the low virulent subtype 1 3249 strain and euthanised at 1, 3, 6 and 8 dpi. Lena-infected pigs exhibited more severe clinical signs, macroscopic lung score and viraemia associated with an increase of IL-6 and IFN-γ in sera compared to 3249-infected pigs. Extensive areas of lung consolidation corresponding with suppurative bronchopneumonia were observed in Lena-infected pigs. Lung viral load and PRRSV-N-protein + cells were always higher in Lena-infected animals. PRRSV-N-protein + cells were linked to a marked drop of CD163 + macrophages. The number of CD14 + and iNOS + cells gradually increased along PRRSV-1 infection, being more evident in Lena-infected pigs. The frequency of CD200R1 + and FoxP3 + cells peaked late in both PRRSV-1 strains, with a strong correlation between CD200R1 + cells and lung injury in Lena-infected pigs. These results highlight the role of molecules involved in the earlier and higher extent of lung lesions in piglets infected with the virulent Lena strain, pointing out the activation of routes potentially involved in the restraint of the local inflammatory response.

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“…However, some recent isolates (e.g. from Italy, Belgium, and Austria) may indicate a trend towards increasing virulence of subtype 1 [ 15 – 17 ]. The challenge strain used in this study, Olot/91, has been shown to be very aggressive when used in a reproductive model [ 13 ] but induces a mild disease in young pigs [ 18 ].…”

Section: Discussionmentioning

confidence: 99%

Vaccination of 1-day-old pigs with a porcine reproductive and respiratory syndrome virus (PRRSV) modified live attenuated virus vaccine is able to overcome maternal immunity

Balasch¹,

Fort²,

Taylor

et al. 2018

Porc Health Manag

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BackgroundThe objective of the study was to evaluate the influence of maternally derived antibodies (MDA) on the efficacy of a PRRSV-1 based attenuated vaccine, when administered in 1 day-old piglets by the intramuscular route. The protective immunity of the modified live virus vaccine was evaluated in pigs born from seropositive sows, vaccinated at 1 day of age, upon inoculation with a PRRSV-1 isolate. The animals were challenged when the levels of MDAs detected by seroneutralization test (SNT) in the non-vaccinated control group became undetectable (10 weeks after vaccination).ResultsA protective effect of vaccination was observed since a significant reduction of viral load in serum compared to the control group was detected in all sampling days after challenge; efficacy was supported by the significant reduction of nasal and oral shedding as well as in rectal temperatures. Clinical signs were not expected after the inoculation of a PRRSV-1 subtype 1 challenge strain. However, the challenge virus was able to develop fever in 61% of the control pigs. Vaccination had a positive impact on rectal temperatures since the percentage of pigs that had fever at least once after challenge was reduced to 31% in vaccinated animals, and control pigs had significantly higher rectal temperatures than vaccinated pigs 3 days post-challenge. The lack of a vaccination effect in body weight gain was probably due to the short evaluation period after challenge (10 days). In the vaccinated group, 9/16 pigs (56%) experienced an increase in ELISA S/P ratio from the day of vaccination to 67 days post-vaccination. All vaccinated pigs were seropositive before challenge, indicating the development of an antibody response following vaccination even in the face of MDAs. In contrast to ELISA results, only 2/16 vaccinated pigs developed neutralizing antibodies detectable by a SNT that used a subtype 1 MA-104 adapted strain. Even in the absence of SN antibodies, vaccinated pigs were protected from challenge with a heterologous strain. The role of cell-mediated immunity should be considered, if protection was not mediated by SN antibodies only.ConclusionsThe efficacy of the attenuated PRRSV-1 vaccine in 1-day-old pigs seropositive to PRRSV prior to a PRRSV-1 challenge was demonstrated by improvement of clinical, virological and immunological variables. With the current experimental design, maternal immunity did not interfere with the development of a protective immune response against a PRRSV-1 challenge, after vaccination of 1 day-old pigs. Confirmation of these results under field conditions will be needed.

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Phenotypic characterization of a highly pathogenic Italian porcine reproductive and respiratory syndrome virus (PRRSV) type 1 subtype 1 isolate in experimentally infected pigs

Cited by 47 publications

References 52 publications

The T-Cell Response to Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)

The T-Cell Response to Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)

Activation of pro- and anti-inflammatory responses in lung tissue injury during the acute phase of PRRSV-1 infection with the virulent strain Lena

Vaccination of 1-day-old pigs with a porcine reproductive and respiratory syndrome virus (PRRSV) modified live attenuated virus vaccine is able to overcome maternal immunity

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