Infection par l’hantavirus Puumala en Isère : une extension géographique de cette zoonose en France

International audience

The porcine innate immune system: an update.

Over the last few years, we have seen an increasing interest and demand for pigs in biomedical research. Domestic pigs (Sus scrofa domesticus) are closely related to humans in terms of their anatomy, genetics, and physiology, and often are the model of choice for the assessment of novel vaccines and therapeutics in a preclinical stage. However, the pig as a model has much more to offer, and can serve as a model for many biomedical applications including aging research, medical imaging, and pharmaceutical studies to name a few. In this review, we will provide an overview of the innate immune system in pigs, describe its anatomical and physiological key features, and discuss the key players involved. In particular, we compare the porcine innate immune system to that of humans, and emphasize on the importance of the pig as model for human disease

<em>In vitro</em> and <em>ex vivo</em> analyses of co-infections with swine influenza and porcine reproductive and respiratory syndrome viruses

International audienceViral respiratory diseases remain problematic in swine. Among viruses, porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (Sly), alone or in combination, are the two main known contributors to lung infectious diseases. Previous studies demonstrated that experimental dual infections of pigs with PRRSV followed by Sly can cause more severe disease than the single viral infections. However, our understanding of the impact of one virus on the other at the molecular level is still extremely limited. Thus, the aim of the current study was to determine the influence of dual infections, compared to single infections, in porcine alveolar macrophages (PAMs) and precision cut lung slices (PCLS). PAMs were isolated and PCLS were acquired from the lungs of healthy 8-week-old pigs. Then, PRRSV (ATCC VR-2385) and a local Sly strain of H1N1 subtype (A/Sw/Saskatchewan/18789/02) were applied simultaneously or with 3 h apart on PAMs and PCLS for a total of 18 h. Immuno-staining for both viruses and beta-tubulin, real-time quantitative PCR and ELISA assays targeting various genes (pathogen recognition receptors, interferons (IFN) type I, cytokines, and IFN-inducible genes) and proteins were performed to analyze the cell and the tissue responses. Interference caused by the first virus on replication of the second virus was observed, though limited. On the host side, a synergistic effect between PRRSV and SIV co-infections was observed for some transcripts such as TLR3, RIG-I, and IFN beta in PCLS. The PRRSV infection 3 h prior to Sly infection reduced the response to Sly while the SIV infection prior to PRRSV infection had limited impact on the second infection. This study is the first to show an impact of PRRSV/SIV co-infection and superinfections in the cellular and tissue immune response at the molecular level. It opens the door to further research in this exciting and intriguing field

Antiviral activity of selected cathelicidins against infectious bronchitis virus

Avian infectious bronchitis (IB) is a highly contagious disease caused by infectious bronchitis virus (IBV), a coronavirus of domestic fowl. IB is a major concern in the poultry industry, causing worldwide economic losses through decreased egg production and quality and by increasing the chicken's susceptibility for secondary bacterial infections, particularly Escherichia coli. In this study, the anti-IBV activity of cathelicidins, small antimicrobial peptides of the innate immune system was investigated. The cell culture adapted (nonvirulent) IBV strain Beaudette was effectively inhibited by the human cathelicidin LL-37 in bovine hamster kidney-21 cells at nontoxic concentrations. The peptide needed to be present during virus inoculation to effectively inhibit the infection of IBV-Beaudette, indicating that LL-37 likely bound viral particles. However, no clear morphological changes in the IBV virion upon binding were observed by electron microscopy. In this cell culture model, chicken cathelicidins (CATH1-3) were inactive against IBV-Beaudette. In contrast, in multicellular infection models using the virulent IBV-M41 strain the activities of human and chicken cathelicidins were different. In particular, upon inoculation of 10-day-old embryonic eggs with IBV-M41, CATH-2 reduced the viral load to a higher extend than LL-37. Similarly, viral infection of chicken tracheal organ cultures with IBV-M41 was significantly reduced in the presence of CATH-2 but not LL-37. These results indicate a potential antiviral role for CATH-2 upon IBV infection in vivo