Abstract
The porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important swine pathogens and often serves as an entry door for other viral or bacterial pathogens, of which Streptococcus suis is one of the most common. Pre-infection with PRRSV leads to exacerbated disease caused by S. suis infection. Very few studies have assessed the immunological mechanisms underlying this higher susceptibility. Since antigen presenting cells play a major role in the initiation of the immune response, the in vitro transcriptional response of bone marrow-derived dendritic cells (BMDCs) and monocytes in the context of PRRSV and S. suis co-infection was investigated. BMDCs were found to be more permissive than monocytes to PRRSV infection; S. suis phagocytosis by PRRSV-infected BMDCs was found to be impaired, whereas no effect was found on bacterial intracellular survival. Transcription profile analysis, with a major focus on inflammatory genes, following S. suis infection, with and without pre-infection with PRRSV, was then performed. While PRRSV pre-infection had little effect on monocytes response to S. suis infection, a significant expression of several pro-inflammatory molecules was observed in BMDCs pre-infected with PRRSV after a subsequent infection with S. suis. While an additive effect could be observed for CCL4, CCL14, CCL20, and IL-15, a distinct synergistic up-regulatory effect was observed for IL-6, CCL5 and TNF-α after co-infection. This increased pro-inflammatory response by DCs could participate in the exacerbation of the disease observed during PRRSV and S. suis co-infection.
Highlights
The porcine reproductive and respiratory syndrome (PRRS), caused by a RNA virus (PRRSV), is characterized by weak live-born pigs, severe pneumonia, reduction in growth performances, mortality, and abortions [1]
Before studying the co-infection between porcine reproductive and respiratory syndrome virus (PRRSV) and S. suis, the toxicity as well as the infectivity and the replication of the IAF-Klop PRRSV and S. suis strains when cultured with porcine monocytes and bone marrow-derived dendritic cells (BMDCs) was assessed
BMDCs are more permissive to the virus (P < 0.05), since at t = 0 h (2 h after incubation with virus), PRRSV load was already greater in BMDCs (23.8 ± 1.3 cycle threshold (Ct)) compared to monocytes (27.2 ± 1.4 Ct)
Summary
The porcine reproductive and respiratory syndrome (PRRS), caused by a RNA virus (PRRSV), is characterized by weak live-born pigs, severe pneumonia, reduction in growth performances, mortality, and abortions [1]. At least two genotypes of PRRSV can be distinguished: PRRSV type 1 (with different sub-types), which comprises strains from Europe; and PRRSV type 2, which includes strains from North America [2] This disease has become the most prevalent in pigs worldwide and is responsible for great economic losses [3]. Streptococcus suis serotype 2 is an important swine bacterial pathogen responsible for meningitis, septicemia with sudden death and other infections in pigs. It is an emerging zoonotic agent [5,6,7]. The pathology caused by S. suis has been mainly associated with an excessive inflammatory response [15,16], through the production of proinflammatory cytokines and chemokines by cells of the immune system such as monocytes/ macrophages [17,18] and DCs [11]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
