Effects of virulent and attenuated transmissible gastroenteritis virus on the ability of porcine dendritic cells to sample and present antigen

Abstract

Virulent transmissible gastroenteritis virus (TGEV) results in an acute, severe pathology and high mortality in piglets, while attenuated TGEV only causes moderate clinical reactions. Dendritic cells (DCs), through uptake and presentation of antigens to T cells, initiate distinct immune responses to different infections. In this study, an attenuated TGEV (STC3) and a virulent TGEV (SHXB) were used to determine whether porcine DCs play an important role in pathogenetic differences between these two TGEVs. Our results showed that immature and mature monocyte-derived dendritic cells (Mo-DCs) were susceptible to infection with SHXB and STC3. However, only SHXB inhibited Mo-DCs to activate T-cell proliferation by down-regulating the expression of cell-surface markers and the secretion of cytokines in vitro. In addition, after 48 h of SHXB infection, there was the impairment in the ability of porcine intestinal DCs to sample the antigen, to migrate from the villi to the lamina propria and to activate T-cell proliferation in vivo. In contrast, these abilities of intestinal DCs were enhanced in STC3-infected piglets. In conclusion, our results show that SHXB significantly impaired the functions of Mo-DCs and intestinal DCs in vitro and in vivo, while STC3 had the opposite effect. These differences may underlie the pathogenesis of virulent and attenuated TGEV in piglets, and could help us to develop a better strategy to prevent virulent TGEV infection.

Cell attenuated porcine epidemic diarrhea virus strain Zhejiang08 provides effective immune protection attributed to dendritic cell stimulation

“…The ability of promoting DC function for cellular maturation, induce lymphocyte cell proliferation, pro-inflammatory cytokine secretion, and antigen presentation is necessary to assess the potential of antigen initiation for both innate and adaptive immune responses [22][23][24][25]. We demonstrated that the Zhejiang08 strain was a stronger and more potent inducer of DC maturation and mRNA expression of IL-12 and IFN-c in DCs than CV777.…”

Immune responses induced by recombinant Lactobacillus plantarum expressing the spike protein derived from transmissible gastroenteritis virus in piglets

“…The piglets were handled and maintained under strict ethical conditions according to international recommendations for animal welfare. All group piglets were euthanized at 21 days after secondary immunization, and the intestinal segments were collected as previously described but with minor alterations (Zhao et al 2014). In detail, upon washing with ice-cold PBS, the fixed tissues were immediately embedded in OCT (embedding medium for frozen tissue specimens; Sakura, USA) and then stored at − 80°C until further use.…”

Porcine epidemic diarrhea virus does not replicate in porcine monocyte-derived dendritic cells, but activates the transcription of type I interferon and chemokine

“…Our observation is further supported by the absence of cell death after PEDV exposure. Similarly, conflicting results have been published regarding the susceptibility of Mo-DC to TGEV, a close relative of PEDV (Guzylack-Piriou et al, 2006;Zhao et al, 2014). Further research is needed to determine the underlying reasons for the discrepancy results.…”