The aim of this study was to analyze the regulatory T cells (Tregs) induced by the porcine reproductive and respiratory syndrome virus (PRRSV) in pigs. Serum, blood, tonsil, and mediastinal lymph nodes' samples were obtained at different time post-infection (dpi). The frequencies of CD4 +CD8 -CD25 +Foxp3 +, CD4 +CD8 +CD25 +Foxp3 +, or CD4 -CD8 +CD25 +Foxp3 + phenotypes were determined in PBMC and lymph node cells, and cells producing IL-10 or TGF-Β were analyzed. PRRSV increased the number of CD4 +CD8 +CD25 +Foxp3 + cells at 14dpi, whereas CD4 +CD8 -CD25 +Foxp3 + remained constant until 28dpi. Positive correlation exists between viremia and induced regulatory cells. CD4 +CD8 +CD25 +Foxp3 +-induced Treg cells were consistently observed in lymphoid tissues. Analysis of IL-10- and TGF-Β-producing cell demonstrated that in response to PRRSV, CD4 +CD8 -Foxp3 low and CD4 +CD8 +Foxp3 high cells increase moderately the proportion of IL-10 + cells. TGF-Β was only observed in the CD4 +CD8 +Foxp3 high population after PRRSV stimulation. In conclusion, PRRSV infection increases the frequency of Tregs with the phenotype CD4 +CD8 +CD25 +Foxp3 high and produces TGF-Β.
Bibliographical noteFunding Information:
We thank Mónica Reséndiz, Karina Espinoza, Salvador Icedo, Alexel Burgara, Guadalupe López and José Luis Davila for technical assistance. This work was partially supported by the SEP-CONACyT Grant no. 82850 . Enric Mateu was supported by a Grant of the Departament d'Innovació Indústria i Universitats of the Generalitat de Catalunya (no. BE2-00119 ).
- Regulatory T cells