Fasciola hepatica induces Foxp3 T cell, proinflammatory and regulatory cytokine overexpression in liver from infected sheep during early stages of infection.

Pacheco IL, Abril N, Zafra R, Molina-Hernández V, Morales-Prieto N, Bautista MJ, Ruiz-Campillo MT, Pérez-Caballero R, Martínez-Moreno A, Pérez

Vet Res. 2018 Jul 3;49(1):56. doi: 10.1186/s13567-018-0550-x

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6029414/

In this study we have evaluated the gene expression of T regulatory cells (Foxp3), IL-10, TGF-β, TNF-α and IL-1β) cytokines was quantified using real time polymerase chain reaction (qRT-PCR) in the liver of sheep during early stages of infection with Fasciola hepatica (1, 3, 9, and 18 days post-infection (dpi), both in CL1 vaccinated and in unvaccinated sheep. Portal fibrosis was evaluated by Masson’s trichrome stain and the number of Foxp3+ cells by immunohistochemistry. An overexpression of Foxp3, IL-10, TGF-β, TNF-α and IL-1β, was found in the two infected groups respect to the uninfected group, particularly at 18 dpi. These findings suggest the induction of a regulatory phenotype by the parasite that would allow its survival at early stages of the disease when it is more vulnerable.

Fig. 1. Gene expression of Foxp3, IL-10, TGF-β, IL-1β, and TNF-α. Each bar represents the mean ± SD of the mRNA molecules/ng of total RNA quantified individually in each of the five animals per experimental condition and sampling time, after three real-time PCR reactions per individual

Fig. 1. Gene expression of Foxp3, IL-10, TGF-β, IL-1β, and TNF-α. Each bar represents the mean ± SD of the mRNA molecules/ng of total RNA quantified individually in each of the five animals per experimental condition and sampling time, after three real-time PCR reactions per individual. a for comparison of each treatment with the negative control, and b for comparisons between the infected and infected and immunized groups. The levels of gene expression were increasing gradually throughout the experiment in the transcription factor, foxp3 and two regulatory cytokines studied (IL-10, TGF-β), reaching its higher expression at 18 dpi, and for IL-10 also markedly at 3 and 9 dpi, coinciding with a slight increase in the expression of Foxp3. Foxp3, IL-10, and TGF-β showed significant differences in comparison with the negative control group at 1, 3, and 9 dpi, respectively. At the same time, differences were shown between immunized and infected groups at 1 and 3 dpi in Foxp3 and 3 dpi in IL-10. The expression of proinflammatory cytokines (IL-1β and TNF-α) was gradually increasing along the experience, showing the typical expression of an acute stage of disease.