Gene expression of innate Th1-, Th2-, and Th17-type cytokines during early life of neonatal foals in response to Rhodococcus equi.

The research focuses on understanding the gene expression patterns of certain cytokines (communication proteins between cells) in young foals in response to Rhodococcus equi infection. Mainly, these cytokines belong to Th1, Th2, and Th17 categories. The study suggests that foals up to 3 weeks old responded to this infection without any age-related impairment, although these responses might still be immature compared to those of older foals or adult horses.

Research Purpose

• The primary aim of the study was to examine cytokine-mediated immune responses in the bronchial cells of newborn foals, specifically in the first three weeks, when the foals were exposed to a bacterial infection, Rhodococcus equi.
• The researchers observed the gene expression patterns of Th1-, Th2-, and Th17-type cytokine molecules, which help modulate the immune response in the body.

Research Methodology

• The researchers employed a laboratory technique to analyze the mRNA transcript profiles of various cytokine molecules (including IFN-γ, IL-4, IL-6, IL-8, IL-12p35, IL-12p40, IL-17, IL-23p19, and TNF-α) in response to R. equi infection.
• This was mainly carried out in bronchial alveolar lavage (BAL) cells taken from ten-day-old foals.
• The team also analyzed peripheral blood mononuclear cells (PBMCs) to observe the temporal response patterns in circulating cells under the same infection scenarios.

Key Findings

• The study highlighted that the cytokine molecules from all three studied types saw a significant upregulation in foals when exposed to R. equi infection.
• However, some discrepancies were observed in the timings and levels of expression for different cytokines.
• Overall, all foals up to three weeks produced almost equal amount of IFN-γ mRNA transcripts, which suggests that there was no age-related decrease in Th1-type cytokine response to the bacterial infection in these early weeks of life.
• IL-4 expression was seen to be significantly reduced at birth, while IL-17 expression was relatively less during the first week of life.

Implications and Future Probe

• Though foals produced similar amounts of IFN-γ, whether this Th1 response is generally immature compared to older foals or adult horses requires further investigation.
• IL-17 emerged as an important cytokine during this study, as its mRNA transcripts saw the highest fold-change induction among all the cytokines studied.
• Despite the manipulation of the infection conditions, the administration of a type of immunostimulant (CpG) did not result in any alteration of Th1-, Th2-, and Th17-type cytokine expression patterns in the PBMCs. This suggests that CpG might not have much of an influence in immune responses in these cases.