# Age-dependent differences in type I interferon, IL-12 and pro-inflammatory cytokine production by porcine peripheral blood mononuclear cells in response to pseudorabies virus-infected cells

## TL;DR

Young pigs have weaker immune responses to a virus compared to older pigs, which may explain why the disease is more severe in newborns.

## Contribution

The study identifies age-related differences in cytokine production in pigs infected with pseudorabies virus, offering insights for improving neonatal immune responses.

## Key findings

- PBMCs from young pigs show low IFN-α and IL-12 production in response to PRV.
- Newborn piglets exhibit high IL-6 and IL-10 levels, suggesting suppressed Th1 immune responses.
- Age-related cytokine shifts correlate with changes in PRV symptom severity in pigs.

## Abstract

Pseudorabies virus is a porcine alphaherpesvirus that causes devastating disease with high mortality in young piglets but much milder, mainly respiratory, problems in older pigs. Here, we report marked age-dependent differences in the cytokine response profile of primary porcine peripheral blood mononuclear cells (PBMCs) to pseudorabies virus (PRV)-infected cells. Notably, IFN-α and IL-12 production in response to PRV remains low to almost undetectable in piglets up to 8.5 weeks of age, followed by a marked increase in older piglets, which coincides with age-related shifts in PRV symptomatology. Additionally, we found that PBMC from newborn piglets exhibit a high IL-6 and IL-10 production which, in combination with the low IL-12 levels, suggests a suppressed Th1 immune response, similar to neonatal humans and mice. Our results reveal a remarkable age-dependent difference in PBMC cytokine response to PRV and provide a basis to identify cytokines or adjuvants that shift the neonatal immune response towards a Th1 response, potentially improving outcomes of severe viral infections in the neonatal period in both pigs and humans.