TGF and CD8+T cells occupy an important position in the lungs of piglets infected with swine flu virus

Swine is considered to be an important host for the production of pandemic influenza viruses, studying the immune characteristics of swine influenza viruses(SIV) infection in piglets is crucial for pandemic prevention. Here, we demonstrated that the 6 major immune cell components in the lungs of piglets infected with Genotype 4(G4) reassigned Eurasian avian-like(EA) H1N1 SIV and H9N2 avian influenza viruses(AIV) by single cell sequencing(scRNA-seq), and H1N1 SIV elicits a stronger immune response. Our study revealed that TGF signaling is uniquely present in H1N1 SIV infection and is closely associated with T cell. Moreover, flow cytometry analysis showed that H1N1 SIV infection resulted in an increase in TGF derived from CD4+ and CD8+T cells. The loss of CD8+T cells can slow down the weight loss and lung inflammation in the early stage of infection, but also affect the recovery in the later stage of infection. Overall, this research discovered TGF which is rarely mentioned in SIV infection and clarified the importance of CD8+T balance in the infection. It provides new insights into the prevention and treatment of SIV and the prevention of human pandemics.