The immune cell landscape and response of Marek's disease resistant and susceptible chickens infected with Marek's disease virus

Authors: WARREN, WESLEY - University Of Missouri; RICE, EDWARD - University Of Missouri; MEYER, ASHLEY - University Of Missouri; Hearn, Cari; STEEP, ALEC - Michigan State University; Hunt, Henry; Monson, Melissa; LAMONT, SUSAN - Iowa State University; Cheng, Hans

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2023
Publication Date: 4/1/2023
Citation: Warren, W.C., Rice, E.S., Meyer, A., Hearn, C.J., Steep, A., Hunt, H.D., Monson, M.S., Lamont, S.J., Cheng, H.H. 2023. The immune cell landscape and response of Marek's disease resistant and susceptible chickens infected with Marek's disease virus. Scientific Reports. 13. Article 5355. https://doi.org/10.1038/s41598-023-32308-x.
DOI: https://doi.org/10.1038/s41598-023-32308-x

Interpretive Summary: Marek's disease (MD) is a serious problem to the poultry industry as Marek's disease virus (MDV), the causative agent, induces tumors and immunosuppression in susceptible birds. To gain a better understanding of the underlying biological basis between MD resistant and MD susceptible chickens, a new technique called single cell RNA sequencing (scRNA seq) was applied on both types of birds in the uninfected and MDV-infected state. Analyses of the immune cells allowed for the identification of cell types and genes that respond to MDV infection and/or were specific to the genetic resistance. This is the first reported scRNA seq study in chickens and provides a significant step forward in the cellular knowledge of immune cells that respond to MDV infection that also confer genetic resistance. Ultimately, translation of this knowledge will enable more precise methods to select for MD resistant birds, which will aid both consumers and poultry industry as well as enhancing animal welfare.

Technical Abstract: Genetically resistant or susceptible chickens to Marek’s disease (MD) have been widely used models to identify the molecular determinants of these phenotypes. However, these prior studies lacked the basic identification and understanding of immune cell types that could be translated toward improved MD control. To gain insights into specific immune cell types and their responses to Marek’s disease virus (MDV) infection, we used single-cell RNA sequencing (scRNAseq) on splenic cells from MD resistant and susceptible birds. In total, 14,378 cells formed clusters that identified various immune cell types. Lymphocytes, specifically T cell subtypes, were the most abundant with significant proportional changes in some subtypes upon infection. The largest number of differentially expressed genes (DEG) response was seen in granulocytes, while macrophage DEGs differed in directionality by subtype and line. Among the most DEG in almost all immune cell types were granzyme and granulysin, both associated with cell-perforating processes. Protein interactive network analyses revealed multiple overlapping canonical pathways within both lymphoid and myeloid cell lineages. This initial estimation of the chicken immune cell type landscape and its accompanying response will greatly aid efforts in identifying specific cell types and improving our knowledge of host response to viral infection.