Comprehensive Transcriptomic Comparison between Porcine CD8(−) and CD8(+) Gamma Delta T Cells Revealed Distinct Immune Phenotype

SIMPLE SUMMARY: This study was conducted to comprehensively understand the functional mechanisms of CD8(+/−) porcine gamma delta (γδ) T cells related to the immune system using RNA-sequencing technology. In total, 646 upregulated and 561 downregulated differentially expressed genes (DEGs) for CD8(+) were identified and functional annotation was performed. A cytokine–cytokine receptor interaction and T cell receptor (TCR) signaling pathway were enriched in the upregulated DEG group, whereas the B cell receptor signaling pathway was enriched in the downregulated DEG group. Chemokine-related genes (CXCR3, CCR5, CCL4, CCL5), interferon gamma (IFNG), and CD40 ligand (CD40LG) identified in the cytokine–cytokine receptor interaction and TCR signaling pathway may affect the inter-regulation of immune signaling. Our results are expected to contribute to the understanding of mechanisms of porcine γδ T cells. ABSTRACT: We aimed to comprehensively understand the functional mechanisms of immunity, especially of the CD8(+/−) subsets of gamma delta (γδ) T cells, using an RNA-sequencing analysis. Herein, γδ T cells were obtained from bronchial lymph node tissues of 38-day-old (after weaning 10-day: D10) and 56-day-old (after weaning 28-day: D28) weaned pigs and sorted into CD8(+) and CD8(−) groups. Differentially expressed genes (DEGs) were identified based on the CD8 groups at D10 and D28 time points. We confirmed 1699 DEGs between D10 CD8(+) versus D10 CD8(−) groups and 1784 DEGs between D28 CD8(+) versus D28 CD8(−) groups; 646 upregulated and 561 downregulated DEGs were common. The common upregulated DEGs were enriched in the cytokine–cytokine receptor interaction and T cell receptor (TCR) signaling pathway, and the common downregulated DEGs were enriched in the B cell receptor signaling pathway. Further, chemokine-related genes, interferon gamma, and CD40 ligand were involved in the cytokine–cytokine receptor interaction and TCR signaling pathway, which are associated with inter-regulation in immunity. We expect our results to form the basic data required for understanding the mechanisms of γδ T cells in pigs; however, further studies are required in order to reveal the dynamic changes in γδ T cells under pathogenic infections, such as those by viruses.