Unravelling the biology of double-positive CD4/CD8αβ T cells in peripheral tissues

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Presentation Time: 02:15 PM - 03:30 PM
Poster Board Number: B1004
Abstract ID: 4154

Presenting Author:
Wei Yang Kong , PhD student at Univ. of Queensland

Abstract:

Double-positive CD4/CD8αβ (DPαβ) T cells are found in the peripheral tissues, and reportedly increase in number during viral infections and cancers. However, the function of these cells remains controversial. The study of DPαβ T cells is impeded by their scarcity and the fact that many analyses do not distinguish between true DPαβ T cells and aggregates of single-positive (SP) CD4 and CD8 T cells. Using a Hoechst staining method, we improved the identification of true DPαβ T cells, achieving a purity of 85.2 % and 20.2% from spleen and lymph nodes, respectively. The intraperitoneal administration of IL-2/antibody complexes were found to boost DPαβ T cell numbers in both the spleen and lymph nodes of mice. DPαβ T cells adoptively transferred into Rag1^-/- mice were readily detectible 3 months later, suggesting that DPαβ T cells maintain a stable phenotype over time. Moreover, when SP CD4 T cells were adoptively transferred into Rag1^-/- mice they were found to express CD8αβ, suggesting DPαβ T cells in the periphery are derived from CD4 T cells. Low numbers of DPαβ T cells were found to reduce ear inflammation in contact hypersensitivity assays following ovalbumin challenge, suggesting immunosuppressive behavior. Collectively, the characterization of DPαβ T cells requires stringent methodology and warrants further study. Single-cell transcriptomic analysis offers a deeper insight into the complexity and contribution of DPαβ T cells to the immunological landscape.