Abstract
CD8+ T cells have a pivotal role in the anti-tumour immune response and are the main focus of adoptive cellular therapy (ACT) for cancer. However, extensive in vitro expansion often leads to cell exhaustion, limiting the efficacy of ACT. Previous research has revealed ACT with chimeric antigen receptor (CAR) T cells expressing a p53 isoform, Δ133p53, enhances tumour clearance and survival of leukaemia-bearing mice. However, the effects of Δ133p53 on in vitro T cell functions are currently unclear.
To understand the functions of human Δ133p53, the Braithwaite lab developed a mouse analogue, Δ122p53, that mirrors Δ133p53. Using T cells from Δ122p53-expressing mice, my project explores the effects of Δ133p53 on the function of CD8+ T cells in vitro. We hypothesised that Δ122p53 could enhance cell expansion whilst maintaining high cell quality, important for the efficacy of ACT. To address this, wild-type and Δ122p53-expressing CD8+ T cells were stimulated with antigen-presenting cells, and their expansion, phenotype, and cytokine production was assessed. To examine exhaustion, multiple antigen stimulations were performed.
Results demonstrate no significant differences in the cytokine production and cell phenotype of WT- and Δ122p53-CD8+ T cells. Although the latter displayed slightly greater proliferative capacity, both cell types exhibited signs of exhaustion after three repeated antigen stimulations, indicated by decreased total expansion and cytokine production, and increased expression of immune checkpoint molecules. These findings suggest that Δ133p53 might aid other aspects of T cells and enhance their anti-tumour functions in vivo, which will be investigated in our future studies.