Article Text

Download PDFPDF

1028 IL-12 and IL-27 upregulate CD39 expression on CD8+ T-cells and differentially affect CD39+CD8+ T-cell effector function
  1. Lara Gerhardt,
  2. Rene Figueredo and
  3. Saman Maleki
  1. Western University, London, ON, Canada


Background Tumor-specific CD8+ T-cells play a critical role in tumor control, as demonstrated by the success of immune checkpoint inhibitors and adoptive cell therapy. Studies of mice and human tumor-infiltrating lymphocytes (TILs) demonstrate that tumor-specific CD8+ TILs can be defined by CD39 expression on their surface. CD39 is commonly considered an immunosuppressive enzyme, as it depletes ATP. However, CD39 is also associated with mitigating activation-induced cell death and mediating leukocyte trafficking. It is, however, unclear whether CD39 expression on tumor-specific T-cells can be regulated by putative anti-tumor factors such as pro-inflammatory cytokines similar to the phenotype and anti-tumor properties of CD8+ TILs. IL-12 and IL-27 have established roles in promoting effector T-cell differentiation, expansion, and cytotoxic activity. Both cytokines are implicated in the upregulation of CD39 by T regulatory cells, suggesting they may regulate CD39 expression in other cell types, including tumor-specific CD8+ T-cells. We hypothesize that IL-12 and IL-27 induce CD39 upregulation on CD8+ T- cells, modulating their anti-tumor properties.

Methods An engineered immunogenic, syngeneic neuroblastoma (neuro-2a) mouse model was used for in vitro and in vivo experiments. CD8+ T-cells or bulk splenocytes isolated from naïve or neuro-2a vaccinated mice were stimulated in vitro using anti-CD3/CD28 Dynabeads and IL-2 ± IL-12 or IL-27. Flow cytometry was used to determine the phenotype of CD8+ T-cells and assess effector activity. Additionally, we inhibited IL-12 activity in vivo to study the effect on CD8+ TIL expression of CD39. An isotype control antibody was administered to a separate group to act as a control.

Results Our in vitro results demonstrate that CD8+ T-cells stimulated in the presence of IL-12 or IL-27 had higher expression of CD39 compared to stimulated controls. In addition, we found a higher frequency of CD39+CD8+ T-cells expressing IFNγ and CD107a than CD39- counterparts. Finally, blocking IL-12 activity in vivo reduced CD39+CD8+ TIL frequency compared to the isotype control group.

Conclusions Our results establish that IL-12 and IL-27 induce CD39 expression on CD8+ T-cells and blocking IL-12 reduced CD39+CD8+ TIL frequency. Furthermore, CD39 expression is associated with improved effector CD8+ T-cell function. Future experiments will assess the functionality of CD39+CD8+ T-cells using ex vivo cytotoxicity assays. Data generated in this study will provide novel information on the mechanism of CD39 induction and its effect on CD8+ T-cell function, which can be exploited to improve future cancer therapies.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.