- Poster presentation
- Open Access
MyD88/CD40-based inducible co-stimulation to improve CAR T cell therapy
© Mata et al. 2015
Published: 4 November 2015
Adoptive immunotherapy with genetically modified T cells holds promise in improving outcomes for cancer patients. While a broad array of genetic modification strategies are being explored, few allow for the specific manipulation of adoptively transferred T cells in vivo. One successful example includes the introduction of an inducible ‘suicide gene’ to enable selective T-cell killing in the event of toxicities. Given the limited antitumor activity of adoptively transferred T cells for solid tumors in early clinical studies, we reasoned that introducing an inducible co-stimulatory molecule into T cells would allow for the selective activation of adoptively transferred T cells in vivo resulting in enhanced antitumor activity. Due to the role of MyD88 and CD40 signaling pathways to fine tune T-cell activation, and the recent success of using inducible (i) MyD88 and CD40 molecules to activate antigen-presenting cells, the goal of this project was to explore if T cells can be activated with iMyD88 and/or iCD40 molecules.
We constructed a panel of retroviral vectors encoding mOrange as a marker gene and an inducible co-stimulatory molecule (iCO-STIM) consisting of a myristoylation tag, two FKBP dimerizer domains, and i) MyD88, ii) CD40, or iii) MyD88 + CD40. T cells expressing iMyD88, iCD40, or iMyD88.CD40 were generated by retroviral transduction, and transduction was confirmed by FACS analysis and Western blot. T cells expressing iCO-STIMs were activated with the CD3 monoclonal antibody OKT3 in the presence or absence of the chemical inducer of dimerization (CID), AP20187. iMyD88.CD40 T cells secreted the highest amount of IL2 in the presence of OKT3 + CID in comparison to iMyD88 or iCD40 T cells. To evaluate if activating iMyD88.CD40 in CAR T cells also enhances cytokine production, we generated T cells that expressed HER2-CARs and iMyD88.CD40 (HER2-CAR/iCO-STIM T cells). CID enhanced IL2 production of HER2-CAR/iCOSTIM T cells that were either stimulated with recombinant HER2 protein or HER2+ cell lines. Enhanced IL2 production was observed with 1st, 2nd, and 3rd generation HER2-CARs.
We have generated CAR T cells with an inducible co-stimulatory molecule based on MyD88 and CD40. Preliminary functional analysis of CAR/iCO-STIM T cells is encouraging, warranting further active exploration of this approach to improve current T-cell therapy approaches for cancer.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.