Dendritic cells (DCs) are the most potent professional antigen presenting cells (APCs) of the immune system. DCs provide three different signals to activate effector T cells during antigen presentation. Signal 1 is delivered by the binding of the T cell receptor (TCR) to the peptide antigen complexed to MHC molecules, which is exposed on the surface of DCs. Signal 2 is provided by the integration of positive and negative co-stimulatory interactions on the surfaces of DCs and T cells. In order to direct the differentiation of T cells into different subtypes a third signal is induced by the secretion of cytokines by the DCs. To enhance cancer immunotherapy we have developed a lentivector, which simultaneously modulates these three signals. First, an antigen of interest is included in the lentivector to provide signal 1. Second, a PD-L1-targeted shRNA that eliminates PD-L1 expression on DCs reinforces positive co-stimulation (signal 2). And finally a cytokine array to modulate signal 3 is expressed to induce the desired anti-cancer effector T cell response. Using this lentivector expression system, we expressed a collection of Th1-, Th2-, Th17-, and Treg-inducing cytokines and evaluated their antigenicity in cultured DCs. We also evaluated these lentivectors by vaccination in mice and found that we could induce distinct T cell profiles combined with low Treg numbers. Finally, we have data demonstrating anti-tumour activities of some of these constructs in a mouse model for melanoma. Concluding, we have developed a lentivector system that is capable of activating as well as fine-tuning adoptive T cell responses according to the disease in question and that induces in vivo anti-tumour responses in mice.
|Journal||Human Gene Therapy|
|Publication status||Published - 1 Dec 2013|
|Event||The European Society for Gene and Cell Therapy and the Spanish Society for Gene and Cell Therapy Collaborative Congress 2013 - Madrid, Spain|
Duration: 25 Oct 2013 → 28 Oct 2013