Objective The ability of adoptively-transferred T cells to mediate an immune response is modulated by the host environment. It has previously been shown that donor T cells proliferate and acquire memory-like characteristics when injected into lymphopenic hosts while in hosts with a « full » T cell compartment, they remain naïve and do not acquire effector function. As it is important to optimize the persistence and responsiveness of transferred T cells for immunotherapy strategies, we assessed whether T cell fate is dependent upon the conditioning regimen used to achieve lymphopenia. We induced lymphopenia in C57Bl/6 mice by sub-lethal irradiation or chemotherapy using busulfan with cyclophosphamide (Bu/Cy) and found that the relative engraftment of CD4 and CD8 T cells was markedly changed by the conditioning protocol: Irradiation-induced lymphopenia resulted in a skewed proliferation of donor CD8 T cells with a CD4:CD8 ratio of <1:5 whereas Bu/Cy-induced lymphopenia resulted in a massive proliferation of donor CD4 T cells with only minimal proliferation of CD8 T cells. These results clearly demonstrate that lymphopenic conditions are not equivalent in their potential to foster the regeneration of T cell pools. I propose to study the characteristics of the host and adoptively-transferred T cells generated in these two lymphopenic environments, with specific assessment of TH1, TH17 and Treg subsets. As the host microenvironment modulates T cell persistence and function, the effects of these regimens on the fate of stromal cell and APC populations will also be monitored. Moreover, I will study the consequences of irradiation and Bu/Cy conditioning on the reconstitution and function of adoptively-transferred T cells harboring a re-directed tumor-specific TCR in mice harbouring B cell lymphomas. The identification of parameters that enhance the survival and reactivity of adoptively-transferred tumor-specific T cells is important for the development of immunotherapy strategies Fields of science medical and health sciencesbasic medicineimmunologyimmunotherapymedical and health sciencesbasic medicinephysiologyhomeostasis Programme(s) FP7-PEOPLE - Specific programme "People" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013) Topic(s) FP7-PEOPLE-2009-RG - Marie Curie Action: "Reintegration Grants" Call for proposal FP7-PEOPLE-2009-RG See other projects for this call Funding Scheme MC-IRG - International Re-integration Grants (IRG) Coordinator CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS EU contribution € 100 000,00 Address RUE MICHEL ANGE 3 75794 Paris France See on map Region Ile-de-France Ile-de-France Paris Activity type Research Organisations Administrative Contact Jocelyn Mere (Mr.) Links Contact the organisation Opens in new window Website Opens in new window Total cost No data