title: Initial depletion of regulatory T cells: the missing solution to preserve the immune functions of T lymphocytes designed for cell therapy.
abstract: We investigated the causes of the altered functionality of T cells cultured under conditions designed for cell and gene therapy and the strategies to prevent their defects. We first showed that human T cells cultured for 6 days with anti-CD3 +/- anti-CD28 antibodies and interleukin-2 presented a 50% decrease of their proliferative responses to allogeneic or recall antigens. Similarly, day-6 cultured murine T cells completely lost their capacity to reject allogeneic skin grafts and to provoke graft-versus-host disease (GVHD) when infused into irradiated semi-allogeneic mice. Interestingly, injection of higher amounts of cultured T cells restored GVHD induction. Moreover, depletion of CD25+ cells prior to T-cell cultures can prevent these deficiencies both in mice and humans. Therefore, we demonstrated that culture conditions used for T-cell therapy preferentially activated and expanded regulatory T cells (Treg's). Thus, we showed that dividing cells sorted from T-cell cultures strongly suppressed the proliferation of autologous T cells in response to allogeneic stimulation. An increased detection of Foxp3 at mRNA and protein levels in the cultures confirmed the Treg expansion. Overall, we demonstrate that T-cell cultures promote Treg expansion over effector T cells, leading to deleterious immune functions, and that this imbalance can be prevented by an initial depletion of CD25+ cells.
authors.affiliation: UMR CNRS 7087/UPMC, Hôpital Pitié Salpêtrière-Bâtiment CERVI, 83, Boulevard de l'Hôpital, 75013 Paris, France.
authors.forename: Mariana
authors.initials: M
authors.lastname: Mesel-Lemoine
authors.forename: Mustapha
authors.initials: M
authors.lastname: Cherai
authors.forename: Sabine
authors.initials: S
authors.lastname: Le Gouvello
authors.forename: Maude
authors.initials: M
authors.lastname: Guillot
authors.forename: Virginie
authors.initials: V
authors.lastname: Leclercq
authors.forename: David
authors.initials: D
authors.lastname: Klatzmann
authors.forename: Véronique
authors.initials: V
authors.lastname: Thomas-Vaslin
authors.forename: François M
authors.initials: FM
authors.lastname: Lemoine
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D018106:CD28 Antigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D018929:Cell Culture Techniques; D049109:Cell Proliferation; D064987:Cell- and Tissue-Based Therapy / Q000379:methods*; D006084:Graft Rejection; D006086:Graft vs Host Disease; D006801:Humans; D007108:Immune Tolerance; D007111:Immunity, Cellular; D007519:Isoantigens / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008212:Lymphocyte Depletion; D051379:Mice; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D018106:CD28 Antigens; D017252:CD3 Complex; D007519:Isoantigens