title: Ex vivo expansion of human Tregs specific for alloantigens presented directly or indirectly.
abstract: Adoptive transfer of regulatory T cells (Tregs) prevents GVHD in experimental animals. Because antigen activation drives Treg function, we measured the frequency, growth requirements, and function of alloantigen-specific (allospecific) Tregs from human blood. When alloantigen was presented directly, the precursor frequency of allo-specific Tregs in normal individuals was 1.02% (95% confidence interval [95% CI]: 0.65-1.59) and non-Tregs 1.56% (95% CI: 0.94-2.55). When alloantigen was presented indirectly, the frequency of specific Tregs was approximately 100-fold less. Purified Tregs were expanded with APCs, rapamycin, IL-2, and IL-15. In 12 days, allo-specific Tregs expanded 793-fold (95% CI: 480-1107), with duplication approximately every 24 hours. Purified allo-specific Tregs suppressed responses to specific alloantigen selectively and were approximately 100-fold more potent than polyspecific Tregs and nonexpanded Tregs. Allo-specific Tregs maintained high expression of Foxp3, Bcl-2, lymphoid homing receptor CD62L, and chemokine receptor CCR7, predicting sustained function and migration to lymphoid tissues in vivo. Allo-specific Tregs produced TGF-β and IL-10 and expressed more cytoplasmic CTLA-4 compared with non-Tregs. These data provide a platform for the selective expansion of Tregs against major and possibly minor histocompatibility antigens and predict the feasibility of adoptive immunotherapy trials using Tregs with indirect allo-recognition for preventing GVHD while sparing GVL effects.
authors.affiliation: Department of Blood and Marrow Transplantation, Moffitt Cancer Center, Tampa, FL, USA.
authors.forename: Anandharaman
authors.initials: A
authors.lastname: Veerapathran
authors.forename: Joseph
authors.initials: J
authors.lastname: Pidala
authors.forename: Francisca
authors.initials: F
authors.lastname: Beato
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Yu
authors.forename: Claudio
authors.initials: C
authors.lastname: Anasetti
mesh_terms: D019264:Adoptive Transfer; D060908:CTLA-4 Antigen / Q000378:metabolism; D002455:Cell Division / Q000276:immunology; D051858:Forkhead Transcription Factors / Q000276:immunology; D006086:Graft vs Host Disease / Q000276:immunology* / Q000517:prevention & control*; D006801:Humans; D016130:Immunophenotyping; D016753:Interleukin-10 / Q000378:metabolism; D007519:Isoantigens / Q000276:immunology*; D019041:L-Selectin / Q000276:immunology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000276:immunology; D054400:Receptors, CCR7 / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: C515370:CCR7 protein, human; D060908:CTLA-4 Antigen; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508609:IL10 protein, human; D007519:Isoantigens; D019253:Proto-Oncogene Proteins c-bcl-2; D054400:Receptors, CCR7; D016212:Transforming Growth Factor beta; D019041:L-Selectin; D016753:Interleukin-10