title: Functional characterization of alloreactive T cells identifies CD25 and CD71 as optimal targets for a clinically applicable allodepletion strategy.
abstract: Immunotherapy with allodepleted donor T cells (ADTs) improves immunity after T cell-depleted stem cell transplantation, but infection/relapse remain problematic. To refine this approach, we characterized the expression of surface markers/cytokines on proliferating alloreactive T cells (ATs). CD25 was expressed on 83% of carboxyfluorescein diacetate succinimidyl ester(dim) ATs, confirming this as an excellent target for allodepletion. Seventy percent of CD25(-) ATs expressed CD71 (transferrin receptor), identifying this as a novel marker to target ATs persisting after CD25 depletion. Comparison of residual alloreactivity after combined CD25/71 versus CD25 immunomagnetic depletion showed enhanced depletion of alloreactivity to host with CD25/71 depletion in both secondary (2 degrees) mixed lymphocyte reactions (P < .01) and interferon-gamma enzyme-linked immunospot assays (P < .05) with no effect on third-party responses. In pentamer/interferon-gamma enzyme-linked immunospot assays, antiviral responses to cytomegalovirus, Epstein-Barr virus, and adenovirus were preserved after CD25/71 allodepletion. CD25/71 ADTs can be redirected to recognize leukemic targets through lentiviral transfer of a chimeric anti-CD19zeta T-cell receptor. Finally, we have established conditions for clinically applicable CD25/71 allodepletion under European Union Good Manufacturing Practice conditions, resulting in highly effective, reproducible, and selective depletion of ATs (median residual alloreactivity to host in 2 degrees mixed lymphocyte reaction of 0.39% vs third-party response of 62%, n = 5). This strategy enables further clinical studies of adoptive immunotherapy with larger doses of ADTs to enhance immune reconstitution after T cell-depleted stem cell transplantation.
authors.affiliation: Department of Molecular Immunology, Institute of Child Health, London, United Kingdom.
authors.forename: Sujith
authors.initials: S
authors.lastname: Samarasinghe
authors.forename: Christoph
authors.initials: C
authors.lastname: Mancao
authors.forename: Martin
authors.initials: M
authors.lastname: Pule
authors.forename: Niga
authors.initials: N
authors.lastname: Nawroly
authors.forename: Helen
authors.initials: H
authors.lastname: Karlsson
authors.forename: Jennifer
authors.initials: J
authors.lastname: Brewin
authors.forename: Peter
authors.initials: P
authors.lastname: Openshaw
authors.forename: H Bobby
authors.initials: HB
authors.lastname: Gaspar
authors.forename: Paul
authors.initials: P
authors.lastname: Veys
authors.forename: Persis J
authors.initials: PJ
authors.lastname: Amrolia
mesh_terms: D015703:Antigens, CD / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology*; D008212:Lymphocyte Depletion; D011990:Receptors, Transferrin / Q000276:immunology*; D033581:Stem Cell Transplantation; D013601:T-Lymphocytes / Q000276:immunology*; D014184:Transplantation, Homologous
chemical_list: D015703:Antigens, CD; C068126:CD71 antigen; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit; D011990:Receptors, Transferrin