IL-7 and IL-15 instruct the generation of human memory stem T cells from naive precursors

Abstract

Key Points• Identification of the biologic requirements for memory stem T cell (T SCM ) generation and expansion from naive precursors ex vivo.• Differentiation, expansion, and genetic manipulation of human T SCM for cancer adoptive cellular therapy. Long-living memory stem T cells (T SCM) IntroductionAdaptive immunity is a potent and flexible system able to combat microbes and cancer cells. 1,2 In the presence of infections or cancer, antigen-specific lymphocytes expand and differentiate into effectors devoted to rapidly clearing the pathogen and memory cells able to persist long-term to patrol the entire organism for recurrence and minimal residual disease. 3,4 However, the mechanism and hierarchical differentiation path underlying the generation of memory precursors and terminal effector cells remain to be fully elucidated. 5 This process has been proposed to involve a self-renewing, stem cell-like memory T-cell subset capable of differentiating into effectors on antigen reencounter. 6,7 This T-cell subset, referred to as memory stem T cells (T SCM ), and initially described in mice, 8,9 begins to be unveiled in humans. 10 T SCM potential biodistribution and long-term persistence represent appealing features to overcome the current limitations of cancer adoptive immune-gene therapy. [11][12][13] At present, clinical-grade protocols able to obtain or preserve T SCM functional and phenotypic characteristics remain to be defined. We previously showed that costimulation of unselected T cells and culture with ␥-chain cytokines allow the preferential generation of gene-modified T cells with a functional central memory (T CM ) phenotype, superior to effector/effector memory (T EM ) counterparts for expansion potential and antitumor activity. 14,15 Compared with T CM and T EM lymphocytes, naive T cells (T N ) are endowed with the highest developmental plasticity and are unique in the ability to generate daughter cells with potential to enter the entire spectrum of immunologic memory, including T SCM . We thus hypothesized that, starting from naive precursors, we could differentiate and genetically engineer human T SCM . We report that IL-7 and IL-15 support the generation of postmitotic costimulated CD8 ϩ T cells with molecular and functional features of T SCM cells. These cells-defined by the expression of CD45RA, CD45R0, CD62L, CCR7, IL-7R␣, and CD95-can be identified among healthy subjects, are selectively enriched in hematopoietic stem cell transplant (HSCT) recipients, and reveal a phenotypic and functional profile distinct from that of T CM and T EM cells for extensive expansion capacity and ability Submitted May 22, 2012; accepted October 25, 2012. Prepublished online as Blood First Edition paper, November 15, 2012; DOI 10.1182 DOI 10. /blood-2012 There is an Inside Blood commentary on this article in this issue.The online version of this article contains a data supplement.The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this arti...

Transgenic antigen-specific, HLA-A*02:01-allo-restricted cytotoxic T cells recognize tumor-associated target antigen STEAP1 with high specificity

“…We then used the protocol of Cieri and colleagues 22 for the infection and generation of STEAP1 P2A5 TCRs transgenic stem-cell-memory-like T cells (T SCM ). Accordingly, we stimulated naive T cells with anti-CD3/CD28 magnetic beads and moderate amounts of rhIL-7 and rhIL-15 (5 ng/mL) during infection.…”

BET bromodomain inhibition enhances T cell persistence and function in adoptive immunotherapy models

“…Ex vivo cultured T cells form surface marker patterns similar to those of memory T cells in vivo as follows: stem cell-like memory (T SCM ), central memory (T CM ), and effector memory (T EM ) T cells. When adoptively transferred, T cells with T SCM and T CM phenotypes showed superior persistence and antitumor effects compared with T cells with the T EM phenotype in both mice and humans (15)(16)(17)(18)(19). However, the in vitro expansion of T cells is inevitably accompanied with their differentiation; T SCM and T CM cells differentiate toward T EM cells as they proliferate upon TCR and cytokine stimulation (20).…”

Low interleukin-2 concentration favors generation of early memory T cells over effector phenotypes during chimeric antigen receptor T-cell expansion

“…In normal donors early TM or CD45RO + TSCMs (i.e.,TSCM-like cells) alone were increased 10%-30% compared with expansions relying on a high IL-2 concentration (100-300 IU/mL) [25,27,30]. Here we accomplished an increase of similar size (5%-30%) in early TM simply by limiting IL-2 supplementation from the current standard.…”

“…Most in vitro expansion protocols lack the ability to generate TSCMs but produce so-called TSCM-like cells that have gained the expression of CD45RO [25][26][27]30].The TSCM-like population was likewise the major memory subset present using our expansion protocol. It is not currently known which of the early T memory subsets (TSCM, TSCM-like or TCM) provides the best clinical efficacy in humans.…”