Leukemia-associated minor histocompatibility antigen discovery using T-cell clones isolated by in vitro stimulation of naive CD8+ T cells

Abstract

T-cell immunotherapy that targets minor histocompatibility (H) antigens presented selectively by recipient hematopoietic cells, including leukemia, could prevent and treat leukemic relapse after hematopoietic cell transplantation without causing graft-versus-host disease. To provide immunotherapy that can be applied to a majority of transplantation recipients, it is necessary to identify leukemiaassociated minor H antigens that result from gene polymorphisms that are balanced in the population and presented by common human leukocyte antigen alleles. Current approaches for deriving minor H antigen-specific T cells, which provide essential reagents for the molecular identification and characterization of the polymorphic genes that encode the antigens, rely on in vivo priming and are often unsuccessful. We show that minor H antigen-specific cytotoxic T lymphocyte precursors are found predominantly in the naive CD8 ؉ T-cell subset and provide an efficient strategy for in vitro priming of native T cells to generate T cells to a broad diversity of minor H antigens presented with common human leukocyte antigen alleles. We used this approach to derive a panel of stable cytotoxic T lymphocyte clones for discovery of genes that encode minor H antigens and identify a novel antigen expressed on acute myeloid leukemia stem cells and minimally in graft-versus-host disease target tissues. (Blood. 2010;115(23): 4923-4933)

Depletion of naive T cells using clinical grade magnetic CD45RA beads: a new approach for GVHD prophylaxis

“…19 Although these data are of relatively low significance because of the small sample size, they are consistent with previous results of several investigators including ourselves showing that naive-depleted (or memory-enriched) CD8 þ T cells contained very low numbers of leukemia-reactive T cells, 6,[20][21][22][23] regardless which T-cell differentiation marker including CD45RA was used for cell selection. This suggests the use of CD45RA-depleted DLIs preferentially in situations where the risk of leukemia relapse is low or the disease is nonmalignant.…”

“…25 Also replenishment of DLIs with in vitro produced leukemia-reactive T cells from the CD45RA þ naive-enriched T-cell subset may be an option. [21][22][23] In conclusion, clinical grade depletion of naive T cells from entire LPs is feasible and highly efficient using magnetic CD45RA beads and the CliniMACS device. The CD45RA À target fraction contains effector and central memory T cells that show preserved reactivity to common viral and fungal pathogens.…”

Alloreactive and leukemia-reactive T cells are preferentially derived from naive precursors in healthy donors: implications for immunotherapy with memory T cells

“…Our data also suggest that depletion of naïve T cells will 14, 15 We and others have reported that cytotoxic T lymphocyte-mediated reactivity to leukemia cells mainly derives from naïve CD8 T cells in healthy unprimed individuals 19,[21][22][23] and that such cytotoxic T lymphocytes target polymorphic minor histocompatibility antigens (mHag) and non-polymorphic leukemia-associated antigens (LAA). 21,22,24 These findings are further supported by HLA-peptide multimer data in ex vivo PBMC showing most precursors of LAA-reactive CD8 T cells in the naïve subset of healthy individuals.…”

Cytotoxic T lymphocytes for leukemia and lymphoma

“…This approach successfully identified mHag-reactive T cells in every donor-recipient pair tested, leading to the description of new mHags defined at the genetic and protein sequence level. 25 However, these sophisticated, time-consuming, and expensive approaches are not widely available at present. Furthermore, the narrow repertoire of mHag-specific CTLs recognizing only hematologic cells that can effectively eliminate leukemia without off-target side effects on nonhematopoietic tissue limits clinical applicability.…”