Successful generation of primary virus-specific and anti-tumor T-cell responses from the naive donor T-cell repertoire is determined by the balance between antigen-specific precursor T cells and regulatory T cells

Abstract

The online version of this article has a Supplementary Appendix. BackgroundOne of the major challenges in allogeneic stem cell transplantation is to find a balance between the harmful induction of graft-versus-host disease and the beneficial graft-versus-leukemia and pathogen-specific immune responses. Adoptive transfer of in-vitro generated donor T cells with specific anti-leukemic or pathogen-specific activity may be effective. However, in many cases this requires the in-vitro priming and expansion of antigen-specific precursor T cells from the naïve donor T-cell repertoire. Design and MethodsAntigen-specific CD8 T cells were generated by co-culture of CD45RO-depleted, regulatory T cell-depleted donor peripheral blood mononuclear cells with autologous peptide-loaded dendritic cells, followed by two re-stimulations with peptide-loaded autologous monocytes. Responding T cells were isolated based on CD137 expression and further purified using peptide/major histocompatibility complex tetramers. ResultsUsing this method we were able to reproducibly generate functionally high avidity T cells directed against multiple viral antigens and minor histocompatibility antigens from the naïve T-cell repertoire of seronegative, minor histocompatibility antigen-negative donors. Furthermore, we demonstrated that reduction of the regulatory T-cell frequency by depletion of CD45RO + responder cells resulted in improved priming and expansion of antigen-specific precursor T cells. ConclusionsIn conclusion, we present a robust method for the in-vitro induction and isolation of antigenspecific T cells from the naïve repertoire. We demonstrate that the likelihood of successful generation of primary immune responses is determined by a delicate balance between the numbers of antigen-specific precursor T cells and the numbers and activation state of regulatory T cells locally at the site of priming of the immune response.Key words: primary immune responses, regulatory T cells, CMV, minor histocompatibility anti gens, immunotherapy. tory T cells. Haematologica 2011;96(8):1204-1212. doi:10.3324/haematol.2010 This is an open-access paper. Citation: Jedema I, van de Meent M, Pots J, Kester MGD, van der Beek MT, and Falkenburg JHF. Successful generation of primary virus-specific and anti-tumor T cell responses from the naïve donor T-cell repertoire is determined by the balance between antigen-specific precursor T cells and regula Successful generation of primary virus-specific and anti-tumor T-cell responses from the naïve donor T-cell repertoire is determined by the balance between antigen-specific precursor T cells and regulatory T cells

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.…”

Monocyte‐derived dendritic cells can induce autoreactive CD4+ T cells showing myeloid lineage directed reactivity in healthy individuals

“…To allow efficient in vitro priming of naive antigen-specific precursor T cells, Treg-cell depletion of the responder T-cell populations has been applied [21]. However, this Treg-cell depletion in combination with priming with autoDCs as professional APCs may allow the outgrowth of autoreactive T cells that are under normal circumstances kept silent by Treg cells [20,[22][23][24][25][26][27][28].…”

Management of multidrug‐resistant viruses in the immunocompromised host

“…In addition, these strategies are only applicable when the donor has immunity to the viruses. More recent attempts to overcome this limitation via manipulation of culture conditions to allow expansion of virus-specific cells in primary immune responses ex vivo are showing some promise (Park et al, 2006;Jedema et al, 2011), though clinical application has yet to be reported. Given that such cells, particularly the CD8 compartment, have been reported to recognize unconventional CMV epitopes (Hanley et al, 2009), the results of clinical application are keenly awaited.…”