Th1/Th2 and Tc1/Tc2 cells: biology, experimental models and clinical translation - Immune Biology of Allogeneic Hematopoietic Stem Cell Transplantation - page 234

received ex vivo -manufactured donor Th2/Tc2 cells that were generated by
costimulation in the presence of IL-4 and IL-2 (no rapamycin). Relative to a
historical cohort that received the same therapy in the absence of Th2/Tc2
cell infusion, Th2/Tc2 cell recipients had a higher level of donor engraft-
ment (avoidance of mixed donor/host chimerism) and restaging results at
day 28 post-transplant suggested that an early GVT effect was operative;
however, a significant incidence and severity of acute GVHD was observed,
and as such, Th2/Tc2-cell dose escalation was not possible (all patients
received 5 × 10 6 Th2/Tc2 cells/kg). In sum, these data demonstrated that, in
this setting, the manufactured Th2/Tc2 cells did not clinically dissect GVT
effects from GVHD.

Ongoing clinical trial efforts using rapamycin-resistant
Th2/Th1 cells

In parallel with the implementation of these first-generation clinical trials,
we determined that murine Th2 cells generated ex vivo in high-dose rapa-
mycin were more effective than control Th2 cells relative to in vivo cyto-
kine-polarization capacity and with respect to prevention of acute GVHD,
prevention of graft rejection, and balancing of GVT effects with GVHD. In
light of these murine results, we developed a clinical-scale manufacturing

237

FIGURE 11.3
Clinical translation of rapamycin-resistant Th1/Th2-cell therapy. (I) Prior to collection of peripheral blood stem cells, transplant donors underwent steady-state
apheresis. CD4 + T cells were isolated by Miltenyi positive selection and costimulated using anti-CD3-, anti-CD28-coated magnetic beads in the presence of IL-4, IL-2,
and rapamycin. (II) After 12 days, manufactured T cells were evaluated for expression of GATA-3, T-bet, and FOXP3, the results indicating a mix of Th2 and Th1 cells (Th2
> Th1) with minimal contamination with Treg cells. (III) Manufactured products were minimally differentiated, as indicated by very low magnitudes of cytokine production;
with additional ex vivo expansion in the absence of rapamycin or polarizing cytokines, manufactured cells displayed their mixed Th2/Th1 effector cytokine secretion profile,
with minimal secretion of the Th17 cell cytokine IL-17. (IV) Th2/Th1 cells manufactured ex vivo in rapamycin were evaluated in a phase II clinical trial (NCT00074490).
Patients with refractory hematologic malignancy (one CD4 count <200/ μ l) received low-intensity chemotherapy conditioning followed by T-cell-replete peripheral blood
hematopoietic stem cell transplantation; initial immune suppression consisted of cyclosporin A in combination with a short course of Sirolimus. At day 14 post-transplant,
in the setting of mixed donor/host chimerism, patients received a preemptive donor lymphocyte infusion with the manufactured, rapamycin-resistant Th2/Th1 cells.