Activated long-term peripheral blood cultures as preparation for adoptive alloreactive cell therapy in cancer patients

Nonmyeloablative stem cell transplantation as immunotherapy for kidney cancer and other metastatic solid tumors

Over the past few decades, great strides have been made to advance the field of allogeneic hematopoietic stem cell transplantation. The donor immune mediated graft-vs-tumor effect that follows the procedure is now widely accepted as the most effective form cancer immunotherapy available for patients with a variety of advanced hematological malignancies. Recognition that a transplanted immune system could cure patients with treatment refractory leukemia led to the development of ;low-intensity' conditioning regimens, which have improved the safety of the procedure and broadened the application of allogeneic immunotherapy to a growing list of neoplastic diseases. Here we discuss the investigational use of allogeneic transplantation as immunotherapy for patients with metastatic, treatment-refractory solid tumors.

Bioprocess development for the cultivation of human T-lymphocytes in a clinical scale

Adoptive transfer of large numbers of donor-derived T-lymphocytesmay offer a promising treatment of a variety of viral and malignant diseases. The key step in this approach is the ex vivo generation of sufficient quantities of these cells in a short time.We have investigated the influence of several important cultivation parameters on the proliferation of human T-lymphocytes to develop a large-scale fermentation process usingdifferent types of stirred bioreactors. Such systems offer manypotential advantages over the static culture systems commonlyused today.Peripheral blood mononuclear cells of healthy but CMV positive donors were stimulated with monoclonal antibodies (anti-CD3 and anti-CD28) and Interleukin-2. The influence of osmolality, Interleukin-2 concentration, pH, oxygen tension, feeding strategyand temperature on T-cell proliferation was investigated and theoptimised conditions were transferred to a novel stirred suspension bioreactor with an especially designed magnetic stirrbar to minimize the shear force (working volume 550 ml) and a standard stirred vessel (working volume 1000 ml).Preferable conditions for the cultivation of primary T-lymphocytes were an osmolality of 276-330 mOsmol kg(-1),an Interleukin-2 concentration of 100 U ml(-1), a pH rangeof 7.0 to 7.3, an oxygen tension of 5-50% and a temperature of 38.5 degrees C. After 238 h of cultivation 2.8 x 10(9) cells in the stirred vesseland 1.5 x 10(9) cells in the suspension bioreactor were obtained with a percentage of T-cells >94%. The specificity of the cells wasmaintained during cultivation as proven by IFN-gamma secretionafter exposure to a hCMV protein.

Ex vivo expansion of functional T lymphocytes from HIV-infected individuals

This study was designed to define the conditions for expansion of functional T lymphocytes from human immunodeficiency virus (HIV)-infected subjects, with the ultimate goal of using these cells for immunotherapy. The most appropriate culture conditions for good T cell proliferation included stimulation with anti-CD3 and anti-CD28 coated microspheres, and propagation in Aim V serum-free media with 20 U/ml interleukin-2 (IL-2), supplemented with decreasing concentrations of serum for the initial 8 days. Under these conditions, a 14-day culture period yielded approximately a 10,000-fold expansion of T lymphocytes from HIV-infected donors. The cultured cells comprised approximately 15% CD4+ cells and 70% CD8+ cells. These cells retained functional capacity as assessed by cytotoxicity towards HIV proteins, and production of IL-2 and interferon-gamma (IFN-gamma). Viral replication within the culture system was controlled, but not eliminated, without the requirement for antiviral agents. These culture conditions were demonstrated to be suitable for larger scale expansion of cells in hollow fibre bioreactors. This methodology provides a suitable means of producing large quantities of functional T cells for use in autologous immunotherapy protocols.

Ex vivo T lymphocyte expansion for retroviral transduction: influence of serum-free media on variations in cell expansion rates and lymphocyte subset distribution

OBJECTIVE

In the setting of allogeneic stem cell transplantation, suicide gene-manipulated donor T cells that can be selectively inactivated in vivo would potentially allow optimal control of the GVL (graft-vs-leukemia)/GVHD (graft-vs-host disease) balance. Retroviral T-cell transduction requires ex vivo cell expansion, which is often achieved by IL-2 and anti-CD3 stimulation. Traditionally, culture media for cell expansion are supplemented with fetal bovine serum (FBS) or human serum. While these sera promote cell growth and viability, they contain uncharacterized elements that may yield inconsistent results from batch to batch. Cell expansion in serum-free media would therefore be preferable.

MATERIALS AND METHODS

We compared T-cell expansion rates in three commercially available serum-free culture media (X-VIVO 15, AIM-V, and Cellgro SCGM), with or without the addition of human serum (HS, 5%). We also aimed to evaluate how the in vitro expansion affected the composition of the various T-cell subsets. Buffy-coats from four healthy donors were expanded for 21 days. The media were compared to standard RPMI 1640 medium, supplemented with HS (5%) or FBS (10%). For retroviral transductions, the LN vector carrying the neomycin- resistance gene was used in four additional donors.

RESULTS

In our hands, X-VIVO 15 gave the highest rate of serum-free expansion (a median of 79-fold expansion, range 20-117). For serum-free expansion, activation with OKT3 for 21 days gave slightly higher expansion rates than a 5-day course (however, without statistical significance). When serum was added, this discrepancy was not seen. Cytokine analysis (IFN-gamma, IL-10, and IL-4) showed a distinct type1 cytokine pattern with elevated IFN-gamma levels during the whole period of culture. Flow cytometric analyses showed substantial inter-media, but also some inter-donor, variability in T-cell subset compositions. Transduction of cells with the LN vector and G418 selection resulted in a 14-fold increase (range 3-18) for serum-free X-VIVO 15 based cultures. Cell phenotypes remained unchanged by the transduction procedure as compared to nontransduced cells.

CONCLUSION

Among the tested serum-free media, X-VIVO 15 has shown to best support the in vitro expansion of T cells, resulting in equal percentages of CD4(+) and CD8(+) cells. These cells can easily be transduced and selected. There seem to be no significant benefits, regarding absolute cell numbers or T-cell subset compositions, with OKT3-stimulation for more than five days. The addition of low levels of HS increases the consistencies in the cell expansion rates for all media.

Large-scale production of CD4+ T cells from HIV-1-infected donors after CD3/CD28 costimulation

We describe a procedure for large-scale enrichment, growth, and harvesting CD4+ T cells. This method may be effective for HIV-1 immunotherapy, as the mode of stimulation, with anti-CD3 plus anti-CD28 coated beads (CD3/CD28 beads) induces a potent antiviral effect. PBMC were obtained by density gradient centrifugation of an apheresis product. Monocytes/macrophages were removed by incubating PBMC with beads coated with IgG. The cells were then magnetically depleted of B cells and CD8+ cells with mouse anti-CD20 and anti-CD8 MAbs and sheep antimouse coated beads. The remaining cells were >80% CD4+ and were transferred to gas-permeable bags containing CD3/CD28 beads and cultured in a closed system. After 14 days, the cell number increased an average of 37-fold, and cells were nearly 100% CD4+. Viral load, assessed by DNA PCR for HIV-1 gag, decreased >10-fold during culture in the absence of antiretroviral agents. Removal of CD3/CD28 beads from the cell suspension was accomplished by passing cells plus beads (3-30 x 10(9) cells in 2-12 L) over a MaxSep magnetic separator using gravity-driven flow. The cells were then concentrated to 300 ml in an automated centrifuge. This process allows safe and efficient growth of large numbers of CD4+ T cells from HIV-1+ donors.