Pretransplant tumor antigen-specific immunization of allogeneic bone marrow transplant donors enhances graft-versus-tumor activity without exacerbation of graft-versus-host disease

Allogeneic bone marrow transplantation (BMT) causes a beneficial graft-versus-tumor (GVT) immune response that is often associated with graft-versus-host disease (GVHD). There is substantial interest in developing therapeutic strategies that augment GVT without GVHD. We have demonstrated recently that immunization of BMT donors with cellular tumor vaccines leads to curative GVT but induces unacceptable GVHD because of the presence of recipient minor histocompatibility antigens (mHAgs) in whole-cell tumor vaccines. This study tested the hypothesis that immunization of BMT donors against a defined tumor-specific antigen with a vaccine not containing recipient mHAgs would help to separate the two responses by enhancing GVT activity without exacerbating GVHD, even when cellular vaccines were used after BMT. Recipient strain C57BL/6 fibrosarcoma cells engineered to express the well-characterized model tumor antigen, influenza nucleoprotein (NP), were used in these studies. C3H.SW donors were immunized against NP prior to BMT, and cytolytic T cells were transferred along with bone marrow into irradiated H-2-matched, mHAg-mismatched C57BL/6 recipients with established micrometastatic 205-NP tumors. Donor immunization led to a significant increase in GVT activity, as measured by reduction in tumor growth and enhanced survival. However, deaths in recipients of tumor antigen-specific immune BMT ultimately occurred because of the growth of antigen-loss variants; such tumor growth did not occur in animals receiving BMT from donors treated with whole-cell vaccines. Donor immunization did not lead to an exacerbation of GVHD, even when BMT recipients received additional immunization after BMT with a 205-NP "whole" tumor cell vaccine (which was shown to induce fatal GVHD when used for donor immunization). In conclusion, immunization of allogeneic BMT donors against a tumor-specific antigen significantly enhances GVT activity without an associated exacerbation of GVHD.     

Donor leukocyte infusion from immunized donors increases tumor vaccine efficacy after allogeneic bone marrow transplantation

Donor T cells play a critical role in mediating both harmful graft-versus-host disease (GVHD) and beneficial graft-versus-tumor effect after allogeneic bone marrow transplantation (BMT). We have recently demonstrated a novel treatment strategy to stimulate specific antitumor activity with preservation of tolerance to host antigens after T cell-depleted allogeneic BMT by vaccination of recipients with irradiated B16 melanoma cells engineered to secrete granulocyte-macrophage colony-stimulating factor. In this murine system, donor leukocyte infusion from a donor immunized with the recipient-derived B16 vaccines enhanced clinical activity of tumor vaccines without exacerbating GVHD. CD4(+) T cells are essential for this enhancement. In vitro analysis of splenocytes from donor leukocyte infusion donor mice demonstrated that immunization of donors with the recipient-derived B16 vaccines elicited potent T-cell proliferation and cytokine responses specific to B16 antigens. These results demonstrate that immunization of donors with recipient-derived tumor vaccines preferentially induces tumor-specific T-cell responses and that vaccination of both donors and recipients can generate potent antitumor immunity without exacerbating GVHD. This strategy has important implications to prevent recurrence of malignancies after BMT.     

Cellular tumor vaccines administered after T cell-depleted allogeneic bone marrow transplantation induce effective anti-tumor immune responses

In allogeneic hematopoietic stem cell (HSC) transplantation, graft vs. tumor (GVT) activity contributes to the cancer cure. It is closely associated with graft vs. host disease (GVHD), an immune response initiated by transplanted donor T-cell responses against host minor histocompatibility antigens (mHAgs). GVHD is prevented by T-cell depletion of the donor graft, but T-cell depletion also abrogates curative GVT. We wished to test the hypothesis that cellular tumor vaccines administered after T cell-depleted HSC transplant can induce significant GVT effects, despite the absence of transplanted mature donor T cells. In this investigation, a murine model of major histocompatibility complex (MHC)-matched, mHAg-mismatched allogeneic HSC transplant was studied. T cell-depleted or normal T cell-containing grafts were given to myeloablated recipients. Following reconstitution the recipients were vaccinated with tumor vaccines. GVT responses were measured in vitro by T-cell function assays and flow cytometry, and in vivo by tumor burden or survival. Post-transplant tumor vaccines induced effective anti-tumor responses in recipients of T cell-depleted transplants, producing cytolytic and cytokine responses, reduced tumor burden and prolonged survival. Recipients of T cell-depleted transplants that still have significant thymic function may be suitable subjects for post-transplant vaccine therapy.     

TRAIL-induced cell death cooperates with IFN-gamma activation in the graft-versus-tumor effect against colon tumors

The graft-versus-tumor (GVT) effect that occurs following allogeneic bone marrow transplantation (BMT) and donor lymphocyte infusion (DLI) is currently being subjected to intensive investigation because of clinical evidence for GVT efficacy against leukemia. In this report, we investigate the efficacy and molecular mechanisms of GVT against solid tumors, using a modification of the mouse parent-to-F1 BMT model. Mouse Colon26 cells in which tumor necrosis factor related apoptosis-inducing ligand (TRAIL) receptor expression was stably knocked down were transplanted to investigate the role of the TRAIL-TRAIL receptor system in the GVT effect. In addition, Fas ligand-(FasL) deficient mice on a C57BL6 (B6) background were used as donors, to determine the significance of the Fas-FasL system for the antitumor effect. The group that received B6 DLI followed by preconditioning with 950 rad irradiation underwent tumor reduction associated with the induction of IFN-gamma, TRAIL and tumor-cell apoptosis. In vitro cultured Colon26 cells were resistant to TRAIL but susceptible to the combination of IFN-gamma and TRAIL in a TRAIL-dose-dependent manner. The infusion of lymphocytes from FasL-defective donors reduced the tumor progression, although efficacy was decreased in the TRAIL receptor knockdown tumors but not in wild-type ones, compared with infusion of B6-derived lymphocytes. The findings indicate that GVT activity against subcutaneous colon tumors is efficiently induced by preconditioning with irradiation and allogeneic DLI, and that TRAIL and IFN-gamma act cooperatively in the antitumor effect.     

Tumor cell vaccine elicits potent antitumor immunity after allogeneic T-cell-depleted bone marrow transplantation

Allogeneic bone marrow transplantation (BMT) is currently restricted to hematological malignancies because of a lack of antitumor activity against solid cancers. We have tested a novel treatment strategy to stimulate specific antitumor activity against a solid tumor after BMT by vaccination with irradiated tumor cells engineered to secrete granulocyte-macrophage colony-stimulating factor (GM-CSF). Using the B16 melanoma model, we found that vaccination elicited potent antitumor activity in recipients of syngeneic BMT in a time-dependent fashion, and that immune reconstitution was critical for the development of antitumor activity. Vaccination did not stimulate antitumor immunity after allogeneic BMT because of the post-BMT immunodeficiency associated with graft-versus-host disease (GVHD). Remarkably, vaccination was effective in stimulating potent and long-lasting antitumor activity in recipients of T-cell-depleted (TCD) allogeneic bone marrow. Recipients of TCD bone marrow who showed significant immune reconstitution by 6 weeks after BMT developed B16-specific T-cell-cytotoxic, proliferative, and cytokine responses as a function of vaccination. T cells derived from donor stem cells were, therefore, able to recognize tumor antigens, although they remained tolerant to host histocompatibility antigens. These results demonstrate that GM-CSF-based tumor cell vaccines after allogeneic TCD BMT can stimulate potent antitumor effects without the induction of GVHD, and this strategy has important implications for the treatment of patients with solid malignancies.     

Posttransplant administration of cyclophosphamide and donor lymphocyte infusion induces potent antitumor immunity to solid tumor

PURPOSE: Nonmyeloablative allogeneic stem cell transplantation (SCT) has been increasingly used for the treatment of hematologic and solid malignancies, and mature donor T cells are considered to be the main effectors of the graft-versus-tumor (GVT) activity. However, the association between degree of donor chimerism and intensity of GVT effects has not been fully elucidated. We recently proposed a unique nonmyeloablative cell therapy using posttransplant cyclophosphamide and donor lymphocyte infusion, by which a significant antitumor effect against murine renal cell carcinoma, RENCA, was induced, although the level of mixed chimerism was relatively low. In this study, we attempted to clarify a role of chimerism for in vivo antitumor effects on GVT effects in radiation-associated nonmyeloablative SCT. EXPERIMENTAL DESIGN: We assessed antitumor effects on RENCA tumors and the degree of donor chimerism after several doses of irradiation followed by allogeneic SCT and compared the results with those of cyclophosphamide-based cell therapy. RESULTS: Allogeneic SCT following sublethal irradiation (6 Gy) induced almost complete donor chimerism, whereas cyclophosphamide-based cell therapy produced low levels of donor chimerism. Nonetheless, GVT activity was much more potent in cyclophosphamide-based cell therapy than irradiation-conditioned SCT. Furthermore, cyclophosphamide-conditioned SCT induced more potent immune reconstitution with less severe graft-versus-host disease than irradiation-conditioned SCT. CONCLUSIONS: Our results indicate that a high level of chimerism is not essential for the in vivo antitumor effect of nonmyeloablative allogeneic cell therapy against solid tumor and that the recovery of peripheral lymphocytes after the initial immunosuppression might be a critical event for the elicitation of in vivo antitumor effects of that treatment modality.     

The role of interleukin-12 in preserving the graft-versus-leukemia effect of allogeneic CD8 T cells independently of GVHD.

Interleukin (IL)-12 is a potent immunostimulatory cytokine and inducer of Th1 cell activity and of cytotoxic T lymphocyte and natural killer cell function. This cytokine also has anti-tumor activity. Although IL-12 has been shown to be an important pathogenic cytokine in the induction of graft-versus-host disease (GVHD), injection of exogenous IL-12 to murine allogeneic bone marrow transplantation (BMT) recipients paradoxically leads to a significant delay in the onset of GVHD mortality in fully MHC plus multiple minor antigen-mismatched strain combinations, and to complete inhibition of GVHD in a single haplotype-mismatched murine BMT model. IL-12-induced inhibition of GVHD is associated with reduced donor T cell activation and expansion, in part through an interferon (IFN)-gamma-mediated mechanism. Fas-mediated apoptosis of donor T cells also plays a significant role in IL-12-induced GVHD protection. Importantly, IL-12 preserves the graft-versus-leukemia (GVL) effect of allogeneic CD8 T cells against EL4, a host-type leukemia/lymphoma, while inhibiting GVHD. Like the protective effect against GVHD, the GVL effect in IL-12-treated mice is dependent on IFN-gamma. Thus, treatment with IL-12 leads to separation of GVHD-promoting and GVL effects of allogeneic BMT via an IFN-gamma-dependent mechanism.     

吲哚胺2，3双加氧酶基因修饰的DCs对同种异基因T细胞增殖反应的抑制

目的〖HT5"SS〗： 探讨吲哚胺2,3双加氧酶(indoleamine 2,3 dioxygenase,IDO)基因修饰的树突状细胞（dendritic cells,DCs）在体外对造血干细胞移植物中异基因T细胞增殖反应的抑制作用。〖HT5W〗方法〖HT5"SS〗： 用携带IDO基因的重组腺病毒转染BALB/c小鼠（受体）骨髓来源的DCs ,用RTPCR法检测DCs表面IDO的表达,用流式细胞术分析IDO基因修饰前后DC表型的变化,并把IDODC与C57BL/6小鼠（供体）脾脏来源     

选择性去除骨髓移植物中异基因反应性淋巴细胞

目的:选择性去除骨髓移植物中异基因反应性淋巴细胞,诱导异基因特异性低反应性.方法:用携带有FasL基因的重组腺病毒转染BALB/c小鼠来源的DC,并与C57BL/6小鼠脾淋巴细胞共培养,通过混合淋巴细胞培养等方法检测异基因特异性低反应性.结果:转染FasL基因的DC诱导了对BALB/c异基因反应性T淋巴细胞凋亡,2次混合淋巴细胞反应显著降低,但并没有抑制针对第三方的反应.结论:转染FasL基因的DC体外可有效去除骨髓移植物中异基因反应性T淋巴细胞,移植用这种方法处理过的骨髓,有希望在抑制GVHD的同时,不影响移植物抗肿瘤复发和抗感染的功能.     

Allogeneic lymphocytes induce tumor regression of advanced metastatic breast cancer.

PURPOSE: Allogeneic T lymphocytes can induce regression of metastatic breast cancer through an immune-mediated graft-versus-tumor (GVT) effect in murine models. To determine if a clinical GVT effect exists against metastatic breast cancer, allogeneic lymphocytes were used as adoptive cellular therapy after a reduced-intensity chemotherapy conditioning regimen and allogeneic hematopoietic stem-cell transplantation (HSCT) from human leukocyte antigen-matched siblings. PATIENTS AND METHODS: Sixteen patients with metastatic breast cancer that had progressed after treatment with anthracyclines, taxanes, hormonal agents, and trastuzumab, received allogeneic HSCT. The reduced-intensity transplant conditioning regimen consisted of cyclophosphamide and fludarabine. To distinguish an immunological GVT effect from any antitumor effect of cytotoxic chemotherapy in the transplant-conditioning regimen, allogeneic T lymphocytes were removed from the stem-cell graft and were subsequently administered late postallogeneic HSCT. Allogeneic lymphocytes containing 1 x 10(6), 5 x 10(6), and 10 x 10(6) CD3(+) cells/kg were infused on days +42, +70, and +98 post-allogeneic HSCT, respectively. RESULTS: Objective tumor regressions occurred after day +28 post-allogeneic HSCT in six patients and were attributed to allogeneic lymphocyte infusions. Two of these responding patients had disease progression post-allogeneic HSCT before subsequent tumor regression. Tumor regressions occurred concomitantly with the establishment of complete donor T-lymphoid engraftment, were associated with the development of graft-versus-host disease (GVHD), and were abrogated by subsequent systemic immunosuppression for GVHD. CONCLUSION: Allogeneic lymphocytes can induce regression of advanced metastatic breast cancer. These results indicate that an immunological GVT effect from allogeneic lymphocytes exists against metastatic breast cancer and provide rationale for further development of allogeneic cellular therapy for this largely incurable disease.     

Transplantation of allogeneic hematopoietic stem cells: an emerging treatment modality for solid tumors

Allogeneic transplantation of hematopoietic cells from an HLA-compatible donor has been used to treat hematologic malignancies. Allogeneic transplantation not only replaces the marrow affected by the disease, but exerts an immune graft-versus-tumor (GVT) effect mediated by donor lymphocytes. The development of nonmyeloablative conditioning regimens before allogeneic transplantation has allowed this therapy to be used in elderly and disabled patients. An allogeneic GVT effect is observed in a proportion of patients with renal, breast, colorectal, ovarian, and pancreatic cancer treated with allogeneic transplantation. In general, the tumor response is associated with the development of acute and chronic graft-versus-host disease. Further improvements will depend on the identification of the antigen targets of GVT, and on reduction of the toxicity of the procedure. Targeted therapies may complement the immune effect of allogeneic transplantation. We present updated results from the literature and data recently placed on file at the European Bone Marrow Transplantation Solid Tumors Working Party.     

Vaccination with allogeneic GM-CSF gene-modified lung cancer cells: antitumor activity comparing with that induced by autologous vaccine

OBJECTIVE: The aim of this study was to investigate the whole allogeneic (differing tissue-type) tumor cells as vaccine in the mouse lung cancer model. The immunogenic and antitumor activity of allogeneic vaccine was compared with that of autologous cancer cell vaccine. METHODS: C57/BL mice inoculated with Lewis lung cancer (LLC) cells were used as the animal model to test the effects of allogeneic vaccination. LA795 and LLC lung cancer cell lines, which were transfected with the mouse granulocyte-macrophage colony-stimulating factor (GM-CSF) gene, were administered as allogeneic and autologous tumor vaccine, respectively. The irradiated tumor cells were administered as subcutaneous vaccines before the tumor challenge. The immunity of cancer vaccine was tested by mouse interferon-gamma (IFN-gamma) enzyme-linked immunospot (ELISPOT) lactate dehydrogenase (LDH) assays. The serum level of IFN-gamma and interleukin (IL)-4 was tested using the enzyme-linked immunosorbent assay method. RESULTS: Prophylactic vaccination with allogeneic LA795 cells protected against the LLC tumor challenge in C57/BL. The tumor growth was inhibited and the survival was accordingly prolonged. The cytotoxicity of the spleen cells or the purified CD(8)(+) T-cells against LLC cells in the mice immunized with either the autologous or allogeneic cancer cell vaccine was significantly increased, relative to that of the control, untreated group (p<0.05). ELISPOT IFN-gamma assays showed that spleen cells from mice immunized with LA795 cells could be activated after coculture with irradiated LLC cells. In addition, the serum level of Th1-king cytokine IFN-gamma significantly increased after vaccination; however, no statistically difference was found in Th2-kind cytokine IL-4. CONCLUSIONS: The allogeneic cancer vaccine could induce immune responses and protection against lung cancer, which had no significant difference with that of autologous vaccine.     

Adoptive immunochemotherapy of a transplantable AKR leukemia (K36).

Adoptive immunotherapy of a transplantable AKR leukemia (K36) was carried out as an adjunct to cytoxan chemotherapy using normal allogeneic H-2-incompatible spleen cells as well as sensitized H-2-matched allogeneic spleen cells. A significant therapeutic effect was obtained with cytoxan and allogeneic C57BL/6 splenocytes, demonstrating the potential use of the graft-versus-host reaction. Utilizing specific adoptive immunochemotherapy, a maximum effect was found with splenocytes from allogeneic but H-2-compatible CBA/J mice immunized against an allogeneic Gross-virus-induced lymphoma (E female G2). This therapeutic effect was most likely the result of prior sensitization of donor lymphocytes to common virus-associated tumor antigens.     

Graft versus leukemia without fatal graft-versus-host disease in AKR mice.

BW 5147 leukemia in AKR mice has been successfully treated by adoptive immunotherapy using allogeneic spleen cells from C57BL/6J mice. Graft-versus-host reaction was prevented by treatment with spleen cells from a second allogeneic strain (CBA, H-2 identical with AKR), followed by cycloposphamide and syngeneic spleen cells. Successful treatment of leukemia without graft-versus-host reaction is dependent upon a close relationship at the H-2 locus between the second allogeneic donor and the host AKR mice, since cells from a non-H-2 identical donor (DBA/2) do not increase survival. The doses of cyclophosphamide and of C57BL/6J spleen cells are also parameters of critical importance in successful treatment.     

基因枪介导的neu基因DNA疫苗抗肿瘤作用的实验研究

目的 探讨DNA疫苗pWRG-neu的皮内免疫,对高表达neu基因的小鼠移植瘤生长和转移的抑制作用。方法 向小鼠黑色素瘤B16F10细胞系转染pcDNA-neu,用有限稀释法筛选一株高表达neu基因的细胞株B16F10-neu。在基因枪介导下,向C57BL／6小鼠导入DNA疫苗pWRG-neu,通过观察免疫动物的生存期,评价DNA疫苗的抗肿瘤作用。分离免疫动物脾细胞,经自体淋巴细胞混合培养实验,分析DNA疫苗体内免疫后机体的CTL应答。结果 筛选到一株高表达neu基因的B16F10-neu细胞株,转基因过程和外源基因的表达没有改变细胞系的增殖特性。用基因枪轰击,进行DNA疫苗pWRG-neu皮内免疫,对小鼠黑色素瘤B16F10-neu进行预防、治疗和抗转移的实验研究,结果表明,DNA疫苗的免疫能够明显推迟移植瘤的生长,延长小鼠生存期,获得明显的抗肿瘤效果。DNA疫苗免疫后可诱导小鼠脾淋巴细胞CTL活性。结论 基因枪介导的DNA疫苗pWRG-neu经皮内免疫,能够有效的诱导机体的细胞免疫应答,预防和治疗小鼠移植瘤的发生,并有一定的预防肿瘤肺转移的作用。     

A reduction of recipient regulatory T cells by cyclophosphamide contributes to an anti-tumor effect of nonmyeloablative allogeneic stem cell transplantation in mice

We have recently established a unique model system of nonmyeloablative allogeneic stem cell transplantation (SCT) for treatment of murine solid tumors, based on cyclophosphamide‐induced tolerance. An injection of allogeneic donor spleen cells and bone marrow cells (BMC) followed by cyclophosphamide treatment induced a stable mixed chimerism with long lasting tolerance to the allografts. A donor lymphocyte infusion (DLI) in the cyclophosphamide‐induced tolerant mice exerted strong anti‐tumor effects on an MBT‐2 murine bladder tumor, MBT‐2 via their graft versus tumor (GVT) activity. In the present study, we determined whether a cyclophosphamide‐induced reduction of naturally occurring regulatory T cells (Tregs) was associated with the anti‐tumor activity in our nonmyeloablative SCT system. The number of recipient CD4+ CD25+ Foxp3+ Tregs significantly decreased 3 days after an intraperitoneal injection of cyclophosphamide in C3H/HeN mice that had been injected with spleen cells and BMC of donor AKR/J mice, compared with the number of CD4+ CD25+ Foxp3‐ T cells. An adoptive transfer of CD4+ CD25+ T cells from naïve C3H/He x AKR/J F1 mice into recipient mice 1 day after DLI significantly suppressed the expansion and IFN‐γ production of host‐reactive donor CD4+T cells and hampered the MBT‐2 anti‐tumor activity when compared with the transfer of CD4+ CD25‐ T cells. These results indicated that cyclophosphamide‐induced reduction of recipient Tregs is associated with retardation of tumor progression via the expansion of host‐reactive donor T cells and IFN‐γ production after DLI in our nonmyeloablative SCT system.     

Immunomodulation with dendritic cells and donor lymphocyte infusion converge to induce graft vs neuroblastoma reactions without GVHD after allogeneic bone marrow transplantation

Background:

Mounting evidence points to the efficacy of donor lymphocyte infusion (DLI) and immunisation with tumour-pulsed dendritic cells (DC) in generating graft vs leukaemia reactions after allogeneic bone marrow transplantation (BMT). We assessed the efficacy of DLI and DC in generating potent graft vs neuroblastoma tumour (GVT) reactions following allogeneic BMT.

Methods:

Mice bearing congenic (H2K^a) Neuro-2a tumours were grafted with allogeneic (H2K^b) T-cell-depleted bone marrow cells. Tumour-pulsed donor DC (DC^Neuro2a) were inoculated (on day +7) in conjunction with donor (H2K^b) and haploidentical (H2K^a/b) lymphocytes.

Results:

Murine Neuro-2a cells elicit immune reactions as efficient as B lymphoma in major histocompatibility complex antigen-disparate mice. Lymphopenia induced by conditioning facilitates GVT, and transition to adaptive immunity is enhanced by simultaneous infusion of and DC^Neuro2a and lymphocytes devoid of graft vs host (GVH) activity (H2K^a/b). In variance, the efficacy of DC-mediated immunomodulation was diminished by severe graft vs host disease (GVHD), showing mechanistic dissociation and antagonising potential to GVT.

Conclsions:

The GVHD is not a prerequisite to induce GVT reactivity after allogeneic BMT, but is rather detrimental to induction of anti-tumour immunity by DC-mediated immunomodulation. Simultaneous inoculation of tumour-pulsed donor DC and DLI synergise in stimulation of potent GVT reactions to the extent of eradication of established NB tumours.     

Rauscher leukemia as a model for studies of marrow transplantation therapy: results using syngeneic, allogeneic and hybrid donors.

SJL/J mice with leukemia induced in their own cells by Rauscher leukemia virus were treated by marrow transplantation therapy. The results obtained using syngeneic, hybrid and two different allogeneic donors were compared. All types of donor tissue produced some degree of protection; the lowest was yielded by SJL/J cells and the highest by C57BL/10J. The incidence of leukemia recurrence after therapy varied with the donor strain used. The highest and earliest recurrence was seen with SJL/J donors. The use of leukemia-resistant SJB10F₁ hybrids resulted in protracted remissions followed by late relapse, which was possibly related to reemergence of host leukemogenic clones not previously eliminated by the pretransplant marrow ablation treatment. A distinctly different pattern of late deaths was seen with the use of allogeneic donors, suggesting a possible graft-vs-leukemia effect. Graft-vs-host (GvH) response was not evident following transplantation of either the hybrid or syngeneic marrow, as determined from studies using normal SJL/J mice as recipients. GvH disease was found using both types of allogeneic donors, C57BL/10J and 129/J. However, although both allogeneic donors were of the same histocompatibility type, H-2^b, they differed in the level of fatal GvH response induced when used as donors. This suggests the possibility of an influence of « minor » histocompatibility factors affecting GvH response incidence and animal survival. The similarities between the model and the results of treatment of human leukemia by marrow transplantation therapy are discussed, and the possible future use of the model to study means of achieving lower leukemia recurrence through better marrow ablation, and to study the question of whether there is a graft-vs-leukemia effect related to GvH response, is proposed.     

Treatment of post-transplanted, relapsed patients with hematological malignancies by infusion of HLA-matched, allogeneic-dendritic cells (DCs) pulsed with irradiated tumor cells and primed T cells.

Patients with hematological malignancies who relapse after bone marrow transplantation (BMT) are often treated with donor lymphocyte infusion. However, this procedure often results in graft-versus-host disease (GVHD). While, Dendritic cells (DCs), which present antigens to naive T cells, have been used in the immunotherapy of cancer, this approach has been logistically difficult due to limiting numbers of DCs. We have now developed a method for obtaining a large number of DCs by treating the granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood stem cells (PBSCs) from healthy donors with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4), and tumor necrosis factor-alpha (TNF-alpha). The resulting cells possess the morphologic, phenotypic, and functional characteristics of mature DCs. In in vitro studies, culture of these HLA-matched donor derived-DCs with irradiated each patient's tumor cells as an antigen source, followed by incubation with T cells from the patient, induced the production of highly cytotoxic T lymphocytes (CTLs) specific for the respective tumor cells in the semi-allogeneic setting. A transient, but objective clinical response was obtained in the absence of GVHD when we injected the DCs which had been pulsed with irradiated tumor cells as well as primed T cells from the same original donor of related- allogeneic stem cell transplantation into the relapsed patients. Our findings suggest that treatment of relapsed patients with such donor-derived DCs, and primed T cells may be effective as an adjunctive immunotherapy.