Ventilation and perfusion imaging by electrical impedance tomography: a comparison with radionuclide scanning

Cytokine gene transfer into tumor cells has been shown to mediate tumor regression and antimetastatic effects in several animal models via immunomodulation. Therefore, clinical protocols have been developed to treat cancer patients with cytokine gene-modified tumor cells. We inserted the genes coding for the p35 and p40 chain of interleukin-12 (IL-12) in two independent eukaryotic expression vectors and transduced melanoma cells of 15 different primary tumor cultures with both plasmids by a ballistic gene transfer approach. Secreted IL-12 demonstrated strong bioactivity by inducing interferon-gamma release from peripheral blood lymphocytes upon coculture with cell culture supernatants after IL-12 gene transfer which could at least partly be blocked by IL-12-specific antisera. Further enrichment of transduced tumor cells by magnetic separation directly after gene transfer increased cytokine secretion from a mean of 119 pg in the unsorted to 507 pg IL-12 (24 h/10(8) cells) in the magnetically enriched cell fraction. Irradiation of these cells led to a further elevation of secreted IL-12 (mean 987 pg). Elevated IL-12 levels were detected over 7 days after irradiation in vitro. In a subsequent first clinical phase I study six patients with metastatic melanoma were vaccinated with autologous, interleukin-12 gene-modified tumor cells. Melanoma cells were expanded in vitro from surgically removed metastases, transduced by ballistic gene transfer, irradiated and were then injected subcutaneously (s.c.) at weekly intervals. Clinically, there was no major toxicity except for mild fever. All patients completed more than four s.c. vaccinations over 6 weeks and were eligible for immunological evaluation. Post-vaccination, peripheral mononuclear cells were found to contain an increased number of tumor-reactive proliferative as well as cytolytic cells as determined by a limiting dilution analysis in two patients. Two patients developed DTH reactivity against autologous melanoma cells and one had a minor clinical response. Biopsies taken from that patient's metastases revealed a heavy infiltration of CD4+ and CD8+ T lymphocytes. In conclusion, vaccination induced immunological changes even in a group of advanced, terminally ill patients. These changes can be interpreted as an increased antitumor immune response.     

Sustained cytokine delivery for anticancer vaccination: liposomes as alternative for gene-transfected tumor cells

Vaccination with tumor cells genetically engineered to produce interleukin (IL)-2 is an attractive strategy to enhance antitumor immune responses. The improved antitumor immunity upon vaccination with IL-2 gene-modified tumor cells may be due to the prolonged presence of the cytokine at the vaccination site. Because liposomes have been used for sustained delivery of a variety of agents, we compared the protective effect of vaccines consisting of IL-2 gene-modified B16 melanoma cells to that of vaccines composed of IL-2 liposomes and irradiated melanoma cells. The results indicate that both approaches equally protect against a lethal challenge with B16 melanoma cells. More than 20% of the protected animals developed vitiligo at the vaccination and/or tumor challenge site.     

Bone marrow-generated dendritic cells pulsed with tumor extracts or tumor RNA induce antitumor immunity against central nervous system tumors

Recent studies have shown that the brain is not a barrier to successful active immunotherapy that uses gene-modified autologous tumor cell vaccines. In this study, we compared the efficacy of two types of vaccines for the treatment of tumors within the central nervous system (CNS): dendritic cell (DC)-based vaccines pulsed with either tumor extract or tumor RNA, and cytokine gene-modified tumor vaccines. Using the B16/F10 murine melanoma (B16) as a model for CNS tumor, we show that vaccination with bone marrow-generated DCs, pulsed with either B16 cell extract or B16 total RNA, can induce specific cytotoxic T lymphocytes against B16 tumor cells. Both types of DC vaccines were able to protect animals from tumors located in the CNS. DC-based vaccines also led to prolonged survival in mice with tumors placed before the initiation of vaccine therapy. The DC-based vaccines were at least as effective, if not more so, as vaccines containing B16 tumor cells in which the granulocytic macrophage colony-stimulating factor gene had been modified. These data support the use of DC-based vaccines for the treatment of patients with CNS tumors.     

Clinical observations on adoptive immunotherapy with vaccine-primed T-lymphocytes secondarily sensitized to tumor in vitro

The adoptive immunotherapy of human malignancy requires reliable methods to sensitize and expand patients' T-cells reactive to autologous tumors. In animal studies, we have generated therapeutic effector cells against a poorly immunogenic tumor by a two-step procedure: vaccination of the host followed by the secondary stimulation of vaccine-primed lymph node (LN) cells by in vitro sensitization (IVS) with tumor in the presence of interleukin 2 (IL-2). Based on these observations, we performed a clinical trial in patients with advanced cancer to evaluate the antitumor efficacy of vaccine-primed LN cells which were similarly activated in vitro. Patients were vaccinated with irradiated autologous tumor admixed with Bacillus Calmette-Guérin and had draining LN excised 10 days later for IVS culture. During IVS culture, LN cells expanded up to 14-fold (average of 8.4-fold). A mean of 6.7 x 10(9) cells was infused in ten patients (seven melanoma, three renal cell cancer) along with the concomitant i.v. administration of IL-2 (180,000 IU/kg every 8 h for 5 days). Phenotype analysis of IVS-LN cells revealed 78 +/- 4% CD3+ T-cells which were predominantly CD4+ (67 +/- 5%) with expression of HLA-DR and IL-2 receptor. IVS-LN cells displayed relative specificity of autologous tumor lysis in four of ten cases compared to zero of seven IVS-peripheral blood lymphocytes derived from the same patients as measured by the 51Cr release assay. One mo after therapy, seven of nine patients treated with IVS-LN cells and IL-2 developed delayed-type hypersensitivity reactivity to autologous tumor compared to zero of nine patients treated with tumor vaccination and IL-2 only (P < 0.002). These observations suggest that antitumor reactivity was passively transferred with the IVS-LN cells. Major toxic side effects including fever, hepatic dysfunction, and weight gain associated with the capillary leak syndrome were associated with exogenous IL-2 administration. Tumor vaccination and cell transfer were well tolerated without significant complications. Of the ten patients treated with IVS-LN cells and IL-2, there were one partial and one minor response, and one patient has had stable disease for 27+ mo. There was no evidence of tumor response in ten patients treated with tumor vaccination and IL-2 only. Further clinical studies evaluating the antitumor reactivity of vaccine-primed LN cells are warranted.     

Adoptive immunotherapy with vaccine-primed lymph node cells secondarily activated with anti-CD3 and interleukin-2

PURPOSE: In preclinical studies, we have reported the ability to induce immune T cells in lymph nodes (LN) primed by in vivo vaccination with tumor cells admixed with a bacterial adjuvant. These LN cells can be activated and expanded ex vivo for the successful immunotherapy of established tumors. We have applied these methods to generate vaccine-primed LN in patients with advanced melanoma and renal cell cancer (RCC) for therapy. MATERIALS AND METHODS: Irradiated autologous tumor cells admixed with bacille Calmette-Guérin (BCG) were used to vaccinate patients. Seven days later, draining LN were removed for activation with anti-CD3 monoclonal antibody (mAb) followed by expansion in interleukin-2 (IL-2). Activated LN cells were administered intravenously (IV) with the concomitant administration of IL-2. RESULTS: A total of 23 patients were evaluated (11 melanoma and 12 RCC). Vaccine-primed LN were expanded ex vivo with a mean of 8.4 x 10(10) cells administered per patient. Among 20 patients assessed, 15 demonstrated minimal cytotoxicity of autologous tumor cells by the activated LN cells, with the remaining mediating nonspecific cytotoxicity. By contrast, a majority of the activated LN cells showed highly specific release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon gamma (IFN-gamma) to autologous but not allogeneic tumor stimulation. This tumor-specific cytokine release was found to be major histocompatibility complex (MHC) class I-restricted, which indicates the involvement of CD8+ cells. Among 11 melanoma patients, one had a partial tumor response. Among 12 RCC patients, two had complete and two partial responses. A trend (P = .066) between the enhancement of delayed-type hypersensitivity (DTH) reactivity to autologous tumor after therapy and tumor regression was observed. CONCLUSION: Tumor vaccines can be used to induce immunologically specific T-cell responses against melanoma and RCC in draining LN. Anti-CD3/IL-2 activation of primed LN cells can be reliably performed for clinical therapy and appears to have activity in patients with metastatic RCC.     

Immunotherapy, including gene therapy, for metastatic melanoma

Current standard therapy for distant metastatic melanoma is ineffective and often compromises the quality of a patient's life. Immunotherapy is briefly reviewed in relation to its many forms: from local non-specific to the more recent specific vaccines, including those using specific melanoma peptides (e.g. from the proteins encoded by melanoma-associated gene (MAGE)) and those involving genetically transduced autologous melanoma cells using retroviral vectors in vitro. The mode of action of genetically transduced melanoma cells incorporating the granulocyte macrophage colony stimulating factor (GM-CSF) gene (GVAX) is presented as a paradigm for cytokine-mediated strategies. Trials of GVAX and other cytokine gene strategies are under way in Brisbane, Boston and Amsterdam, and some interim perspectives on the clinical outcomes and immunological mechanisms involved are sketched. Some of the compounding problems in immunotherapeutic strategies for cancer are identified, and possible adjunct manoeuvres for overcoming them are discussed.     

Induction of antitumor immunity by interleukin-2 gene-transduced mouse mammary tumor cells versus transduced mammary stromal fibroblasts

BACKGROUND: Tumor cell-targeted cytokine gene transfer has been used to generate tumor cell vaccines, but this approach is limited by the need to establish and implant live tumor cells. PURPOSE: The purpose of this study was to determine if stromal fibroblasts could be used as an alternative vehicle for delivery of the cytokine interleukin-2 (IL-2) into the tumor microenvironment. We attempted to establish the feasibility of (a) genetic immunotherapy in a mammary tumor system and (b) engineering stromal fibroblasts as well as tumor cells. We compared the effects of tumor cell-mediated and stromal fibroblast-mediated local IL-2 expression on the generation of antitumor immune responses. METHODS: Retroviral vectors containing a human IL-2 gene were used to transduce a mouse mammary tumor line, 4TO7, and an immortalized but nontumorigenic fibroblast line established from syngeneic mammary fatpads. Expression of the IL-2 gene in transduced cells was determined by measuring IL-2 secretion, by RNA-polymerase chain reaction, and by immunochemistry. Groups of 5-12 BALB/c mice were injected with either 4TO7 cells or various doses of IL-2-secreting 4TO7 cells (4TO7-IL-2); tumor growth was monitored. To test whether local IL-2 expression by transduced cells could influence the growth of unmodified tumor cells, we determined tumor development in groups of mice treated with 4TO7 cells co-injected with either 4TO7-IL-2 cells or IL-2-secreting fibroblasts. RESULTS: 4TO7-IL-2 cells induced active immunity able to reject the immunizing tumor and to resist challenge with parental 4TO7 cells on the contralateral side. Mice pretreated with 4TO7-IL-2 were significantly protected compared with untreated control animals or mice pretreated with irradiated 4TO7 cells. The immunity induced by 4TO7-IL-2 cells did not protect against challenge with another subline, 4T1, which was derived from the same spontaneously arising mammary tumor as 4TO7. Co-injection of 4TO7 cells with 4TO7-IL-2 cells reduced tumorigenicity, whereas co-injection of 4TO7 cells with IL-2 secreting fibroblasts did not. CONCLUSION: Our results suggest that induction of anti-tumor immune response by local IL-2 production is most effective when the helper cytokine is secreted by the tumor cell. IMPLICATION: Our studies caution against the use of IL-2 gene-transduced syngeneic stromal cells as an alternative strategy of gene therapy for cancer. However, they may allow study of the mechanisms of tumor antigen recognition and the possible involvement of co-stimulatory signals for effective tumor vaccination by gene-modified cells.     

Tumour cell vaccines that secrete interleukin-2 (IL-2) and interferon gamma (IFN gamma) are recognised by T cells while resisting destruction by natural killer (NK) cells

The inoculation into mice of genetically engineered tumour cells that secrete IL-2 or IFN gamma results in rejection, while unmodified parental tumour cells grow progressively. In vivo studies demonstrated synergy between IL-2 and IFN gamma leading to the rejection of the transduced tumour cells. IL-2 is required for T cell proliferation and differentiation. IFN gamma induced the upregulation of MHC class I molecules that present peptides to CD8+ T cells. Furthermore, IFN gamma can correct defects in antigen processing. Thus, for T cells, IL-2/IFN gamma-secreting double cytokine tumour cell vaccines might serve as class I+ peptide/antigen presenting depots for developing effector cells. In contrast to T cells, NK cells exert spontaneous killing and kill class I+ targets less well than those that are class I-. For this reason, they may actually have a detrimental effect by destroying a class I+ tumour cell vaccine before adequate T cell stimulation occurs. Based upon this rationale, we tested the hypothesis that an unrecognised benefit of increased class I expression by tumour cells in response to IFN gamma secretion would be to enable cytokine-secreting vaccine cells to resist destruction by NK cells. Our results demonstrated that T cells recognised tumour cells secreting IFN gamma better than those secreting IL-2. NK cells, in contrast, were inhibited by tumour cells that secreted IFN gamma, but not by those that secreted IL-2. The findings suggest that, in addition to upregulating adhesion molecules, MHC molecules, and correcting defects in antigen presentation pathways, IFN gamma secretion may protect tumour cell vaccines from early NK-mediated destruction, keeping them available for T cell priming.     

Recombinant adeno-associated virus for the generation of autologous, gene-modified tumor vaccines: evidence for a high transduction efficiency into primary epithelial cancer cells

To explore the potential of recombinant vectors based on recombinant adeno-associated virus (rAAV) for cancer vaccination, we investigated the transduction efficiency of rAAV into cancer cells ex vivo. Infection of human epithelial cancer cell lines with rAAV carrying reporter genes encoding beta-galactosidase (rAAV/LacZ) or luciferase (rAAV/Luc) resulted in high levels of reporter gene expression (>90% positive cells). In marked contrast, rAAV poorly transduced all murine tumor cell lines, as well as human hematopoietic cell lines. Either irradiation or adenovirus infection of tumor cells prior to rAAV infection induced a 10- to 100-fold increase of reporter gene expression. To determine the transduction efficiency of rAAV into primary cancer cells, freshly isolated, irradiated tumor cells from malignant melanoma and ovarian carcinoma patients were infected with rAAV/Luc, resulting in up to 6.9-fold higher levels of gene expression than in a HeLa tumor cell line. Time course experiments with freshly isolated tumor cells infected with rAAV/Luc showed maximal levels of luciferase expression between days 3 and 9 posttransduction. Simultaneous infection of primary tumor cells with up to three rAAV vectors containing genes encoding the immunostimulatory proteins B7-2 (CD86), p35 subunit of IL-12, and p40 subunit of IL-12 resulted in high expression of B7-2 in more than 90% of the tumor cells and in the secretion of high levels of IL-12. Taken together, our results demonstrate that rAAV efficiently transduces freshly isolated human, epithelial tumor cells and might therefore be a potent tool to produce improved, gene-modified cancer vaccines.     

Regression of bladder tumors in mice treated with interleukin 2 gene-modified tumor cells

This study explored the use of interleukin 2 (IL-2) and interferon gamma (IFN-gamma) gene-modified tumor cells as cellular vaccines for the treatment of bladder cancer. The mouse MBT-2 tumor used is an excellent model for human bladder cancer. This carcinogen-induced tumor of bladder origin resembles human bladder cancer in its etiology and histology, and responds to treatment in a manner similar to its human counterpart. Using retroviral vectors, the human IL-2 and mouse IFN-gamma genes were introduced and expressed in MBT-2 cells. The tumor-forming capacity of the cytokine gene-modified MBT-2 cells was significantly impaired, since no tumors formed in mice injected intradermally with either IL-2- or IFN-gamma-secreting cells, using cell doses far exceeding the minimal tumorigenic dose of parental MBT-2 cells. Furthermore, mice that rejected the IL-2- or IFN-gamma-secreting tumor cells became highly resistant to a subsequent challenge with parental MBT-2 cells, but not to 38C13 cells, a B cell lymphoma of the same genetic background. To approximate the conditions as closely as possible to the conditions prevailing in the cancer patient, inactivated cytokine-secreting cells were used to treat animals bearing tumors established by orthotopic implantation of MBT-2 cells into the bladder wall of the animal. Treatment of mice carrying a significant tumor burden with IL-2-secreting MBT-2 cells had a significant inhibitory effect on tumor progression with extended survival. Moreover, in 60% of the mice the tumor regressed completely and the animals remained alive and free of detectable tumor for the duration of the observation period. Treatment of tumor-bearing animals with IL-2-secreting MBT-2 cells was superior to the use of cisplatin, a chemotherapeutic agent used in the treatment of bladder cancer. The therapeutic effect of IFN-gamma-secreting cells was minimal and treatment with unmodified MBT-2 cells had no effect on tumor growth or survival, showing that the parental MBT-2 cells were nonimmunogenic in this experimental setting. Most importantly, mice that exhibited complete tumor regression after treatment with IL-2-secreting MBT-2 cells became resistant to a subsequent challenge with a highly tumorigenic dose of parental MBT-2 cells, indicating that long-term immunological memory was established in the "cured" mice.     

Cellular vaccines

This project is devoted to the development of novel cellular vaccines designed to treat cancer patients. These cellular vaccines present and enhance immunogens, which will elicit a potent immune response. The goal is to achieve safe and effective immune reaction against the patient's own tumour. (1) Autologous cellular vaccines are prepared by processing circulating blood mononuclear cells outside of the patient's body (ex vivo) to differentiate them into antigen-presenting cells (APCs). Monocyte-derived APCs (MD-APCs) are then grown in the presence of exogenous target antigens (tumour cell debris, or apoptotic bodies) to become fully mature APCs. (2) Functionality for antigen presentation to T cells of ex vivo MD-APCs is evaluated in vivo. (3) Cellular vaccines are tested in selected rodent animal models. Efficiency and immune response are monitored in pertinent experimental systems for cancer. Pharmacological data are generated for clinical investigation. Tolerance and biologic effects are documented in primates. (4) The first clinical trials on cancer patients are taking place in 1998 on melanoma and prostate cancer to validate the concept. Specialized cell processors with dedicated software and standardized controls are being developed and used for the preparation of cellular vaccines. (5) The evaluation of new non-viral vectors and the validation of new non-viral transfection methods of mononuclear cells with marker genes is in progress and will lead to the ex vivo transfection of genes coding for immunostimulating cytokines or for tumour antigens in MD-APCs. Efficiency will be validated in vitro and in animal models. The ex vivo and animal model studies validate the clinical relevance of this new cellular immunotechnology. Clinical validation of individual autologous cellular vaccines in specific indications for which no treatment is presently available will allow the development of cellular and gene immunotherapy for other types of cancers.     

Immortalization with herpesvirus saimiri modulates the cytokine secretion profile of established Th1 and Th2 human T cell clones

T blasts of six established human CD4+ T cell clones with defined Ag specificity and cytokine secretion profile (3 Th1 and 3 Th2) were immortalized with Herpesvirus saimiri (HVS) and compared with their uninfected counterparts for their ability to proliferate, produce cytokines, and express cytolytic activity. HVS-transformed Th1 and Th2 clones neither substantially changed their original surface markers nor lose their ability to proliferate in response to their specific Ag but did acquire the ability to proliferate in response to contact signals delivered by SRBC or autologous APC alone. In addition, transformation by HVS substantially enhanced the lectin-dependent cytolytic activity of Th1 clones and enabled noncytolytic Th2 clones to exert cytolytic activity. HVS-transformed Th1 clones but not their uninfected counterparts spontaneously transcribed and secreted Th1-type cytokines (IL-2, IFN-gamma, and TNF-beta) and such a production was further enhanced by stimulation with either SRBC or PMA plus anti-CD3 mAb. HVS transformed but not uninfected Th2 clones constitutively expressed both IL-4 and IL-2 mRNA and secreted IFN-gamma. Stimulation with PMA plus anti-CD3 mAb induced uninfected Th2 clones to secrete high amounts of IL-4 and IL-5 but not Th1-type cytokines, whereas the same HVS-transformed Th2 showed minimal IL-4 and IL-5 secretion with concomitant high production of IL-2, IFN-gamma, and TNF-beta. Transformation by HVS also resulted in up-regulation of TNF-alpha and IL-3 production by both Th1 and Th2 clones. The ongoing proliferation of HVS-transformed clones was partially inhibited by either anti-IL-2 or anti-IL-3 antibodies and virtually abolished by the combined addition of the two anticytokine antibodies, suggesting that both IL-2 and IL-3 can function as autocrine growth factors for HVS-transformed Th1 and Th2 clones.     

Mycobacterium vaccae (SRL172): a potential immunological adjuvant evaluated in rat prostate cancer

OBJECTIVE: To evaluate the potential of heat-killed Mycobacterium vaccae (SRL172) as a nonspecific immunostimulant and as an adjuvant to whole tumour cell vaccination in the rat model of prostate cancer. MATERIALS AND METHODS: SRL172 was used as a vaccine in the prevention and treatment of subcutaneous tumours in rats. Prevention experiments were conducted using subcutaneous MAT-LyLu tumours in Copenhagen rats, comparing vaccination with SRL172 alone, SRL172 plus autologous cells, and bacille Calmette-Guèrin (BCG) plus autologous cells before tumour implantation. Treatment experiments were conducted using subcutaneous MAT-LyLu tumours in the Copenhagen rat and subcutaneous PAIII tumours in the Lobund-Wistar rat. Tumours were induced by subcutaneous injection with tumour cells. Animals were then vaccinated with autologous cells, autologous cells plus SRL172, or SRL172 alone. RESULTS: SRL172 was effective as an adjuvant to autologous whole tumour cell vaccination in the prevention of MAT-LyLu tumours and the survival benefit was equivalent to that provided when the adjuvant was live-attenuated BCG. SRL172 alone did not reduce tumour take or tumour growth in this model and neither strategy was effective in delaying the growth of established MAT-LyLu tumours. In the Lobund-Wistar rat vaccination with autologous whole tumour cells and SRL172 significantly delayed the growth of established tumours. CONCLUSION: Mycobacterium vaccae deserves further evaluation as an adjuvant to whole tumour cell vaccination in a phase I clinical trial in patients with prostate cancer.     

A personal (biased) perspective on cancer "vaccines"

The use of active specific immunotherapy (ASI) for cancer (cancer "vaccines") is still in its scientific infancy despite several decades of clinical and basic research. What has been established is the principle that stimulation of the immune response by "crude" (i.e., whole cell-derived) vaccines has led, in a proportion of patients, to rejection of tumor masses, in some instances for 10 years or more. Scientific investigations into the nature of recognition of tumor antigenic determinants (epitopes) by cytolytic T cells have begun to elucidate the mechanisms underlying rejection, making more precise vaccines possible. Yet there should be caution about assuming that a single epitope or even a few epitopes combined will be as effective as the "crude" materials, which might better be thought of as "polyvalent." ASI in at least one instance may have cured melanoma in a patient with metastatic disease, but that patient developed another immunologically and genetically distinct melanoma. This may provide an example of both immunological surveillance against the emergence of new melanomas and immunological selection of an immunologically resistant tumor. Combinations of vaccines with cytokines, cytolytic T cell infusions, or chemotherapy may improve the response rates and durations of survival achievable with vaccines alone. The best rationale for synthetically derived vaccines may be for prophylaxis-that is, as a true vaccine-where the use of tumor-derived materials in normal individuals is difficult to justify ethically.     

Ex-vivo gene therapy using cytokine-transduced tumor vaccines: molecular and clinical pharmacology

Whether the current generation of cytokine gene-transduced tumor vaccines will show clinical efficacy is under study. Fortunately, the large safety profile so far observed with gene-transduced tumor vaccines can allow outpatient testing in large populations of patients in the adjuvant therapy situation. This will allow large studies statistically powered to see potentially important adjuvant therapy effects in the range that are observed for tamoxifen in breast cancer. For example, the outpatient, adjuvant therapy safety context has been established in the use of GM-CSF gene-transduced autologous prostate cancer vaccines following radical prostatectomy. Similar adjuvant therapy clinical trial efforts are anticipated with allogeneic breast, colon, pancreatic, and ovarian cancer in addition to prostate, renal cell carcinoma, and melanoma. The reverse translation of early clinical data back to basic laboratory research also suggests the field of cytokine gene-transduced tumor vaccine research will remain vibrant. Efforts are currently being directed on optimizing DC activation with polycistronic constructs of cytokine genes, and overexpressing the most relevant tumor-associated peptides. As in the case of antineoplastic drug development, not all lead compounds will become approved drugs in medical oncology. Rigorous yet innovative clinical trial designs will be key to the accelerated identification of cytokine gene-transduced vaccines that improve survival in cancer patients.     

Development of human granulocyte-macrophage colony-stimulating factor-transfected tumor cell vaccines for the treatment of spontaneous canine cancer

Cytokine gene-engineered tumor vaccines are currently an area of intense investigation in both basic research and clinical medicine. Our efforts to utilize tumor vaccines in an immunotherapeutic manner involve canines with spontaneous tumors. We hypothesized that canine tumor cells, transfected with human granulocyte-macrophage colony-stimulating factor (hGM-CSF) cDNA in a plasmid vector, would prove nontoxic following intradermal administration, generate biologically relevant levels of protein, effect local histological changes at the sites of vaccination, and create a systemic antitumor response. Sixteen tumor-bearing dogs were admitted to a study of ex vivo gene therapy. Tumor tissue was surgically removed, enzymatically and mechanically dissociated, irradiated, transfected, and intradermally injected back into the patients. The dogs were vaccinated with primary autologous tumor cells transfected with hGM-CSF or a reporter control gene. hGM-CSF protein was detected (0.07 to 14.15 ng/vaccination site) at 24 hr postinjection and dramatic histological changes were observed, characterized by neutrophil and macrophage infiltration at the sites of injection of hGM-CSF-transfected tumor cells. This was in stark contrast to the lesser neutrophilic and eosinophilic infiltrates found at control vaccination sites. Objective evidence of an antitumor response was observed in three animals. These data, in a large animal translational model of spontaneous tumors, demonstrate in vivo biological activity of hGM-CSF-transfected autologous tumor cell vaccines.     

Myositis associated with interleukin-2 therapy in a patient with metastatic renal cell carcinoma

BACKGROUND: Interleukin-2 (IL-2) has been used successfully in the treatment of some patients with metastatic renal cell carcinoma and melanoma, with a partial response rate of 15%-20%. It produces a well documented spectrum of side effects. Autoimmune diseases have been associated with IL-2 immunotherapy and the development of autoimmune thyroiditis may correlate with antitumor clinical response. METHODS: A patient with metastatic renal cell carcinoma is described who developed a polymyositis-like myopathy after an autologous tumor vaccine and IL-2 therapy. RESULTS: The patient had a delayed response for 15 months after developing this previously unreported toxicity. CONCLUSIONS: To the authors' knowledge, this represents the first reported case of necrotizing myositis in association with IL-2 therapy. Subsequent continuous partial response of the advanced malignancy was observed for 15 months. In this case, IL-2 may have broken tolerance to both normal muscle cells and tumor cells.     

Vaccination against cancer soon a therapeutic possibility. B-cell tumors, colonic cancer and melanoma may be suitable for this treatment

The theoretical basis of cancer vaccination having been well established during the past two decades, the translation of this knowledge into clinically applicable immunisation procedures is now an urgent need. Numerous antigenic preparations are available that are capable of inducing specific anti-tumour immunity which can be augmented by appropriate cytokines. Promising tumour vaccination results have been obtained in B-cell malignancies, colorectal carcinoma, and melanoma; tumour regression has been noted in myeloma, non-Hodgkin lymphoma, colorectal carcinoma, and melanoma patients, and significantly prolonged disease-freed survival in non-Hodgkin lymphoma and colorectal carcinoma patients. The presence of only minimal residual disease would seem to be a clinical prerequisite for tumour vaccination.