Efficient tumor regression by adoptively transferred CEA-specific CAR-T cells associated with symptoms of mild cytokine release syndrome.

Carcinoembryonic antigen (CEA) is a cell surface antigen highly expressed in various cancer cell types and in healthy tissues. It has the potential to be a target for chimeric antigen receptor (CAR)-modified T-cell therapy; however, the safety of this approach in terms of on-target/off-tumor effects needs to be determined. To address this issue in a clinically relevant model, we used a mouse model in which the T cells expressing CEA-specific CAR were transferred into tumor-bearing CEA-transgenic (Tg) mice that physiologically expressed CEA as a self-antigen. The adoptive transfer in conjunction with lymphodepleting and myeloablative preconditioning mediated significant tumor regression but caused weight loss in CEA-Tg, but not in wild-type mice. The weight loss was not associated with overt inflammation in the CEA-expressing gastrointestinal tract but was associated with malnutrition, reflected in elevated systemic levels of cytokines linked to anorexia, which could be controlled by the administration of an anti-IL-6 receptor monoclonal antibody without compromising efficacy. The apparent relationship between lymphodepleting and myeloablative preconditioning, efficacy, and off-tumor toxicity of CAR-T cells would necessitate the development of CEA-specific CAR-T cells with improved signaling domains that require less stringent preconditioning for their efficacy. Taken together, these results suggest that CEA-specific CAR-based adoptive T-cell therapy may be effective for patients with CEA+ solid tumors. Distinguishing the fine line between therapeutic efficacy and off-tumor toxicity would involve further modifications of CAR-T cells and preconditioning regimens.

Adoptive Transfer of MAGE-A4 T-cell Receptor Gene-Transduced Lymphocytes in Patients with Recurrent Esophageal Cancer.

PURPOSE: Preparative lymphodepletion, the temporal ablation of the immune system, has been reported to promote persistence of transferred cells along with increased rates of tumor regression in patients treated with adoptive T-cell therapy. However, it remains unclear whether lymphodepletion is indispensable for immunotherapy with T-cell receptor (TCR) gene-engineered T cells. EXPERIMENTAL DESIGN: We conducted a first-in-man clinical trial of TCR gene-transduced T-cell transfer in patients with recurrent MAGE-A4-expressing esophageal cancer. The patients were given sequential MAGE-A4 peptide vaccinations. The regimen included neither lymphocyte-depleting conditioning nor administration of IL2. Ten patients, divided into 3 dose cohorts, received T-cell transfer. RESULTS: TCR-transduced cells were detected in the peripheral blood for 1 month at levels proportional to the dose administered, and in 5 patients they persisted for more than 5 months. The persisting cells maintained ex vivo antigen-specific tumor reactivity. Despite the long persistence of the transferred T cells, 7 patients exhibited tumor progression within 2 months after the treatment. Three patients who had minimal tumor lesions at baseline survived for more than 27 months. CONCLUSIONS: These results suggest that TCR-engineered T cells created by relatively short-duration in vitro culture of polyclonal lymphocytes in peripheral blood retained the capacity to survive in a host. The discordance between T-cell survival and tumor regression suggests that multiple mechanisms underlie the benefits of preparative lymphodepletion in adoptive T-cell therapy.

Stimulation through very late antigen-4 and -5 improves the multifunctionality and memory formation of CD8⁺ T cells.

T cells express multiple integrin molecules. The significance of signaling through these molecules on acquisition of T-cell effector functions and memory formation capacity remains largely unknown. Moreover, the impact of stimulation through these signals on the generation of T cells for adoptive immunotherapy has not been elucidated. In this study, using a recombinant fragment of fibronectin, CH-296, we demonstrated that stimulation via very late Ag (VLA)-4 and VLA-5 in human and BALB/c mouse CD8(+) T cells, in combination with TCR stimulation, enhances effector multifunctionality and in vivo memory formation. Using TCR-transgenic mouse-derived CD8(+) T cells expressing TCR specific for the syngeneic CMS5 fibrosarcoma-derived tumor Ag, we showed that stimulation by CH-296 improved the ability of tumor-specific CD8(+) T cells to inhibit CMS5 tumor growth when adoptively transferred into hosts with progressing tumors. Improved antitumor effects were associated with decreased infiltration of Foxp3(+) CD4(+) Treg cells in tumors. These results suggest that stimulation via VLA-4 and VLA-5 modulates the qualities of effector T cells and could potentially increase the efficacy of adoptive therapy against cancer.

CD19 target-engineered T-cells accumulate at tumor lesions in human B-cell lymphoma xenograft mouse models.

Adoptive T-cell therapy with CD19-specific chimeric antigen receptors (CARs) is promising for treatment of advanced B-cell malignancies. Tumor targeting of CAR-modified T-cells is likely to contribute therapeutic potency; therefore we examined the relationship between the ability of CD19-specific CAR (CD19-CAR)-transduced T-cells to accumulate at CD19(+) tumor lesions, and their ability to provide anti-tumor effects in xenograft mouse models. Normal human peripheral blood lymphocytes, activated with immobilized RetroNectin and anti-CD3 antibodies, were transduced with retroviral vectors that encode CD19-CAR. Expanded CD19-CAR T-cells with a high transgene expression level of about 75% produced IL-2 and IFN-γ in response to CD19, and lysed both Raji and Daudi CD19(+) human B-cell lymphoma cell lines. Furthermore, these cells efficiently accumulated at Raji tumor lesions where they suppressed tumor progression and prolonged survival in tumor-bearing Rag2(-/-)γc(-/-) immunodeficient mice compared to control cohorts. These results show that the ability of CD19-CAR T-cells to home in on tumor lesions is pivotal for their anti-tumor effects in our xenograft models, and therefore may enhance the efficacy of adoptive T-cell therapy for refractory B-cell lymphoma.

Dendritic cell-based vaccination in metastatic melanoma patients: phase II clinical trial.

Metastatic and chemoresistant melanoma can be a good target of immunotherapy because it is an intractable cancer with a very poor prognosis. Previously, we tested a dendritic cell (DC)-based phase I vaccine, and confirmed that it was safe. In the present study, we performed a phase II trial of a DC vaccine for metastatic melanoma patients with mainly the HLA-A24 genotype, and investigated the efficacy of the vaccine. Twenty-four patients with metastatic melanoma were enrolled into a phase II study of DC-based immunotherapy. The group included 19 HLA-A24-positive (A*2402) patients and 3 HLA-A2-positive (A*0201) patients. The protocol for DC production was similar to that in the phase I trial. Briefly, a cocktail of 5 melanoma-associated synthetic peptides (gp100, tyrosinase, MAGE-A2, MAGE-A3 and MART-1 or MAGE­A1) restricted to HLA-A2 or A24 and KLH were used for DC pulsing. Finally, DCs were injected subcutaneously (s.c.) into the inguinal region in the dose range of 1-5x107 per shot. The DC ratio (lin-HLA-DR+) of the vaccine was 38.1±13.3% and the frequency of CD83+ DCs was 25.7±20.8%. Other parameters regarding DC processing were not different from phase I. Immune response-related parameters including the ELISPOT assay, DTH reaction to peptide or KLH, DC injection numbers were shown to be related to a good prognosis. The ELISPOT reaction was positive in 75% of the patients vaccinated. The increase of anti-melanoma antigen antibody titer before vaccination was also shown to be a prognosis factor, but that post-vaccination was not. Based on immunohistochemical analysis, CD8 and IL-17 were not involved in the prognosis. Adverse effects of more than grade III were not seen. Overall survival analysis revealed a significant survival prolongation effect in DC-given melanoma patients. These results suggest that peptide cocktail-treated DC vaccines may be a safe and effective therapy against metastatic melanoma in terms of prolongation of overall survival time.

T-cell receptor gene therapy targeting melanoma-associated antigen-A4 inhibits human tumor growth in non-obese diabetic/SCID/γcnull mice.

Adoptive cell therapy with lymphocytes that have been genetically engineered to express tumor-reactive T-cell receptors (TCR) is a promising approach for cancer immunotherapy. We have been exploring the development of TCR gene therapy targeting cancer/testis antigens, including melanoma-associated antigen (MAGE) family antigens, that are ideal targets for adoptive T-cell therapy. The efficacy of TCR gene therapy targeting MAGE family antigens, however, has not yet been evaluated in vivo. Here, we demonstrate the in vivo antitumor activity in immunodeficient non-obese diabetic/SCID/γc(null) (NOG) mice of human lymphocytes genetically engineered to express TCR specific for the MAGE-A4 antigen. Polyclonal T cells derived from human peripheral blood mononuclear cells were transduced with the αß TCR genes specific for MAGE-A4, then adoptively transferred into NOG mice inoculated with MAGE-A4 expressing human tumor cell lines. The transferred T cells maintained their effector function in vivo, infiltrated into tumors, and inhibited tumor growth in an antigen-specific manner. The combination of adoptive cell therapy with antigen peptide vaccination enhanced antitumor activity, with improved multifunctionality of the transferred cells. These data suggest that TCR gene therapy with MAGE-A4-specific TCR is a promising strategy to treat patients with MAGE-A4-expressing tumors; in addition, the acquisition of multifunctionality in vivo is an important factor to predict the quality of the T-cell response during adoptive therapy with human lymphocytes.

Clinical response in Japanese metastatic melanoma patients treated with peptide cocktail-pulsed dendritic cells.

BACKGROUND: Metastatic, chemotherapy-resistant melanoma is an intractable cancer with a very poor prognosis. As to immunotherapy targeting metastatic melanoma, HLA-A2+ patients were mainly enrolled in the study in Western countries. However, HLA-A24+ melanoma patients-oriented immunotherapy has not been fully investigated. In the present study, we investigated the effect of dendritic cell (DC)-based immunotherapy on metastatic melanoma patients with HLA-A2 or A24 genotype. METHODS: Nine cases of metastatic melanoma were enrolled into a phase I study of monocyte-derived dendritic cell (DC)-based immunotherapy. HLA-genotype analysis revealed 4 cases of HLA-A*0201, 1 of A*0206 and 4 of A*2402. Enriched monocytes were obtained using OptiPreptrade mark from leukapheresis products, and then incubated with GM-CSF and IL-4 in a closed serum-free system. After pulsing with a cocktail of 5 melanoma-associated synthetic peptides (gp100, tyrosinase, MAGE-2, MAGE-3 and MART-1 or MAGE-1) restricted to HLA-A2 or A24 and KLH, cells were cryopreserved until used. Finally, thawed DCs were washed and injected subcutaneously (s.c.) into the inguinal region in a dose-escalation manner. RESULTS: The mean percentage of DCs rated as lin-HLA-DR+ in melanoma patients was 46.4 +/- 15.6 %. Most of DCs expressed high level of co-stimulatory molecules and type1 phenotype (CD11c+HLA-DR+), while a moderate number of mature DCs with CD83 and CCR7 positive were contained in DC products. DC injections were well tolerated except for transient liver dysfunction (elevation of transaminases, Grade I-II). All 6 evaluable cases except for early PD showed positive immunological responses to more than 2 melanoma peptides in an ELISPOT assay. Two representative responders demonstrated strong HLA-class I protein expression in the tumor and very high scores of ELISPOT that might correlate to the regression of metastatic tumors. Clinical response through DC injections was as follows : 1CR, 1 PR, 1SD and 6 PD. All 59 DC injections in the phase I study were tolerable in terms of safety, however, the maximal tolerable dose of DCs was not determined. CONCLUSIONS: These results suggested that peptide cocktail-treated DC-based immunotherapy had the potential for utilizing as one of therapeutic tools against metastatic melanoma in Japan.

Recognition of Epstein-Barr virus-associated gastric carcinoma cells by cytotoxic T lymphocytes induced in vitro with autologous lymphoblastoid cell line and LMP2-derived, HLA-A24-restricted 9-mer peptide.

Epstein-Barr virus (EBV) is associated with several types of malignancies including Burkitt's lymphoma, Hodgkin's disease, nasopharyngeal carcinoma, and gastric carcinoma. Previous reports have suggested that EBV-related antigen-targeting immunotherapy is one of the promising approaches for the treatment of these malignancies other than gastric carcinoma. EBV-associated gastric carcinoma (EBVaGC) has been shown to express Epstein-Barr virus nuclear antigen 1 (EBNA1) and latent membrane protein 2 (LMP2). In the present study, DNA and mRNA freshly isolated from tumors of patients with gastric cancer were subjected to polymerase chain reaction (PCR) using EBV-specific primers and reverse transcription (RT)-PCR specific for LMP2 transcripts. EBV-specific region was identified in genomic DNA isolated from cancerous tissues in 22% of gastric cancer patients. LMP2 mRNA was also detected in 3 out of these 5 DNA positive samples tested. To investigate the feasibility of specific immunotherapy for EBVaGC, we induced cytotoxic T lymphocytes (CTLs) from peripheral blood lymphocytes using two kinds of antigen-presenting cells (APCs) such as autologous lymphoblastoid cell line (LCL) and LMP2-derived peptide-pulsed dendritic cells (DCs). The cytotoxicity of these CTLs against peptide-pulsed targets was examined by standard 51Cr release assay and interferon (IFN)-gamma production assay. We further assessed the recognition of tumor cells endogenously expressing LMP2 by these T cells. T cells induced by peptide-loaded DCs and autologous LCL efficiently lysed peptide-pulsed targets. Furthermore, these T cells could recognize not only tumor cells transfected with LMP2, but also LMP2-positive gastric cancer cells which were successfully isolated and cultured from specimens obtained by surgery. Collectively, sensitization of peripheral blood lymphocytes with LMP2-derived peptide was able to induce CTL response against EBVaGC cells. Thus, EBVaGC is susceptible for the LMP2-targeting immunotherapy.

Cytotoxic T cell induction against human malignant melanoma cells using HLA-A24-restricted melanoma peptide cocktail.

Many human leukocyte antigen (HLA)-class I (mainly A*0201)-restricted peptide-specific cytotoxic T cells (CTLs) have been derived from peripheral blood lymphocytes (PBLs) of melanoma patients. However, few studies regarding HLA-A*2402-restricted melanoma-associated peptides have been performed, because HLA-A24 is not a common allele in Caucasians. In this study, we investigated the specific CTL-inducing activity of 5 HLA-A*2402-restricted peptides derived from gp100, tyrosinase, MAGE1, MAGE2 and MAGE3. A CTL induction culture was performed using PBLs and cultured dendritic cell (DC) pulsed with HLA-A*2402-restricted melanoma peptide cocktail. The CTLs derived from volunteers killed the A24 peptide-pulsed TISI cells and even HLA-A*2402-positive melanoma cells, but not HLA-A*0201-positive cells. IFN-gamma levels produced by the melanoma patients' CTLs were obviously low in each peptide group compared with those produced by the volunteers' CTLs, which indicated the presence of immunosuppressive factors in metastatic melanoma. These results suggested that polyvalent immunotherapy using multiple epitopes from melanoma antigens might be a better way of improving the efficacy of treatment.

Dendritic cell-based immunotherapy of cancer with carcinoembryonic antigen-derived, HLA-A24-restricted CTL epitope: Clinical outcomes of 18 patients with metastatic gastrointestinal or lung adenocarcinomas.

We conducted a clinical study of cancer vaccine therapy with dendritic cells (DCs) and HLA-A24-restricted carcinoembryonic antigen (CEA)-derived peptide to assess the feasibility and efficacy of such therapy. Eighteen patients with CEA-expressing metastatic gastrointestinal or lung adenocarcinomas who were positive for human leukocyte antigen (HLA)-A24 were enrolled. DCs were generated from the patients' autologous monocyte-enriched fractions of granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cells in the presence of granulocyte/macrophage colony-stimulating factor and interleukin-4. The generated DCs were pulsed with CEA-derived, HLA-A24-restricted 9-mer peptide (CEA652) and injected into the patients intradermally and subcutaneously every 2 weeks. Toxicity and clinical and immunological responses were closely monitored in each patient. No severe toxicity directly attributable to the treatment was observed, and the vaccine was well tolerated. Although no definite tumor shrinkage occurred in any patient, long-term stable disease or marked decreases in the serum CEA level were observed in some patients after therapy. Most of the patients in whom treatment was clinically effective showed a positive skin response to CEA652-pulsed DCs (delayed-type hypersensitivity skin test) and a positive in vitro CTL response to CEA652 peptide after therapy. We conclude that active specific immunotherapy using DCs pulsed with CEA652 is a safe and feasible treatment that is clinically effective in some patients with metastatic gastrointestinal or lung adenocarcinomas. Our results will hopefully encourage further refinement and development of DC-based immunotherapy with HLA-A24-restricted CEA-derived peptide for refractory solid cancers that express CEA.

Enhancement of cytotoxic T-lymphocyte responses in patients with gastrointestinal malignancies following vaccination with CEA peptide-pulsed dendritic cells.

Carcinoembryonic antigen (CEA) is strongly expressed in a vast majority of gastrointestinal carcinomas. Recently, epitope peptides of CEA were identified. We have demonstrated HLA-A24-restricted peptide, CEA652[9] (TYACFVSNL), was capable of eliciting specific cytotoxic T lymphocytes (CTLs) which could lyse tumor cells expressing HLA-A24 and CEA. HLA-A24 is the most applicable MHC class I allele in the Japanese population. In this pilot study, we have used the peptide-pulsed dendritic cells (DCs) generated from peripheral blood mononuclear cells (PBMCs) supplemented with GM-CSF and IL-4 as the source of the vaccine. Eight patients with advanced CEA-expressing gastrointestinal malignancies received subcutaneous injections every 2 or 3 weeks. Immunomonitoring was performed by ELISpot (enzyme-linked immunosorbent spot) assay to measure the precursor frequency of CTLs and their capacity to elicit antitumor CTLs in vitro. Four of seven patients have developed their CTL response after vaccinations. DTH reaction was observed in one of eight patients at the DC-injected site. Skin biopsy at the injected site showed the infiltration of the lymphocytes. Furthermore, A24/CEA peptide tetramer assay revealed an increase in peptide-specific T-cell precursor frequency in vaccinated patients. No significant toxic adverse effects were observed, except for mild diarrhea in one case after three vaccinations. Three patients have shown stabilization of the disease after vaccinations. In conclusion, our results clearly demonstrated that our vaccination protocol was safe and might develop a CEA-specific CTL response in cancer patients.

Screening of HLA-A24-restricted epitope peptides from prostate-specific membrane antigen that induce specific antitumor cytotoxic T lymphocytes.

PURPOSE: Prostate-specific membrane antigen (PSMA), which is a transmembrane glycoprotein predominantly expressed in prostate cancer, is an attractive target for tumor-specific immunotherapy. To identify human leukocyte antigen (HLA)-A24-restricted epitope peptides from PSMA for further application of the dendritic cell (DC)-based immunotherapy targeting prostate cancer, we have screened several PSMA-encoded HLA-A24-binding peptides for their capabilities to elicit specific antitumor CTL response in vitro. EXPERIMENTAL DESIGN: The amino acid sequence of PSMA was screened for peptides consisting of 9 or 10 amino acids, which possess the known HLA-A24-binding motif. Nine candidate peptides were screened for binding to HLA-A24 molecules. Then, each of these nine peptides was studied to determine whether CTL responses could be induced by primary in vitro immunization of CD8(+) T cells using peptide-pulsed autologous DCs derived from peripheral blood mononuclear cells of HLA-A24(+) healthy donor as antigen-presenting cells. The antigen specificity of the CTL lines was confirmed using several tumor cell lines as target cells, which were genetically modified to express both HLA-A24 and PSMA. RESULTS: Two peptides, LYSDPADYF and NYARTEDFF, were demonstrated to elicit CTL lines that lyse peptide-pulsed, HLA-A24(+) B-lymphoblastoid cells. Each of the CTL lines recognized their specific PSMA-expressing target cells in a HLA-A24-restricted manner. The capability to release IFN-gamma by the CTL lines was specifically inhibited by anti-MHC class I and anti-CD8 monoclonal antibodies but not by anti-MHC class II and anti-CD4 monoclonal antibodies. CONCLUSION: Two novel HLA-A24-restricted PSMA-derived epitopes were identified in this study. These epitopes can be used to further evaluate the clinical utility of DC-based immunotherapeutic strategies for treatment of hormone-refractory prostate cancers.

[Issues in the development of drugs for treating deep-seated mycosis].

This review is a collection of abstracts of seven papers presented at the panel discussion Issues in the Development of Drugs for Treating Deep-Seated Mycosis - From Drug Discovery to Clinical Studies held at the 45th Annual Meeting of the Japanese Society of Medical Mycology. The first three presentations concerned the discovery of new drugs. The first discussed the screening, analysis of chemical structure and elucidation of the mechanism of action of new antifungal agents focusing on aureobasidin A. The second was on the search for and development of novel agents with selective targets of action, specifically FK463 (micafungin) which inhibits (1-3)-beta-glucan synthase. The third described the development of novel derivatives based on the structure-activity correlation of triazole agents, with CS-758 as an example. The remaining four presentations discussed the status and issues of clinical studies targeting hematological disorders and respiratory diseases, as well as various problems from the company point of view on new drug development and those from the government side concerning the approval of new drugs. This type of meeting which provides an opportunity for discussion of various multi-faceted issues from the discovery of a new drug to its preclinical and clinical studies can contribute greatly to progress in the future development of new antifungal agents.

[Analysis of IgE reactivities of purified allergens from Candida albicans and Malassezia furfur among patients with atopic dermatitis].

We analyzed the reactivities of a series of purified allergens from Candida albicans (C. albicans) and Malassezia furfur (M. furfur) with IgE antibodies in sera from patients with atopic dermatitis. We compared the specific IgE antibody levels to manganese superoxide dismutase (Mn SOD), cyclophilin, enolase, secretory aspartic protease (SAP 2) and type A mannan from C. albicans and Mn SOD, cyclophilin and Mal f 2 from M. furfur in 21 sera from patients with atopic dermatitis and 20 sera from patients with asthma without atopic dermatitis. The prevalence of IgE antibodies and the mean IgE antibody levels to all of the allergens tested were higher among patients with atopic dermatitis than among those with asthma without atopic dermatitis. More than 50% of patients with atopic dermatitis were IgE antibody-positive to Mn SOD, cyclophilin and type A mannan from C. albicans, and Mn SOD and cyclophilin from M. furfur. The availability of these purified allergens will facilitate studies on the contribution of fungal allergens to the development of atopic dermatitis.

Protection of mice from lethal endogenous Candida albicans infection by immunization with Candida membrane antigen.

The protective effects of immunization with Candida membrane antigen (CMA) on a systemic infection originating from intestinally colonized Candida albicans were examined. The colonization of orally inoculated C. albicans in the intestinal tract was established in BALB/c mice that had been concomitantly treated with oral doses of antibacterial drugs. In these animals, a systemic dissemination of C. albicans with fatal outcome was induced by a repeated dosing of prednisolone. In this endogenous infection model, the effects of immunization by CMA on the infection were examined. CMA-immunized mice showed a longer lifespan than unimmunized mice. The protective effect of CMA immunization in immunosuppressed mice was also measured by a decrease in body weight loss after treatment with prednisolone and in the number of viable Candida cells in the target organs, the kidneys and livers. However, the CFU of C. albicans in the intestinal tract was not significantly lowered. These results suggest that CMA immunization inhibited the dissemination of systemic Candida infection from the intestinal tract induced by treatment with prednisolone.

Immunotherapy of solid cancer using dendritic cells pulsed with the HLA-A24-restricted peptide of carcinoembryonic antigen.

Carcinoembryonic antigen (CEA), an oncofetal glycoprotein overexpressed in most gastrointestinal and lung cancers, is a candidate molecule for cancer immunotherapy. Recently, a CEA-derived 9-mer peptide, CEA652 (TYACFVSNL), has been identified as the epitope of cytotoxic T lymphocytes restricted with human leukocyte antigen (HLA)-A24, which is present in 60% of the Japanese population and in some Caucasians. The authors performed a clinical study of a vaccine using autologous dendritic cells (DCs) pulsed with CEA652 and adjuvant cytokines, natural human interferon alpha (nhuIFN-alpha), and natural human tumor necrosis factor alpha (nhuTNF-alpha), for the treatment of patients with CEA-expressing advanced metastatic malignancies. Ten HLA-A24 patients with advanced digestive tract or lung cancer were enrolled in the study to assess toxicity, tolerability and immune responses to the vaccine. DCs were generated from plastic adherent monocytes of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (PBMCs) in the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4). Generated DCs showing an immature phenotype were loaded with CEA652 and injected into patients intradermally and subcutaneously with 50% of the dose administered by each route every 2 weeks for a total of ten vaccinations. The total dose of administered DCs ranged from 2.7x10(7)cells to 1.6x10(8)cells. Adjuvant cytokines, i.e., 1x10(6) U/body of nhuIFN-alpha and nhuTNF-alpha, were administered to patients twice a week during the vaccination period. No severe toxicity directly attributable to the treatment was observed, and the vaccine was well tolerated. In the delayed-type hypersensitivity (DTH) skin test, two patients showed a positive skin response to peptide-pulsed DCs after vaccination, although none of the patients tested positive prior to vaccination. In the two patients who showed a positive skin response disease remained stable for 6 and 9 months respectively. These results suggest that active immunization using DCs pulsed with CEA652 peptide in combination with the administration of adjuvant cytokines is a safe and feasible treatment procedure.