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| 2. |
- Ullenhag, Gustav, et al.
(author)
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Immunization of colorectal carcinoma patients with a recombinant canarypox virus expressing the tumor antigen Ep-CAM/KSA (ALVAC-KSA) and granulocyte macrophage colony- stimulating factor induced a tumor-specific cellular immune response
- 2003
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In: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 9:7, s. 2447-2456
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Journal article (peer-reviewed)abstract
- PURPOSE: Colorectal carcinoma cells express the tumor-associated antigen epithelial cellular adhesion molecule (Ep-CAM)/KSA. Passive immunotherapy with monoclonal antibodies using this antigen has shown promising results. Ep-CAM might also be a target for active specific immunotherapy. Expression of the tumor antigen in a viral vector may facilitate appropriate antigen presentation. The feasibility of an Ep-CAM/KSA-specific therapeutic vaccination was investigated in cancer patients.EXPERIMENTAL DESIGN: The full-length Ep-CAM gene was inserted into the avipox virus ALVAC (ALVAC-KSA). Twelve radically operated colorectal carcinoma patients without evidence of remaining macroscopic disease (stages I, II, and III) entered the study. The first 6 patients were immunized with three injections of ALVAC-KSA (10(7.09) CCID(50) per immunization) alone in weeks 0, 3, and 6. The subsequent 6 patients received the same schedule of ALVAC-KSA together with the adjuvant cytokine granulocyte macrophage colony-stimulating factor (GM-CSF; 75 micro g/day for 4 consecutive days).RESULTS: The adverse reactions to the vaccinations were mild except for local skin reactions. In the ALVAC-KSA group a weak T-cell response was induced in 2 of 6 patients. In the ALVAC-KSA/GM-CSF group a marked IFN-gamma response (enzyme-linked immunospot) was induced in 5 of 6 patients. The T-cell response appeared late, 1 month after the last immunization, with a peak at 4-5 months after immunization. No IgG antibodies against Ep-CAM were detected. Before vaccination the majority of patients had a type 1 T-cell response (IFN-gamma) against the vector, which was noted in healthy donors as well. All of the patients developed high titers of IgG antibodies against the vector, and the T-cell response was vigorously boosted.CONCLUSIONS: ALVAC-KSA, in combination with low dose local administration of GM-CSF may induce a strong, IFN-gamma T-cell response (type 1). ALVAC-KSA seems to be an interesting candidate as a cancer vaccine for future clinical development.
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| 3. |
- Ullenhag, Gustav J, et al.
(author)
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Durable carcinoembryonic antigen (CEA)-specific humoral and cellular immune responses in colorectal carcinoma patients vaccinated with recombinant CEA and granulocyte/macrophage colony-stimulating factor.
- 2004
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In: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 10:10, s. 3273-3281
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Journal article (peer-reviewed)abstract
- PURPOSE: Previous studies have indicated that carcinoembryonic antigen (CEA) might be a suitable immunotherapeutic target in colorectal carcinoma (CRC). The aim of the present study was to analyze the immunological and clinical effects of vaccination with CEA together with the adjuvant granulocyte/macrophage colony-stimulating factor (GM-CSF).EXPERIMENTAL DESIGN: Twenty-four resected CRC patients without macroscopic disease were immunized seven times with recombinant CEA at four different dose levels over a 12-month period. Half of the patients received GM-CSF (80 microg/day for 4 consecutive days) at each immunization. Patients were monitored immunologically for 36 months and clinically for 76 months. T-cell response was evaluated by a [(3)H]thymidine incorporation assay, and IgG response was determined by ELISA.RESULTS: Minor local side effects were common. All 12 patients (100%) in the GM-CSF group developed a CEA-specific T-cell as well as an IgG response. The corresponding figures in the CEA alone group were 9 of 12 (75%) and 8 of 12 (66%), respectively. GM-CSF significantly augmented the amplitude of the T-cell response and the IgG titers. No dose-response relationship was noted. The immune responses at 12 months persisted 24 months after the last vaccination. Anti-CEA IgG titers were associated with increased survival (P < 0.05), whereas standard prognostic factors had no relationship, with the exception of serum CEA value.CONCLUSIONS: Vaccination with recombinant CEA and GM-CSF appears to be a nontoxic regimen inducing potent and durable antigen-specific IgG and T-cell response. The results of this study justify more extensive trials with recombinant CEA protein for immunotherapy of CRC.
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| 4. |
- Ullenhag, Gustav J, et al.
(author)
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Functional HLA-DR T cell epitopes of CEA identified in patients with colorectal carcinoma immunized with the recombinant protein CEA.
- 2004
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In: Cancer Immunology and Immunotherapy. - : Springer Science and Business Media LLC. - 0340-7004 .- 1432-0851. ; 53:4, s. 331-337
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Journal article (peer-reviewed)abstract
- A baculovirus-produced recombinant CEA (rCEA) protein comprising the extracellular region was used for vaccination of CRC patients with or without GM-CSF as an adjuvant cytokine. Ten patients with a significant proliferative T cell response against rCEA were selected for T cell epitope mapping. Fifteen-aa-long overlapping peptides covering the entire aa sequence of the external domain of CEA were used in a proliferation assay. In six of the patients a repeatable T cell response against at least one peptide was demonstrated. For the first time, nine functional HLA-DR epitopes of CEA were defined. Two of the peptides were recognized by more than one patient, i.e., two and three patients, respectively. Those 15-mer peptides that induced a proliferative T cell response fitted to the actual HLA-DR type (SYFPEITHI). The affinity of the native peptides for the T cell receptor was in the low to intermediate range (scores 6-19). The 15-mer peptides also contained 9-mer peptide sequences that could be predicted to bind to the actual HLA-ABC genotypes (SYFPEITHI/BIMAS). Blocking experiments using monoclonal antibodies indicated that the proliferative T cell response was both MHC class I and II restricted. The defined HLA-DR T cell epitopes were spread over the entire CEA molecule, but a higher frequency was noted towards the C-terminal. Peptides with a dual specificity may form a basis for production of subunit cancer vaccines, but modifications should be done to increase the T cell affinity, thereby optimizing the antitumoral effects of the vaccine.
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| 5. |
- Ullenhag, Gustav J, et al.
(author)
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Induction of IgG subclass responses in colorectal carcinoma patients vaccinated with recombinant carcinoembryonic antigen.
- 2002
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In: Cancer Research. - 0008-5472 .- 1538-7445. ; 62, s. 1364-
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Journal article (peer-reviewed)abstract
- There is scanty information on the IgG subclass response after vaccination against cancer antigens. The induction and development of the IgG subclass responses in 18 colorectal carcinoma patients vaccinated s.c. seven times with recombinant human carcinoembryonic antigen (rhCEA) over a 12-month period were analyzed by ELISA. The patients were followed for 3 years. Four rhCEA doses were used, and half of the patients also received granulocyte macrophage-colony stimulating factor (GM-CSF) as an adjuvant. Anti-rhCEA-specific IgG1 and IgG4 responses and, to a lesser degree, IgG2 responses were markedly enhanced by concomitant GM-CSF administration, whereas the antigen dose was of minor importance. Almost no IgG3 response was observed. A significant antibody response was noted within the first weeks for IgG1 and IgG2 but noted several months later for IgG4. The responses gradually increased by repeated immunizations and peaked around 12 months for IgG1 and a few months later for IgG2 and IgG4. A sustained but reduced response was noted for these three subclasses at 24 and 36 months. Interestingly, there was a gradual shift from a predominant IgG1 response at 6 months to an IgG4 response at 15 months. No significant change in total concentrations of the four IgG subclasses was observed comparing prevaccination concentrations with concentrations at 12 months, indicating an antigen-specific effect of GM-CSF administration on the anti-rhCEA response. The clinical significance of the individual IgG subclass antibodies for tumor response is not clear and requires additional studies.
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| 6. |
- Ullenhag, Gustav, 1968-
(author)
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Vaccine Therapy of Colorectal Cancer Patients with Tumor Associated Antigens
- 2003
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Doctoral thesis (other academic/artistic)abstract
- In this thesis, two different vaccines were evaluated as adjuvant therapy for patients with colorectal cancer. The ability of the two candidate vaccines to generate antigen-specific cellular and humoral responses, respectively, was studied. The effectiveness of granulocyte colony stimulating factor (GM-CSF) as a cytokine adjuvant to augment the immune response was also examined.The first vaccination strategy involved immunization with the recombinant tumor-associated protein, carcinoembryonic antigen (CEA). Recombinant CEA was administered at 4 different dose levels 7 times during one year. Peripheral blood samples were regularly analyzed during 36 months. This vaccination regimen induced a strong immunoglobulin 1 (IgG1) and IgG4 response, a moderate IgG2 response and a weak IgG3 response against CEA. GM-CSF markedly augmented the effect on IgG1 and IgG4 as well as the T cell response. In contrast, dose of rCEA had no or modest effect on induced immune responses. The response gradually increased during the 12 months immunization period. Responses of all three IgG subclasses and of T cells were protracted up to 36 months. The anti-CEA IgG titers related significantly to survival. Functional HLA-DR epitopes of CEA could be defined. These major histocompatibility class II epitopes may serve as putative components of a peptide-based vaccination strategy. The other vaccine strategy consisted of the tumor-associated antigen epithelial cell adhesion molecule (Ep-Cam) expressed as a transgene in a viral vector, ALVAC. Patients were immunized subcutaneously/intradermally 3 times over 6 weeks and monitored for immune responses for 46 weeks. No anti-Ep-Cam specific humoral response was induced, but Ep-Cam specific type 1 T cells (interpheron-gamma production) were induced, mainly in the GM-CSF group. The cytotoxic cellular response appeared late, or a few months after the last immunization.Both vaccines were well tolerated. Since GM-CSF was an important component for both regimens, immungenicity of this cytokine was assessed. Multiple immunizations with low dose GM-CSF were associated with a low incidence of GM-CSF antibodies that did not neutralize the biological effect of GM-CSF. In conclusion, both vaccines are promising candidate vaccines. GM-CSF is necessary to induce a strong humoral and cellular immune response. Large clinical trials are urgently warranted to evaluate the clinical efficacy.
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