| 1. |
- Ullenhag, Gustav J, et al.
(författare)
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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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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 10:10, s. 3273-3281
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Ullenhag, Gustav J, et al.
(författare)
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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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Ingår i: Cancer Immunology and Immunotherapy. - : Springer Science and Business Media LLC. - 0340-7004 .- 1432-0851. ; 53:4, s. 331-337
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Tidskriftsartikel (refereegranskat)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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| 3. |
- Ullenhag, Gustav J, et al.
(författare)
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Induction of IgG subclass responses in colorectal carcinoma patients vaccinated with recombinant carcinoembryonic antigen.
- 2002
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 62, s. 1364-
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Tidskriftsartikel (refereegranskat)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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