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| Author(s): |
Wendy Martin Rios
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2013-07-02 |
| Examining board members: |
Celio Lopes Silva;
Luis Carlos de Souza Ferreira;
Anderson Miyoshi;
Isabel Kinney Ferreira de Miranda Santos;
Sandro Gomes Soares
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| Advisor: | Celio Lopes Silva |
| Abstract | |
Glioblastoma multiforme (GBM) is the most common form of primary brain cancer and the most severe tumour affecting glia cells. GBM is a grade IV astrocytoma known by uncontrolled proliferation, diffused infiltrate, necrosis tendency, angiogenesis, apoptosis resistance and a wide genetic heterogeneity. The standard of care consists of maximal surgical resection, followed by a combination of radiation and chemotherapy. Despite that, tumour becomes resistant to drugs used to treatment, and the patient experiences recurrence followed by death in less than 15 months after diagnosis. An alternative in GBM treatment could be immunotherapy which aims to stimulate patients immunological system in order to obtain a specific and long-term response that can protect against recurrence. One of these alternatives involves the use of DNA vaccines codifying tumoral antigens and immunomodulatory proteins that can effectively activate tumour antigen specific B and T lymphocytes. In this context, the objective of this work was the construction of DNA vaccines using GBM antigen genes (EGFRvIII, cERBB2, MAGE e GLEA) and immunomodulatory proteins (hsp65, hsp70, gp96 e gD), followed by their immunogenicity evaluation. Genes were evaluated in silico, synthesized in vitro and used in DNA vaccines construction. Molecular biology tools and the pVAX vector were used to obtain the vaccine. They were characterized by sequencing, western blot and were used in the immunization of C57BL/6 mice. Immunizations were performed in 3 doses of a DNA vaccine combining a tumoral antigen and an immunomodulatory protein at each 12 days. Immunogenicity was evaluated 20 days after the last dose. The ex vivo assays were performed with the serum of immunized animals for antibody evaluation and spleen cells were stimulated with EGFRvIII, cERBB2, MAGE e GLEA proteins to assess tumoral antigen specific cells. The pVAXgDGLEA vaccine was the only able to induce IgG2a subtype anti-GLEA antibodies. Vaccines pVAXgDGLEA, pVAXgDEGFRvIII e pVAXgDMAGE were able to activate antigen-specific cells that produced IFN-g e IL-10 quickly after reestimulation. The gD immunomodulatory protein was able to induce a Th1 immune response, specific to GBM antigens, which is important in tumor combat while IL-10 could favor and/or balance the response in brain, which should be effective but not exacerbated. (AU) | |