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| Author(s): |
Luciana Previato de Almeida
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2008-01-17 |
| Examining board members: |
Arlete Aparecida Martins Coelho Castelo;
Luis Carlos de Souza Ferreira;
João Santana da Silva
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| Advisor: | Arlete Aparecida Martins Coelho Castelo |
| Abstract | |
Although B cells are important as antigen presenting cells (APC), their role in DNA vaccination models is unknown. In the current study, we demonstrated that B cells can present antigens in vitro and in vivo after DNA vaccination with pcDNA3 constructed with 65 kDa-heat shock protein gene from M. leprae (pcDNA3-HSP65). After intramuscular immunization, different APC such as dendritic cells (DC), B cells, and macrophages was cocultured with CD4 and CD8 T lymphocytes subsets from immunized mice to determine their ability in antigen presentation. Fifteen days after DNA immunization, DC and B cells, but not macrophages, induced activation of T cells. DC activated mainly CD4 regulatory T cells (Treg, FoxP3+), whereas B cells activated both CD4 T helper (Th) 2 cells (GATA3+) and CD8 Treg (FoxP3+). Thirty days after immunization, macrophages and B cells activated CD4 Treg and CD8 T (T-bet+) cells, respectively, whereas no cells was activated by dendritic cells. To evaluate if pcDNA3-HSP65-transfected B cells induced immune activation and memory, we carried out adoptive transfer of transfected B cells to B cell-deficient mice (Bko). Bko reconstituted with pcDNA3-hsp65-transfected B cells produced memory CD8 T cells (CD44hi and CD62hi). Moreover, mice challenged with virulent Mycobacterium tuberculosis on day seven after adoptive transfer presented, on the day 30 postinfection, fewer number of colony-forming units (CFU) than WT mice, suggesting that B cells play important role in the induction of CD8 T cells and bacterial clearance. On the other hand, histopathology analysis of reconstituted Bko mice showed more severe inflammation than control mice. Since the B cell isolation protocol eliminated B regulatory (Breg) cells, we hypothesized that Breg absence could increase the lung damage. Altogether, our data demonstrate that B cells can play a crucial role in the success of DNA vaccination and immunomodulation. (AU) | |
| FAPESP's process: | 05/03087-3 - Antigen-presenting capacity comparison among macrophages, B cells and dendritic cells in DNA vaccine model |
| Grantee: | Luciana Previato de Almeida |
| Support Opportunities: | Scholarships in Brazil - Master |