Evaluation of bacterial vaccine vehicles Bacillus subtilis and Listeria innocua on the induction of specific immune response in ex-vivo model

• Grant number: 12/05747-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: June 30, 2012
• End date: December 29, 2012
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Luis Carlos de Souza Ferreira
• Grantee: Rafael Ciro Marques Cavalcante
• Supervisor: Darren E. Higgins
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Harvard University, Boston, United States

Abstract

We initially proposed for PhD thesis the construction of heterologous expression systems able to produce high amounts of recombinant proteins in B.subtilis. To achieve this aim, we have been used with different plasmids with bidirectional replication, as well as some promoting sequences derived from B.subtilis genes. During the second year doctoral, through a partnership between our laboratory and the laboratory of Professor Darren Higgins from Harvard Medical School, we have begun an international partnership for the construction of plasmids able to replicate and promote strong heterologous expression in B. subtilis and L.innocua. Thereafter, we added another goal to our work, to compare the performance of the two hosts with the same expression system as regards the potential application as vaccine vehicles, since both laboratories have extensive knowledge in this area. In this sense, several constructions were tested, and we managed to build two different sets of plasmids. Both functional on the two hosts and based in the PHyper (design by the group of Professor Higgins) and plasmids derived from pAMB1 and pMTLBS72 (used by our group). The main aim of this work is to assess the potential of the expression systems constructed and the two hosts in ex vivo experiments by using a model for activation of immune response mediated by antigen-presenting cells and genetically modified T lymphocytes in colorimetric assays. This correlate is routinely applied in the laboratory of Professor Higgins, is not available in our country, is relatively fast and affords to selection of the best vaccination strategies, drastically reducing the use of experimental animals. Hopefully, after this work, we will provide an unprecedented comparative analysis between the performance of both hosts and expression systems constructed. Undoubtedly, these results will contribute greatly for the study of B. subtilis and L.innocua and certainly will guide the use of these vehicles in future vaccine strategies. (AU)