Evaluation of MPLA as in vaccine formulations against leptospirosis

• Grant number: 13/00939-5
• Support Opportunities: Scholarships in Brazil - Master
• Start date: May 01, 2013
• End date: March 31, 2015
• Field of knowledge: Biological Sciences - Immunology
• Principal Investigator: Elizabeth Angelica Leme Martins
• Grantee: Marina Yukari Kubota
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

For the development of vaccines against Leptospirosis, it is important to search for antigens that are good immunogens and well conserved among the different sorovars, to confer longer and wide spectrum protective immunity. In this context proteic antigens are more suitable. However, the immune response can be amplified and modulated according to adjuvants added to the vaccine formulations. For more than 70 years aluminum salts have been the conventional adjuvant, enhancing specially the humoral immune response. Complex adjuvant, such as Freund´s, increase the cellular immune response, but they can determine exacerbate inflammatory responses.Bacterial components such as lipopolysaccharides (LPS), also called endotoxins, can determine an innate immune and inflammatory response mediated by receptors on cells of the immune system. The comprehension of the interaction of bacterial endotoxin and the receptors on the mammalian cells and its consequent triggering of intracellular signal transduction allow to propose the use of subfractions of detoxified LPS as new adjuvants. The molecule of LPS, which composes the external structure of the bacteria, was characterized as an antigenic portion (oligosaccharides - OS) linked to the lipid A moiety, the stronger determinant of the inflammatory response. The structures of lipid A from various bacteria have been investigated as well as their interactions with different mammalian receptors Toll (TLRs). A new adjuvant approved for use in Europe, AS04, uses detoxified lipid A from Salmonella, the monophosphoril lipid A (MPLA) combined with aluminum salts. It has been reported that the MPLA of leptospires is less endotoxic and that it acted as adjuvant when LPS from leptospires was used as antigen.The purpose of this project is to analyze the MPLA from leptospires as adjuvant to verify possible increase in the immune response to a vaccine candidate, the protein Lip32. For this proposal we will utilize the protocols for LPS purification and MPLA obtaining described for other bacteria for the extraction of MPLA from leptospires. Purification of MPLA from leptospira will be evaluated by measurements of a specific sugar of LPS, the KDO, and phosphates and its characterization will be done by different mass analysis of the molecular structures. Mice immunization assays will be conducted using MPLA from leptospira and from salmonella (purified and commercial products) as adjuvants for studies of the immune response such as the induction of cytokines and titles of different antibody isotypes. Immunization and challenge assay will be conducted in hamsters to check the possible occurrence of increasing on protective immune response.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

KUBOTA, Marina Yukari. Avaliation of MPLA as adjuvant in vaccine formulation against leptospirosis.. 2015. Master's Dissertation - Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI) São Paulo.