VACCINE CANDIDATES AGAINST SCHISTOSOMIASIS: A BIOREACTOR-OPTIMIZED PRODUCTION OF OUTER MEMBRANE VESICLES FROM Neisseria lactamica and RECOMBINANT PROTEINS OF Escherichia coli

• Grant number: 25/01217-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: October 01, 2025
• End date: September 30, 2028
• Field of knowledge: Engineering - Chemical Engineering - Chemical Process Industries
• Principal Investigator: Viviane Maimoni Gonçalves
• Grantee: Kevy Pontes Eliodório
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated research grant: 17/24832-6 - Development of vaccines based on recombinant BCG: Tuberculosis, Pertussis, Pneumococcus and Schistosoma, AP.TEM

Abstract

Schistosomiasis is a neglected parasitic disease caused by Schistosoma mansoni, affecting approximately 240 million people worldwide in endemic areas. Recently, there has been significant progress in vaccine research due to advancements in studies of the proteome and transcriptome of S. mansoni. These investigations have identified proteins that are potential vaccine candidates against schistosomiasis. Our research group recently demonstrated the potential of S. mansoni proteins Cathepsin B (SmCatB), Asparaginyl endopeptidase (SmAE), and MEG-4 as potential vaccine candidates using rhesus macaque models. However, there is a need to improve the ability of these antigens to trigger an appropriate immune response in addition to their industrial-scale production. In this regard, the present project, based on the advancements of Barbosa et al. (2021a), aims to contribute to optimizing cultivation conditions for recombinant proteins and vaccine adjuvants. The previous work established a novel antigen presentation platform by constructing a MAPS-OMV-SmAg system. In addition to protein production by recombinant Escherichia coli, the platform uses outer membrane vesicles (OMVs) produced by Neisseria lactamica. This project focuses on optimizing cultivation conditions for both microorganisms, aiming to maximize the production of OMVs and antigens. The project will be divided into stages for each microorganism. In the first stage, the main nutritional requirements of N. lactamica will be investigated, aiming to produce a defined medium that allows the identification of compounds triggering OMV formation. The cultures in this stage will be performed in flasks and microreactors with different compound supplements and compared with the growth and OMV production in the original medium. The reactor optimization phase will be facilitated by a preliminary investigation of the medium and selecting an appropriate experimental design, enabling the investigation of additional cultivation parameters such as operation mode, temperature, agitation, dissolved oxygen, pH, and stationary phase time. Stage 2 of this project aims to maximize the production of newly identified proteins (SmCatB and SmAE) of interest using recombinant E. coli strains. High cell-density E. coli cultivation strategies in chemically defined medium (HDF) with exponential substrate feeding in bioreactors will be evaluated to optimize protein production by manipulating induction variables such as time, temperature, optical density at induction, and IPTG concentration. Additionally, growth curves obtained under optimized conditions will be kinetically characterized in this stage, evaluating the viability of producing these antigens. This research enables the production of MAPS-OMV-SmAg complexes, facilitating their potential application in schistosomiasis vaccine research. By employing bioreactor optimization techniques to enable the sequential scaling of the process, this project significantly contributes to the industrial viability of vaccine candidates. (AU)