Project Design

Leijuvant is a whole new kind of adjuvant that uses Leishmania as an effective T cell stimulator. Leishmania is a parasite that specifically lives within macrophage, a professional antigen presenting cell (APC). As a potential vaccine adjuvant, Leishmania possess many advantages, including APC recruitment, pattern recognition receptor (PRR) activation, inflammasome activation, activation of MHC-presenting pathway and most important of all, T cell activation. We adapted a combinational approach by loading the Leishmania DT mutants both endogenously and exogenously with different chemicals. After the chemicals are illuminated by specific wavelength of light, double-photo inactivation will kill Leishmania thoroughly. Thus, transgenic mutant of Leishmania that can be inactivated by light exposure acts as a safe carrier to deliver specific antigens to APCs.

Photo-inactivated Leishmania has been proven to activate CD8 and CD4 T cells. However, further activation of B cells has not been confirmed. As a vaccine adjuvant, persistent antibody production against specific antigen is an essential parameter in evaluating vaccine efficacy. B cell needs the stimulation from both the intact antigen and antigen-specific CD4 T cell simultaneously in order to differentiate into plasma cell in producing antibodies.Therefore, we hypothesized that genetically engineered Leishmania that express specific antigen can serve as an adjuvant that deliver antigens into APCs. The photo-inactivated Leishmania will be engulfed by APCs and activate T cells via MHC molecules. With the company of intact vaccine antigen, they can stimulate B cell form both ways and induce antibody production.

Experimental design

Our experiments can be divided into four main parts:

• Ecoli-Leishmania shuttle vector-the Leishmania antigen expression system
• In vivo test for validation of our concept of LEIJUVANT
• In vitro test for proving our software prediction system, McHug, and our concept
• As for the social experiments, we designed questionnaires to study the public's general knowledge level on vaccines

In order to use Leishmania to deliver antigen into the APCs to further activate the immune response, we designed an E.coli-Leishmania shuttle vector to carry the antigen sequence into Leishmania through electroporation. After drug selection, the successfully tranfected Leishmania is selected and we then performed double-photo inactivation to disarm Leishmania. After insuring the death of Leiahmania, we tested the antibody production and T cell responses through in vivo experiments via co-injecting Leijuvant with OVA protein into mice. As for testing the ability of T cell activation, we focused on the MHC presentation through in vitro experiment and also validate the accuracy of our prediction system, McHug, through MS spectrometry.

To launch a medical product, it must go through multiple processes including R&D, scale-up production, risk-benefit assessment, and assessing the public perception. Thus, we went to different levels of vaccine industries to dig into the research and development of vaccine and their opinions on our project. We also carried out a survey to acquire public perception toward our product and also a series of selected questions to get to know the public's knowledge level on vaccines.