Research Projects

Vaccines are highly cost-effective, drastically reducing infectious diseases and mortality rates through widespread immunization campaigns. They have eradicated smallpox, reduced polio and measles and prevented epidemics, fostering herd immunity and protecting both vaccinated and unvaccinated individuals. This leads to lower healthcare costs and increased productivity. Oral vaccines offer advantages over injectables by simplifying administration, eliminating the need for trained professionals, reducing needle-stick injuries and blood-borne pathogen transmission, more acceptable (especially for children) and can induce mucosal immunity, relevant for pathogens which establish infection through mucosal routes such as respiratory, gastrointestinal, and sexually transmitted pathogens. To improve the gut-stability of oral immunization, applicant propose to develop CRISPR-Cas9 derived engineered Lactococcus lactis (non-spore forming, short-term gut-colonizing) and Bacillus coagulans (spore-forming, long-term gut-colonizing) clones with site-specific genomic integration of the transgene, which would produce the vaccine antigen to generate robust gut-associated immune response. To establish a proof-of-concept, a comparative immunogenicity in mice using the engineered L. lactis and B. coagulans clones each expressing one of the two following antigens: CRM197 (a genetically detoxified mutant of diphtheria toxin, used as a carrier protein in vaccines), and a novel multi-stage malaria vaccine (flPfCSP-PfsPro6C), with respective subcutaneous immunizations of these antigens formulated with Alhydrogel adjuvant, would be carried out. The selection of CRM197 and flPfCSP-PfsPro6C as target antigens is both strategic and translationally relevant. CRM197, a non-toxic analog of diphtheria toxin, serves as a proven carrier protein in widely used conjugate vaccines against pneumococcal and meningococcal diseases. flPfCSP-PfsPro6C is a next-generation, multi-stage chimeric malaria vaccine candidate with demonstrated immunogenicity and functional efficacy in preclinical models. This study represents, to our knowledge, the first direct comparison of immune responses elicited by short-term versus long-term gut-colonizing engineered lactic acid bacteria (eLABs) delivering these antigens, in parallel with injectable immunization. By evaluating antigen delivery platforms that are scalable, needle-free and capable of eliciting mucosal immunity, this study aims to contribute directly to the development of accessible oral vaccines with high relevance to global immunization efforts and public health needs in resource-limited settings.

Oral vaccination, malaria vaccine, CRISPR-CAS9, Lactic acid bacteria, gut bacteria, CRM