Group A Streptoccocus (GAS) is one of the most common pathogens causing mortality and morbidity. Post infection complication causing rheumatic fever and rheumatic heart disease are responsible for several millions of deaths per decade. As classical antibiotic therapy has been not able to control the infection, development of a vaccine appears to be most preferable alternative.
We have investigated lipid core peptide (LCP)-based self-adjuvanting system as a preventive vaccine against GAS. The lead vaccine candidate contains GAS M-protein derived conserved B-cell epitope as well as T-helper. Both peptides upon conjugation into LCP system demonstrated excellent ability to stimulate systemic humoral immunity after subcutaneous administration in mice.
Oral and/or intranasal deliveries of drugs/vaccines are the most preferable routes of administration. In addition, induction of mucosal immunity by GAS vaccine is highly preferable as the first step of GAS infection is typically following mucosal colonization. To induce strong mucosal immune responses, we developed un/coated liposomal delivery systems for LCP-based vaccine. These delivery systems induced higher uptake of the vaccine candidate by antigen presenting cells as well as significantly higher antibody titers (IgG and IgA) than LCP alone in mice upon immunization. Both oral and intranasal administrations have also shown ability to induce long lasting immunity. Thus, using liposomes and liposomes coated with polymers we have developed promising delivery system for simple oral and intranasal vaccination.