Development of multistage recombinant protein vaccine formulations against toxoplasmosis using a new chitosan and porin based adjuvant system

• Published in: International journal of pharmaceutics 2022-10, Vol.626, p.122199-122199, Article 122199
• Main Authors: Parmaksız, Selin, Gül, Aytül, Erkunt Alak, Sedef, Karakavuk, Muhammet, Can, Hüseyin, Gül, Ceren, Karakavuk, Tuğba, López-Macías, Constantino, Puralı, Nuhan, Döşkaya, Mert, Şenel, Sevda
• Format: Article
• Language: English
• Subjects: Chitosan; Particulate adjuvant; Porins; rBAG1; rGRA1; Toxoplasmosis
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/j.ijpharm.2022.122199

[Display omitted] •Introducing a new particulate adjuvant system based on combination of chitosan and porins (MicroAS and NanoAS) for delivery of multivalent antigens, rGRA1 and rBAG1 against T. gondii.•Adjuvanted formulations induce significantly higher humoral and cellular immune responses and protection against T. gondii.•Higher protective immune responses were obtained with microparticulate adjuvant (MicroAS) following initial immunization when compared to nanoparticulate adjuvant (NanoAS). Toxoplasmosis is a global health problem affecting both human and animal populations. The lack of effective treatment makes the development of a vaccine against toxoplasmosis one of the main goals in the management of this disease. In our study, vaccine formulations containing the multistage recombinant antigens, rBAG1 + rGRA1 were developed with a combined adjuvant system consisting of chitosan and Salmonella Typhi porins in micro (MicroAS) and nanoparticulate (NanoAS) forms. BALB/c mice were immunized intraperitoneally with vaccine formulations two times at three-week intervals. Three weeks after the second vaccination, mice were challenged with 7–8 live tissue cysts of the virulent T. gondii PRU strain by oral gavage. Higher cellular uptake by macrophages and enhanced cellular (IFN-γ and I-4 in stimulated spleen cells) and humoral (IgG, IgG1, IgG2a) responses were obtained with the adjuvanted formulation, higher with microsystem when compared to that of nanosystem. Microsystem was found to stimulate Th1-polarized immune responses, whereasnon-adjuvanted antigens stimulated Th2-polarized immune response. The highest survival rate and reduction in cysts numbers and T. gondii DNA were obtained with the adjuvanted antigens.Our study showed that adjuvanted multistage recombinant vaccine systems increase theimmune response with strong protection againstT. gondii, more profoundly in microparticulate form.