Periodontitis is a chronic inflammatory disease affecting the tissues that surround and support the teeth. In the U. S., approximately 65 million people are affected by this condition. Its occurrence is also associated with many important systemic diseases such as cardiovascular disease, rheumatoid arthritis, and Alzheimer’s disease. Among the most important etiologies of periodontitis is Porphyromonas gingivalis, a keystone bacterial pathogen. Keystone pathogens can orchestrate inflammatory disease by remodeling a normally benign microbiota causing imbalance between normal and pathogenic microbiota (dysbiosis). The important characteristics of P. gingivalis causing dysbiosis are its virulence factors that cause effective subversion of host defenses to its advantage [1], allowing other pathogens to grow. However, the mechanisms involving these processes are poorly understood. However, various microbial strategies target host sialoglycoproteins for immune dysregulation. In addition, the enzymes that break down sialoglycoproteins/sialoglycans are the “sialoglycoproteases”, resulting in exposed terminal sialic acid. This process could lead to pathogen-toll like receptor (TLR) interactions mediated through sialic acid receptor–ligand mechanisms. By assessing the function of P. gingivalis sialoglycoproteases, could pave the way to designing carbohydrate analogues and sialic acid mimetics to serve as drug targets.

Chagas disease, caused by Trypanosoma cruzi, leads to severe complications in 30% of infected individuals, including acute myocarditis and chronic fibrosing cardiomyopathy. Despite the significant burden of the disease, there is currently no licensed vaccine available to prevent it. This study aimed to evaluate the mucosal and systemic immunogenicity as well as the prophylactic efficacy of a mucosal vaccine and its impact on both acute and chronic cardiomyopathy. The results showed that nasal administration of Trans-sialidase (TS) plus c-di-AMP (TS+A). TS+A vaccine elicited NALT expression of IFN-γ, IL-17a, and IL-4 mRNA, and nasal-specific IgA production. Ex vivo challenge with TS also triggered enhanced proliferation of lymphocyte from the NALT, sentinel cervical lymph node and spleen. TS+A immunization increased plasma levels of Th1/Th2/Th17 cytokines and an evident cellular response to judge enhanced delayed-type hypersensitivity responses following TS footpad challenge. After oral infection, TS+A-vaccinated mice showed significantly reduced parasitemia and parasite load in heart, muscle and intestine, while markers of hepatic and muscle damage as well as clinical manifestations of acute infection are strongly diminished. TS+A also attenuated acute myocarditis and heart expression of inflammatory markers. The protection conferred by TS+A extended into the chronic phase, where it resulted in a clear reduction in chronic myocarditis, fibrosis, and functional electrocardiographic abnormalities, associated with decreased expression of the pro-fibrotic TGF-β. These results revealed that it is possible to develop a mucosal vaccine against T. cruzi based on TS and c-di-AMP, capable to reduce the development of Chagas cardiomyopathy, the hallmark of Chagas disease.