Nasal immunization with a fusion protein consisting of the hemagglutinin A antigenic region and the maltose-binding protein elicits CD11c(+) CD8(+) dendritic cells for induced long-term protective immunity

Mucosal Vaccination Against Periodontal Disease: Current Status and Opportunities

Approximately 9 out of 10 adults have some form of periodontal disease, an infection-induced inflammatory disease of the tooth-supporting tissues. The initial form, gingivitis, often remains asymptomatic, but this can evolve into periodontitis, which is typically associated with halitosis, oral pain or discomfort, and tooth loss. Furthermore, periodontitis may contribute to systemic disorders like cardiovascular disease and type 2 diabetes mellitus. Control options remain nonspecific, time-consuming, and costly; largely relying on the removal of dental plaque and calculus by mechanical debridement. However, while dental plaque bacteria trigger periodontal disease, it is the host-specific inflammatory response that acts as main driver of tissue destruction and disease progression. Therefore, periodontal disease control should aim to alter the host's inflammatory response as well as to reduce the bacterial triggers. Vaccines may provide a potent adjunct to mechanical debridement for periodontal disease prevention and treatment. However, the immunopathogenic complexity and polymicrobial aspect of PD appear to complicate the development of periodontal vaccines. Moreover, a successful periodontal vaccine should induce protective immunity in the oral cavity, which proves difficult with traditional vaccination methods. Recent advances in mucosal vaccination may bridge the gap in periodontal vaccine development. In this review, we offer a comprehensive overview of mucosal vaccination strategies to induce protective immunity in the oral cavity for periodontal disease control. Furthermore, we highlight the need for additional research with appropriate and clinically relevant animal models. Finally, we discuss several opportunities in periodontal vaccine development such as multivalency, vaccine formulations, and delivery systems.

Escherichia coli Maltose-Binding Protein Induces M1 Polarity of RAW264.7 Macrophage Cells via a TLR2- and TLR4-Dependent Manner

Maltose-binding protein (MBP) is a critical player of the maltose/maltodextrin transport system in Escherichia coli. Our previous studies have revealed that MBP nonspecifically induces T helper type 1 (Th1) cell activation and activates peritoneal macrophages obtained from mouse. In the present study, we reported a direct stimulatory effect of MBP on RAW264.7 cells, a murine macrophage cell line. When stimulated with MBP, the production of nitric oxide (NO), IL-1β, IL-6 and IL-12p70, and the expressions of CD80, MHC class II and inducible nitric oxide synthase (iNOS) were all increased in RAW264.7 cells, indicating the activation and polarization of RAW264.7 cells into M1 macrophages induced by MBP. Further study showed that MBP stimulation upregulated the expression of TLR2 and TLR4 on RAW264.7 cells, which was accompanied by subsequent phosphorylation of IκB-α and p38 MAPK. Pretreatment with anti-TLR2 or anti-TLR4 antibodies largely inhibited the phosphorylation of IκB-α and p38 MAPK, and greatly reduced MBP-induced NO and IL-12p70 production, suggesting that the MBP-induced macrophage activation and polarization were mediated by TLR2 and TLR4 signaling pathways. The observed results were independent of lipopolysaccharide contamination. Our study provides a new insight into a mechanism by which MBP enhances immune responses and warrants the potential application of MBP as an immune adjuvant in immune therapies.

Induction of immune response and prevention of alveolar bone loss with recombinant Porphyromonas gingivalis peptidylarginine deiminase

OBJECTIVE

Treatments for periodontitis are not absolutely perfect, and a vaccine against Porphyromonas gingivalis (P. gingivalis) could become a valuable adjunct therapy for periodontitis.

DESIGN

In this study, a vaccine of peptidylarginine deiminase (PAD) from P. gingivalis was evaluated in P. gingivalis-induced murine lesion and periodontitis models. The prevention of alveolar bone loss analysis determined by micro-computed X-ray tomography (micro-CT), and histological assays. Furthermore, the induction of immune response of mouse anti-PAD done with ELISA and Western Blot analysis.

RESULTS

Compared with animal immunization with incomplete Freund's adjuvant (IFA) alone, PAD group significantly inhibited (P<0.05) bone resorption. ELISA and Western Blot showed that PAD induced response involving immunoglobulin G1 (Ig G1) predominantly.

CONCLUSIONS

These results suggest that PAD could be a candidate antigen for a vaccine against P. gingivalis infection.

Sublingual vaccination with fusion protein consisting of the functional domain of hemagglutinin A of Porphyromonas gingivalis and Escherichia coli maltose-binding protein elicits protective immunity in the oral cavity

This study demonstrated that sublingual immunization with a fusion protein, 25k-hagA-MBP, which consists of a 25-kDa antigenic region of hemagglutinin A purified from Porphyromonas gingivalis fused to maltose-binding protein (MBP) originating from Escherichia coli as an adjuvant, elicited protective immune responses. Immunization with 25k-hagA-MBP induced high levels of antigen-specific serum IgG and IgA, as well as salivary IgA. High level titers of serum IgG and IgA were also induced for almost 1 year. In an IgG subclass analysis, sublingual immunization with 25k-hagA-MBP induced both IgG1 and IgG2b antibody responses. Additionally, numerous antigen-specific IgA antibody-forming cells were detected from the salivary gland 7 days after the final immunization. Mononuclear cells isolated from submandibular lymph nodes (SMLs) showed significant levels of proliferation upon restimulation with 25k-hagA-MBP. An analysis of cytokine responses showed that antigen-specific mononuclear cells isolated from SMLs produced significantly high levels of IL-4, IFN-γ, and TGF-β. These results indicate that sublingual immunization with 25k-hagA-MBP induces efficient protective immunity against P. gingivalis infection in the oral cavity via Th1-type and Th2-type cytokine production.