Porphyromonas gingivalis (Pg) is one of the main pathogens in chronic periodontitis (CP). Studies on the immunogenicity of its virulence factors may contribute to understanding the host response to infection. The present study aimed to use in silico analysis as a tool to identify epitopes from Lys-gingipain (Kgp) and neuraminidase virulence factors of the Pg ATCC 33277 strain. Protein sequences were obtained from the NCBI Protein Database and they were scanned for amino acid patterns indicative of MHC II binding using the MHC-II Binding Predictions tool from the Immune Epitope Database (IEDB). Peptides from different regions of the proteins were chemically synthesized and tested by the indirect ELISA method to verify IgG immunoreactivity in serum of subjects with CP and without periodontitis (WP). T cell epitope prediction resulted in 16 peptide sequences from Kgp and 18 peptide sequences from neuraminidase. All tested Kgp peptides exhibited IgG immunoreactivity whereas tested neuraminidase peptides presented low IgG immunoreactivity. Thus, the IgG reactivity to Kgp protein could be reaffirmed and the low IgG reactivity to Pg neuraminidase could be suggested. The novel peptide epitopes from Pg were useful to evaluate its immunoreactivity based on the IgG-mediated host response. In silico analysis was useful for preselecting epitopes for immune response studies in CP.Electronic supplementary materialThe online version of this article (10.1186/s13568-019-0757-x) contains supplementary material, which is available to authorized users.

BackgroundCorynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis (CL), a chronic disease that affects goats and sheep. CL is characterized by the formation of granulomas in lymph nodes and other organs, such as the lungs and liver. Current knowledge of CL pathogenesis indicates that the induction of humoral and cellular immune responses are fundamental to disease control. The aim of this study was to evaluate the humoral and cellular immune responses in BALB/c mice inoculated with a C. pseudotuberculosis strain isolated in the state of Bahia, Brazil.ResultsThe lymphocyte proliferation and in vitro production of IFN-γ, IL-4, IL-10, IL-12 and nitric oxide by spleen cells stimulated with secreted and somatic antigens from the studied strain were evaluated. IgG subclasses were also analyzed. Results showed a significant increase of Th1-profile cytokines after 60 days post-inoculation, as well as an important humoral response, represented by high levels of IgG2a and IgG1 against C. pseudotuberculosis.ConclusionThe T1 strain of C. pseudotuberculosis was shown to induce humoral and cellular immune responses in BALB/c mice, but, even at a dosage of 1x107 CFU, no signs of the disease were observed.

Background: Periodontitis is a progressive inflammatory process, and its pathogenesis is related to the presence of a dysbiotic subgingival biofilm that elicits the immune response. Porphyromonas gingivalis is a keystone pathogen, and its Lys-gingipain (Kgp) virulence factor is involved in the pathogen-host interaction through the production of cytokines by host cells, but the specific mechanisms of this interaction have not been elucidated. The present study evaluated the in vitro production of interferongamma (IFN-), interleukin (IL)-6, and IL-1 cytokines in response to antigenic stimulation of peripheral blood mononuclear cells (PBMCs) with novel Kgp synthetic peptides. Methods:Our previous in silico study predicted 16 immunogenic peptides from Kgp protein. Nine peptides derived from different regions of the protein were chemically synthesized. The synthetic peptides Kgp12, 17, and 18 were selected based on the immunoglobulin G immunoreactivity in the serum of patients with periodontitis (P) and individuals without periodontitis (WP), and they were used in in vitro stimulation of PBMC derived from groups P and WP. Enzyme-linked immunosorbent assay and microsphere-based flow cytometric assay were used to verify the levels of the cytokines produced in PBMC cultures after 48 hours.Results: Kgp12, 17, and 18 peptides induced lower production of IFN-. Kgp12 induced higher levels of IFN-in WP than in P individuals. Kgp12 induced higher production of IL-6 and IL-1 compared with the other stimuli. Conclusion:The novel Kgp synthetic peptides tested herein are immunogenic peptides (epitopes) since they induced the production of cytokines by PBMC and therefore may be useful tools in evaluating the pathogen-host interaction. K E Y W O R D Scytokines, immunology, microbiology, periodontitis J Periodontol. 2019;90:993-1001.

As espécies do gênero Lippia (Verbenaceae) possuem diversas moléculas bioativas, oriundas do seu metabolismo secundário, que apresentam atividade antimicrobiana, analgésica, antifúngica e imunomoduladora. Este estudo teve como objetivo avaliar a atividade antimicrobiana in vitro do extrato metanólico das folhas de L. alnifolia, L. origanoides, L. insignis e L. thymoides frente a microrganismos de importância clínica.  Foi realizada uma triagem fitoquímica dos extratos das plantas e a avaliação da atividade antimicrobiana pelo método de difusão em disco, além da determinação da concentração inibitória mínima (MIC) frente às bactérias Bacillus subtilis, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Staphylococcus aureus e Salmonella choleraesuis, e os fungos Candida albicans e Candida glabrata. A presença de saponinas, terpenos, esteroides, cumarinas, ácidos fenólicos e flavonoides foi observada na análise fitoquímica. Os extratos metanólicos das folhas de L. alnifolia, L. origanoides e L. insignis apresentaram atividade antimicrobiana contra todas os microrganismos testados. O extrato metanólico da L. thymoides apresentou atividade antimicrobiana frente aos microrganismos M. luteus, P. aeruginosa, S. aureus, C. albicans e C. glabrata. A maioria dos extratos apresentou atividade bacteriostática e todos os extratos apresentaram atividade fungistática para C. albicans e fungicida para C. glabrata. A utilização dos extratos de Lippia pode ser uma alternativa viável no tratamento de doenças infecciosas de origem bacteriana e fúngica.

INTRODUCTION: Periodontitis is a chronic inflammatory disease that arises from an interaction of local dysbiosis in the subgingival biofilm and the host immune response. The disease triggers an inflammatory process that can cause periodontal tissue breakdown. In addition, the production of inflammatory mediators can negatively affect other areas of the body and influence the development and/or severity of associated disorders, including asthma, diabetes and cardiovascular diseases. OBJECTIVE: Conduct a literature review to comprehensively investigate the role of ST2 and IL-33 and the contribution of the IL-33 / ST2 axis in the pathogenesis of periodontitis. METHODS: It is a narrative literature review, which used the databases Pubmed and Academic Google a total of 114 results. RESULTS: A range of immunological markers has been shown to be relevant in the immunopathogenesis of periodontitis, cytokines of the interleukin 1 (IL-1) family, such as IL-1β and IL-33. IL-33, through its ST2 receptor, appears to be involved in the development of periodontitis, acting as a molecule that signals tissue damage from infection and also emits an endogenous signal that activates the immune response and / or worsens bone resorption by activating osteoclastogenesis, either through increases in RANK-L and reduced OPG, or regardless of that pathway. CONCLUSION: The diversity of information contained in the methodologies of these studies hampers attempts to standardize and make correlations between published data, in this sense, the IL-33 / ST2 axis remains a relevant topic in investigations focused on the diagnosis and treatment of periodontal disease.