Environmental Biofilms from an Urban Community in Salvador, Brazil, Shelter Previously Uncharacterized Saprophytic Leptospira.

Biofilms are complex microecosystems with valuable ecological roles that can shelter a variety of microorganisms. Spirochetes from the genus Leptospira have been observed to form biofilms in vitro, in rural environments, and in the kidneys of reservoir rats. The genus Leptospira is composed of pathogenic and non-pathogenic species, and the description of new species is ongoing due to the advent of whole genome sequencing. Leptospires have increasingly been isolated from water and soil samples. To investigate the presence of Leptospira in environmental biofilms, we collected three distinct samples of biofilms formed in an urban setting with poor sanitation: Pau da Lima, in Salvador, Bahia, Brazil. All biofilm samples were negative for the presence of pathogenic leptospires via conventional PCR, but cultures containing saprophytic Leptospira were identified. Whole genomes were generated and analyzed for twenty isolates obtained from these biofilms. For species identification, we used digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) analysis. The obtained isolates were classified into seven presumptive species from the saprophytic S1 clade. ANI and dDDH analysis suggest that three of those seven species were new. Classical phenotypic tests confirmed the novel isolated bacteria as saprophytic Leptospira. The isolates presented typical morphology and ultrastructure according to scanning electron microscopy and formed biofilms under in vitro conditions. Our data indicate that a diversity of saprophytic Leptospira species survive in the Brazilian poorly sanitized urban environment, in a biofilm lifestyle. We believe our results contribute to a better understanding of Leptospira biology and ecology, considering biofilms as natural environmental reservoirs for leptospires.

The protein moiety of Brucella abortus outer membrane protein 16 is a new bacterial pathogen-associated molecular pattern that activates dendritic cells in vivo, induces a Th1 immune response, and is a promising self-adjuvanting vaccine against systemic and oral acquired brucellosis.

Knowing the inherent stimulatory properties of the lipid moiety of bacterial lipoproteins, we first hypothesized that Brucella abortus outer membrane protein (Omp)16 lipoprotein would be able to elicit a protective immune response without the need of external adjuvants. In this study, we demonstrate that Omp16 administered by the i.p. route confers significant protection against B. abortus infection and that the protective response evoked is independent of the protein lipidation. To date, Omp16 is the first Brucella protein that without the requirement of external adjuvants is able to induce similar protection levels to the control live vaccine S19. Moreover, the protein portion of Omp16 (unlipidated Omp16 [U-Omp16]) elicits a protective response when administered by the oral route. Either systemic or oral immunization with U-Omp16 elicits a Th1-specific response. These abilities of U-Omp16 indicate that it is endowed with self-adjuvanting properties. The adjuvanticity of U-Omp16 could be explained, at least in part, by its capacity to activate dendritic cells in vivo. U-Omp16 is also able to stimulate dendritic cells and macrophages in vitro. The latter property and its ability to induce a protective Th1 immune response against B. abortus infection have been found to be TLR4 dependent. The facts that U-Omp16 is an oral protective Ag and possesses a mucosal self-adjuvanting property led us to develop a plant-made vaccine expressing U-Omp16. Our results indicate that plant-expressed recombinant U-Omp16 is able to confer protective immunity, when given orally, indicating that a plant-based oral vaccine expressing U-Omp16 could be a valuable approach to controlling this disease.

The role of innate immune receptors in the control of Brucella abortus infection: toll-like receptors and beyond.

Research into intracellular sensing of microbial products is an up and coming field in innate immunity. Toll-like receptors (TLRs) recognize Brucella spp. and bacterial components and initiate mononuclear phagocyte responses that influence both innate and adaptive immunity. Recent studies have revealed the intracellular signaling cascades involved in the TLR-initiated immune response to Brucella infection. TLR2, TLR4 and TLR9 have been implicated in host interactions with Brucella; however, TLR9 has the most prominent role. Further, the relationship between specific Brucella molecules and various signal transduction pathways needs to be better understood. MyD88-dependent and TRIF-independent signaling pathways are involved in Brucella activation of innate immune cells through TLRs. We have recently reported the critical role of MyD88 molecule in dendritic cell maturation and interleukin-12 production during B. abortus infection. This article discusses recent studies on TLR signaling and also highlights the contribution of NOD and type I IFN receptors during Brucella infection. The better understanding of the role by such innate immune receptors in bacterial infection is critical in host-pathogen interactions.

In Vitro Immunomodulatory Activity of a Transition-State Analog Inhibitor of Human Purine Nucleoside Phosphorylase in Cutaneous Leishmaniasis.

Cutaneous leishmaniasis (CL) is the most common clinical form of American tegumentary leishmaniasis caused by Leishmania (Viannia) braziliensis. CL is associated with a strong Th1 immune response. This exacerbated inflammatory response is correlated with severity of disease and delays the healing time of the ulcer. The fourth-generation immucillin derivative (DI4G), a potent inhibitor of purine nucleoside phosphorylase, has been proposed as a promising agent in the treatment of diseases associated with T cell activation. Herein, we evaluated the in vitro immunomodulatory activity of DI4G in cells of patients presenting with CL. Peripheral blood mononuclear cells (PBMC) from CL patients were stimulated with soluble leishmania antigen (SLA), in the presence or absence of DI4G, and IFN-γ, TNF, CXCL9, and CXCL10 levels were determined by ELISA. Lymphocyte proliferation in the presence or absence of DI4G was also evaluated, using flow cytometry. DI4G was able to decrease (p < 0.05) IFN-γ production but did not change the TNF, CXCL9, and CXCL10 levels. DI4G decreased (p < 0.05) the lymphoproliferative response mediated by CD8+ T cells, but not that by CD4+ T cells. DI4G is able to attenuate the exaggerated immune response in CL, exhibiting immunomodulatory activity in IFN-γ production and in CD8+ T cell proliferation.

Inflammatory and immunological profiles in patients with COPD: relationship with FEV 1 reversibility.

OBJECTIVE:: To determine whether COPD severity correlates with sputum cell counts, atopy, and asthma. METHODS:: This was a cross-sectional study involving 37 patients with COPD and 22 healthy subjects with normal lung function (controls). Sputum cell counts were determined by microscopy after centrifugation of samples. Skin prick tests were performed, and serum cytokines were determined by ELISA. RESULTS:: Patients were stratified by bronchodilator response: a non-reversible airflow limitation (nonRAL) group comprised 24 patients showing no significant post-bronchodilator change in FEV1; and a partially reversible airflow limitation (partialRAL) group comprised 13 patients showing FEV1 reversibility (post-bronchodilator FEV1 increase ≥ 12%). The proportion of eosinophils in sputum was higher in the partialRAL group than in the nonRAL group (p < 0.01), and there was an inverse correlation between the proportion of eosinophils and FEV1 (p < 0.05). However, none of the patients had a history of asthma and skin prick test results did not differ between the two groups. In the patient sputum samples, neutrophils predominated. Serum levels of TNF, IL-6, IL-8, and RANTES (CCL5) were higher in patients than in controls (p < 0.001) but did not differ between the two patient groups. CONCLUSIONS:: COPD patients with partial FEV1 reversibility appear to have higher sputum eosinophil counts and greater airway hyperresponsiveness than do those with no FEV1 reversibility. However, we found that COPD severity did not correlate with atopy or with the cytokine profile. OBJETIVO:: Determinar se a gravidade da DPOC se correlaciona com a contagem de células no escarro, atopia e asma. MÉTODOS:: Estudo transversal com 37 pacientes com DPOC e 22 indivíduos saudáveis com função pulmonar normal (controles). As contagens de células no escarro foram determinadas por microscopia após a centrifugação das amostras. Foram realizados testes cutâneos de puntura, e as citocinas séricas foram determinadas por ELISA. RESULTADOS:: Os pacientes foram estratificados pela resposta ao broncodilatador: o grupo de limitação ao fluxo aéreo não reversível (LFAnr) envolveu 24 pacientes sem alteração significativa do VEF1 pós-broncodilatador, e o grupo de limitação ao fluxo aéreo parcialmente reversível (LFApr) envolveu 13 pacientes com reversibilidade do VEF1 (aumento do VEF1 pós-broncodilatador ≥ 12%). A proporção de eosinófilos no escarro foi maior no grupo LFApr do que no LFAnr (p < 0,01), e houve uma correlação inversa entre a proporção de eosinófilos e VEF1 (p < 0,05). Entretanto, nenhum dos pacientes apresentou histórico de asma e os resultados dos testes cutâneos não diferiram entre os dois grupos. Nas amostras de escarro dos pacientes, os neutrófilos predominaram. Os níveis séricos de TNF, IL-6, IL-8 e RANTES (CCL5) foram maiores nos pacientes que nos controles (p < 0,001), mas não diferiram entre os dois grupos de pacientes. CONCLUSÕES:: Pacientes com DPOC e reversibilidade parcial do VEF1 parecem apresentar maiores contagens de eosinófilos no escarro e maior hiper-responsividade das vias aéreas que aqueles sem reversibilidade do VEF1. Entretanto, a gravidade da DPOC não se correlacionou com atopia ou perfil das citocinas.

Inflammatory and immunological profiles in patients with COPD: relationship with FEV 1 reversibility / Perfil inflamatório e imunológico em pacientes com DPOC: relação com a reversibilidade do VEF 1

ABSTRACT Objective: To determine whether COPD severity correlates with sputum cell counts, atopy, and asthma. Methods: This was a cross-sectional study involving 37 patients with COPD and 22 healthy subjects with normal lung function (controls). Sputum cell counts were determined by microscopy after centrifugation of samples. Skin prick tests were performed, and serum cytokines were determined by ELISA. Results: Patients were stratified by bronchodilator response: a non-reversible airflow limitation (nonRAL) group comprised 24 patients showing no significant post-bronchodilator change in FEV1; and a partially reversible airflow limitation (partialRAL) group comprised 13 patients showing FEV1 reversibility (post-bronchodilator FEV1 increase ≥ 12%). The proportion of eosinophils in sputum was higher in the partialRAL group than in the nonRAL group (p < 0.01), and there was an inverse correlation between the proportion of eosinophils and FEV1 (p < 0.05). However, none of the patients had a history of asthma and skin prick test results did not differ between the two groups. In the patient sputum samples, neutrophils predominated. Serum levels of TNF, IL-6, IL-8, and RANTES (CCL5) were higher in patients than in controls (p < 0.001) but did not differ between the two patient groups. Conclusions: COPD patients with partial FEV1 reversibility appear to have higher sputum eosinophil counts and greater airway hyperresponsiveness than do those with no FEV1 reversibility. However, we found that COPD severity did not correlate with atopy or with the cytokine profile.

RESUMO Objetivo: Determinar se a gravidade da DPOC se correlaciona com a contagem de células no escarro, atopia e asma. Métodos: Estudo transversal com 37 pacientes com DPOC e 22 indivíduos saudáveis com função pulmonar normal (controles). As contagens de células no escarro foram determinadas por microscopia após a centrifugação das amostras. Foram realizados testes cutâneos de puntura, e as citocinas séricas foram determinadas por ELISA. Resultados: Os pacientes foram estratificados pela resposta ao broncodilatador: o grupo de limitação ao fluxo aéreo não reversível (LFAnr) envolveu 24 pacientes sem alteração significativa do VEF1 pós-broncodilatador, e o grupo de limitação ao fluxo aéreo parcialmente reversível (LFApr) envolveu 13 pacientes com reversibilidade do VEF1 (aumento do VEF1 pós-broncodilatador ≥ 12%). A proporção de eosinófilos no escarro foi maior no grupo LFApr do que no LFAnr (p < 0,01), e houve uma correlação inversa entre a proporção de eosinófilos e VEF1 (p < 0,05). Entretanto, nenhum dos pacientes apresentou histórico de asma e os resultados dos testes cutâneos não diferiram entre os dois grupos. Nas amostras de escarro dos pacientes, os neutrófilos predominaram. Os níveis séricos de TNF, IL-6, IL-8 e RANTES (CCL5) foram maiores nos pacientes que nos controles (p < 0,001), mas não diferiram entre os dois grupos de pacientes. Conclusões: Pacientes com DPOC e reversibilidade parcial do VEF1 parecem apresentar maiores contagens de eosinófilos no escarro e maior hiper-responsividade das vias aéreas que aqueles sem reversibilidade do VEF1. Entretanto, a gravidade da DPOC não se correlacionou com atopia ou perfil das citocinas.

Central role of MyD88-dependent dendritic cell maturation and proinflammatory cytokine production to control Brucella abortus infection.

Brucella abortus is a facultative intracellular bacterium that infects humans and domestic animals. The enhanced susceptibility to virulent B. abortus observed in MyD88 knockout (KO) mice led us to investigate the mechanisms involved in MyD88-dependent immune responses. First, we defined the role of MyD88 in dendritic cell (DC) maturation. In vitro as well as in vivo, B. abortus-exposed MyD88 KO DCs displayed a significant impairment on maturation as observed by expression of CD40, CD86, and MHC class II on CD11c+ cells. In addition, IL-12 and TNF-alpha production was totally abrogated in MyD88 KO DCs and macrophages. Furthermore, B. abortus-induced IL-12 production was found to be dependent on TLR2 in DC, but independent on TLR2 and TLR4 in macrophages. Additionally, we investigated the role of exogenous IL-12 and TNF-alpha administration on MyD88 KO control of B. abortus infection. Importantly, IL-12, but not TNF-alpha, was able to partially rescue host susceptibility in MyD88 KO-infected animals. Furthermore, we demonstrated the role played by TLR9 during virulent B. abortus infection. TLR9 KO-infected mice showed 1 log Brucella CFU higher than wild-type mice. Macrophages and DC from TLR9 KO mice showed reduced IL-12 and unaltered TNF-alpha production when these cells were stimulated with Brucella. Together, these results suggest that susceptibility of MyD88 KO mice to B. abortus is due to impaired DC maturation and lack of IL-12 synthesis. Additionally, DC activation during Brucella infection plays an important regulatory role by stimulating and programming T cells to produce IFN-gamma.