Temporal changes in biomarkers of neutrophil extracellular traps and NET-promoting autoantibodies following adenovirus-vectored, mRNA, and recombinant protein COVID-19 vaccination

Neutrophil extracellular traps (NETs) play a role in innate pathogen defense and also trigger B-cell response by providing antigens. NETs have been linked to vaccine-induced thrombotic thrombocytopenia. We postulated a potential link between NET biomarkers, NET-promoting autoantibodies, and adverse events (AEs) after COVID-19 vaccine boosters. Healthy donors (HDs) who received ChAdOx1-S (A), mRNA-1273 (M), or recombinant protein (MVC-COV1901) vaccines at the National Taiwan University Hospital between 2021 and 2022 were recruited. We measured serial NET-associated biomarkers, citrullinated-histone3 (citH3), and myeloperoxidase (MPO)-DNA. Serum citH3 and MPO-DNA were significantly or numerically higher in HDs who reported AEs (n = 100, booster Day 0/Day 30, p = 0.01/p = 0.03 and p = 0.30/p = 0.35, respectively). We also observed a positive correlation between rash occurrence in online diaries and elevated citH3. A linear mixed model also revealed significantly higher citH3 levels in mRNA-1273/ChAdOx1-S recipients than MVC-COV1901 recipients. Significant positive correlations were observed between the ratios of anti-heparin platelet factor 4 and citH3 levels on Booster Day 0 and naïve and between the ratios of anti-NET IgM and citH3 on Booster Day 30/Day 0 in the AA-M and MM-M group, respectively. The increased levels of citH3/MPO-DNA accompanied by NET-promoting autoantibodies suggest a potential connection between mRNA-1273/ChAdOx1-S vaccines and cardiovascular complications. These findings provide insights for risk assessments of future vaccines.

Streptococcus mutans PrsA mediates AtlA secretion contributing to extracellular DNA release and biofilm formation in the pathogenesis of infective endocarditis

The role of secretion chaperone-regulated virulence proteins in the pathogenesis of infective endocarditis (IE) induced by viridans streptococci such as Streptococcus mutans is unclear. In this study, we investigated the contribution of the foldase protein PrsA, a putative parvulin-type peptidyl-prolyl isomerase, to the pathogenesis of S. mutans-induced IE. We found that a prsA-deficient strain had reduced virulence in terms of formation of vegetation on damaged heart valves, as well as reduced autolysis activity, eDNA release and biofilm formation capacity. The secretion and surface exposure of AtlA in vitro was reduced in the prsA-deficient mutant strain, and complementation of recombinant AtlA in the culture medium restored a wild type biofilm phenotype of the prsA-deficient mutant strain. This result suggests that secretion and surface localization of AtlA is regulated by PrsA during biofilm formation. Together, these results demonstrate that S. mutans PrsA could regulate AtlA-mediated eDNA release to contribute to biofilm formation in the pathogenesis of IE.

Biomarker of neutrophil extracellular traps is associated with deep-seated infections and predicts mortality and cardiovascular morbidity in commensal streptococcal bacteremia

BACKGROUND

Neutrophil extracellular traps (NETs) play important roles in sepsis and deep-seated infections, but whether NET formation correlates with clinical outcomes of patients with streptococcal bloodstream infections (BSIs) is unclear.

METHODS

We analyzed serum levels of complexes of myeloperoxidase and DNA (MPO-DNA) in patients with streptococcal-BSIs. In vitro assay of NET induction by serum from BSI patients was performed.

RESULTS

MPO-DNA values for the Streptococci-BSI group (n = 59) were significantly higher than those for healthy controls (p < 0.00001) and matched control groups (n = 59, p = 0.004). The rate of higher MPO-DNA levels (>1.87 μg/mL) were higher in abscess-prone streptococcal groups (streptococcus milleri group) (72.2% vs. 52.5%, p = 0.02). For patients with BSIs due to highly infective endocarditis (IE)-prone pathogens, the values of serum MPO-DNA were also higher in patients diagnosed of IE compared to their counterparts (p = 0.009). Notably, serum from patients with leukopenia could induce higher amounts of in vitro NET formation, despite having low MPO-DNA levels, suggesting that NET formation could be influenced by WBC counts. Therefore, we combined WBC counts with MPO-DNA to predict all-cause 30-day mortality in patients with commensal streptococcal-BSIs. The mortality risk was lowest among patients who had neither high MPO-DNA levels nor abnormal WBC counts (p = 0.058). Furthermore, this group of patients also had a favorable composite outcome consisting of major adverse cardiovascular events (MACE) and all-cause mortality (p = 0.026).

CONCLUSION

Together, these study data suggested that serum MPO-DNA can be a biomarker for predicting a composite outcome consisting of MACE and all-cause mortality in patients with commensal streptococcal-BSIs.

Afatinib and Pembrolizumab for Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma (ALPHA Study): A Phase II Study with Biomarker Analysis

PURPOSE

EGFR pathway inhibition may promote anti-programmed cell death protein 1 (PD-1) responses in preclinical models, but how EGFR inhibition affects tumor antigen presentation during anti-PD-1 monotherapy in humans remain unknown. We hypothesized that afatinib, an irreversible EGFR tyrosine kinase inhibitor, would improve outcomes in patients treated with pembrolizumab for recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) by promoting antigen presentation and immune activation in the tumor microenvironment.

PATIENTS AND METHODS

The ALPHA study (NCT03695510) was a single-arm, Phase II study with Simon's 2-stage design. Afatinib and pembrolizumab were administered to patients with platinum-refractory, recurrent, or metastatic HNSCC. The primary endpoint was the objective response rate (ORR). The study applied gene expression analysis using a NanoString PanCancer Immune Profiling Panel and next-generation sequencing using FoundationOne CDx.

RESULTS

From January 2019 to March 2020, the study enrolled 29 eligible patients. Common treatment-related adverse events were skin rash (75.9%), diarrhea (58.6%), and paronychia (44.8%). Twelve patients (41.4%) had an objective partial response to treatment. The median progression-free survival was 4.1 months, and the median overall survival was 8.9 months. In a paired tissue analysis, afatinib-pembrolizumab were found to upregulate genes involved in antigen presentation, immune activation, and natural killer cell-mediated cytotoxicity. Unaltered methylthioadenosine phosphorylase and EGFR amplification may predict the clinical response to the therapy.

CONCLUSIONS

Afatinib may augment pembrolizumab therapy and improve the ORR in patients with HNSCC. Bioinformatics analysis suggested the enhancement of antigen presentation machinery in the tumor microenvironment.

Effects of Interleukin-6 on STAT3-regulated signaling in oral cancer and as a prognosticator of patient survival

OBJECTIVES

Human oral squamous cell carcinoma (OSCC) produces an inflammatory microenvironment enriched with cytokines including interleukin-6 (IL-6); however, the underlying molecular mechanisms of OSCC progression are unclear. We aimed to delineate the STAT3-mediated signaling pathways involved in tumor cell survival and growth.

MATERIALS AND METHODS

Immunohistochemistry was used to semi-quantitate IL-6 and STAT3 in 111 OSCC tissues. IL-6-induced STAT3 signaling pathways and effects on tumor cell survival and progression were investigated in vitro and in xenograft mouse models. Effects of blocking IL-6-induced activation of STAT3 in an OSCC cell line were determined in vitro.

RESULTS

A higher level of IL-6 or STAT3 in situ was associated with an unfavorable prognosis in OSCC patients with regard to both disease-free and overall survival rates. Overexpressed or exogenous IL-6 could induce SAS cell proliferationin vitroand significantly enhanced tumor growthin vivo. In addition, knockdown or inhibition of STAT3 expression in SAS cells significantly reduced tumor growth and abolished the responsiveness to IL-6 stimulation. Siltuximab or Tocilizumab could also significantly suppress IL-6-induced STAT3 phosphorylation and STAT3 nuclear translocation, resulting in a significant decrease of downstream anti-apoptotic proteins Bcl-2, Bcl-xL, and survivin.

CONCLUSION

The IL-6 level in the tumor microenvironment could serve as a stage-independent predictor of OSCC progression and survival. Further, IL-6 may play a role in this disease through STAT3-dependent upregulation of anti-apoptotic genes and subsequent proliferation of tumor cells.

Transient bacteremia promotes catheter-related central venous thrombosis through neutrophil extracellular traps

Formation of intravenous catheter-related thrombosis leads to central venous stenosis in patients requiring renal replacement therapy or chemotherapy infusion, yet the triggering or mechanisms remain unclear, especially in patients without symptoms of infection. In this study, we found that neutrophil extracellular traps (NETs) could be detected in the fibrin sheaths from dialysis patients without clinical manifestations of infection. Confocal microscopy revealed bacteria imbedded in NETs in the fibrin sheaths. Thirty-nine of 50 (78%) fibrin sheath specimens contained bacteria detectable by 16S ribosomal RNA genome typing with a predominance of Staphylococcus aureus (69%). In rat models, transient bacteremia of S. aureus induced NETs in enlarged fibrin sheaths, and treatment with DNase I alone significantly reduced both NET and fibrin sheath formation surrounding the catheter. Therefore, transient bacteremia could be a silent trigger that induces NET-related immunothrombosis enhancing catheter-related central venous stenosis.

PspC domain-containing protein (PCP) determines Streptococcus mutans biofilm formation through bacterial extracellular DNA release and platelet adhesion in experimental endocarditis

Bacterial extracellular DNA (eDNA) and activated platelets have been found to contribute to biofilm formation by Streptococcus mutans on injured heart valves to induce infective endocarditis (IE), yet the bacterial component directly responsible for biofilm formation or platelet adhesion remains unclear. Using in vivo survival assays coupled with microarray analysis, the present study identified a LiaR-regulated PspC domain-containing protein (PCP) in S. mutans that mediates bacterial biofilm formation in vivo. Reverse transcriptase- and chromatin immunoprecipitation-polymerase chain reaction assays confirmed the regulation of pcp by LiaR, while PCP is well-preserved among streptococcal pathogens. Deficiency of pcp reduced in vitro and in vivo biofilm formation and released the eDNA inside bacteria floe along with reduced bacterial platelet adhesion capacity in a fibrinogen-dependent manner. Therefore, LiaR-regulated PCP alone could determine release of bacterial eDNA and binding to platelets, thus contributing to biofilm formation in S. mutans-induced IE.

FoxP3+CD4+, IFN-γ+CD4+, and IFN-γ+CD8+ cell levels in erosive and non-erosive types of oral lichen planus patients

Background/purpose

Oral lichen planus (OLP) is a localized autoimmune oral mucosal disease. This study evaluated whether different types of OLP patients including erosive OLP (EOLP), major EOLP, minor EOLP, and non-erosive OLP (NEOLP) patients had significantly higher percentages of FoxP3⁺CD4⁺ or IFN-γ⁺CD4⁺ cells in total CD4⁺ cells, and of IFN-γ⁺CD8⁺ cells in total CD8⁺ cells than healthy control subjects and whether the patient's age had significant influences on these cell percentages in OLP patients.

Materials and methods

Flow cytometry was used to count the FoxP3⁺CD4⁺, IFN-γ⁺CD4⁺, or IFN-γ⁺CD8⁺ cell levels in 183 OLP patients (67 major EOLP, 81 minor EOLP, and 35 NEOLP patients) and 20 healthy control subjects.

Results

Major EOLP patients had a significantly higher FoxP3⁺CD4⁺ cell percentage than health control subjects (P = 0.049) or minor EOLP patients (P = 0.008). Major EOLP patients had a significantly higher IFN-γ⁺CD4⁺ or IFN-γ⁺CD8⁺ cell percentage than healthy control subjects, NEOLP patients, or minor EOLP patients (all P-values < 0.01). In addition, both 61–80 year and 41–60 year OLP patients had significantly higher IFN-γ⁺CD8⁺ cell percentages than healthy control subjects or 20–40 year OLP patients (all P-values < 0.005).

Conclusion

Major EOLP patients tend to have significantly higher percentages of FoxP3⁺CD4⁺, IFN-γ⁺CD4⁺, and IFN-γ⁺CD8⁺ cells than healthy control subjects, NEOLP patients or minor EOLP patients, suggesting that FoxP3⁺CD4⁺ Treg cells are increased to modulate OLP disease activity. Increased number of IFN-γ-producing activated T cell may be involved in oral epithelial cell destruction in OLP patients.

Polyfunctional endogenous EBV-specific T cell response in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is associated with Epstein-Barr virus (EBV) infection and can be treated by adoptive transfer of EBV-specific T cells. Although EBV-specific T cell immune response has been identified in NPC, the phenotype and functionality of EBV-specific, tissue-resident memory T cells has not been explored. Tumor-infiltrating lymphocytes (TILs) were isolated from newly-diagnosed NPC and two types of EBV-unrelated malignancies; oral squamous cell carcinoma (OSCC) and renal cell carcinoma (RCC) tissue samples. We found that endogenous EBV-specific T cell response can be detected in the all the tissue types, including NPC, OSCC and RCC, but were rare in peripheral blood. In all tissues, EBV-specific T cells in tumor tissues exhibit resident memory phenotype characterized by high CD69 and CD103 expression and also an exhaustion phenotype characterized by high CD39 and PD-1 expression. Unexpectedly, EBV-specific T cell frequency as well as response magnitude were not enhanced in NPC when compared to other tissue types. The lack of an enhanced EBV-specific T cell response magnitude in NPC tissue confirms the concept that enhancement of EBV-specific immunity by adoptive T cell therapy may improve the outcome of NPC.

IL-6 Promotes Cell Growth and Is Associated With Poor Prognosis In Patients With Oral Cancer

Interleukin-6 (IL-6) is a pleiotropic inflammatory cytokine that regulates growth and differentiation of various types of malignant tumors, including oral cancers. Compared to healthy controls, the levels of IL-6 are elevated in sera of patients with oral cancer. In this study, the role of IL-6 in the growth regulation of oral cancer cells was evaluated.

The effects of IL-6 on cell growth were evaluated by expressing IL-6 cDNA into the human tongue cancer cell line (SAS), resulting in high-producer clones. In vivo, the effects of tumor-derived IL-6 on growth were studied by using an experimental vaccine model. Two stable clones, consisting of low-producer (IL-6LE), and high-producer (IL-6OE), were subcutaneously inoculated on the flank of each severe combined immune-deficient (SCID) mice. A total of 111 surgically treated HNSCC patients were studied. IL-6 and STAT3 levels were measured by immunohistochemical staining and correlated with clinicopathological variables and patient survival.

Treatment of recombinant IL-6 and overexpression of IL-6 by intorducing IL-6 into SAS cells significantly increased clonogenic ability and cell proliferation in vitro compared to the parental SAS cells and the vector controls. In animal model, a statistically significant difference of tumor weight was obtained between the IL-6LE and IL-6OE (*P=0.024) groups in experiment. Clinical data revealed significant relationships between IL-6 and stage*, lymph node metastasis*, recurrence**, disease-free survival* and overall survival* (P &lt; 0.01; *P &lt; 0.05).

These findings strongly support the hypothesis that IL-6 acts as a significant autocrine growth factor in vivo and in vivo oral cancers.

IL-7 Receptor Alpha Chain Expression Identifies Human CD8+ Memory T Cell Subsets with Distinct Gene Expression Profiles and TCR Repertoire Compositions

Heterogeneity of CD8 T cell play crucial roles in cancer patients and reveals the co-evolution between tumor and immunity. While CD127 expression identifies memory precursor cells during acute infections, the role of CD127 expression in defining memory T cell heterogeneity is not investigated. Here, we analyzed the Vβ-CDR3 usage of human effector memory TEM and TEMRA cells accompanied by functional and gene expression patterns based on surface CD127 expression. We found that, CD127hi subsets are associated with higher level of TCR diversity regardless of their TEM or TEMRA phenotype. CD127lo populations are presented with relatively low TCR repertoire diversity. Moreover, there is a high correlation between CD127hi and CD127lo populations which imply possible differentiation tract between CD127hi and CD127lo T cells, but not between TEM and TEMRA cells. On the other hand, both TEM and TEMRA CD127lo populations showed higher expression of effector genes including perforin, granzyme B, granzyme H, and pan-inhibitory killer immunoglobulin-like receptors, exhibited lower phenotype plasticity upon TCR activation and cytokine-driven proliferation, when compared to their CD127hi counterparts. In other words, depending on the expression of CD127, T cells from either TEM or TEMRA are similar in their gene expression and functionality patterns. These results provide the first evidence that T cell repertoire and gene expression signature can be uncoupled based on distinct CD127-dependent phenotype expression patterns but are delicately balanced in the memory T cell pool.

Lack of Polyfunctional Cytomegalovirus-specific T cells in Hemodialysis Patients

Polyfunctional T cells are critical for maintaining protection against pathogens. Patients with end-stage renal disease (ESRD) are at increased risks for infectious complications and their T cell immunity against viruses may be impaired. Our current study intends to investigate the effects of renal disease on T cell immunity by analyzing T cell differentiation and polyfunctionality response against cytomegalovirus (CMV), an ubiquitous pathogen. Based on our research, when compared to same-age healthy individuals, ESRD patients are characterized by a significant loss of polyfunctional CMV specific CD4+ and CD8+ T cells, upregulation of effector phenotypic markers and increased surface PD-1 and TIM-3 expression. Furthermore, we performed transcriptome experiment and identified the functional impairment pathway that is distinct from T cell exhaustion and cannot be reversed by checkpoint blockade. These results give the new insight of designing future immunomodulation therapies.

Anti-alpha-enolase T cell response in oral squamous cell carcinoma

In Taiwan, oral cancer ranks as the 6th highest incidence of cancer in general population. Characterized by high metastatic potency, oral squamous cell carcinoma (OSCC) is the most common type of oral cancer. Alpha-enolase (α-enolase) is a glycolytic enzyme expressed in most tissues. Many researches have pointed out the over-expression of α-enolase in various cancer type. Its role as glycolytic enzyme and plasminogen receptor were reported to promote cancer invasion, proliferation, and metastasis.

Our works focused on the relationship between α-enolase and OSCC. We found the increased α-enolase expression in OSCC and were able to detect anti-α-enolase antibodies in serum of some OSCC patients. These results revealed a non-negligible influence of α-enolase in OSCC. Next, we spliced α-enolase from whole protein into peptide pool and tested T cell response upon its stimulation. Both CD8+ T cells and CD4+ T cells from peripheral blood mononuclear cells (PBMCs) and tumor infiltrating lymphocytes (TILs) were able to detect the cytokine production, like interferon gamma (IFN-γ) or tumor necrosis factor (TNF-α), and as well as the expression of activation marker like CD107a. Taken together, our works indicated that α-enolase is a potential antigen that may be involved in anti-tumor response in OSCC.

Neutrophil Extracellular Traps Enhance Staphylococcus Aureus Vegetation Formation through Interaction with Platelets in Infective Endocarditis

The mechanisms or host factors involved in septic thrombus or vegetation formation in Staphylococcus aureus-induced infective endocarditis (IE) are unclear. Using an experimental endocarditis rat model, here we demonstrated that S. aureus HG001-induced vegetation was composed of bacterial floes encased in aggregated platelets and surrounded by neutrophil extracellular traps (NETs). In vitro data demonstrated that platelets contribute to both biofilm and NET formation. Prophylactic administration of DNase I significantly reduced the size of vegetation induced by methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains, even though MRSA and MSSA isolates express different biofilm phenotypes and NET-induction abilities in the presence of platelets. Moreover, delivery of both DNase I and daptomycin prophylactically and therapeutically produced synergistic effects by reducing vegetation size and bacterial numbers on damaged valve tissues in MRSA-induced IE. Together, these data suggest that NETs contribute to vegetation formation in S. aureus endocarditis and DNase I has the potential to control S. aureus-induced IE in the clinic.

A comprehensive characterization of aggravated aging-related changes in T lymphocytes and monocytes in end-stage renal disease: the iESRD study

Background

Patients with end-stage renal disease (ESRD) exhibit a premature aging phenotype of the immune system. Nevertheless, the etiology and impact of these changes in ESRD patients remain unknown.

Results

Compared to healthy individuals, ESRD patients exhibit accelerated immunosenescence in both T cell and monocyte compartments, characterized by a dramatic reduction in naïve CD4+ and CD8+ T cell numbers but increase in CD8+ T_EMRA cell and proinflammatory monocyte numbers. Notably, within ESRD patients, aging-related immune changes positively correlated not only with increasing age but also with longer dialysis vintage. In multivariable-adjusted logistic regression models, the combination of high terminally differentiated CD8+ T cell level and high intermediate monocyte level, as a composite predictive immunophenotype, was independently associated with prevalent coronary artery disease as well as cardiovascular disease, after adjustment for age, sex, systemic inflammation and presence of diabetes. Levels of terminally differentiated CD8+ T cells also positively correlated with the level of uremic toxin p-cresyl sulfate.

Conclusions

Aging-associated adaptive and innate immune changes are aggravated in ESRD and are associated with cardiovascular diseases. For the first time, our study demonstrates the potential link between immunosenescence in ESRD and duration of exposure to the uremic milieu.

Electronic supplementary material

The online version of this article (10.1186/s12979-018-0131-x) contains supplementary material, which is available to authorized users.

The Chinese Herbal Mixture Tien-Hsien Liquid Augments the Anticancer Immunity in Tumor Cell-Vaccinated Mice

BACKGROUND

The Chinese herbal mixture, Tien-Hsien liquid (THL), has been used as an anticancer dietary supplement for more than 20 years. Our previous studies have shown that THL can modulate immune responseand inhibit tumor growth. In this study, we further evaluated the effect of THL on anticancer immune response in mice vaccinated with γ-ray-irradiated tumor cells.

METHODS

The antitumor effect of THL was determined in mice vaccinated with low-tumorigenic CT-26-low colon cancer cells or γ-ray-irradiated high-tumorigenic CT-26-high colon cancer cells. The number of natural killer (NK) cells and T lymphocytes in the spleen was analyzed by flow cytometry. The tumor-killing activities of NK cells and cytotoxic T lymphocytes (CTLs) were analyzed by flow cytometry using YAC-1 and CT-26-high cells, respectively, as target cells. The levels of IFN-γ, IL-2, and TNF-α were determined by ELISA.

RESULTS

THL suppressed the growth of CT-26-high tumor in mice previously vaccinated with low-tumorigenic CT-26-low cells or γ-irradiated CT-26-high cells. THL increased the populations of NK cells and CD4+ T lymphocytes in the spleen and enhanced the tumor-killing activities of NK cells and CTL in mice vaccinated with γ-irradiated CT-26-high cells. THL increased the production of IFN-γ, IL-2, and TNF-α in mice vaccinated with γ-irradiated CT-26-high cells.

CONCLUSION

THL can enhance the antitumor immune responses in mice vaccinated with killed tumor cells. These results suggest that THL may be used as a complementary medicine for cancer patients previously treated with killed tumor cell vaccines, radiotherapy, or chemotherapy.

Enrichment of Human CCR6+ Regulatory T Cells with Superior Suppressive Activity in Oral Cancer

Human oral squamous cell carcinoma (OSCC) constitutes an inflammatory microenvironment enriched with chemokines such as CCL20, which promote cancer cell invasion and tumor progression. We found that in OSCC there is a correlation between the expression of CCL20 and FOXP3 mRNA. Therefore, we hypothesized that OSCC may favor the recruitment and retention of regulatory T (Treg) cells that express the CCL20 receptor, CCR6. Interestingly, most (∼60%) peripheral blood Treg cells express CCR6, and CCR6⁺ Treg cells exhibit an activated effector/memory phenotype. In contrast, a significant portion (>30%) of CCR6^- Treg cells were found to be CD45RA⁺ naive Treg cells. Compared to CCR6^- naive or memory Treg cells, CCR6⁺ Treg cells exhibit stronger suppressive activity and display higher FOXP3 expression along with lower methylation at the Treg-specific demethylated region of the FOXP3 gene. This predominance of CCR6⁺ Treg cells was also found in the draining lymph nodes and tumor-infiltrating lymphocytes of OSCC patients with early or late clinical staging. Moreover, CCR6⁺ Treg cells isolated from tumor-infiltrating lymphocytes or draining lymph nodes maintained similar phenotypic and suppressive characteristics ex vivo as did their counterparts isolated from peripheral blood. These results suggest that CCR6 marks activated effector or memory Treg phenotypes with superior suppressive activity in humans.

Lack of polyfunctional cytomegalovirus-specific T cells in hemodialysis patients

Polyfunctional T cells are critical for maintaining protection against pathogens. Patients with end-stage renal disease (ESRD) are at increased risks for infectious complications and their T cell immunity against viruses may be impaired. The current study intends to investigate the effects of renal disease on T cell immunity by analyzing T cell differentiation (based on expression of CCR7 and CD45RA) and polyfunctionality response against cytomegalovirus (CMV), an ubiquitous pathogen. Two CMV peptide pools (IE1 and pp65) were used to stimulate PBMCs and four effector functions were measured by multicolor flow cytometry (IL-2, TNFα, IFNγ and CD107a) to identify polyfunctional T cells. 17 healthy individuals, 13 patients with pre-dialysis chronic kidney disease (CKD) and 37 ESRD patients were enrolled in this study. All the donors were seropositive with an average age of 60. Patients with renal disease, especially the ESRD patients, showed increased levels of T cell differentiation, including the decrease in CD4+ and CD8+ TN cells and the increase in the CD4+ and CD8+ TEM and TEMRA cells. While the cellular frequency of CMV-reactive CD4+ and CD8+ T cells were similar among different groups, polyfunctional cell were dramatically reduced in ESRD. Among healthy individuals, CKD and ESRD patients, CD4+ CMV-IE1-reactive polyfunctional cell frequencies were 2.0%, 2.2%, and 0%, respectively (p=0.002). The CD8+ CMV-pp65-reactive polyfunctional cell frequencies were 12.4%, 8.8% and 0.8% in the three groups (p&lt;0.001). Such phenomenon resembles T cell exhaustion observed in HIV infection and further studies should investigate the level of inhibitory receptor expression levels such as PD-1 and CTLA-4 in these patients.

The GlnR Regulon in Streptococcus mutans Is Differentially Regulated by GlnR and PmrA

GlnR-mediated repression of the GlnR regulon at acidic pH is required for optimal acid tolerance in Streptococcus mutans, the etiologic agent for dental caries. Unlike most streptococci, the GlnR regulon is also regulated by newly identified PmrA (SMUGS5_RS05810) at the transcriptional level in S. mutans GS5. Results from gel mobility shift assays confirmed that both GlnR and PmrA recognized the putative GlnR box in the promoter regions of the GlnR regulon genes. By using a chemostat culture system, we found that PmrA activated the expression of the GlnR regulon at pH 7, and that this activation was enhanced by excess glucose. Deletion of pmrA (strain ΔPmrA) reduced the survival rate of S. mutans GS5 at pH 3 moderately, whereas the GlnR mutant (strain ΔGlnR) exhibited an acid-sensitive phenotype in the acid killing experiments. Elevated biofilm formation in both ΔGlnR and ΔPmrA mutant strains is likely a result of indirect regulation of the GlnR regulon since GlnR and PmrA regulate the regulon differently. Taken together, it is suggested that activation of the GlnR regulon by PmrA at pH 7 ensures adequate biosynthesis of amino acid precursor, whereas repression by GlnR at acidic pH allows greater ATP generation for acid tolerance. The tight regulation of the GlnR regulon in response to pH provides an advantage for S. mutans to better survive in its primary niche, the oral cavity.

Endocarditis pathogen promotes vegetation formation by inducing intravascular neutrophil extracellular traps through activated platelets

BACKGROUND

Endocarditis-inducing streptococci form multilayered biofilms in complex with aggregated platelets on injured heart valves, but the host factors that interconnect and entrap these bacteria-platelet aggregates to promote vegetation formation were unclear.

METHODS AND RESULTS

In a Streptococcus mutans endocarditis rat model, we identified layers of neutrophil extracellular traps interconnecting and entrapping bacteria-platelet aggregates inside vegetation that could be reduced significantly in size along with diminished colonizing bacteria by prophylaxis with intravascular DNase I alone. The combination of activated platelets and specific immunoglobulin G-adsorbed bacteria are required to induce the formation of neutrophil extracellular traps through multiple activation pathways. Bacteria play key roles in coordinating the signaling through spleen tyrosine kinase, Src family kinases, phosphatidylinositol-3-kinase, and p38 mitogen-activated protein kinase pathways to upregulate the expression of P-selectin in platelets, while inducing reactive oxygen species-dependent citrullination in the arm of neutrophils. Neutrophil extracellular traps in turn serve as the scaffold to further enhance and entrap bacteria-platelet aggregate formation and expansion.

CONCLUSIONS

Neutrophil extracellular traps promote and expand vegetation formation through enhancing and entrapping bacteria-platelet aggregates on the injured heart valves.

A legume product fermented by Saccharomyces cerevisiae modulates cutaneous atopic dermatitis-like inflammation in mice

Background

Isoflavone-containing soy products modulate allergic inflammation in mice. In our previously study, IFN-γ and IL-10 production increased in mice fed with Saccharomyces cerevisiae legume fermented product (SCLFP), demonstrating that SCLFP had immunomodulatory activity. In this study, we tested the anti-inflammatory effects of SCLFP in a mouse model of cutaneous atopic dermatitis inflammation induced by epicutaneous sensitization.

Methods

Epicutaneous exposure to protein allergens plus Staphylococcal enterotoxin B induced a T helper (Th)-2–dominant immune response as well as cutaneous atopic dermatitis-like inflammation in BALB/c mice. The thickness of the skin epithelium, eosinophil migration, and T helper responses were determined in patched skin and draining lymph nodes of mice fed with and without SCLFP.

Results

Epicutaneous exposure to protein allergens plus Staphylococcal enterotoxin B induced a T helper (Th)-2–dominant immune response as well as cutaneous atopic dermatitis-like inflammation in BALB/c mice. SCLFP feeding attenuated this cutaneous Th2 response, as evidenced by decreased thickening of the epidermis, less eosinophil infiltration, and lower levels of IL-5, IL-13, and CXCL11 expression compared to controls. Oral administration of SCLFP also modulated Th1 responses in draining lymph nodes, with lower levels of IFN-γ, IL-4, and IL-17 expression.

Conclusion

Oral intake of SCLFP modulated the induced Th2 inflammatory responses in skin and might have potential applications for the prevention and treatment of atopic dermatitis.

Skewed distribution of IL-7 receptor-α-expressing effector memory CD8+ T cells with distinct functional characteristics in oral squamous cell carcinoma

CD8⁺ T cells play important roles in anti-tumor immunity but distribution profile or functional characteristics of effector memory subsets during tumor progression are unclear. We found that, in oral squamous carcinoma patients, circulating CD8⁺ T cell pools skewed toward effector memory subsets with the distribution frequency of CCR7⁻CD45RA⁻CD8⁺ T cells and CCR7⁻ CD45RA⁺CD8⁺ T cells negatively correlated with each other. A significantly higher frequency of CD127^lo CCR7⁻CD45RA⁻CD8⁺ T cells or CCR7⁻CD45RA⁺CD8⁺ T cells among total CD8⁺ T cells was found in peripheral blood or tumor infiltrating lymphocytes, but not in regional lymph nodes. The CD127^hi CCR7⁻CD45RA⁻CD8⁺ T cells or CCR7⁻CD45RA⁺CD8⁺ T cells maintained significantly higher IFN-γ, IL-2 productivity and ex vivo proliferative capacity, while the CD127^lo CCR7⁻CD45RA⁻CD8⁺ T cells or CCR7⁻CD45RA⁺CD8⁺ T cells exhibited higher granzyme B productivity and susceptibility to activation induced cell death. A higher ratio of CCR7⁻CD45RA⁺CD8⁺ T cells to CCR7⁻CD45RA⁻CD8⁺ T cells was associated with advanced cancer staging and poor differentiation of tumor cells. Therefore, the CD127^lo CCR7⁻CD45RA⁻CD8⁺ T cells and CCR7⁻CD45RA⁺CD8⁺ T cells are functionally similar CD8⁺ T cell subsets which exhibit late differentiated effector phenotypes and the shift of peripheral CD8⁺ effector memory balance toward CCR7⁻CD45RA⁺CD8⁺ T cells is associated with OSCC progression.

Fermentation product of soybean, black bean, and green bean mixture induces apoptosis in a wide variety of cancer cells

Previous studies have shown that soybean fermentation products can act as cancer chemoprevention or therapeutic agents. In this study, the anticancer activities of a fermentation product of soybean, black bean, and green bean mixture (BN999) were investigated. We found that BN999 inhibited the growth of human breast cancer AU565 cells and prostate adenocarcinoma PC-3 cells but not that of normal human cells. BN999 induced apoptosis in various human cancer cells but not in normal human cells. BN999 treatment of AU565 cancer cells resulted in activation of calpain and caspase-8, -9, and -3, suggesting that BN999 induces apoptosis via receptor-, mitochondria-, and endoplasmic reticulum-mediated pathways. Finally, we showed that BN999 inhibited the growth of mouse CT-26 colon cancer xenografts in syngenic BALB/c mice without causing obvious side effects. Together, these data suggest that BN999 has potential to be used as a cancer chemoprevention or therapeutic agent.

Activated human nasal epithelial cells modulate specific antibody response against bacterial or viral antigens

Nasal mucosa is an immune responsive organ evidenced by eliciting both specific local secretory IgA and systemic IgG antibody responses with intra-nasal administration of antigens. Nevertheless, the role of nasal epithelial cells in modulating such responses is unclear. Human nasal epithelial cells (hNECs) obtained from sinus mucosa of patients with chronic rhinosinusitis were cultured in vitro and firstly were stimulated by Lactococcus lactis bacterium-like particles (BLPs) in order to examine their role on antibody production. Secondly, both antigens of immunodominant protein IDG60 from oral Streptococcus mutans and hemagglutinin (HA) from influenza virus were tested to evaluate the specific antibody response. Stimulated hNECs by BLPs exhibited a significant increase in the production of interleukin-6 (IL-6), and thymic stromal lymphopoietin (TSLP). Conditioned medium of stimulated hNECs has effects on enhancing the proliferation of CD4+ T cells together with interferon-γ and IL-5 production, increasing the costimulatory molecules on dendritic cells and augmenting the production of IDG60 specific IgA, HA specific IgG, IgA by human peripheral blood lymphocytes. Such production of antigen specific IgG and IgA is significantly counteracted in the presence of IL-6 and TSLP neutralizing antibodies. In conclusion, properly stimulated hNECs may impart immuno-modulatory effects on the antigen-specific antibody response at least through the production of IL-6 and TSLP.

The role of type III secretion system and lens material on adhesion of Pseudomonas aeruginosa to contact lenses

PURPOSE

To determine the distribution of invasive and cytotoxic genotypes among ocular isolates of P. aeruginosa and investigate the influence of the type III secretion system (T3SS) on adhesion to conventional, cosmetic, and silicone hydrogel contact lenses (CL).

METHODS

Clinical isolates from 2001 to 2010 were analyzed by multiplex PCR for exoS, exoU, and exoT genes. Bacterial adhesion to etafilcon, nelfilcon (gray colored), balafilcon, and galyfilcon CL with or without artificial tear fluid (ATF) incubation were compared. Surface characteristics were determined with scanning electron microscopy (SEM).

RESULTS

Among 87 total isolates, 64 strains were from microbial keratitis cases. CL-related microbial keratitis (CLMK) isolates were mostly of the cytotoxic genotype (expressing exoU) (P = 0.002). No significant differences were found in bacterial adhesion to all types of CL between the genotypes under T3SS-inducing conditions. A trend for least bacterial adhesion of galyfilcon compared to the other CL was noted for both genotypes. Needle complex pscC mutants adhered less to all materials than the wild type (P < 0.05), indicating a role of the T3SS in contact lens adhesion. ATF-incubated CL had significantly more bacterial adhesion (P < 0.05). SEM showed most of the bacteria adhering on CL surfaces.

CONCLUSIONS

CLMK isolates were mostly of cytotoxic genotype. Different genotypes did not significantly differ in its adhesion to various CL. T3SS and other adhesins are involved in bacteria-contact lens adhesion through complex interactions. Contact lens materials may also play an important role in the adherence of both genotypes of P. aeruginosa.

Imaging granularity of leukocytes with third harmonic generation microscopy

Using third harmonic generation (THG) microscopy, we demonstrate that granularity differences of leukocytes can be revealed without a label. Excited by a 1230 nm femtosecond laser, THG signals were generated at a significantly higher level in neutrophils than other mononuclear cells, whereas signals in agranular lymphocytes were one order of magnitude smaller. Interestingly, the characteristic THG features can also be observed in vivo to track the newly recruited leukocytes following lipopolysaccharide (LPS) challenge. These results suggest that label-free THG imaging may provide timely tracking of leukocyte movement without disturbing the normal cellular or physiological status.

Platelets enhance biofilm formation and resistance of endocarditis-inducing streptococci on the injured heart valve

Infective endocarditis is a typical biofilm-associated infectious disease frequently caused by commensal streptococci, but the contribution of host factors in biofilm formation is unclear. We found that platelets are essential for in vitro biofilm formation by Streptococcus mutans or Streptococcus gordonii grown in human plasma. The biofilms were composed of bacterial floes embedded with platelet aggregates in layers, and a similar architecture was also detected in situ on the injured valves of a rat model of experimental endocarditis. Similar to planktonic cells, the streptococci in biofilms were also able to induce platelet aggregation, which facilitates multilayer biofilm formation. Entrapping of platelets directly enhances the resistance of streptococcal biofilms to clindamycin. Prophylactic antibiotics or aspirin can reduce but not prevent or abolish biofilm formation on injured heart valves. Therefore, the platelet is a host factor for commensal streptococci in the circulation to consolidate biofilm formation and protect bacteria against antibiotics.

Increased prevalence of interleukin-17-producing CD4(+) tumor infiltrating lymphocytes in human oral squamous cell carcinoma

BACKGROUND

T helper 17 (Th17) and regulatory T cells share plasticity in the expression of interleukin (IL)-17 and forkhead box P3 (FOXP3), but their mutual presence in human diseases is unclear.

METHODS

IL-17 and FOXP3 were analyzed by immunohistostaining and flow cytometry. The cytokine milieu was analyzed by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Oral squamous cell carcinoma expresses high levels of IL-1β, IL-6, and transforming growth factor (TGF)-β. A unique subset of FOXP3(+) IL-17-producing CD4(+) T cells was consistently identified in tumor-infiltrating lymphocytes from advanced stages of cancer, but not in the circulation, at a frequency of 0.5% to 5.5 % of total CD4(+) T and positively correlated with the frequency of IL-17(+)FOXP3(-) T cells. The IL-17(+)FOXP3(+) T cells express CCR6 and suppress the proliferation of autologous CD4(+) CD25(-) responder T-cells in vitro.

CONCLUSIONS

The prevalence of IL-17-producing FOXP3(+) CD4(+) tumor infiltrating lymphocytes is increased in oral squamous cell carcinoma.

Streptococcus mutans autolysin AtlA is a fibronectin-binding protein and contributes to bacterial survival in the bloodstream and virulence for infective endocarditis

Streptococcus mutans, a commensal of the human oral cavity, can survive in the bloodstream and cause infective endocarditis (IE). However, the virulence factors associated with this manifestation of disease are not known. Here, we demonstrate that AtlA, an autolysin of S. mutans is a newly identified fibronectin (Fn) binding protein and contributes to bacterial resistance to phagocytosis and survival in the bloodstream. Interestingly, prior exposure to plasma at low concentrations was sufficient to enhance bacterial survival in the circulation. Calcium ions at physiological plasma concentrations induced maturation of AtlA from the 104-90 kDa isoform resulting in increased Fn binding and resistance to phagocytosis. An isogenic mutant strain defective in AtlA expression exhibited reduced survival and virulence when tested in a rat model of IE compared with the wild-type and complemented strains. The data presented suggest that plasma components utilized by S. mutans enhanced survival in the circulation and AtlA is a virulence factor associated with infective endocarditis.

Treatment with levamisole and colchicine can result in a significant reduction of IL-6, IL-8 or TNF-alpha level in patients with mucocutaneous type of Behcet's disease

BACKGROUND

Mucocutaneous type of Behcet's disease (MCBD) is a multisystemic inflammatory disease with oral and genital ulcers with or without skin lesions.

METHODS

A solid phase, two-site sequential chemiluminescent immunometric assay was used to measure serum levels of interleukin (IL)-6, IL-8 and tumour necrosis factor (TNF)-alpha in 54 normal control subjects and in 64 MCBD patients before and after treatment with levamisole plus colchicine.

RESULTS

We found that 67%, 83% or 67% of MCBD patients had a serum IL-6, IL-8 or TNF-alpha level greater than the upper normal limit of 4.7, 8.7 or 7.4 pg/ml, respectively. The mean serum level of IL-6 (9.9 +/- 2.4 pg/ml, P < 0.005), IL-8 (107.5 +/- 21.4 pg/ml, P < 0.001) or TNF-alpha (22.5 +/- 4.1 pg/ml, P < 0.001) in 64 MCBD patients was significantly higher than that (2.1 +/- 0.2, 5.7 +/- 0.2 or 3.8 +/- 0.2 pg/ml for IL-6, IL-8 or TNF-alpha level, respectively) in normal control subjects. In 43 MCBD patients with all the serum IL-6, IL-8 and TNF-alpha levels higher than their upper normal limits, treatment with levamisole plus colchicine for a period of 0.5-11.5 (mean, 3.2 +/- 2.4) months could significantly reduce the mean serum IL-6, IL-8 and TNF-alpha levels from 9.0 +/- 1.7 to 1.6 +/- 0.2 pg/ml (P < 0.001), 134.6 +/-28.2-6.0 +/- 0.4 pg/ml (P < 0.001) and 25.7 +/- 5.6-3.5 +/- 0.4 pg/ml (P < 0.001), respectively.

CONCLUSIONS

Treatment with levamisole and colchicine can result in a significant reduction of serum IL-6, IL-8 or TNF-alpha level in MCBD patients.

Chromosomal inversion between rrn operons among Streptococcus mutans serotype c oral and blood isolates

Streptococcus mutans causes dental caries and infective endocarditis. The aim of this study was to determine genomic diversity among serotype c S. mutans laboratory and clinical strains and to characterize the genetic events involved. A genome-based approach using PFGE coupled with Southern hybridization was employed to examine a total of 58 serotype c oral and blood isolates and seven laboratory strains and to compare them with S. mutans UA159. No significant differences were found in the phenotypic characteristics of the strains tested, except that some of the strains exhibited smooth rather than rough colony morphology. In contrast, PFGE profiles of clinical isolates, from either diseased or healthy subjects, exhibited diverse patterns, suggesting that recombination or point mutations occurred frequently in vivo. Diverse PFGE patterns, with various lengths of insertions and deletions, could be detected even within a localized chromosomal region between rRNA operons. Comparative analysis using Southern hybridization with specific markers revealed that a large chromosomal inversion had also occurred between rrn operons in 25 strains.

The two-component system ScnRK of Streptococcus mutans affects hydrogen peroxide resistance and murine macrophage killing

To survive macrophage killing is critical in the pathogenesis of viridians streptococci-induced infective endocarditis (IE). Streptococcus mutans, an opportunistic IE pathogen, generally does not survive well phagocytic killing in murine macrophage RAW 264.7 cells. A putative two-component system (TCS), ScnR/ScnK from S. mutans, was investigated to elucidate the mechanisms underlying bacteria-cellular interaction in this study. Both the wild-type and mutant strains were phagocytosed by RAW 264.7 cells at a comparable rate and an increased intracellular susceptibility during a 5 h incubation period was observed with the scnRK-null mutants. The amount of reactive oxygen species (ROS) in activated macrophages was reduced significantly after ingesting wild-type, but not scnRK-null mutant strains, suggesting that increased macrophage killing of these mutants is due to the impaired ability of S. mutans to counteract ROS. Additionally, both scnR- or scnRK-null mutants were more susceptible to hydrogen peroxide. Interestingly, scnRK expression was unaffected by hydrogen peroxide. These experimental results indicate that scnRK is important in counteracting oxidative stress in S. mutans, and decreased susceptibility to phagocytic killing is at least partly attributable to inhibition of intracellular ROS formation.

Levamisole can reduce the high serum tumour necrosis factor-? level to a normal level in patients with erosive oral lichen planus

In this study, we measured the baseline serum levels of tumour necrosis factor (TNF)-alpha in 158 patients with oral lichen planus (OLP) and in 54 normal control subjects. In total, 60 patients with erosive OLP (EOLP) with relatively high TNF-alpha levels were treated with levamisole and the serum TNF-alpha levels measured after treatment. We found that the mean +/- SD serum level of TNF-alpha in patients with either type of EOLP (12.0 +/- 1.7 pg/mL, P<0.005), major EOLP (15.5 +/- 4.4 pg/mL, P<0.001), minor EOLP (11.1 +/- 1.8 pg/mL, P<0.01), or nonerosive OLP (6.1 +/- 1.7 pg/mL, P<0.05) was significantly higher than that (3.8 +/- 0.2 pg/mL) of normal control subjects. Treatment with levamisole for a period of 0.5-7.5 months significantly reduced the mean serum TNF-alpha level from 22.6 +/- 3.4 pg/mL to 6.2 +/- 0.8 pg/mL (P<0.001) in 60 patients with EOLP. We conclude that levamisole can reduce high serum TNF-alpha levels to normal in patients with EOLP.

Glucosyltransferases of viridans group streptococci modulate interleukin-6 and adhesion molecule expression in endothelial cells and augment monocytic cell adherence

Recruitment of monocytes plays important roles during vegetation formation and endocardial inflammation in the pathogenesis of infective endocarditis (IE). Bacterial antigens or modulins can activate endothelial cells through the expression of cytokines or adhesion molecules and modulate the recruitment of leukocytes. We hypothesized that glucosyltransferases (GTFs), modulins of viridans group streptococci, may act directly to up-regulate the expression of adhesion molecules and also interleukin-6 (IL-6) to augment monocyte attachment to endothelial cells. Using primary cultured human umbilical vein endothelial cells (HUVECs) as an in vitro model, we demonstrated that GTFs (in the cell-bound or free form) could specifically modulate the expression of IL-6, and also adhesion molecules, in a dose- and time-dependent manner. Results of inhibition assays suggested that enhanced expression of adhesion molecules was dependent on the activation of nuclear factor kappaB (NF-kappaB) and extracellular signal-regulated kinase and that p38 mitogen-activated protein kinase pathways also contributed to the release of IL-6. Streptococcus-infected HUVECs or treatment with purified IL-6 plus soluble IL-6 receptor alpha enhanced the expression of ICAM-1 and the adherence of the monocytic cell line U937. These results suggest that streptococcal GTFs might play an important role in recruiting monocytic cells during inflammation in IE through induction of adhesion molecules and IL-6, a cytokine involved in transition from neutrophil to monocyte recruitment.

Levamisole can modulate the serum tumor necrosis factor-alpha level in patients with recurrent aphthous ulcerations

BACKGROUND

Recurrent aphthous ulcerations (RAU) are common oral inflammatory lesions. Tumor necrosis factor (TNF)-alpha is an important inflammatory mediator and a critical cytokine for adequate host defense. Our previous studies have shown that 14-43% and 59-63% of patients in the ulcerative stage of major, minor or herpetiform RAU have significantly higher than normal serum levels of interleukin (IL)-6 and IL-8, respectively. In this study, we examined whether RAU patients in the ulcerative stage had a significantly higher than normal serum level of TNF-alpha and assessed whether treatment with levamisole can modulate serum TNF-alpha levels in RAU patients.

METHODS

This study used a solid phase, two-site sequential chemiluminescent immunometric assay to determine the baseline serum levels of TNF-alpha in 146 patients with RAU, nine patients with traumatic ulcers (TU), and 54 normal control subjects. Fifty-five RAU patients with serum TNF-alpha levels higher than 5.0 pg/ml were treated with levamisole for 0.5-4 months and their serum TNF-alpha levels were measured after treatment.

RESULTS

We found that 29% (42 of 146) RAU patients as well as 39% (24 of 61) major type, 20% (14 of 69) minor type, and 25% (four of 16) herpetiform type RAU patients had a serum level of TNF-alpha greater than the upper normal limit of 7.4 pg/ml. The mean serum level of TNF-alpha in patients with RAU (9.1 +/- 1.0 pg/ml, P < 0.001), major type RAU (11.6 +/- 1.9 pg/ml, P < 0.001), minor type RAU (6.9 +/- 0.9 pg/ml, P < 0.005), or herpetiform type RAU (9.6 +/- 2.7 pg/ml, P < 0.001) was higher than that (3.8 +/- 0.2 pg/ml) in normal control subjects. The mean serum TNF-alpha level was significantly higher in patients with major type RAU than in patients with minor type RAU (P < 0.05) and was significantly higher in major type RAU patients in the exacerbation stage than in the post-exacerbation stage (P < 0.05). In 55 RAU patients with serum TNF-alpha levels higher than 5.0 pg/ml, treatment with levamisole for a period of 0.5-4 months could significantly reduce the serum TNF-alpha level from 16.4 +/- 1.9 to 5.8 +/- 0.6 pg/ml (P < 0.001).

CONCLUSIONS

We conclude that a significantly higher than normal serum level of TNF-alpha can be detected in 20-39% of patients in the ulcerative stage of major, minor or herpetiform RAU. The serum TNF-alpha level may be associated with the severity and the stage of RAU. Levamisole can modulate serum TNF-alpha levels in RAU patients.

Differential regulation of Streptococcus mutans gtfBCD genes in response to copper ions

To persist in the oral cavity, bacteria must be able to tolerate environmental fluctuation, particularly in pH, nutrients, and essential elements. Glucosyltransferases B, C, and D of Streptococcus mutans synthesize glucans, and play essential roles in the sucrose-dependent adhesion of the organism to tooth surfaces. Transcriptions of gtfB, gtfC, and gtfD could be differentially regulated through independent promoters. To test the hypothesis that environmental factors frequently encountered in the dental plaque might serve as effector molecules involved in regulation, transcripts of individual gtfs were identified by reverse transcriptase-polymerase chain reaction assay and confirmed by Northern blot analysis using anti-sense RNA probes. When S. mutans was grown in different medium at low pH, differential regulation of the gtfs was observed. More specifically, the transcription and translational expression of gtfD but not gtfB and gtfC was specifically induced by copper ion (Cu(2+)). The up-regulation was independent of the Cu(2+)-transport operon copYAZ. These findings support the involvement of Cu(2+) as an effector molecule in the regulation of S. mutans gtfD. Nutrient change dominates influence of pH but not the effect of Cu(2+).

Bactericidal effects of diode laser onStreptococcus mutans after irradiation through different thickness of dentin

BACKGROUND AND OBJECTIVES

A reliable method to eradicate the bacteria of residual carious dentin has not yet been developed. The aim of this study was to evaluate the antibacterial effect of a diode laser on Streptococcus mutans through different thickness (500, 1,000, and 2,000 microm) of human dentin. The thermal effect of laser irradiation was also investigated.

STUDY DESIGN/MATERIALS AND METHODS

Dentin specimens were inoculated with 2 microl of S. mutans on one side and irradiated by a diode laser on the other side with a power output ranging from 0.5 to 7 W. The laser tip was swept with the whole irradiation area of 7 mm x 3 mm at a speed of about 10 mm/second with a total irradiation time of 30 seconds. Cooling with distilled water (30 ml/minute) was applied simultaneously during laser irradiation. After laser irradiation, the bacteria was removed from the dentin surfaces and cultured for 48 hours at 37 degrees C anaerobically to assess the colony forming units (CFU) per ml. The morphology of the lased bacteria and the temperature rise during laser irradiation were observed by scanning electron microscope (SEM) and measured by thermocouple, respectively.

RESULTS

The results revealed that 7 W of laser power could kill 97.7% of CFU through 500 microm thickness of dentin. However, the bactericidal efficiency was significantly reduced as the dentin thickness was increased. The morphological changes of lased bacteria ranged from less affected such as loss of their wall bands and existence of minicells to more severely degenerated, such as disintegration and fusion of cells with pores on the cell wall. Only the dentin specimens with a thickness of 500 microm exhibited a temperature rise greater than 5.5 degrees C after receiving 5 or 7 W of laser irradiation.

CONCLUSIONS

A diode laser can eliminate the Streptococcus mutans of the residual carious dentin without inducing high pulpal temperature rise when the remaining dentin thickness is greater than 1 mm.

"Tien-Hsien liquid" can modulate antigen-stimulated cytokine production by T-cells isolated from patients with recurrent aphthous ulcerations

Recurrent aphthous ulcerations (RAU) represent a common oral mucosal disease with altered humoral and cellular immunities. Tien-Hsien liquid (THL) is an extract of Chinese medicinal herbs with immunomodulating effects. Our previous study found that THL can modulate the antigen-stimulated proliferative response of peripheral blood mononuclear cells and T-cells isolated from RAU patients. In this study, we further tested whether THL can modulate the antigen-stimulated cytokine production by T-cells isolated from RAU patients. To achieve this goal, T-cells isolated from 19 RAU patients were incubated with phytohemagglutinin (PHA), glutaraldehyde-inactivated tetanus toxoid (TT), glucosyltransferase D (GtfD), or antigens of Streptococcus mutans in the presence or absence of THL. The levels of interleukin (IL)-2, interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), IL-6, or IL-10 in the supernatants of T-cell cultures were measured by cytokine enzyme-linked immunosorbent assay (ELISA) kits. We found that THL significantly increased the PHA- or TT-stimulated TNF-alpha, IL-6, and IL-10 production by T-cells isolated from RAU patients. However, THL could also significantly decrease the TT-stimulated IL-2 production, the GtfD-stimulated IL-2, TNF-alpha, IL-6 and IL-10 production, and the S. mutans-stimulated IFN-gamma, TNF-alpha, and IL-10 production by T-cells isolated from RAU patients. These results indicate that THL can modulate the antigen-stimulated cytokine production by T-cells isolated from RAU patients. Because RAU is probably a Thl-mediated disease with elevated levels of IL-2, IFN-gamma, TNF-alpha and IL-6 in either the patient's sera or oral lesions and these increased levels of cytokines can be reduced by THL, we suggest that THL may be a potential immunoceutical agent for treatment of RAU.

The chinese herbal medicine Tien-Hsien liquid inhibits cell growth and induces apoptosis in a wide variety of human cancer cells

OBJECTIVE

Tien-Hsien liquid (THL) is a commercially available Chinese herbal mixture that has been used as an anticancer dietary supplement for more than 10 years. We recently showed that THL has strong immunomodulatory effects on peripheral blood mononuclear cells (PBMC) and T cells. To investigate the antitumor activity of THL further, we sought to test whether THL could induce apoptosis in various human cancer cell lines based on the fact that THL contains several components with tumor killing functions.

DESIGN

The growth inhibitory effect of THL on human cervical carcinoma C-33A cells, human lung carcinoma H1299 cells, and human PBMC was assessed by counting viable cells using the trypan blue dye exclusion method. The apoptosis-inducing activity of THL in H1299 cells was assessed by analyzing the cells with four assays: (1) Hoechst 33258 nuclear DNA staining; (2) the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) assay; (3) the nucleosomal DNA fragment ladder assay; and (4) the sub-G1 cell analysis. The activities of caspase-8, -9, and -3 in H1299 cells treated with or without THL were also measured to elucidate the possible mechanism underlying THL apoptosis-inducing effect. Finally, the apoptotic effect of THL on fifteen human cancer cell lines and normal human cells were analyzed by the TUNEL assay.

RESULTS

THL could induce apoptosis in all human cancer cell lines tested but not in normal human cells. THL treatment of H1299 cancer cells resulted in activation of caspase-8, -9, and -3 and the inhibitors of these caspases could partially block THL-induced apoptosis.

CONCLUSIONS

THL has been used by numerous patients with cancer for many years with no known adverse effect. Our present study showing that THL had a broad-range tumor killing function has provided a molecular basis underlying THL therapeutic activity. Furthermore, because THL had apoptotic effects only on cancer cells but not on normal cells, this selectivity suggests that THL could be a potential cancer therapeutic agent.

Species identification of mutans streptococci by groESL gene sequence

The near full-length sequences of the groESL genes were determined and analysed among eight reference strains (serotypes a to h) representing five species of mutans group streptococci. The groES sequences from these reference strains revealed that there are two lengths (285 and 288 bp) in the five species. The intergenic spacer between groES and groEL appears to be a unique marker for species, with a variable size (ranging from 111 to 310 bp) and sequence. Phylogenetic analysis of groES and groEL separated the eight serotypes into two major clusters. Strains of serotypes b, c, e and f were highly related and had groES gene sequences of the same length, 288 bp, while strains of serotypes a, d, g and h were also closely related and their groES gene sequence lengths were 285 bp. The groESL sequences in clinical isolates of three serotypes of S. mutans were analysed for intraspecies polymorphism. The results showed that the groESL sequences could provide information for differentiation among species, but were unable to distinguish serotypes of the same species. Based on the determined sequences, a PCR assay was developed that could differentiate members of the mutans streptococci by amplicon size and provide an alternative way for distinguishing mutans streptococci from other viridans streptococci.

Glucosyltransferases of viridans streptococci are modulins of interleukin-6 induction in infective endocarditis

The glucosyltransferases (GTFs) of viridans streptococci, common pathogens of infective endocarditis, are extracellular proteins that convert sucrose into exopolysaccharides and glucans. GTFs B, C, and D of Streptococcus mutans are modulins that induce, in vitro and in vivo, the production of cytokines, in particular interleukin-6 (IL-6), from monocytes. The roles of S. mutans GTFs in infectivity and inflammation in situ were tested in a rat experimental model of endocarditis. No significant differences in infectivity, in terms of 95% infective dose and densities of bacteria inside vegetations, were observed between laboratory strain GS-5 and two clinical isolates or isogenic mutant NHS1DD, defective in the expression of GTFs. In aortic valves and surrounding tissues, IL-6 was detected by Western blots and immunostaining 24 h after GS-5 infection, was maintained over 72 h, and was followed by production of tumor necrosis factor alpha but not IL-1beta. Animals infected with NHS1DD showed markedly lower levels of IL-6 (less than 5% of that of parental GS-5-infected rats), while tumor necrosis factor alpha was unaffected. In contrast, animals infected with NHR1DD, another isogenic mutant expressing only GtfB, showed a much smaller reduction (down to 56%). These results suggest that GTFs are specific modulins that act during acute inflammation, inducing IL-6 from endothelial cells surrounding the infected valves without affecting bacterial colonization in vegetations, and that IL-6 might persist in chronic inflammation in endocarditis.

Serum interleukin-8 level is a more sensitive marker than serum interleukin-6 level in monitoring the disease activity of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease. Interleukin (IL)-8 is a pro-inflammatory cytokine of host response to injury and inflammation.

OBJECTIVES

To investigate whether serum IL-8 level was a more sensitive marker than serum IL-6 level in monitoring the disease activity of OLP and to assess whether IL-8 was a useful serum marker in evaluating the therapeutic effects of levamisole on OLP patients.

METHODS

In this study, we used a solid phase, two-site sequential chemiluminescent immunometric assay to determine the baseline serum levels of IL-6 and IL-8 in 158 patients with OLP, nine patients with traumatic ulcers (TU) and 54 normal control subjects. Some OLP patients with the serum IL-6 or IL-8 levels higher than the upper limit of normal serum concentration were treated with levamisole for 0.5-6.0 months and their serum IL-6 and IL-8 levels were measured after treatment.

RESULTS

We found that 28% (44 of 158) OLP, 28% (40 of 142) erosive OLP (EOLP), and 25% (four of 16) nonerosive OLP (NEOLP) patients had a serum IL-6 level greater than the upper normal limit of 4.7 pg mL(-1). In contrast, 63% (99 of 158) OLP, 63% (90 of 142) EOLP and 56% (nine of 16) NEOLP patients had a serum IL-8 level greater than the upper normal limit of 8.7 pg mL(-1). In some OLP patients with the serum IL-6 or IL-8 levels higher than the upper limit of normal serum concentration, treatment with levamisole for a period of 0.5-6.0 months could significantly reduce the mean serum IL-6 level from 14.3 +/- 1.9 pg mL(-1) to 3.2 +/- 0.6 pg mL(-1) (P < 0.001) and could significantly reduce the mean serum IL-8 level from 95.8 +/- 17.1 pg mL(-1) to 14.8 +/- 5.8 pg mL(-1) (P < 0.001).

CONCLUSIONS

Because measurement of the serum IL-8 level can detect more OLP patients with an abnormal serum level than measurement of the serum IL-6 level (63% vs. 28%), we conclude that serum IL-8 level is a more sensitive marker than serum IL-6 level in monitoring the disease activity of OLP. Levamisole can modulate both the serum IL-6 and IL-8 levels in OLP patients. IL-8, like IL-6, is also a useful serum marker in evaluating the therapeutic effects of levamisole on OLP patients.

Immunomodulating effects of "tien-hsien liquid" on peripheral blood mononuclear cells and T-lymphocytes from patients with recurrent aphthous ulcerations

Recurrent aphthous ulcerations (RAU) represent a common oral mucosal disease with altered humoral and cellular immunities. In our institution, an immunomodulating agent, levamisole, is used to treat RAU with satisfactory therapeutic effect. Tien-Hsien liquid (THL) is an extract of Chinese medicinal herbs with immunomodulating effects. To test whether THL has immunomodulating effects on antigen-stimulated proliferation response (PR) of peripheral blood mononuclear cells (PBMC) and T-cells isolated from RAU patients and to test whether THL is a potential drug for treating RAU, PBMC or T-cells isolated from RAU patients were incubated with lipopolysaccharides (LPS) from Escherica coli, phytohemagglutinin (PHA), staphylococcal enterotoxin B (SEB), glutaraldehyde-inactivated tetanus toxoid (TT), glucosyltransferase D (GtfD), or antigens of Streptococcus mutans in the presence or absence of THL. We found that THL significantly increased the LPS-stimulated PR of PBMC from active RAU patients, the GtfD-stimulated PR of PBMC and of T-cells from inactive RAU patients, and the S. mutans-stimulated PR of PBMC from inactive RAU patients. However, THL could also significantly reduce the SEB-stimulated PR of PBMC and of T-cells from active RAU patients and S. mutans-stimulated PR of T-cells from active RAU patients. These results suggest that THL can modulate the antigen-stimulated PR of PBMC and T-cells from RAU patients. Therefore, it may be a potential immunoceutical agent for treatment of RAU.

Platelet aggregation induced by serotype polysaccharides from Streptococcus mutans

Platelet aggregation plays an important role in the pathogenesis of infective endocarditis induced by viridans streptococci or staphylococci. Aggregation induced in vitro involves direct binding of bacteria to platelets through multiple surface components. Using platelet aggregometry, we demonstrated in this study that two Streptococcus mutans laboratory strains, GS-5 and Xc, and two clinical isolates could aggregate platelets in an irreversible manner in rabbit platelet-rich plasma preparations. The aggregation was partially inhibited by prostaglandin I(2) (PGI(2)) in a dose-dependent manner. Whole bacteria and heated bacterial cell wall extracts were able to induce aggregation. Cell wall polysaccharides extracted from the wild-type Xc strain, containing serotype-specific polysaccharides which are composed of rhamnose-glucose polymers (RGPs), could induce platelet aggregation in the presence of plasma. Aggregation induced by the serotype-specific RGP-deficient mutant Xc24R was reduced by 50% compared to the wild-type strain Xc. In addition, cell wall polysaccharides extracted from Xc24R failed to induce platelet aggregation. The Xc strain, but not the Xc24R mutant, could induce platelet aggregation when preincubated with plasma. Both Xc and Xc24R failed to induce platelets to aggregate in plasma depleted of immunoglobulin G (IgG), but aggregation was restored by replenishment of anti-serotype c IgG. Analysis by flow cytometry showed that S. mutans RGPs could bind directly to rabbit and human platelets. Furthermore, cell wall polysaccharides extracted from the Xc, but not the Xc24R, strain could induce pseudopod formation of both rabbit and human platelets in the absence of plasma. Distinct from the aggregation of rabbit platelets, bacterium-triggered aggregation of human platelets required a prolonged lag phase and could be blocked completely by PGI(2). RGPs also trigger aggregation of human platelets in a donor-dependent manner, either as a transient and reversible or a complete and irreversible response. These results indicated that serotype-specific RGPs, a soluble product of S. mutans, could directly bind to and activate platelets from both rabbit and human. In the presence of plasma containing IgG specific to RGPs, RGPs could trigger aggregation of both human and rabbit platelets, but the degree of aggregation in human platelets depends on the donors.

Serum interleukin-8 level is a more sensitive marker than serum interleukin-6 level in monitoring the disease activity of recurrent aphthous ulcerations

BACKGROUND

Recurrent aphthous ulcerations (RAU) are common oral inflammatory lesions. Interleukin (IL)-8 is a pro-inflammatory cytokine of host response to injury and inflammation. Our recent study has found that measurement of serum IL-6 level can detect only 24% RAU patients with an abnormal serum level. In this study, we examined both the serum IL-6 and IL-8 levels in a group of RAU patients. The abilities of IL-6 and IL-8 to detect patients with an abnormal serum level were compared in order to find out whether IL-8 was a more sensitive serum marker than IL-6 in monitoring the disease activity of RAU.

METHODS

In this study, we used a solid-phase, two-site sequential chemiluminescent immunometric assay to determine the baseline serum levels of IL-6 and IL-8 in 146 patients with RAU, 9 patients with traumatic ulcers (TU), and 54 normal control (NC) subjects. Eighty-two RAU patients, with the serum IL-6 or IL-8 levels higher than the upper limit of normal serum concentration, were treated with levamisole for 0.5-3.5 months, and their serum IL-6 and IL-8 levels were measured after treatment.

RESULTS

We found that 25% (37/146) RAU patients, as well as 33% (20/61) major-type, 19% (13/69) minor-type, and 25% (4/16) herpetiform-type RAU patients, had a serum level of IL-6 greater than the upper normal limit of 4.7 pg/ml. In contrast, 60% (87/146) RAU patients, as well as 59% (36/61) major-type, 59% (41/69) minor-type, and 63% (10/16) herpetiform-type RAU patients, had a serum level of IL-8 greater than the upper normal limit of 8.7 pg/ml. In 82 RAU patients with the serum IL-6 or IL-8 levels higher than the upper limit of normal serum concentration, treatment with levamisole for a period of 0.5-3.5 months could significantly reduce the serum IL-6 level from 12.0 +/- 1.6 to 3.0 +/- 0.5 pg/ml (P < 0.001), and could significantly lower the serum IL-8 level from 70.9 +/- 11.2 to 13.8 +/- 3.1 pg/ml (P < 0.001).

CONCLUSIONS

Because measurement of serum IL-8 level can detect 60% RAU patients with an abnormal serum level, while measurement of serum IL-6 level can detect only 25% RAU patients with an abnormal serum level, we conclude that serum IL-8 level is a more sensitive marker than serum IL-6 level in monitoring the disease activity of RAU. Levamisole can modulate both the serum IL-6 and IL-8 levels in RAU patients. IL-8, like IL-6, is also a useful serum marker in evaluating therapeutic effects of levamisole on RAU patients.

Structural analysis of the functional influence of the surface peptide Gtf-P1 on Streptococcus mutans glucosyltransferase C activity

Glucosyltransferases (GtfB/C/D) in Streptococcus mutans are responsible for synthesizing water-insoluble and water-soluble glucans from sucrose and play very crucial roles in the formation of dental plaque. A monoclonal antibody against a 19-mer peptide fragment named Gtf-P1 was found in GtfC to reduce the enzyme activity to 50%. However, a similar experiment suggested almost unchanged activity in GtfD, despite of the very high sequence homology between the two enzymes. No further details are yet available to elucidate the biochemical mechanism responsible for such discrimination. For a better understanding of the catalytic behavior of these glucosyltransferases, structural and functional analyses were performed. First, the exact epitope was identified to specify the residue(s) required for monoclonal antibody recognition. The results suggest that the discrimination is determined solely by single residue substitution. Second, based on a combined sequence and secondary structure alignment against known crystal structure of segments from closely related proteins, a three-dimensional homology model for GtfC was built. Structural analysis for the region communicating between Gtf-P1 and the catalytic triad revealed the possibility for an "en bloc" movement of hydrophobic residues, which may transduce the functional influence on enzyme activity from the surface of molecule into the proximity of the active site. Figure Side chain interactions between Gtf-P1 and catalytic Asp-477 in GtfC. Calpha-tracing of GtfC with the two crucial peptides (Gtf-P1, orange; Gtf-P2, blue) and the catalytic triad residues ( red) highlighted to show their relative spatial organization. Side chains for the residues are also depicted according to their atom types. The structure is viewed with the barrel opening facing down