Recognition of Candida albicans by gingival fibroblasts: The role of TLR2, TLR4/CD14, and MyD88.

Recent evidence indicates that nonprofessional immune cells such as epithelial cells, endothelial cells, and fibroblasts also contribute to innate immunity via secretion of cytokines. Fibroblasts are the principal type of cell found in the periodontal connective tissues and they are involved in the immune response during periodontal disease. The role of fibroblasts in the recognition of pathogens via Toll-like receptors (TLRs) has been established; however, few studies have been conducted concerning the involvement of innate immune receptors in the recognition of Candida albicans by gingival fibroblast. In the current study, we investigate the functional activity of TLR2, cluster of differentiation 14 (CD14), and myeloid differentiation primary response gene 88 (MyD88) molecules in the recognition of C. albicans by gingival fibroblast. First, we identified that gingival fibroblasts expressed TLR2, TLR3, and TLR4. Our results showed that TLR agonists had no effect on these receptors' expression by TLR2, MyD88, and CD14-deficient cells. Notably, C. albicans and a synthetic triacylated lipoprotein (Pam3CSK4) induced a remarkable increase of TLR3 expression on MyD88-deficient gingival fibroblasts. TLR4 expression levels were lower than TLR2 and TLR3 levels and remained unchanged after TLR agonist stimulation. Gingival fibroblasts presented morphological similarities; however, TLR2 deficiency on these cells leads to a lower proliferative response, whereas the deficiency on CD14 expression resulted in lower levels of type I collagen by these cells. In addition, the recognition of C. albicans by gingival fibroblasts had an effect on the secretion of cytokines and it was dependent on a specific recognition molecule. Specifically, tumor necrosis factor-α (TNF-α) production after the recognition of C. albicans was dependent on MyD88, CD14, and TLR2 molecules, whereas the production of interleukin-1ß (IL-1ß) and IL-13 was dependent on TLR2. These findings are the first to describe a role of gingival fibroblast in the recognition of C. albicans and the pathways involved in this process. An understanding of these pathways may lead to alternative treatments for patients with periodontal disease.

PD-1 blockage delays murine squamous cell carcinoma development.

Engagement of programmed death-1 (PD-1) with its two ligands [programmed death ligand-1 (PD-L1) and PD-L2] has been associated with the suppression of tumor-reactive T cells; however, the underlying mechanism for this T-cell dysfunction is not clear. We hypothesized that PD-1 and PD-L1 signals are, in part, responsible for squamous cell carcinoma (SCC) escape from immune antitumor regulation by modulation of the tumor environment. In the present study, we used a multistage model of SCC to examine the role of PD-1/PD-L1 activation during tumor development. Tumor sites presented an increased percentage of CD4(+) and CD8(+) T cells expressing PD-1 when compared with non-tumorigenic control mice, whereas the expression of PD-L1 was particularly increased in F4/80(+) macrophages in tumor sites. Further, the systemic immune neutralization of PD-1 resulted in a decreased number and delayed incidence rate of papillomas followed by a differential expression of cytokeratins, suggesting that the PD-1-PD-L1 interaction contributes to the progression of SCC by downregulation of antitumor responses. In fact, blocking PD-1 increased the percentage of CD8(+) and CD4(+) T cells, and the levels of interferon-γ in the tumor sites. Our results indicated involvement of PD-1(+) T cells in SCC development and in the modulation of the inflammatory immune response.

Regulatory T cells in the actinic cheilitis.

BACKGROUND: Actinic cheilitis (AC) is an oral potentially malignant lesion which is the counterpart of actinic keratosis of the skin and has potential to develop into squamous cell carcinoma. Regulatory T cells (Tregs) have a critical role in modulating the antitumor immune responses. The presence of regulatory T cells in potentially malignant lesions has not been described. We chose investigate the involvement of regulatory T cells in potentially malignant lesions. METHODS: The frequency, phenotype, and activity of CD4+CD25+ T cells isolated from blood and lesion of AC patients were analyzed by flow cytometry. Cytokines were quantified by ELISA. Data were compared with samples from healthy subjects. RESULTS: The frequency and suppressor activity of circulating CD4+CD25+ T cells was similar in AC patients and control subjects. However, the frequencies of IL-10-positive Tregs were higher in AC patients, and these cells inhibited interferon-gamma (IFN-γ) and increased interleukin (IL)-10 productions in co-cultures. Furthermore, CD4+CD25+ T cells accumulate in AC lesions. Lesions-derived regulatory T cells suppressed lymphocyte proliferation and pro-inflammatory cytokine production. Moreover, high levels of IL-10 and transforming growth factor-ß (TGF-ß), and low IFN-γ were detected in the potentially malignant lesions. CONCLUSION: Therefore, our data show that Tregs accumulate in AC lesions, and these cells could be suppressing immune responses in a potentially malignant microenvironment.

Activation profile of CXCL8-stimulated neutrophils and aging.

Neutrophils are pivotal effector cells of innate immunity representing the first line of defense against aggression. They are the first cells to arrive at the site of the aggression, where they can directly eliminate the invading microorganisms. Their activation and recruitment into peripheral tissues is indispensable for host defense. With aging, there are alterations of the receptor by driven functions of human neutrophils as a decrease in the functional changes in signaling elicited by specific receptors, as CXCR1. We investigated the activation of neutrophils from elderly after the cells were cultivated with CXCL8. Although, CXCL8 induced elastase (ELA) secretion, data showed neither myeloperoxidase (MPO) activity nor production of IL-6, IL-10, GM-CSF by neutrophils from elderly compared with young individuals. On the other hand, in the presence of only LPS or LPS associated with CXCL8 neutrophils from elderly individuals, there were significant levels of IL-6, IL-10, GM-CSF but not MPO. These results indicate that neutrophils from elderly do not respond to CXCL8 stimulus, but they are activated by LPS to produce cytokines. However, MPO activity from elderly individuals was not different in the presence or absence of LPS and CXCL8.

CD25+ T cell depletion impairs murine squamous cell carcinoma development via modulation of antitumor immune responses.

Squamous cell carcinoma (SCC) constitutes a microenvironment that could modulate the antitumor immune response. Also, tumor-infiltrating lymphocytes are believed to play complex regulatory roles in antitumor immunity against SCC. The presence of regulatory T cells (Tregs) has been associated with the suppression of tumor-reactive T cells. However, the underlying mechanism for this T cell dysfunction is not clear. We used a multistage model of SCC to examine the role of Treg cells during tumor development. 7,12-dimethylbenz[a]-anthracene/phorbol 12-myristate 13-acetate treatment and systemic depletion of Treg cells using an anti-CD25 monoclonal antibody (PC61) resulted in a decrease in the number and incidence of papilloma. Furthermore, CD25 depletion increased the proportion of CD8(+) and CD4(+) T cells that were isolated from tumor lesions. The levels of interleukin (IL)-1ß, IL-10, IL-12, IL-13, interferon-γ, transforming growth factor-ß and tumor necrosis factor-α, but not IL-17, were increased in the tumor microenvironment after Treg depletion. Therefore, our results indicated involvement of CD25(+) T cells in SCC development and in the suppression of the inflammatory immune response.

Enhanced programmed death 1 (PD-1) and PD-1 ligand (PD-L1) expression in patients with actinic cheilitis and oral squamous cell carcinoma.

PD-1 and PD-L1 can be involved in tumor escape, and little is known about the role of these molecules in oral tumors or pre-malignant lesions. In the present study, we investigated the expression of PD-1 and PD-L1 in the blood and lesion samples of patients with actinic cheilitis (AC) and oral squamous cell carcinoma (OSCC). Our results showed that lymphocytes from peripheral blood and tissue samples exhibited high expression of PD-1 in both groups analyzed. Patients with AC presented higher percentage as well as the absolute numbers of CD4+PD-1+ and CD8+PD-1+ lymphocytes in peripheral blood mononuclear cells (PBMC) than healthy individuals, while patients with OSCC presented an increased frequency of CD8+PD1+ in PBMC when compared with controls. On the other hand, increased frequency of CD4+ and CD8+ T cells expressing PD-1(+) accumulate in samples from OSCC, and the expression of PD-L1 was intense in OSCC and moderate in AC lesion sites. Lower levels of IFN-γ and higher levels of TGF-ß were detected in OSCC samples. Our data demonstrate that PD-1 and PD-L1 molecules are present in blood and samples of AC and OSCC patients. Further studies are required to understand the significance of PD-1 and PD-L1 in oral tumors microenvironment.

Fcγ receptors on aging neutrophils.

OBJECTIVE: Neutrophils are key effector cells of the innate immune system. They recognize antigens through membrane receptors, which are expressed during their maturation and activation. Neutrophils express FcγRII (CD32), FcγRIII (CD16), and FcγRI (CD64) after being activated by different factors such as cytokines and bacterial products. These receptors are involved with phagocytosis of IgG-opsonized microbes and enhance defense mechanisms. Based on that, our study seeks to compare the expression of FcγRII, FcγRIII, FcγRI, and CD11b on neutrophils from elderly and young subjects and their expression after in vitro activation with cytokines and LPS. METHODOLOGY: Neutrophils were isolated from human peripheral blood and from mice bone marrow by density gradient. After isolation, FCγRs expression was immediately analyzed by flow cytometry or after in vitro stimulation. RESULTS: In freshly isolated cells, the percentage of FcγRIIIb+ and CD11b+ neutrophils were higher in samples from young individuals; FcγRIIIa expression was more prominent on aged neutrophils; FcγRIA expression was similar in all samples analyzed. Exposure to CXCL8 and LPS resulted in a higher percentage of FcγRIa+ neutrophils on elderly individuals' samples but lower when compared with neutrophils from young donors. We observed that LPS caused an increase in FcγRIIa expression on aging human neutrophils. In contrast, FcγRIIIb expression in response to CXCL8 and LPS stimulation was not altered in the four groups. CD11b expression was lower in neutrophils from elderly individuals even in response to LPS and CXCL8. In mice, we observed differences only regarding CD11b expression, which was increased on aged neutrophils. LPS exposure caused an increase in all FcγRs. CONCLUSIONS: Our results suggest that, in humans, the overall pattern of FcγR expression and integrin CD11b are altered during aging and immunosenescence might contribute to age-related infection.

Patients with oral squamous cell carcinoma are characterized by increased frequency of suppressive regulatory T cells in the blood and tumor microenvironment.

Oral squamous cell carcinoma (OSCC) is a cancerous lesion with high incidence worldwide. The immunoregulatory events leading to OSCC persistence remain to be elucidated. Our hypothesis is that regulatory T cells (Tregs) are important to obstruct antitumor immune responses in patients with OSCC. In the present study, we investigated the frequency, phenotype, and activity of Tregs from blood and lesions of patients with OSCC. Our data showed that >80% of CD4(+)CD25(+) T cells isolated from PBMC and tumor sites express FoxP3. Also, these cells express surface Treg markers, such as GITR, CD45RO, CD69, LAP, CTLA-4, CCR4, and IL-10. Purified CD4(+)CD25(+) T cells exhibited stronger suppressive activity inhibiting allogeneic T-cell proliferation and IFN-gamma production when compared with CD4(+)CD25(+) T cells isolated from healthy individuals. Interestingly, approximately 25% of CD4(+)CD25(-) T cells of PBMC from patients also expressed FoxP3 and, although these cells weakly suppress allogeneic T cells proliferative response, they inhibited IFN-gamma and induced IL-10 and TGF-beta secretion in these co-cultures. Thus, our data show that Treg cells are present in OSCC lesions and PBMC, and these cells appear to suppress immune responses both systemically and in the tumor microenvironment.

Absence of functional TLR4 impairs response of macrophages after Candida albicans infection.

Candida albicans is recognized by phagocytic cells through a set of recognition receptors patterns. Recently, we showed the importance of TLR2 in the regulation of neutrophil survival after C. albicans infection. In the present work, we analyzed the involvement of TLR4 in the recognition of C. albicans by neutrophils and macrophages. Our results show that the absence of functional TLR4 resulted in lower chemotaxis of neutrophils to the site of infection, lower levels of TNF-α, CXCL1 and nitric oxide, and dissemination and persistence of the pathogen in lymph nodes and spleen. In vitro, the phagocytic activity, nitric oxide production and myeloperoxidase activity, CXCL1, IL-1ß production by neutrophils from TLR4-defective mice were not changed. In contrast, macrophages from TLR4-defective mice demonstrated lower phagocytosis and lower levels of CXCL1, IL-1ß and TNF-α. Together, these data demonstrate that TLR4 signals are important for the recognition of C. albicans by macrophages and their absence allows persistence of the infection.

Absence of TLR2 influences survival of neutrophils after infection with Candida albicans.

Candida albicans is an opportunistic pathogen, which causes local and/or disseminated diseases in immunosuppressed humans. Phagocytic cells play a critical role in the immune response against C. albicans. Toll like receptors (TLR) are important in the identification of invading microorganisms and in the regulation of neutrophil survival. TLR2 has been shown to participate in the response against pathogenic yeasts and to increase the functional life span of neutrophils. In view of these observations, we studied the involvement of TLR2 in neutrophil function after C. albicans infection. The absence of TLR2 resulted in lower chemotaxis of neutrophils to the site of infection. This in turn was associated with lower levels of chemokines from neutrophils, facilitating the dissemination of the pathogen to the lymph nodes and spleen. A high frequency of apoptotic neutrophils and macrophages in the inflammatory exudates from TLR2(-/-) mice was found. In addition, the phagocytic activity of neutrophils and macrophages, nitric oxide production and myeloperoxidase activity were diminished in cells from TLR2(-/-) mice. Together, these data demonstrate the importance of TLR2 signals for neutrophils activation and survival after C. albicans infection.

The essential role of toll like receptor-4 in the control of Aggregatibacter actinomycetemcomitans infection in mice.

OBJECTIVE: Aggregatibacter actinomycetemcomitans is an oral Gram-negative bacterium that contributes to periodontitis progression. Isolated antigens from A. actinomycetemcomitans could be activating innate immune cells through Toll-like receptors (TLRs). In this study, we evaluated the role of TLR4 in the control of A. actinomycetemcomitans infection. MATERIAL AND METHODS: We examined the mechanisms that modulate the outcome of A. actinomycetemcomitans-induced periodontal disease in TLR4(-/-) mice. The production of cytokines was evaluated by ELISA. The bacterial load was determined by counting the number of colony-forming units per gram of tissue. RESULTS: The results showed that TLR4-deficient mice developed less severe periodontitis after A. actinomycetemcomitans infection, characterized by significantly lower bone loss and inflammatory cell migration to periodontal tissues. However, the absence of TLR4 facilitated the A. actinomycetemcomitans dissemination. Myeloperoxidase activity was diminished in the periodontal tissue of TLR4(-/-) mice. We observed a significant reduction in the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta in the periodontal tissue of TLR4(-/-) mice. CONCLUSION: The results of this study highlighted the role of TLR4 in controlling A. actinomycetemcomitans infection.

Isolation of Candida dubliniensis from denture wearers.

Candida albicans is considered the most important Candida species able to cause oral infections in denture wearers. In recent years, Candida dubliniensis has emerged as a pathogenic yeast in humans. The close phenotypic similarities of C. albicans and C. dubliniensis have led to the misidentification of these species. In this work, our aim was to verify through PCR the presence of C. dubliniensis in palate and maxillary denture samples from 112 denture wearers presenting with or without denture-related stomatitis (DRS). C. dubliniensis was isolated at low rates from both palate (5.3 % and 10.7 %) and maxillary denture (5.3 % and 8.9 %) samples from wearers regardless of the presence of the disease. However, when C. dubliniensis was detected in individuals with DRS, it was always associated with C. albicans. In addition, our results showed that C. albicans was the most commonly identified candidal species in maxillary denture and hard palate samples from DRS patients (78.5 % and 89.2 %, respectively) as well as from controls (31.2 % and 28.5 %, respectively). In conclusion, C. dubliniensis was detected in the oral environment of denture wearers. The association of C. dubliniensis with C. albicans occurred in approximately 10 % of the DRS cases.

Ageing exacerbates damage of systemic and salivary neutrophils from patients presenting Candida-related denture stomatitis.

BACKGROUND: Ageing leads to a decline in the function of the immune system, increasing the body's susceptibility to infections through the impairment of T-cells, macrophages, neutrophils and dendritic cells Denture stomatitis is a primary oral disease affecting elderly denture wearers. The major etiologic factor involved in this pathology is the infection by Candida albicans, an opportunistic pathogen that causes local and disseminated diseases in immunosuppressed humans. Neutrophils play a critical role in the immune response against C. albicans and are continually present in the salivary fluid and in the blood. The aim of this study was to determine ageing-related changes in salivary and blood neutrophils and their potential implications in Candida-related denture stomatitis. RESULTS: Our results showed a lower number of neutrophils in the saliva from patients presenting Candida-related denture stomatitis in comparison to their matched controls. Furthermore, fewer neutrophils were isolated from the saliva of aged control individuals in comparison to matched younger subjects. CXCR1, CD62L and CD11b expression were significantly greater on systemic neutrophils from younger control individuals. Elderly individuals showed more apoptotic salivary neutrophils and lower GM-CSF levels than younger ones, regardless of the occurrence of Candida infection. On the other hand, CXCL-8 concentrations were higher in the saliva from elderly individuals. Besides, TNF-alpha was detected at elevated levels in the saliva from infected elderly subjects. Salivary neutrophils from elderly and young patients presented impaired phagocytic activity against C. albicans. However, just systemic neutrophils from elderly showed decreased phagocytosis when compared to the younger ones, regardless of the occurrence of infection. In addition, neutrophils from aged individuals and young patients presented low fungicidal activity. CONCLUSION: The data suggests that the Candida related-denture stomatitis is associated to neutrophils function deficiency, and ageing drastically appears to alter important characteristics of such cells, facilitating the establishment of this infection.

CAMPANELLIProgrammed Death 1 (PD-1) and PD-1 Ligand (PD-L1) Expression in Chronic Apical Periodontitis.

OBJECTIVE: This study aimed to examine programmed death protein 1 (PD-1) and programmed death lig-and 1 (PD-L1) expression on leukocytes from chronic apical periodontitis, and to determine the levels of cytokines in the apical periodontitis lesions. METHODS: Leukocytes from healthy gingival tissue (n=16) and chronic apical periodontitis (n=10) were eval-uated using flow cytometry. The PD-1 and PDL-1 expressions were evaluated using flow cytometry. The cy-tokine levels were evaluated by enzyme-linked immunosorbent assay. Data were analyzed using one-way ANOVA. The statistical significance level was set at P<0.05. RESULTS: Results showed that the apical periodontitis lesions are more infiltrated by PD-1+ and PDL1+ lym-phocytes than the control samples. In addition, the PDL-1 expression was detected on macrophages in the apical periodontitis lesions, and was significantly higher compared to leukocytes from healthy gingival tis-sue. The IFN-γ, TGF-ß, IL-10, and TNF-α levels were significantly higher in the apical periodontitis lesions com-pared to control samples. CONCLUSION: The PD-1, PD-L1, and CTLA-4 molecules are evident in apical periodontitis, and can be an impor-tant immune checkpoint in chronic periapical periodontitis.

ST2/IL-33 signaling promotes malignant development of experimental squamous cell carcinoma by decreasing NK cells cytotoxicity and modulating the intratumoral cell infiltrate.

Squamous cell carcinoma (SCC) is the second most common form of skin cancer and the mechanism(s) involved in the progression of this tumor are unknown. Increases in the expression of IL-33/ST2 axis components have been demonstrated to contribute to neoplastic transformation in several tumor models and interleukin-33 is correlated with poor prognosis of patients with squamous cell carcinoma of the tongue. Based on these observations, we sought to determine the role of the IL-33/ST2 pathway during the development of SCC. Our findings show that ST2-deficiency led to a marked decrease in the severity of skin lesions, suggesting that ST2 signaling contributed to tumor development. An analysis of tumor lesions in wild-type and ST2KO mice revealed that a lack of ST2 was associated with specific and significant reductions in the numbers of CD4+ T cells, CD8+ T cells, dendritic cells, and macrophages. In addition, NK cells that were isolated from ST2KO mice exhibited higher cytotoxic activity than cells isolated from wild-type mice. Notably, ST2 deficiency resulted in lower IFN-γ, TNF-α, IL-10, and IL-17 production in tumor samples. Our findings indicate that the IL-33/ST2 pathway contributes to the development of SCC by affecting leukocyte migration to tumor microenvironment and impairing NK cytotoxic activity.

Isolation and characterization of progenitor cells from surgically created early healing alveolar defects in humans: A preliminary study.

BACKGROUND: The granulation tissue present in surgically-created early healing sockets has been considered as a possible source of osteoprogenitor cells for periodontal regeneration, as demonstrated in animal studies. However, the in vitro osteogenic properties of tissue removed from human surgically-created early healing alveolar defects (SC-EHAD) remains to be established, being that the aim of this study. METHODS: Surgical defects were created in the edentulous ridge of two systemically healthy adults. The healing tissue present in these defects was removed 21 days later for the establishment of primary culture. The in vitro characteristics of the cultured cells were determined by Armelin method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, immunohistochemistry, alkaline phosphatase (ALP) activity, mineralization assay, and flow cytometry for detection of stem cells/osteoprogenitor cell markers. RESULTS: Cells were able to adhere to the plastic and assumed spindle-shaped morphology at earlier passages, changing to a cuboidal one with increasing passages. Differences in the proliferation rate were observed with increasing passages, suggesting osteogenic differentiation. ALP and mineralization activities were detected in conventional and osteogenic medium. Fresh samples of SC-EHAD tissue exhibited CD34- and CD45- phenotypes. Cells at later passages (14th) exhibited CD34- , CD45- , CD105- , CD166- , and collagen type I+ phenotype. CONCLUSION: Tissue removed from SC-EHAD is a possible source of progenitor cells.

CCR5-Dependent Homing of T Regulatory Cells to the Tumor Microenvironment Contributes to Skin Squamous Cell Carcinoma Development.

Squamous cell carcinoma (SCC) is one of the most common human cancers worldwide. Recent studies show that regulatory T cells (Treg) have a critical role in the modulation of an antitumor immune response, and consequently the SCC development. Because the accumulation of Tregs at the tumor site is, in part, due to selective recruitment through CCR5- and CCR5-associated chemokines, we investigated the role of CCR5 in the SCC development. Our findings showed that CCR5-deficient mice (CCR5KO) were efficient in controlling papilloma's incidence when compared with wild-type mice. Analysis of tumor lesions in wild-type (WT) and CCR5KO mice revealed that lack of CCR5 lead to significant reduction in frequency of Tregs and increased of CD4 T cells into the tumors. Moreover, the adoptive transfer of naturally occurring Tregs CD4+CD25+CCR5+, CD4+CD25-CCR5+ or CD8+CCR5+ conventional T cells to CCR5KO mice resulted in an increased papilloma incidence. Interestingly, adoptive transfer of WT CD4+CD25+CCR5+ cells to CCR5KO mice induced more undifferentiated SCC lesions, characterized by higher infiltration of macrophages and dendritic cells. In this study, we also demonstrated that Treg migration to the tumor microenvironment is mediated by CCR5, and these cells are promoting tumor growth via inhibition of antitumor cells such as cytotoxic CD8+ T cells. Our findings reinforce the therapeutic potential of CCR5 inhibition for cancer treatment, and indicate an attractive approach for SCC treatment. Mol Cancer Ther; 16(12); 2871-80. ©2017 AACR.

Immune Checkpoints in Leprosy: Immunotherapy As a Feasible Approach to Control Disease Progression.

Leprosy remains a health problem in several countries. Current management of patients with leprosy is complex and requires multidrug therapy. Nonetheless, antibiotic treatment is insufficient to prevent nerve disabilities and control Mycobacterium leprae. Successful infectious disease treatment demands an understanding of the host immune response against a pathogen. Immune-based therapy is an effective treatment option for malignancies and infectious diseases. A promising therapeutic approach to improve the clinical outcome of malignancies is the blockade of immune checkpoints. Immune checkpoints refer to a wide range of inhibitory or regulatory pathways that are critical for maintaining self-tolerance and modulating the immune response. Programmed cell-death protein-1 (PD-1), programmed cell death ligand-1 (PD-L1), cytotoxic T-lymphocyte-associated protein 4, and lymphocyte-activation gene-3 are the most important immune checkpoint molecules. Several pathogens, including M. leprae, are supposed to utilize these mechanisms to evade the host immune response. Regulatory T cells and expression of co-inhibitory molecules on lymphocytes induce specific T-cell anergy/exhaustion, leading to disseminated and progressive disease. From this perspective, we outline how the co-inhibitory molecules PD-1, PD-L1, and Th1/Th17 versus Th2/Treg cells are balanced, how antigen-presenting cell maturation acts at different levels to inhibit T cells and modulate the development of leprosy, and how new interventions interfere with leprosy development.

Effects of budlein A on human neutrophils and lymphocytes.

OBJECTIVE: In this study, we evaluated whether budlein A modulates the activation of innate and adaptive immune cells such as neutrophils and lymphocytes. MATERIAL AND METHODS: Our research group has investigated several plant species and several compounds have been isolated, identified, and their medical potential evaluated. Budlein A is a SL isolated from the species Aldama buddlejiformis and A. robusta (Asteraceae) and shows anti-inflammatory and anti-nociceptive activities. Advances in understanding how plant-derived substances modulate the activation of innate and adaptive immune cells have led to the development of new therapies for human diseases. RESULTS: Budlein A inhibited MPO activity, IL-6, CXCL8, IL-10, and IL-12 production and induces neutrophil apoptosis. In contrast, budlein A inhibited lymphocyte proliferation and IL-2, IL-10, TGF-ß, and IFN-γ production, but it did not lead to cell death. CONCLUSIONS: Collectively, our results indicate that budlein A shows distinct immunomodulatory effects on immune cells.

Fcγ receptors on aging neutrophils

Abstract Objective Neutrophils are key effector cells of the innate immune system. They recognize antigens through membrane receptors, which are expressed during their maturation and activation. Neutrophils express FcγRII (CD32), FcγRIII (CD16), and FcγRI (CD64) after being activated by different factors such as cytokines and bacterial products. These receptors are involved with phagocytosis of IgG-opsonized microbes and enhance defense mechanisms. Based on that, our study seeks to compare the expression of FcγRII, FcγRIII, FcγRI, and CD11b on neutrophils from elderly and young subjects and their expression after in vitro activation with cytokines and LPS. Methodology Neutrophils were isolated from human peripheral blood and from mice bone marrow by density gradient. After isolation, FCγRs expression was immediately analyzed by flow cytometry or after in vitro stimulation. Results In freshly isolated cells, the percentage of FcγRIIIb+ and CD11b+ neutrophils were higher in samples from young individuals; FcγRIIIa expression was more prominent on aged neutrophils; FcγRIA expression was similar in all samples analyzed. Exposure to CXCL8 and LPS resulted in a higher percentage of FcγRIa+ neutrophils on elderly individuals' samples but lower when compared with neutrophils from young donors. We observed that LPS caused an increase in FcγRIIa expression on aging human neutrophils. In contrast, FcγRIIIb expression in response to CXCL8 and LPS stimulation was not altered in the four groups. CD11b expression was lower in neutrophils from elderly individuals even in response to LPS and CXCL8. In mice, we observed differences only regarding CD11b expression, which was increased on aged neutrophils. LPS exposure caused an increase in all FcγRs. Conclusions Our results suggest that, in humans, the overall pattern of FcγR expression and integrin CD11b are altered during aging and immunosenescence might contribute to age-related infection.