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.

Effects of budlein A on human neutrophils and lymphocytes

ABSTRACT Sesquiterpene lactones (SLs) are the active constituents of a variety of medicinal plants used in traditional medicine for the treatment of inflammatory diseases and other ailments. 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-β, 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.

Activation and cytokine profile of monocyte derived dendritic cells in leprosy: in vitro stimulation by sonicated Mycobacterium leprae induces decreased level of IL-12p70 in lepromatous leprosy

Dendritic cells (DCs) play a pivotal role in the connection of innate and adaptive immunity of hosts to mycobacterial infection. Studies on the interaction of monocyte-derived DCs (MO-DCs) using Mycobacterium leprae in leprosy patients are rare. The present study demonstrated that the differentiation of MOs to DCs was similar in all forms of leprosy compared to normal healthy individuals. In vitro stimulation of immature MO-DCs with sonicated M. leprae induced variable degrees of DC maturation as determined by the increased expression of HLA-DR, CD40, CD80 and CD86, but not CD83, in all studied groups. The production of different cytokines by the MO-DCs appeared similar in all of the studied groups under similar conditions. However, the production of interleukin (IL)-12p70 by MO-DCs from lepromatous (LL) leprosy patients after in vitro stimulation with M. lepraewas lower than tuberculoid leprosy patients and healthy individuals, even after CD40 ligation with CD40 ligand-transfected cells. The present cumulative findings suggest that the MO-DCs of LL patients are generally a weak producer of IL-12p70 despite the moderate activating properties ofM. leprae. These results may explain the poor M. leprae-specific cell-mediated immunity in the LL type of leprosy.

Randomized controlled clinical trial of long-term chemo-mechanical caries removal using PapacarieTM gel

Objectives: Compare the effectiveness of PapacarieTM gel for the chemo-mechanical removal of carious lesions on primary teeth to conventional caries removal with a low-speed bur with regard to execution time, clinical aspects and radiographic findings. Material and Methods: A randomized controlled clinical trial with a split-mouth design was carried out. The sample was composed of 20 children aged four to seven years, in whom 40 deciduous teeth were randomly divided into two groups: chemo-mechanical caries removal with PapacarieTM and removal of carious dentin with a low-speed bur. Each child underwent both procedures and served as his/her own control. Restorations were performed with glass ionomer cement. The time required to perform the procedure was also analyzed. The patients underwent longitudinal clinical and radiographic follow-up of the restorations. Results: No statistically significant difference between groups was found regarding the time required to perform the procedures and the radiographic follow up. Statistically significant differences between groups were found in the clinical evaluation at 6 and 18 months after treatment. Conclusion: PapacarieTM is as effective as the traditional method for the removal of carious dentin on deciduous teeth, but offers the advantages of the preservation of sound dental tissue as well as the avoidance of sharp rotary instruments and local anesthesia. .

Efficacy of Papacarie¯ in reduction of residual bacteria in deciduous teeth: a randomized, controlled clinical trial

OBJECTIVES: The aim of the present study was to analyze the efficacy of Papacarie¯ gel compared with the traditional method (low-speed bur) in reducing the counts of total bacteria, Lactobacillus, total Streptococcus and Streptococcus mutans group. METHODS: A randomized, controlled clinical trial with a split-mouth design was performed. The sample comprised 40 deciduous teeth in 20 children (10 males and 10 females) aged four to seven years. The teeth were randomly allocated to two groups: G1, or chemomechanical caries removal with Papacarie Duo¯, and G2, or the removal of carious dentin tissue with a low-speed bur. Infected dentin was collected prior to the procedure, and the remaining dentin was collected immediately following the removal of the carious tissue. Initial and final counts of bacterial colonies were performed to determine whether there was a reduction in the number of colony-forming units (CFUs) of each microorganism studied. ClinicalTrials.gov: NCT01811420. RESULTS: Reductions were found in the numbers of total bacteria, total Streptococcus and Streptococcus mutans group following either of the caries removal methods (p<0.05). A reduction was also noted in the number of Lactobacillus CFUs; however, this difference did not achieve statistical significance (p>0.05). CONCLUSION: Papacarie¯ is an excellent option for the minimally invasive removal of carious tissue, achieving significant reductions in total bacteria, total Streptococcus and S. mutans with the same effectiveness as the traditional caries removal method. .

CCL3 and CXCL12 production in vitro by dental pulp fibroblasts from permanent and deciduous teeth stimulated by Porphyromonas gingivalis LPS

ABSTRACT Objective: The aim of this study was to compare the production of the chemokines CCL3 and CXCL12 by cultured dental pulp fibroblasts from permanent (PDPF) and deciduous (DDPF) teeth under stimulation by Porphyromonas gingivalis LPS (PgLPS). Material and Methods: Primary culture of fibroblasts from permanent (n=3) and deciduous (n=2) teeth were established using an explant technique. After the fourth passage, fibroblasts were stimulated by increasing concentrations of PgLPS (0 – 10 µg/mL) at 1, 6 and 24 h. The cells were tested for viability through MTT assay, and production of the chemokines CCL3 and CXCL12 was determined through ELISA. Comparisons among samples were performed using One-way ANOVA for MTT assay and Two-way ANOVA for ELISA results. Results: Cell viability was not affected by the antigen after 24 h of stimulation. PgLPS induced the production of CCL3 by dental pulp fibroblasts at similar levels for both permanent and deciduous pulp fibroblasts. Production of CXCL12, however, was significantly higher for PDPF than DDPF at 1 and 6 h. PgLPS, in turn, downregulated the production of CXCL12 by PDPF but not by DDPF. Conclusion: These data suggest that dental pulp fibroblasts from permanent and deciduous teeth may present a differential behavior under PgLPS stimulation. .

Increased hepcidin expression in multibacillary leprosy

Iron is essential for all organisms and its availability can control the growth of microorganisms; therefore, we examined the role of iron metabolism in multibacillary (MB) leprosy, focusing on the involvement of hepcidin. Erythrograms, iron metabolism parameters, pro-inflammatory cytokines and urinary hepcidin levels were evaluated in patients with MB and matched control subjects. Hepcidin expression in MB lesions was evaluated by quantitative polymerase chain reaction. The expression of ferroportin and hepcidin was evaluated by immunofluorescence in paucibacillary and MB lesions. Analysis of hepcidin protein levels in urine and of hepcidin mRNA and protein levels in leprosy lesions and skin biopsies from healthy control subjects showed elevated hepcidin levels in MB patients. Decreases in haematologic parameters and total iron binding capacity were observed in patients with MB leprosy. Moreover, interleukin-1 beta, ferritin, soluble transferrin receptor and soluble transferrin receptor/log ferritin index values were increased in leprosy patients. Hepcidin was elevated in lepromatous lesions, whereas ferroportin was more abundant in tuberculoid lesions. In addition, hepcidin and ferroportin were not colocalised in the biopsies from leprosy lesions. Anaemia was not commonly observed in patients with MB; however, the observed changes in haematologic parameters indicating altered iron metabolism appeared to result from a mixture of anaemia of inflammation and iron deficiency. Thus, iron sequestration inside host cells might play a role in leprosy by providing an optimal environment for the bacillus.

Non-inflammatory destructive periodontal disease: a clinical, microbiological, immunological and genetic investigation

Periodontitis comprises a group of multifactorial diseases in which periodontopathogens accumulate in dental plaque and trigger host chronic inflammatory and immune responses against periodontal structures, which are determinant to the disease outcome. Although unusual cases of non-inflammatory destructive periodontal disease (NIDPD) are described, their pathogenesis remains unknown. A unique NIDPD case was investigated by clinical, microbiological, immunological and genetic tools. The patient, a non-smoking dental surgeon with excessive oral hygiene practice, presented a generalized bone resorption and tooth mobility, but not gingival inflammation or occlusion problems. No hematological, immunological or endocrine alterations were found. No periodontopathogens (A. actinomycetemcomitans, P. gingivalis, F. nucleatum and T. denticola) or viruses (HCMV, EBV-1 and HSV-1) were detected, along with levels of IL-1β and TNF-a in GCF compatible with healthy tissues. Conversely ALP, ACP and RANKL GCF levels were similar to diseased periodontal sites. Genetic investigation demonstrated that the patient carried some SNPs, as well HLA-DR4 (*0404) and HLA-B27 alleles, considered risk factors for bone loss. Then, a less vigorous and diminished frequency of toothbrushing was recommended to the patient, resulting in the arrest of alveolar bone loss, associated with the return of ALP, ACP and RANKL in GCF to normality levels. In conclusion, the unusual case presented here is compatible with the previous description of NIDPD, and the results that a possible combination of excessive force and frequency of mechanical stimulation with a potentially bone loss prone genotype could result in the alveolar bone loss seen in NIDPD.

Estudo do papel de células T reguladoras e moléculas co-estimulatórias ma regulação da resposta imune em doenças infecciosas e tumor de cabeça e pescoço / The role of the regulatory T cells and PD-1 molecules in the modulation of the immune response in chronic infections and head and neck tumors

O sistema imune serve como uma barreira contra os patógenos e ao crescimento anormal de células. Para impedir as respostas imunes excessivas ou indiscriminadas que podem comprometer a sobrevivência do organismo, diversos mecanismos regulatórios são ativados visando manter o delicado balanço entre início e término de uma resposta imune. As celular T reguladoras (Treg) parecem desempenhar papel central na regulação da resposta imune em infecções crônicas e durante o desenvolvimento de tumores. Outro mecanismo importante no controle da resposta imune é desempenhado por moléculas co-estimulatórias, dentre as quais estão CTLA-4 e PD-1, todas associadas à função das células T reguladoras. Um aspecto importante é q a sobrevida de tecido tumoral e de transplantes tem sido associada à função das células T reguladoras. Assim, buscamos definir o envolvimento de células T reguladoras e PD-1 na modulação da resposta imune L. braziliensis, ao fungo P. brasiliensis, à doença periodontal e ao tumor de cabeça e pescoço. Baseado nos resultados já publicados e em dados preliminares, as hipóteses são que: (a) a interação do parasita (ou célula tumoral) com o hospedeiro leva à migração de linfócitos T e efetores e células T reguladoras para o local da lesão; (b) a dinâmica do acúmulo dessas células em tais sítios determina a eficiência da eliminação do patógeno ou tumor. No caso das parasitoses, há o desenvolvimento de imunidade concomitante; (c) as células T regulam a resposta imune local de forma contato dependente e modulando a função de APC através da liberação de IL-10 e/ou TGF-β; (d) infecção e progressão tumoral levam à modulação da expressão de PD-1 nos leucócitos e seus ligantes nos órgãos; (e) a interação PD-PDL-1 regula a resposta imune local de forma a favorecer a persistência do patógeno e os mecanismos de escape tumoral.

The immune system serves as a barrier against pathogens and abnormal cellular growth. To avoid tissue and organ damage during immune response several regulatory mechanisms are activated to limit, terminate and attenuate T-cells response. Regulatory T cells (Treg) play a central role in the regulation of the immune response in chronic infections and tumor-specific immunity. Programmed death-1 (PD-1) is a transmembrane protein that acts as a negative regulator in effector T cells, modulating the delicate balance between effective antimicrobial immune defenses and immune-mediated tissue damage. However, recent data suggest that the PD-1:PD-L1 pathway can also block antitumor immune responses even when tumor antigens can be recognized. An important aspect it that the survival of tumor and transplant tissues has been associated with the function or regulatory T cells. Thus, we discuss the role of Treg cells and PD-1 molecules in the modulation of the immune response to L. braziliensis, P. brasiliensis, periodontal disease and head and neck tumors. Based on published results and preliminary data, the hypotheses are that: (a) the interaction of the parasite (or tumoral cells) with the host leads to the migration of effector T lymphocytes and Treg cells to the local; (b) the dynamics of cells accumulation in such sites determinate the elimination efficiency of tumors. In infectious disease, there is the development of concomitant immunity; (c) Treg cells regulate the local immune response, modulating the APC function through the release of IL-10 and/or TGF-β; (d) infection and tumor progression leads to the modulation of PD-1 expression in the leukocytes and their ligands in the tissue; (e) PD-PDL-1 interactions regulate the immune response and may mediate the persistence of pathogen and contribute to immune evasion by cancers.T.