Increased IL-12p70 Levels in Intraoperative Pericardial Fluid Are Predictive of Postoperative Atrial Fibrillation Onset after Coronary Artery Bypass Surgery.

Background: Postoperative atrial fibrillation (POAF) is a frequent complication of heart surgery, prolonging hospital stays, as well as increasing morbidity and mortality rates. While previous studies have investigated the determinants influencing atrial fibrillation (AF) following heart surgery, the specific risk factors contributing to POAF occurrence after coronary artery bypass graft surgery (CABG) are not well understood. Here we used the human magnetic Luminex assay to assess whether biomarkers, particularly cytokines, within intraoperative pericardial fluid could serve as predictive markers for POAF onset among CABG individuals. Methods: In this study we identified 180 patients who underwent CABG with no atrial arrhythmia history. The human magnetic Luminex assay was used to quantify the levels of 36 cytokines in pericardial fluid samples collected during the surgery. The occurrence of POAF was continuously monitored, using both postoperative electrocardiograms and telemetry strips, until the time of discharge. Results: In our cohort of 124 patients, POAF was observed in 30 patients, accounting for 24.19% of the study population. These patients exhibited significantly higher levels of interleukin (IL)-12p70 in their intraoperative pericardial fluids compared to those with normal sinus rhythms (SR, p < 0.001). Subsequently, IL-12p70 was found to be an independent risk factor for POAF, and receiver operating characteristic (ROC) analysis established a cut-off threshold for predicting POAF onset of 116.435 pg/mL, based on the maximum Youden index (area under the curve: 0.816). Conclusions: this study establishes a significant association between elevated IL-12p70 levels in intraoperative pericardial fluid and the risk of POAF, particularly when IL-12p70 concentrations exceed the identified cut-off value of 116.435 pg/mL. These findings suggest that IL-12p70 levels could potentially be utilized as a predictive biomarker for the onset of POAF in patients undergoing CABG. This marker may aid in the early identification and management of patients at heightened risk for this complication.

Comparing machine learning screening approaches using clinical data and cytokine profiles for COVID-19 in resource-limited and resource-abundant settings.

Accurate screening of COVID-19 infection status for symptomatic patients is a critical public health task. Although molecular and antigen tests now exist for COVID-19, in resource-limited settings, screening tests are often not available. Furthermore, during the early stages of the pandemic tests were not available in any capacity. We utilized an automated machine learning (ML) approach to train and evaluate thousands of models on a clinical dataset consisting of commonly available clinical and laboratory data, along with cytokine profiles for patients (n = 150). These models were then further tested for generalizability on an out-of-sample secondary dataset (n = 120). We were able to develop a ML model for rapid and reliable screening of patients as COVID-19 positive or negative using three approaches: commonly available clinical and laboratory data, a cytokine profile, and a combination of the common data and cytokine profile. Of the tens of thousands of models automatically tested for the three approaches, all three approaches demonstrated > 92% sensitivity and > 88 specificity while our highest performing model achieved 95.6% sensitivity and 98.1% specificity. These models represent a potential effective deployable solution for COVID-19 status classification for symptomatic patients in resource-limited settings and provide proof-of-concept for rapid development of screening tools for novel emerging infectious diseases.

Changes in Serum IL-12 Levels following the Administration of H1-Antihistamines in Patients with Chronic Spontaneous Urticaria.

INTRODUCTION: Research regarding the role of the IL-12 cytokine family in modulating immune and inflammatory responses is continuously evolving. In this study, the contribution of the p35 and p40 subunits as monomers (noted as IL-12p35 and IL-12p40) and heterodimers (noted as IL-12p70 or IL-12p35/p40) was analysed in the pathophysiology and progression of chronic spontaneous urticaria (CSU). MATERIALS AND METHODS: We conducted a longitudinal, case-control study involving 42 CSU cases and 40 control cases comprising adults without associated conditions. Serial measurements were performed to assess the serum levels of IL-12p70, IL-12p35, and IL-12p40 at the onset of the disease (pre-therapy phase) and 6 weeks after the initiation of the treatment (post-therapy phase). RESULTS: During the pre-therapeutic phase of CSU, elevated serum levels of IL-12 cytokine subtypes were detected compared to the control group. The relationship between IL-12 profiles and the course of CSU highlighted the pro-inflammatory role of IL-12p70 and the anti-inflammatory role of IL-12p35. Significant correlations were observed between IL-12p70 levels and the duration of the disease, as well as between IL-12 and the effectiveness of H1-antihistamines. CONCLUSIONS: The molecular background for the pleiotropic activities mediated by IL-12-derived cytokines in patients with CSU lies in the strict regulation of the production, signalling pathways, and cytokine-specific influences on the same pathophysiological events. The results of the present study suggest that the superficial layers of the skin serve as a cellular source of IL-12, a cytokine produced through antigenic stimulation. In patients with CSU, we identified independent, additive, or divergent functions of IL-12p70, IL-12p35, and IL-12p40, all relevant to systemic inflammation. These findings prove that the prototype programming of IL-12 is abnormal in CSU.

Study on the correlation between IL-12p70, IL-17A and migraine in children.

Objective: To compare the serum levels of 12 cytokines in migraine group, encephalitis with headache symptoms group, pneumonia without headache symptoms group and migraine subgroups to explore the cytokines associated with migraine in children and their levels. Methods: A total of 44 children with migraine, 27 children in the encephalitis group with headache symptoms and 44 children in the pneumonia group without headache symptoms were selected from January 2022 to August 2023 in Hebei Children's Hospital. They were all tested for serum cytokines by immunofluorescence assay. The migraine group was further divided into subgroups according to different age, gender, course of disease, and presence of coinfection. The differences of serum cytokine levels among the above groups were compared, and the correlation analysis was carried out. Results: Except IL-5, there were no significant differences in the expression levels of other 11 inflammatory cytokines between migraine subgroups. Compared with encephalitis with headache symptoms group and pneumonia without headache symptoms group the serum levels of IL-4, TNF-α, IL-17A, and IL-12p70 were higher in migraine group than in pneumonia group, and the levels of IL-12p70 were higher than those in encephalitis group (p < 0.05). An increase in serum IL-12p70 (OR = 1.267, 95%CI 1.054-1.523, p = 0.012) and IL-17A (OR = 1.066, 95%CI 1.016-1.119, p = 0.010) levels had a significant effect on migraine. Conclusion: Elevated serum levels of IL-12p70 and IL-17A may increase the risk of migraine in children, which has certain diagnostic and predictive value.

Early IFNß secretion determines variable downstream IL-12p70 responses upon TLR4 activation.

The interleukin-12 (IL-12) family comprises the only heterodimeric cytokines mediating diverse functional effects. We previously reported a striking bimodal IL-12p70 response to lipopolysaccharide (LPS) stimulation in healthy donors. Herein, we demonstrate that interferon ß (IFNß) is a major upstream determinant of IL-12p70 production, which is also associated with numbers and activation of circulating monocytes. Integrative modeling of proteomic, genetic, epigenomic, and cellular data confirms IFNß as key for LPS-induced IL-12p70 and allowed us to compare the relative effects of each of these parameters on variable cytokine responses. Clinical relevance of our findings is supported by reduced IFNß-IL-12p70 responses in patients hospitalized with acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or chronically infected with hepatitis C (HCV). Importantly, these responses are resolved after viral clearance. Our systems immunology approach defines a better understanding of IL-12p70 and IFNß in healthy and infected persons, providing insights into how common genetic and epigenetic variation may impact immune responses to bacterial infection.

Correlation between Cerebrospinal Fluid IL-12 Levels and Severity of Encephalopathy in Children.

The roles of cytokines in the cerebrospinal fluid (CSF) of patients with acute encephalopathy remain unclear and controversial. In this study, the profiles of 26 cytokines and others were determined in 17 children with infection-associated neurological complications. Interleukin (IL)-12 levels were found to be high in a few of the patients. A comparison of the IL-12 levels in the CSF of patients demonstrated that IL-12 (p70) is almost always increased in those with encephalopathy. Levels of IL-12 in the CSF were highly correlated with the levels of PDGF-bb and IL-RA. IL-12 levels were found to be weakly correlated with IFN-γ levels, and strongly correlated with VEGF levels. These results demonstrate that IL-12 levels may affect the clinical symptoms of pediatric patients with encephalopathy.

The secretion of cytokines by peripheral blood mononuclear cells of patients with periodontitis and healthy controls when exposed to H2S.

Background: Hydrogen sulfide(H2S) is a bacterial metabolite produced as a result of bacterial growth in subgingival pockets, suggested to partake in the pathogenesis of periodontitis. H2S has previously been shown to induce the secretion of the pro-inflammatory cytokines IL-1ß and IL-18 via the NLRP3 inflammasome in monocytes. Objective: To investigate the non-NLRP3 inflammasome-dependent immunological response of human peripheral blood mononuclear cells (PBMCs) of periodontitis patients and healthy controls exposed to H2S in vitro. Methods: PBMCs of periodontitis patients(N = 31) and healthy controls(N = 32) were exposed to 1 mM sodium hydrosulfide (NaHS) at 37°C for 24 h and the secretion of cytokines was compared to resting cells. TNF-α, IFN-γ, IL-6, IL-8, IL-12p40, IL-12p70, IL-17, MCP-1, and IL-1Ra secretions were measured with Bio-Plex Pro™ Human Cytokine Assay. Results: H2S triggered the secretion of the pro-inflammatory IFN-γ, IL-6, IL-17, TNF-α, IL-12p40, and IL-12p70, while the reverse was seen for IL-1Ra. In addition, a higher basal secretion of IFN-γ, IL-6, IL-12p70, IL-17 and MCP-1 was seen from PBMCs of periodontitis patients compared to healthy controls. Conclusion: The bacterial metabolite H2S triggers the secretion of pro-inflammatory cytokines from PBMCs and may thus have a prominent role in the host-bacteria interplay in periodontitis.

Clinical Response and Changes of Cytokines and Zonulin Levels in Patients with Diarrhoea-Predominant Irritable Bowel Syndrome Treated with Bifidobacterium Longum ES1 for 8 or 12 Weeks: A Preliminary Report.

Bifidobacterium longum (B. longum) ES1 is a probiotic strain capable of modulating microbiome composition, anti-inflammatory activity and intestinal barrier function. We investigated the use of B. Longum ES1 in the treatment of patients with diarrhoea-predominant irritable bowel syndrome (IBS-D). Sixteen patients were treated for 8 or 12 weeks with B. Longum ES1 (1 × 109 CFU/day). Serum zonulin and cytokines were measured at baseline (T0) and at the end of therapy (T1). Clinical response to therapy was assessed by IBS Severity Scoring System. Interleukin (IL)-6, IL-8, IL-12p70 and tumor necrosis factor (TNF) α levels decreased from T0 to T1, irrespective of treatment duration (p < 0.05), while zonulin levels diminished only in patients treated for 12 weeks (p = 0.036). Clinical response was observed in 5/16 patients (31%): 4/8 (50%) treated for 12 weeks and 1/8 (13%) treated for 8 weeks. Abdominal pain improved only in patients treated for 12 weeks (5/8 vs. 0/8, p = 0.025), while stool consistency improved regardless of therapy duration (p < 0.001). In conclusion, the results of this pilot study showed, in IBS-D patients treated for 12 weeks with B. longum ES1, a reduction in the levels of pro-inflammatory cytokines, and intestinal permeability as well as an improvement in gastrointestinal symptoms, but further studies including a placebo-control group are necessary to prove a causal link.

Enhanced Human T Lymphocyte Antigen Priming by Cytokine-Matured Dendritic Cells Overexpressing Bcl-2 and IL-12.

Dendritic cell (DC)-based vaccination is a promising immunotherapeutic strategy for cancer. However, clinical trials have shown only limited efficacy, suggesting the need to optimize protocols for human DC vaccine preparation. In this study, we systemically compared five different human DC vaccine maturation protocols used in clinical trials: (1) a four-cytokine cocktail (TNF-α, IL-6, IL-1ß, and PGE2); (2) an α-DC-cytokine cocktail (TNF-α, IL-1ß, IFN-α, IFN-γ, and poly I:C); (3) lipopolysaccharide (LPS)/IFN-γ; (4) TNF-α and PGE2; and (5) TriMix (mRNAs encoding CD40L, CD70, and constitutively active Toll-like receptor 4 electroporated into immature DCs). We found that the four-cytokine cocktail induced high levels of costimulatory and HLA molecules, as well as CCR7, in DCs. Mature DCs (mDCs) matured with the four-cytokine cocktail had higher viability than those obtained with the other protocols. Based on these features, we chose the four-cytokine cocktail protocol to further improve the immunizing capability of DCs by introducing exogenous genes. We showed that introducing exogenous Bcl-2 increased DC survival. Furthermore, introducing IL-12p70 rescued the inhibition of IL-12 secretion by PGE2 without impairing the DC phenotype. Introducing both Bcl-2 and IL-12p70 mRNAs into DCs induced enhanced cytomegalovirus pp65-specific CD8+ T cells secreting IFN-γ and TNF-α. Taken together, our data suggest that DC matured by the four-cytokine cocktail combined with exogenous Bcl-2 and IL-12p70 gene expression represents a promising approach for clinical applications in cancer immunotherapy.

Enteric bacteria induce IFNγ and Granzyme B from human colonic Group 1 Innate Lymphoid Cells.

Group 1 Innate Lymphoid Cells (which include Natural Killer cells and ILC1s) aid in gut anti-bacterial defense through the production of IFNγ, which is critical for mobilizing protective responses against enteric pathogens. When intestinal epithelial barrier integrity is compromised, commensal bacteria are likely to translocate from the gut lumen into the lamina propria. Few studies have addressed the mechanisms by which commensal bacteria impact the function of gut Group 1 ILCs, especially ILC1s. Utilizing an in vitro human colonic lamina propria mononuclear cell (LPMC) model, we evaluated Group 1 ILC cytokine and cytolytic protein production in response to a panel of enteric Gram-positive and Gram-negative commensal and pathogenic bacteria. IFNγ-production by NK cells and ILC1s was significantly increased after LPMC exposure to Gram-negative commensal or pathogenic bacteria, but not after exposure to the Gram-positive bacteria commensals tested. Stimulation of IFNγ production from Group 1 ILCs was not through direct recognition of bacteria by NK cells or ILC1s, but rather required accessory cells within the LPMC population. Myeloid dendritic cells generated IL-12p70, IL-18, and IL-1ß upon exposure to enteric bacteria and these cytokines contributed to Group 1 ILC production of IFNγ. Furthermore, Gram-negative commensal or pathogenic bacteria induced significant expression of Granzyme B in NK cells and ILC1s. Overall, these data demonstrate that some enteric commensal bacteria indirectly induce inflammatory cytokine production and cytolytic protein expression from human colonic Group 1 ILCs, a process which could contribute to inflammation in the setting of microbial translocation.

Increased platelet distribution width and reduced IL-2 and IL-12 are associated with thrombocytopenia in Plasmodium vivax malaria

BACKGROUND Thrombocytopenia in malaria involves platelet destruction and consumption; however, the cellular response underlying this phenomenon has still not been elucidated. OBJECTIVE To find associations between platelet indices and unbalanced Th1/Th2/Th17 cytokines as a response to thrombocytopenia in Plasmodium vivax infected (Pv-MAL) patients. METHODS Platelet counts and quantification of Th1/Th2/Th17 cytokine levels were compared in 77 patients with uncomplicated P. vivax malaria and 37 healthy donors from the same area (endemic control group - ENCG). FINDINGS Thrombocytopenia was the main manifestation in 55 patients, but was not associated with parasitaemia. The Pv-MAL patients showed increases in the mean platelet volume (MPV), which may be consistent with larger or megaplatelets. Contrary to the findings regarding the endemic control group, MPV and platelet distribution width (PDW) did not show an inverse correlation, due the increase in the heterogeneity of platelet width. In addition, the Pv-MAL patients presented increased IL-1β and reduced IL-12p70 and IL-2 serum concentrations. Furthermore, the reduction of these cytokines was associated with PDW values. MAIN CONCLUSIONS Our data demonstrate that an increase in MPV and the association between reductions of IL-2 and IL-12 and PDW values may be an immune response to thrombocytopenia in uncomplicated P. vivax malaria.

Long-Term Exposure to Inflammation Induces Differential Cytokine Patterns and Apoptosis in Dendritic Cells.

The activation of dendritic cells (DCs) has profound implications and governs the control of adaptive immunity. However, long-term activation might drive exhaustion of immune cells and negatively affect functionality. Here, long-term vs. short-term exposure to bacterial lipopolysaccharide and interferon (IFN)γ was evaluated on human monocyte-derived DCs. Long-term activated DC1s began to undergo apoptosis concomitant with a profound TAM-receptor and efferocytosis-dependent induction of interleukin (IL)-10. Whereas, levels of IL-12p70 and IL-10 were positively correlated upon short-term activation, an inverse association occured upon long-term activation and, while short-term activated CD1a+ DCs were main producers of IL-12p70, CD1a- DCs were the main fraction that underwent apoptosis and released IL-10 upon long-term activation. Moreover, pre-apoptotic long-term activated DCs were no longer able to activate alloreactive IFNγ-responsive T cells present in peripheral blood mononuclear cells from healthy volunteers. The IFNγ response was mediated by IL-12p70, as a strong reduction in IFNγ was observed following blockade with an IL-12p70 neutralizing antibody. Finally, multiplex analysis of DC supernatants revealed a particular pattern of proteins associated with apoptosis, cancer and chronic inflammation partly overlapping with gold standard DCs well-known for their inability to secrete IL-12p70. In conclusion, long-term activated DC1s significantly changed their profile toward a non-functional, tumor-promoting and anti-inflammatory phenotype.

The Level of Cytokines in the Vitreous Body of Severe Proliferative Diabetic Retinopathy Patients Undergoing Posterior Vitrectomy.

OBJECTIVE: The objective of the study was to compare cytokine levels in the vitreous body of patients with proliferative diabetic retinopathy (PDR) undergoing posterior vitrectomy. PATIENTS AND METHODS: The study included 39 patients (39 eyes) undergoing pars plana vitrectomy (PPV). Patients were divided into three groups: patients with proliferative diabetic retinopathy (PDR) without aflibercept injection prior to the surgery, PDR patients administered aflibercept injection prior to the surgery, and patients without diabetes mellitus (control group). All patients underwent a comprehensive eye examination one day before and 3 weeks after the surgery, including measurements of: best-corrected visual acuity (BVCA) and intraocular pressure (IOP), slit-lamp examination and spectral domain optical coherence tomography (SOCT). Concentrations of cytokines: IL-6, IL-8, IL-12p70, TNF, IL-10, IL-1ß were measured in the vitreous body of patients with BD™ Cytometric Bead Array (CBA) Human Inflammatory Cytokines Kit. RESULTS: PDR patients who received pretreatment with aflibercept injection showed significantly lower concentrations of IL-12p70, TNF, IL-10 and IL-1ß in the vitreous body compared to the control group. Meanwhile, patients without prior aflibercept injection had a significantly higher concentration of IL-8. There was also a significant positive correlation between IOP before PPV and IL-8 concentration in both PDR patients' groups. CONCLUSION: Findings of our study suggest an important role of IL-8 in the development of severe PDR. Aflibercept administration on the day before elective vitrectomy facilitated the surgery.

Inflammation in individuals with schizophrenia - Implications for neurocognition and daily function.

Individuals with schizophrenia display substantial deficits in neurocognition, resulting in poor daily functioning and disability. Recent reports have suggested that neurocognitive dysfunction in this population is linked to increased inflammation. However, there is paucity of evidence supporting this link, as well as lack of information about the putative link of inflammation to daily functioning. We examined neurocognition (MCCB) and daily functioning (SLOF), as well as inflammatory markers (TNF-α, IL-6, IL-1ß, and IL-12p70) in 41 individuals with schizophrenia. Poor neurocognition was significantly associated with increased peripheral TNF-α and IL-12p70 (r = -0.44 and r = -0.38, respectively, controlling for BMI, depression and antipsychotic medication). Notably, difficulties with daily functioning were significantly associated with increased peripheral TNF-α (r = -0.51) and a trend with increased IL-12p70. Our findings support previous hypotheses linking neurocognitive impairment to increased inflammation in individuals with schizophrenia. Our results extend these associations in this population, linking inflammation to poor daily functioning in this population.

Optimization and qualification of the single molecule array digital immunoassay for IL-12p70 in plasma of cancer patients.

AIM: Cytokine/chemokine levels can reflect the pharmacodynamics of checkpoint inhibitors. The single molecule array (Simoa) HD-1 is a sensitive next-generation immunoassay platform for quantification of low abundance proteins, with potential for cancer immunotherapy mechanism of action studies. RESULTS: The Simoa IL-12p70 reagents, standard curve and test conditions were optimized for improved precision and linearity of dilution in plasma of cancer patients. The assay achieved a lower limit of quantification of 0.08 pg/ml, with 27/29 samples recording above lower limit of quantification, precision ≤20% CV and accuracy within 80-120%. CONCLUSION: Simoa enabled quantification of IL-12p70 at sub-pg/ml levels in cancer patients and was superior to Simple Plex™ and Aushon® in overall performance. This study qualifies the user-modified IL-12p70 immunoassay to measure pharmacodynamic changes in plasma during cancer immunotherapy.

Wound healing and anti-inflammatory activities induced by a Plantago australis hydroethanolic extract standardized in verbascoside.

ETHNOPHARMACOLOGICAL RELEVANCE: Plantago australis is a popular plant found to be widely spread in Latin America. In folk medicine, the seeds and leaves are used mainly for anti-inflammatory, wound healing, among others. The verbascoside, a phenolic glycoside, is an active chemical component described in this species of plant, which has antioxidant, anti-inflammatory and healing effects. PURPOSE: The aim of the present study was to evaluate whether P. australis hydroethanolic extract (PAHE) standardized in verbascoside could promote wound healing associated with anti-inflammatory action within both in vitro and in vivo models. METHODS: For the wound healing activity, we used a Scratch Test, an assay capable of evaluating the migratory ability of keratinocyte cells (HaCat) in vitro and thereby confirming the activity in rats. For the anti-inflammatory activity, the inflammation was induced with LPS in microglial murine cells (N9). Inflammatory mediators (IL-6, IL-10, IL-12p70, INFγ, MCP-1 and TNFα) were measured and the activity of superoxide dismutase (SOD), catalase (CAT), and mitochondrial membrane potential were evaluated. In addition, using paw edema induced by carrageenan in rats, the anti-inflammatory activity in vivo was analyzed. RESULTS: The PAHE and verbascoside, induced a significant increase in migration of keratinocytes, at all concentrations tested when compared to the negative control. The wound healing activity in vivo showed that the PAHE accelerated the process. The treatments with PAHE and verbascoside induce increases in the antioxidants enzymes, suggesting a possible activation of these enzymes. However, this did not result in an increase in the expression of inflammatory mediators in microglial cells. In LPS activated cells the verbascoside displayed a significant reduction of TNFα, IL-6, IL-12p70, MCP-1 and INFγ, while the PAHE only displayed statistically significant reduction in TNFα. Interestingly, both the compounds could reduce the oxidative parameters in N9 cells activated by LPS. Additionally, pretreatment with PAHE inhibited the paw edema in rats. CONCLUSION: The results suggest that PAHE has wound healing activity, improving cells migration and, as well as was able to reverse the oxidation effect in LPS-activated N9 cells. The wound-healing and anti-inflammatory activities of PAHE were confirmed in vivo. In addition, the presence of verbascoside can be related to PAHE effects, since this compound was capable of increase keratinocytes migration and inhibiting inflammation mediators.

Signaling Lymphocyte Activation Molecule Family 5 Enhances Autophagy and Fine-Tunes Cytokine Response in Monocyte-Derived Dendritic Cells via Stabilization of Interferon Regulatory Factor 8.

Signaling lymphocyte activation molecule family (SLAMF) receptors are essential regulators of innate and adaptive immune responses. The function of SLAMF5/CD84, a family member with almost ubiquitous expression within the hematopoietic lineage is poorly defined. In this article, we provide evidence that in human monocyte-derived dendritic cells (moDCs) SLAMF5 increases autophagy, a degradative pathway, which is highly active in dendritic cells (DCs) and plays a critical role in orchestration of the immune response. While investigating the underlying mechanism, we found that SLAMF5 inhibited proteolytic degradation of interferon regulatory factor 8 (IRF8) a master regulator of the autophagy process by a mechanism dependent on the E3-ubiquitin ligase tripartite motif-containing protein 21 (TRIM21). Furthermore, we demonstrate that SLAMF5 influences the ratio of CD1a+ cells in differentiating DCs and partakes in the regulation of IL-1ß, IL-23, and IL-12 production in LPS/IFNγ-activated moDCs in a manner that is consistent with its effect on IRF8 stability. In summary, our experiments identified SLAMF5 as a novel cell surface receptor modulator of autophagy and revealed an unexpected link between the SLAMF and IRF8 signaling pathways, both implicated in multiple human pathologies.

Leishmania amazonensis-Induced cAMP Triggered by Adenosine A2B Receptor Is Important to Inhibit Dendritic Cell Activation and Evade Immune Response in Infected Mice.

Differently from others Leishmania species, infection by the protozoan parasite L. amazonensis is associated with a lack of antigen-specific T-cell responses. Dendritic cells (DC) are essential for the innate immune response and for directing the differentiation of T-helper lymphocytes. Previously, we showed that L. amazonensis infection impairs DC activation through the activation of adenosine A2B receptor, and here, we evaluated the intracellular events triggered by this receptor in infected cells. To this aim, bone marrow-derived DC from C57BL/6J mice were infected with metacyclic promastigotes of L. amazonensis. Our results show, for the first time, that L. amazonensis increases the production of cAMP and the phosphorylation of extracellular signal-regulated protein kinases 1/2 (ERK1/2) in infected DC by a mechanism dependent on the A2B receptor. Furthermore, L. amazonensis impairs CD40 expression and IL-12 production by DC, and the inhibition of adenylate cyclase, phosphoinositide 3-kinase (PI3K), and ERK1/2 prevent these effects. The increase of ERK1/2 phosphorylation and the inhibition of DC activation by L. amazonensis are independent of protein kinase A (PKA). In addition, C57BL/6J mice were inoculated in the ears with metacyclic promastigotes, in the presence of PSB1115, an A2B receptor antagonist. PSB1115 treatment increases the percentage of CD40+ DC on ears and draining lymph nodes. Furthermore, this treatment reduces lesion size and tissue parasitism. Lymph node cells from treated mice produce higher levels of IFN-γ than control mice, without altering the production of IL-10. In conclusion, we suggest a new pathway used by the parasite (A2B receptor → cAMP → PI3K → ERK1/2) to suppress DC activation, which may contribute to the decrease of IFN-γ production following by the deficiency in immune response characteristic of L. amazonensis infection.

Folate deficiency affects dendritic cell function and subsequent T helper cell differentiation.

Insufficient folate status may be related to the increasing prevalence of immune- or inflammation-related chronic diseases. To investigate the effects of folate on immune regulation, we examined the impact of folate deficiency (FD) on dendritic cell (DC) maturation and function and, thus, T helper (Th) cells differentiation. First, bone marrow-derived DCs (BMDCs) were generated from BALB/c mice bone marrow cells cultured in folate-containing (F-BMDCs) or folate-deficient (FD-BMDCs) medium. FD-BMDC displayed more immature phenotype including reduced levels of major histocompatibility complex class II (MHC II), co-stimulatory molecules and characteristic of higher endocytic activity. FD-BMDC produced less IL-12p70 and proinflammatory cytokines in response to lipopolysaccharide. This aberrant DC maturation due to FD resulted in reduced BMDC-induced Th cell activity and lower IL-2, IFNγ, IL-13 and IL-10 productions. Further in vivo study confirmed significantly lower IFNγ and IL-10 productions by T cells and showed higher splenic naïve Th and lower memory T, effector T and regulatory T cell (Treg) percentages in mice fed with the FD diet for 13 weeks. To investigate the role of DCs on T cell activity, splenic DCs (spDC) from FD mice were cocultured with Th cells. The FD spDC had lower MHC II and CD80 expressions and subsequently impaired DC-induced Th differentiation, shown as decreased cytokine productions. This study demonstrated that folate deficiency impaired DC functions and, thus, Th differentiation and responses, suggesting that folate plays a crucial role in maintaining Th cells homeostasis.

Infants with low vaccine antibody responses have altered innate cytokine response.

We recently identified a population of 10% of infants who respond with sub-protective antibody levels to most routine primary pediatric vaccinations due to altered innate and adaptive immune responses. We term these infants as low vaccine responders (LVRs). Here we report new data showing that TLR7/8 agonist - R848 stimulation of PBMCs of LVR infants elicit significantly lower IFN-α, IL-12p70 and IL-1ß, while inducing higher levels of CCL5 (RANTES) compared to normal vaccine responder (NVR) infants.