Patterns of mucosal inflammation in pediatric inflammatory bowel disease: striking overexpression of IL-17A in children with ulcerative colitis.

BACKGROUND: Aberrant immune responses play a key role in the pathogenesis of inflammatory bowel disease (IBD). Most studies conducted to delineate the underlying molecular mechanisms focus on adults; an understanding of these mechanisms in children remains to be determined. Here, cytokines and transcription factors produced by immune cells within the intestinal mucosa of pediatric patients stricken with ulcerative colitis (UC) and Crohn's disease (CD) are characterized; potential diagnostic and therapeutic targets are identified. METHODS: Fifty-two pediatric IBD and non-IBD patients were enrolled in the study. Specimens were taken during ileocolonoscopy. Expression of 16 genes that encode cytokines or transcription molecules was determined by quantitative polymerase chain reaction. Clinical data were collected via retrospective chart review. RESULTS: Overexpression of interleukin-17A (IL-17A) was evident in children with UC compared to both non-IBD and CD patients. IL-22 was strongly increased in UC patients only. Typical proinflammatory and immunoregulatory cytokines were pronounced in IBD patients, although to a lower extent in the latter case. Clustered gene expression enabled differentiation between UC and non-IBD patients. CONCLUSION: Our findings highlight the crucial involvement of IL-17A immunity in the early course of IBD, particularly UC, and the potential value of gene panels in diagnosing pediatric IBD.

Gut microbiota differs between children with Inflammatory Bowel Disease and healthy siblings in taxonomic and functional composition: a metagenomic analysis.

Current treatment for pediatric inflammatory bowel disease (IBD) patients is often ineffective, with serious side effects. Manipulating the gut microbiota via fecal microbiota transplantation (FMT) is an emerging treatment approach but remains controversial. We aimed to assess the composition of the fecal microbiome through a comparison of pediatric IBD patients to their healthy siblings, evaluating risks and prospects for FMT in this setting. A case-control (sibling) study was conducted analyzing fecal samples of six children with Crohn's disease (CD), six children with ulcerative colitis (UC) and 12 healthy siblings by metagenomic sequencing. In addition, lifetime antibiotic intake was retrospectively determined. Species richness and diversity were significantly reduced in UC patients compared with control [Mann-Whitney U-test false discovery rate (MWU FDR) = 0.011]. In UC, bacteria positively influencing gut homeostasis, e.g., Eubacterium rectale and Faecalibacterium prausnitzii, were significantly reduced in abundance (MWU FDR = 0.05). Known pathobionts like Escherichia coli were enriched in UC patients (MWU FDR = 0.084). Moreover, E. coli abundance correlated positively with that of several virulence genes (SCC > 0.65, FDR < 0.1). A shift toward antibiotic-resistant taxa in both IBD groups distinguished them from controls [MWU Benjamini-Hochberg-Yekutieli procedure (BY) FDR = 0.062 in UC, MWU BY FDR = 0.019 in CD). The collected results confirm a microbial dysbiosis in pediatric UC, and to a lesser extent in CD patients, replicating associations found previously using different methods. Taken together, these observations suggest microbiotal remodeling therapy from family donors, at least for children with UC, as a viable option.NEW & NOTEWORTHY In this sibling study, prior reports of microbial dysbiosis in IBD patients from 16S rRNA sequencing was verified using deep shotgun sequencing and augmented with insights into the abundance of bacterial virulence genes and bacterial antibiotic resistance determinants, seen against the background of data on the specific antibiotic intake of each of the study participants. The observed dysbiosis, which distinguishes patients from siblings, highlights such siblings as potential donors for microbiotal remodeling therapy in IBD.

Inflammatory Characteristics of Monocytes from Pediatric Patients with Tuberous Sclerosis.

OBJECTIVE: Therapeutic options for the tuberous sclerosis complex (TSC) syndrome showed varying outcomes. Malfunctional tsc1/tsc2 genes leave mTOR uninhibited, a positive downstream modulator of the innate proinflammatory immune system, which has not yet been described in pediatric patients with TSC. METHODS: Using polymerase chain reaction (PCR) gene expression levels of monocytes after cultivation with lipopolysaccharide (LPS) or with LPS + mTOR inhibitor rapamycin, patients with TSC (n = 16) were compared with healthy subjects (n = 20). RESULTS: Compared with monocytes from healthy controls, LPS showed a more prominent gene expression pattern in patients with TSC (CCL24, CXCL10, IL-6, IL-10, and IL-1B). Proinflammatory reactions against LPS were modulated by rapamycin. With LPS + rapamycin monocytes from patients with TSC showed gene expression patterns different from healthy subjects. Furthermore, developmental differences were discernible in patients with TSC, compared with gene expression levels for patients 0 to 5 years to those 6 to 11 years of age, the latter with marked expression of IL-6 IL-1A, IL-1B, RIPK2, but also IL-10. CONCLUSION: The effects of LPS, even more of LPS with rapamycin on monocytes from patients with TSC suggested that inflammatory processes are distinct from those in healthy subjects. Furthermore, reaction to rapamycin indicates age-related gene expression levels. Our findings offer a model to decipher the unknown and varying gene expression pattern induced by rapamycin.

Effects of pathogen reduction systems on platelet microRNAs, mRNAs, activation, and function.

Pathogen reduction (PR) systems for platelets, based on chemically induced cross-linking and inactivation of nucleic acids, potentially prevent transfusion transmission of infectious agents, but can increase clinically significant bleeding in some clinical studies. Here, we documented the effects of PR systems on microRNA and mRNA levels of platelets stored in the blood bank, and assessed their impact on platelet activation and function. Unlike platelets subjected to gamma irradiation or stored in additive solution, platelets treated with Intercept (amotosalen+ ultraviolet-A [UVA] light) exhibited significantly reduced levels of 6 of the 11 microRNAs, and 2 of the 3 anti-apoptotic mRNAs (Bcl-xl and Clusterin) that we monitored, compared with platelets stored in plasma. Mirasol (riboflavin+ UVB light) treatment of platelets did not produce these effects. PR neither affected platelet microRNA synthesis or function nor induced cross-linking of microRNA-sized endogenous platelet RNA species. However, the reduction in the platelet microRNA levels induced by Intercept correlated with the platelet activation (p < 0.05) and an impaired platelet aggregation response to ADP (p < 0.05). These results suggest that Intercept treatment may induce platelet activation, resulting in the release of microRNAs and mRNAs from platelets. The clinical implications of this reduction in platelet nucleic acids secondary to Intercept remain to be established.

In the presence of IL-21 human cord blood T cells differentiate to IL-10-producing Th1 but not Th17 or Th2 cells.

IL-21, a member of the IL-2 cytokine family, is mainly produced by activated CD4(+) T cells and controls the activity of immune and also non-immune cells. As a pleiotropic cytokine, IL-21 acts on both innate and adaptive immune responses, suggesting that IL-21 may be a master regulator of the T-cell-dependent adaptive immune response. Although IL-21 is described as mostly promoting inflammation, evidence also suggests inhibitory effects of IL-21. However, its role, particularly in the human neonatal immune system, has not been detailed so far. Here, we assessed the effect of IL-21 in the specific context of the neonatal immune response and delineated differences between the human newborn and adult immune response. In umbilical cord blood, we demonstrated that IL-21 polarized naive CD4(+) T cells into T(h)1 cells, producing IL-10, a key negative regulator during certain infections and autoimmunity. Furthermore, IL-21 stimulation increased IFNγ secretion and inhibited the development of T(h)2 and T(h)17 cells and molecules associated with their function. Thus, in neonates, known to show limitations in establishing T(h)1 responses, IL-21 played a clear role in supporting T(h)1 responses in vitro, while appearing irrelevant for the adult immune response. Overall, we demonstrated the capability of IL-21 to induce the immunosuppressive cytokine IL-10 and outlined its potential to compensate the restricted T(h)1 response in human newborns and consequently to reduce the susceptibility for infectious diseases in the first period of life.

Enhanced in vivo targeting of murine nonparenchymal liver cells with monophosphoryl lipid A functionalized microcapsules.

A broad spectrum of infectious liver diseases emphasizes the need of microparticles for targeted delivery of immunomodulatory substances to the liver. Microcapsules (MCs) are particularly attractive for innovative drug and vaccine formulations, enabling the combination of antigen, drugs, and adjuvants. The present study aimed to develop microcapsules characterized by an enhanced liver deposition and accelerated uptake by nonparenchymal liver cells (NPCs). Initially, two formulations of biodegradable microcapsules were synthesized from either hydroxyethyl starch (HES) or mannose. Notably, HES-MCs accumulated primarily in the liver, while mannose particles displayed a lung preference. Functionalization of HES-MCs with anti-CD40, anti-DEC205, and/or monophosphoryl lipid A (MPLA) enhanced uptake of MCs by nonparenchymal liver cells in vitro. In contrast, only MPLA-coated HES-MCs promoted significantly the in vivo uptake by NPCs. Finally, HES-MCs equipped with MPLA, anti-CD40, and anti-DEC205 induced the secretion of TNF-α, IL-6 by Kupffer cells (KCs), and IFN-γ and IL-12p70 by liver dendritic cells (DCs). The enhanced uptake and activation of KCs by MPLA-HES-MCs is a promising approach to prevent or treat infection, since KCs are exploited as an entry gate in various infectious diseases, such as malaria. In parallel, loading and activating liver DCs, usually prone to tolerance, bears the potential to induce antigen specific, intrahepatic immune responses necessary to prevent and treat infections affecting the liver.

Bifidobacterium and Lactobacillus Probiotics and Gut Dysbiosis in Preterm Infants: The PRIMAL Randomized Clinical Trial.

Importance: The effects of probiotic interventions on colonization with resistant bacteria and early microbiome development in preterm infants remain to be clarified. Objective: To examine the efficacy of Bifidobacterium longum subsp infantis, Bifidobacterium animalis subsp lactis (BB-12), and Lactobacillus acidophilus (La-5) probiotics to prevent colonization with multidrug-resistant organisms or highly epidemic bacteria (MDRO+) and to shape the microbiome of preterm infants toward the eubiotic state of healthy full-term infants. Design, Setting, and Participants: The multicenter, double-blinded, placebo-controlled, group sequential, phase 3 Priming Immunity at the Beginning of Life (PRIMAL) randomized clinical trial, conducted from April 2018 to June 2020, included infants with gestational age of 28 to 32 weeks at 18 German neonatal units. Data analyses were conducted from March 2020 to August 2023. Intervention: A total of 28 days of multistrain probiotics diluted in human milk/formula starting within the first 72 hours of life. Main Outcomes and Measures: Colonization with MDRO+ at day 30 of life (primary end point), late-onset sepsis and severe gastrointestinal complication (safety end points), and gut dysbiosis, ie, deviations from the microbiome of healthy, term infants (eubiosis score) based on 16-subunit ribosomal RNA and metagenomic sequencing. Results: Among the 643 infants randomized until the stop of recruitment based on interim results, 618 (median [IQR] gestational age, 31.0 [29.7-32.1] weeks; 333 male [53.9%]; mean [SD] birth weight, 1502 [369] g) had follow-up at day 30. The interim analysis with all available data from 219 infants revealed MDRO+ colonization in 43 of 115 infants (37.4%) in the probiotics group and in 39 of 104 infants (37.5%) in the control group (adjusted risk ratio, 0.99; 95% CI, 0.54-1.81; P = .97). Safety outcomes were similar in both groups, ie, late-onset sepsis (probiotics group: 8 of 316 infants [2.5%]; control group: 12 of 322 infants [3.7%]) and severe gastrointestinal complications (probiotics group: 6 of 316 infants [1.9%]; control group: 7 of 322 infants [2.2%]). The probiotics group had higher eubiosis scores than the control group at the genus level (254 vs 258 infants; median scores, 0.47 vs 0.41; odds ratio [OR], 1.07; 95% CI, 1.02-1.13) and species level (96 vs 83 infants; median scores, 0.87 vs 0.59; OR, 1.28; 95% CI, 1.19-1.38). Environmental uptake of the B infantis probiotic strain in the control group was common (41 of 84 [49%]), which was highly variable across sites and particularly occurred in infants with a sibling who was treated with probiotics. Conclusions and Relevance: Multistrain probiotics did not reduce the incidence of MDRO+ colonization at day 30 of life in preterm infants but modulated their microbiome toward eubiosis. Trial Registration: German Clinical Trials Register: DRKS00013197.

Principles in Immunology for the Design and Development of Vaccines.

Vaccinology has come a long way from early, empirically developed vaccines to modern vaccines rationally designed and produced. Vaccines are meant to cooperate with the human immune system, the later largely unknown in the early years of vaccine development. In the recent years, a tremendous depth of knowledge has been accumulated in the field of immunology that has provided an opportunity to understand the mechanisms of action of the vaccine components. In parallel, our knowledge in microbiology, molecular biology, infectiology, epidemiology, and furthermore in bioinformatics has fostered our understanding of the interaction of microorganisms with the human immune system. Strategies engaged by pathogens strongly determine the targets of a vaccine, which should be formulated to stimulate potent and efficiently protective immune responses. The improved knowledge of immune response mechanisms has facilitated the development of new vaccines with the capacity to selectively address the key pathogenic mechanisms. The primary goal of a vaccine design might no longer be to mimic the pathogen but to identify the relevant processes of the pathogenic mechanisms to be effectively interrupted by a highly specific immune response, eventually surpassing natural limitations. Vaccines have become complex sets of components meant to orchestrate the fine-tuning of the immune processes leading to a lasting and specific immune memory. In addition to antigenic materials, which are comprised of the most critical immunogenic epitopes, adjuvant components are frequently added to induce a favorable immunological activation. Furthermore, for reasons of production and product stability preservatives, stabilizers, inactivators, antibiotics, or diluents could be present, but need to be evaluated. While on the one hand vaccine effectiveness is a primary goal, on the other hand side effects need to be excluded due to safety and tolerability. Further challenges in vaccinology include variability of the vaccinees, the variability of the pathogen, the population-based settings of vaccine application, and the process technology in vaccine production. Vaccine design has become more tailored and in turn has opened up the potential of extending its application to hitherto not accessible complex microbial pathogens plus providing new immunotherapies to tackle diseases such as cancer, Alzheimer's disease, and autoimmune disease. This chapter gives an overview of the key considerations and processes involved in vaccine design and development. It also describes the basic principles of normal immune responses and in their function in defense of infectious agents by vaccination.

Long-Term, CD4+ Memory T Cell Response to SARS-CoV-2.

The first cases of coronavirus disease-19 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were reported by Chinese authorities at the end of 2019. The disease spread quickly and was declared a global pandemic shortly thereafter. To respond effectively to infection and prevent viral spread, it is important to delineate the factors that affect protective immunity. Herein, a cohort of convalescent healthcare workers was recruited and their immune responses were studied over a period of 3 to 9 months following the onset of symptoms. A cross-reactive T cell response to SARS-CoV-2 and endemic coronaviruses, i.e., OC43 and NL63, was demonstrated in the infected, convalescent cohort, as well as a cohort composed of unexposed individuals. The convalescent cohort, however, displayed an increased number of SARS-CoV-2-specific CD4+ T cells relative to the unexposed group. Moreover, unlike humoral immunity and quickly decreasing antibody titers, T cell immunity in convalescent individuals was maintained and stable throughout the study period. This study also suggests that, based on the higher CD4 T cell memory response against nucleocapsid antigen, future vaccine designs may include nucleocapsid as an additional antigen along with the spike protein.

Meconium Microbiome of Very Preterm Infants across Germany.

Meconium constitutes infants' first bowel movements postnatally. The consistency and microbial load of meconium are different from infant and adult stool. While recent evidence suggests that meconium is sterile in utero, rapid colonization occurs after birth. The meconium microbiome has been associated with negative health outcomes, but its composition is not well described, especially in preterm infants. Here, we characterized the meconium microbiomes from 330 very preterm infants (gestational ages 28 to 32 weeks) from 15 hospitals in Germany and in fecal samples from a subset of their mothers (N = 217). Microbiome profiles were compiled using 16S rRNA gene sequencing with negative and positive controls. The meconium microbiome was dominated by Bifidobacterium, Staphylococcus, and Enterococcus spp. and was associated with gestational age at birth and age at sample collection. Bifidobacterial abundance was negatively correlated with potentially pathogenic genera. The amount of bacterial DNA in meconium samples varied greatly across samples and was associated with the time since birth but not with gestational age or hospital site. In samples with low bacterial load, human mitochondrial sequences were highly amplified using commonly used, bacterial-targeted 16S rRNA primers. Only half of the meconium samples contained sufficient bacterial material to study the microbiome using a standard approach. To facilitate future meconium studies, we present a five-level scoring system ("MecBac") that predicts the success of 16S rRNA bacterial sequencing for meconium samples. These findings provide a foundational characterization of an understudied portion of the human microbiome and will aid the design of future meconium microbiome studies. IMPORTANCE Meconium is present in the intestines of infants before and after birth and constitutes their first bowel movements postnatally. The consistency, composition and microbial load of meconium is largely different from infant and adult stool. While recent evidence suggests that meconium is sterile in utero, rapid colonization occurs after birth. The meconium microbiome has been associated with short-term and long-term negative health outcomes, but its composition is not yet well described, especially in preterm infants. We provide a characterization of the microbiome structure and composition of infant meconium and maternal feces from a large study cohort and propose a method to evaluate meconium samples for bacterial sequencing suitability. These findings provide a foundational characterization of an understudied portion of the human microbiome and will aid the design of future meconium microbiome studies.

Booster vaccination after neonatal priming with acellular pertussis vaccine.

After a birth dose of acellular pertussis (aP) and diphtheria (DT)aP-hepatitis B virus (HBV)-inactivated polio vaccine (IPV)/Haemophilus influenza type b (Hib) at 2, 4, and 6 months, a booster dose of DTaP-HBV-IPV/Hib at 12 to 23 months induced strong anti-pertussis booster responses. Thus, neonatal aP priming did not lead to immune tolerance to pertussis antigens. However, it elicited bystander interference on HBV, Hib, and diphtheria responses.

Safety, immunogenicity and immediate pain of intramuscular versus subcutaneous administration of a measles-mumps-rubella-varicella vaccine to children aged 11-21 months.

This study compared intramuscular and subcutaneous administration of two doses of measles-mumps-rubella-varicella (MMRV) combination vaccine (Priorix-Tetra, GlaxoSmithKline Biologicals) in children. Healthy children (N = 328) were randomised to receive MMRV either intramuscularly or subcutaneously. Reactogenicity was similar between treatment groups for immediate vaccination pain, vaccination site pain, redness and incidence of fever and rashes. Slightly less vaccination site swelling occurred during days 0-3 of the post-vaccination period after intramuscular administration. Seroconversion rates for all components, 42-56 days post-dose 2, ranged from 99.3% to 100% in the intramuscular group and from 98.6% to 100% in the subcutaneous. Cell-mediated immunity data supported the humoral immunogenicity findings. In summary, the MMRV vaccine is well tolerated and highly immunogenic when administered either subcutaneously or intramuscularly to children in the second year of life.

Efficacy of Bifidobacterium longum, B. infantis and Lactobacillus acidophilus probiotics to prevent gut dysbiosis in preterm infants of 28+0-32+6 weeks of gestation: a randomised, placebo-controlled, double-blind, multicentre trial: the PRIMAL Clinical Study protocol.

INTRODUCTION: The healthy 'eubiosis' microbiome in infancy is regarded as the microbiome derived from term, vaginally delivered, antibiotic free, breastfed infants at 4-6 months. Dysbiosis is regarded as a deviation from a healthy state with reduced microbial diversity and deficient capacity to control drug-resistant organisms. Preterm infants are highly sensitive to early gut dysbiosis. Latter has been associated with sepsis and necrotising enterocolitis, but may also contribute to long-term health problems. Probiotics hold promise to reduce the risk for adverse short-term outcomes but the evidence from clinical trials remains inconclusive and none has directly assessed the effects of probiotics on the microbiome at high resolution. METHODS AND ANALYSIS: A randomised, double blind, placebo-controlled study has been designed to assess the safety and efficacy of the probiotic mix of Bifidobacterium longum and infantis and Lactobacillus acidophilus in the prevention of gut dysbiosis in preterm infants between 28+0 and 32+6 weeks of gestation. The study is conducted in 18 German neonatal intensive care units. Between April 2018 and March 2020, 654 preterm infants of 28+0-32+6 weeks of gestation will be randomised in the first 48 hours of life to 28 days of once daily treatment with either probiotics or placebo. The efficacy endpoint is the prevention of gut dysbiosis at day 30 of life. A compound definition of gut dysbosis is used: (1) colonisation with multidrug-resistant organisms or gram-negative bacteria with high epidemic potential or (2) a significant deviation of the gut microbiota composition as compared with healthy term infants. Dysbiosis is determined by (1) conventional microbiological culture and (2) phylogenetic microbiome analysis by high-throughput 16S rRNA and metagenome sequencing. Persistence of dysbiosis will be assessed at 12-month follow-up visits. Side effects and adverse events related to the intervention will be recorded. Key secondary endpoint(s) are putative consequences of dysbiosis. A subgroup of infants will be thoroughly phenotyped for immune parameters using chipcytometry. ETHICS AND DISSEMINATION: Ethics approval was obtained in all participating sites. Results of the trial will be published in peer-review journals, at scientific meetings, on the website (www.primal-study.de) and via social media of parent organisations. TRIAL REGISTRATION NUMBER: DRKS00013197; Pre-results.

Enhanced expression of IL-27 mRNA in human newborns.

Interleukin (IL)-27, a heterodimer composed of Epstein-Barr virus-induced gene 3 (EBI3) and p28, is an early product of activated dendritic cells (DC). Binding of IL-27 to the WSX-1 receptor initiates Th1 (Thelper 1) responses in naïve T cells. In order to assess the Th1 responses in human neonates with high susceptibility to infectious diseases, expression of EBI3-, p28- and WSX-1-mRNA in response to Toll-like receptor ligands was compared in neonate and adult monocyte-derived (m)DC. Only the combined addition of ligands induced expression of IL-27p28 mRNA. Surprisingly, neonatal mDC produced significantly more IL-27p28 mRNA than that obtained from adults. Furthermore, there was enhanced expression of EBI3 mRNA in cord blood as compared with adult blood. In addition, the secretion of WSX-1 mRNA in neonatal mDC and T cells was also significantly increased. Taken together, these findings indicate that the restricted Th1 responses in human newborns owing to deficient IL-12 production may be compensated for, in part, by enhanced IL-27 secretion.

Immunogenicity and reactogenicity of acellular pertussis booster vaccines in children: standard pediatric versus a reduced-antigen content formulation.

Booster vaccination with a reduced-antigen-content dTpa, pediatric DTPa or adult Td vaccine in DTPa-primed children aged 4-6 years was evaluated. Immunogenicity and CMI was assessed one month and 3.5 years after vaccination. Symptoms were solicited for 15 days post-vaccination. There were no differences between groups in diphtheria or tetanus seroprotection or pertussis vaccine-response rates. Anti-diphtheria and anti-PRN concentrations were higher after DTPa, but groups differences reduced over time. Non-significant trends toward reduced reactogenicity of dTpa were observed. Many factors influence vaccine choice at preschool age. The dTpa vaccine was as immunogenic and possibly better tolerated than DTPa at this age.

Cordycepin is an immunoregulatory active ingredient of Cordyceps sinensis.

We have reported that cordycepin, an adenosine derivative from the fungus Cordyceps, increased interleukin (IL)-10 expression, decreased IL-2 expression and suppressed T lymphocyte activity. In the present study, we further characterized the regulatory effects of cordycepin on human immune cells. Moreover, a traditional Chinese drug, Cordyceps sinensis (CS) that contains cordycepin, was also investigated. Cytometric Bead Array (CBA) was used to determine the concentrations of IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, TNF-alpha and IFN-gamma in culture of peripheral blood mononuclear cells (PBMCs). The results showed that both cordycepin and CS up-regulated IL-10, IL-1beta, IL-6, IL-8 and TNF-alpha; at the same time, they suppressed phytohemagglutinin (PHA)-induced production of IL-2, IL-4, IL-5, IFN-gamma and IL-12. As compared to cordycepin, CS displayed its regulatory effects on IL-2 and IL-10 in a similar dose-dependent manner even with higher efficiency. The binding activity of transcription factors in a human monocytic cell line THP-1 was tested by the trans-AM method, and a higher binding activity of SP1 and SP3 was observed in cordycepin or CS treated cells compared to the control. These results led to the opinion that cordycepin and CS pleiotropically affected the actions of immune cells and cytokine network in a similar fashion. Cordycepin could be an important immunoregulatory active ingredient in Cordyceps sinensis. In addition, CS may contain substances which possess synergism with cordycepin, as CS showed a higher efficiency in the production of IL-10 and IL-2 than cordycepin. However, merits of these effects in pharmacology and clinical medicine have yet to be proven and the precise mechanism of these immune regulatory actions should be researched.

Combined Toll-like receptor agonists synergistically increase production of inflammatory cytokines in human neonatal dendritic cells.

Dendritic cells (DC) are thought to be responsible for the reduced ability of human newborns to induce protective T-helper 1 (Th1) immune responses. The key player in Th1 differentiation, interleukin-12 (IL-12), is primarily produced in response to Toll-like receptor (TLR) binding by adult DC but not by neonatal DC. The potential use of various TLR agonist combinations for initiating neonatal monocyte-derived DC to prime Th1 responses was investigated. Single TLR ligands induced maturation only in adult DC; neonatal DC matured with combined targeting of TLR3/TLR8 or TLR4/TLR8, based on the expression of maturation markers. Similarly, the synergistic effects of combined TLR ligands could also be shown with adult and neonatal cytokine production, but different expression patterns were noted. In particular, IL-12p70 was produced by neonatal DC exclusively after combined TLR stimulation. Surprisingly, it was found that supernatants of combined stimulated neonatal DC could induce interferon-gamma production in autologous naïve T cells. Moreover, this interferon-gamma secretion was blocked by anti-IL-12p70 antibodies and increased after addition of recombined IL-12. In conclusion, these findings underline the differences between adult and neonatal DC and might suggest new strategies for promoting newborn Th1 immunity in response to pathogens and vaccine antigens.

Age-dependent association of human mannose-binding lectin mutations with susceptibility to invasive meningococcal disease in childhood.

BACKGROUND: Mannose-binding lectin (MBL) is an important factor of the innate immune system, and MBL-initiated complement activation is an important early defense mechanism against various bacterial infections, including invasive meningococcal disease. METHODS: In a pediatric cohort (ages 2-215 months) with invasive meningococcal disease, we investigated the overall and age-stratified frequency of 3 MBL exon 1 variations (C154T, G161A, G170A), previously shown to result in markedly decreased MBL plasma concentrations, by allele specific fluorescent hybridization probe real-time PCR assays and direct sequencing. Healthy age-matched volunteers with the same ethnic background and no history of meningococcal disease served as a control group. RESULTS: The overall frequency of a MBL exon 1 variant genotype was significantly higher in patients than in controls (31.8% vs. 8.2%, P < 0.001). In the patient group with disease onset less than 24 months of age, the prevalence of MBL structural variant genotype was further increased (39.3%; P < 0.001) and most pronounced in children with disease onset less than 12 months of age (57.1%; P < 0.001) when compared with healthy controls. Analysis of clinical severity and outcome revealed no significant difference between patients with wild-type and mutant alleles. CONCLUSIONS: Our data suggest that MBL exon 1 structural variants are significantly associated with susceptibility to childhood meningococcal disease in an age-dependent manner.

The non-neuronal cholinergic system in peripheral blood cells: effects of nicotinic and muscarinic receptor antagonists on phagocytosis, respiratory burst and migration.

Peripheral blood cells express the complete non-neuronal cholinergic system. For example synthesis of acetylcholine and nicotinic as well muscarinic receptors have been demonstrated in leucocytes isolated from human peripheral blood. In the present experiments mononuclear cells and granulocytes were isolated from the peripheral blood to investigate content and synthesis of acetylcholine as well as phenotypic functions like respiratory burst, phagocytosis and migration. Mononuclear cells (T-cells and monocytes) contained 0.36 pmol/10(6) cells acetylcholine, whereas acetylcholine content in granulocytes was 100-fold lower. Acetylcholine synthesis amounted to 23.2+/-4.7 nmol/mg protein/h and 2.90+/-0.84 in CD15+ (granulocytes) and CD3+ cells (T-lymphocytes), respectively. Neither atropine (blockade of muscarinic receptors) nor tubocurarine (blockade of nicotinic receptors) exerted an effect on the respiratory burst. Tubocurarine (30 muM), alone or in combination with atropine (1 microM), reduced phagocytosis in granulocytes by 13% and 19%, respectively (p<0.05). Spontaneous transwell migration of granulocytes was doubled by tubocurarine combined with atropine (p>0.05). Also alpha-bungarotoxin (10 microg/ml) enhanced spontaneous granulocyte migration, but hexamethonium (300 microM) was without effect. The present experiments demonstrate a cholinergic modulation of immune functions in peripheral leucocytes under in vitro conditions, i.e. in the absence of a neuronal innervation. Blockade of nicotine receptors (alpha1 muscular subtype) facilitates spontaneous migration of granulocytes.

Human toll-like receptor 4 mutations are associated with susceptibility to invasive meningococcal disease in infancy.

Toll-like receptor 4 (TLR4) is required for efficient recognition of bacterial infections. We investigated an association between 2 TLR4 mutations (Asp(299)Gly and Thr(399)Ile) and meningococcal disease in 197 patients and 214 healthy controls by allele-specific real time polymerase chain reaction and direct sequencing. Although the allele frequency was not higher in the overall patient population, a significantly higher frequency in the 40 patients younger than 12 months of age (P = 0.007) was observed. We conclude that TLR4 mutations represent a risk factor for meningococcal disease in this age group.