Immune system development during early childhood in tropical Latin America: evidence for the age-dependent down regulation of the innate immune response

Urinary neopterin reflects immunological variation associated with age, helminth parasitism, and the microbiome in a wild primate

Neopterin, a product of activated white blood cells, is a marker of nonspecific inflammation that can capture variation in immune investment or disease-related immune activity and can be collected noninvasively in urine. Mounting studies in wildlife point to lifetime patterns in neopterin related to immune development, aging, and certain diseases, but rarely are studies able to assess whether neopterin can capture multiple concurrent dimensions of health and disease in a single system. We assessed the relationship between urinary neopterin stored on filter paper and multiple metrics of health and disease in wild geladas (Theropithecus gelada), primates endemic to the Ethiopian highlands. We tested whether neopterin captures age-related variation in inflammation arising from developing immunity in infancy and chronic inflammation in old age, inflammation related to intramuscular tapeworm infection, helminth-induced anti-inflammatory immunomodulation, and perturbations in the gastrointestinal microbiome. We found that neopterin had a U-shaped relationship with age, no association with larval tapeworm infection, a negative relationship with metrics related to gastrointestinal helminth infection, and a negative relationship with microbial diversity. Together with growing research on neopterin and specific diseases, our results demonstrate that urinary neopterin can be a powerful tool for assessing multiple dimensions of health and disease in wildlife.

Antioxidant Effects of Dietary Supplements on Adult COVID-19 Patients: Why Do We Not Also Use Them in Children?

Respiratory tract infections (RTIs) are very common in children, especially in the first five years of life, and several viruses, such as the influenza virus, Respiratory Syncytial Virus, and Rhinovirus, are triggers for symptoms that usually affect the upper airways. It has been known that during respiratory viral infections, a condition of oxidative stress (OS) occurs, and many studies have suggested the potential use of antioxidants as complementary components in prophylaxis and/or therapy of respiratory viral infections. Preliminary data have demonstrated that antioxidants may also interfere with the new coronavirus 2’s entry and replication in human cells, and that they have a role in the downregulation of several pathogenetic mechanisms involved in disease severity. Starting from preclinical data, the aim of this narrative review is to evaluate the current evidence about the main antioxidants that are potentially useful for preventing and treating Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in adults and to speculate on their possible use in children by exploring the most relevant issues affecting their use in clinical practice, as well as the associated evidence gaps and research limitations.

Immunopathogenesis of patients with COVID-19: from the perspective of immune system 'evolution' and 'revolution'

The pandemic caused by severe acute respiratory syndrome coronavirus 2 is sweeping the world, threatening millions of lives and drastically altering our ways of living. According to current studies, failure to either activate or eliminate inflammatory responses timely and properly at certain stages could result in the progression of the disease. In other words, robust immune responses to coronavirus disease 2019 (COVID-19) are critical. However, they do not theoretically present in some special groups of people, including the young, the aged, patients with autoimmunity or cancer. Differences also do occur between men and women. Our immune system evolves to ensure delicate coordination at different stages of life. The innate immune cells mainly consisted of myeloid lineage cells, including neutrophils, basophils, eosinophils, dendritic cells and mast cells; they possess phagocytic capacity to different degrees at different stages of life. They are firstly recruited upon infection and may activate the adaptive immunity when needed. The adaptive immune cells, on the other way, are comprised mainly of lymphoid lineages. As one grows up, the adaptive immunity matures and expands its memory repertoire, accompanied by an adjustment in quantity and quality. In this review, we would summarise and analyse the immunological characteristics of these groups from the perspective of the immune system 'evolution' as well as 'revolution' that has been studied and speculated so far, which would aid the comprehensive understanding of COVID-19 and personalised-treatment strategy.

Differential maturation trajectories of innate antiviral immunity in health and atopy

BACKGROUND

The maturation of innate immune responses in health and atopy is still incompletely understood.

METHODS

We aimed to evaluate age-related trajectories of the TLR3 and TLR7/8 pathways from birth to adulthood and whether these differ between healthy and atopic individuals. Peripheral blood mononuclear cells (PBMCs) were isolated from 39 otherwise healthy, atopic and 39 non-atopic subjects, aged 0-45 years. Selected cytokines involved in antiviral responses were measured by Luminex in culture supernatants of poly(I:C)- and R848-stimulated PBMCs. The non-parametric correlation between age and cytokine expression and differences in developmental trajectories between healthy and atopic subjects were estimated. Patterns of cytokine development were identified with principal component analysis.

RESULTS

Normal innate immune maturation entails significant and progressive age-related changes in the production of IL-1β, TNF-α, MIP-1β, MCP-3, IP-10, IL-10, IL-12p70, and IFN-γ upon TLR3 and/or TLR7/8 stimulation. Individual cytokines made small contributions to the observed variability; chemokines MCP-3 and IP-10 were key contributors. The development of these pathways deviated in atopic subjects with significant differences observed in the trajectories of IL-1β, MIP-1β, and IL-10 syntheses.

CONCLUSION

TLR3 and TLR7/8 pathways mature during childhood, while atopy is associated with an abnormal maturation pattern. Suboptimal responses in Th1, inflammatory cytokine, and chemokine production may be implicated in poor antiviral immunity in atopics. Moreover, the deficient maturation of IL-10 synthesis may be implicated in the breaking of tolerance, characterizing the onset of atopic disease.

Telehealth: A Useful Tool for the Management of Nutrition and Exercise Programs in Pediatric Obesity in the COVID-19 Era

The COVID-19 pandemic has led to the implementation of policies that mandate various restrictions on daily life, including social distancing, the closure of public services and schools, and movement limitations. Even though these restrictive measures decreased the COVID-19 spread, they may have detrimental effects on various lifestyle components such as physical inactivity, sedentary behavior, and dietary habits, influencing the maintenance of weight and contributing to obesity among children and adolescents. The coexistence of childhood obesity and COVID-19 and changes in the bioecological environment have put children and adolescents at increased risk for developing obesity and exacerbating the severity of this disorder. The use of telehealth technology is a modern approach useful for the delivery of health care services by health care professionals, where distance is a critical factor. Telehealth is effective in promoting increased self-monitoring and behavioral change, and provides the opportunity to perform online nutritional support and exercise training programs to promote a healthy lifestyle and reduce sedentary behaviors in children and adolescents. Telehealth, including tele-exercise and tele-nutrition, has the potential to address many of the key challenges in providing health services, including in patients with obesity during the COVID-19 outbreak. This narrative review aims to describe the role of telehealth as an opportunity in the management of pediatric obesity in the COVID-19 era, and to deliver nutrition and exercise programs for the maintenance of health.

Cell-Mediated Immune Ontogeny Is Affected by Sex but Not Environmental Context in a Long-Lived Primate Species

Ecoimmunology conceptualizes the role of immunity in shaping life history in a natural context. Within ecoimmunology, macroimmunology is a framework that explains the effects of habitat and spatial differences on variation in immune phenotypes across populations. Within these frameworks, immune ontogeny—the development of the immune system across an individual life span—has received little attention. Here, we investigated how immune ontogeny from birth until adulthood is affected by age, sex, and developmental environment in a long-lived primate species, the bonobo. We found a progressive, significant decline of urinary neopterin levels, a marker for the cell-mediated immune response, from birth until 5 years of age in both sexes. The overall pattern of age-related neopterin changes was sex-specific, with males having higher urinary neopterin levels than females in the first 3 years of life, and females having higher levels than males between 6 and 8 years. Environmental condition (zoo-housed vs. wild) did not influence neopterin levels, nor did age-related changes in neopterin levels differ between environments. Our data suggest that the post-natal development of cell-mediated immune ontogeny is sex-specific but does not show plasticity in response to environmental conditions in this long-lived primate species. This indicates that cell-mediated immune ontogeny in the bonobo follows a stereotypic and maybe a genetically determined pattern that is not affected by environmental differences in pathogen exposure and energy availability, but that sex is an important, yet often overlooked factor shaping patterns of immune ontogeny. Investigating the causes and consequences of variation in immunity throughout life is critical for our understanding of life-history evolution and strategies, mechanisms of sexual selection, and population dynamics with respect to pathogen susceptibility. A general description of sex-specific immune ontogeny as done here is a crucial step in this direction, particularly when it is considered in the context of a species’ ecology and evolutionary history.

[Epidemiological features and mechanism of coronavirus disease 2019 in children]

Compared with adults, children tend to have lower incidence rate, hospitalization rate, and mortality rate of coronavirus disease 2019 (COVID-19), while the cause of such age-based differences in disease severity remains unclear. An investigation of pathogenesis in children may help to analyze the therapies for the high-risk population. Human angiotensin-converting enzyme Ⅱ is the main receptor of severe acute respiratory syndrome coronavirus 2 and can limit pulmonary capillary leakage and inflammation mediated by angiotensin 2 and exert a protective effect against acute lung injury. Its expression decreases with age. Regular vaccination and frequent upper respiratory virus infection in children can lead to regular immune activation, and its combination with strong innate immunity can help to achieve virus clearance in the early stage of infection in children with COVID-19. Meanwhile, there are strong regeneration and repair abilities of alveolar epithelial cells in children, which may help with the early recovery of infection. In addition, risk factors, such as underlying cardiopulmonary diseases, obesity, and smoking, are relatively uncommon in children. Social factors, including home quarantine and timely closure of schools, may help to reduce the infection rate in children. However, children with immunodeficiency are a high-risk population and should be closely monitored. Further studies are needed to investigate the immune and protection mechanisms against COVID-19 in children.

[Epidemiological features and mechanism of coronavirus disease 2019 in children]

Compared with adults, children tend to have lower incidence rate, hospitalization rate, and mortality rate of coronavirus disease 2019 (COVID-19), while the cause of such age-based differences in disease severity remains unclear. An investigation of pathogenesis in children may help to analyze the therapies for the high-risk population. Human angiotensin-converting enzyme Ⅱ is the main receptor of severe acute respiratory syndrome coronavirus 2 and can limit pulmonary capillary leakage and inflammation mediated by angiotensin 2 and exert a protective effect against acute lung injury. Its expression decreases with age. Regular vaccination and frequent upper respiratory virus infection in children can lead to regular immune activation, and its combination with strong innate immunity can help to achieve virus clearance in the early stage of infection in children with COVID-19. Meanwhile, there are strong regeneration and repair abilities of alveolar epithelial cells in children, which may help with the early recovery of infection. In addition, risk factors, such as underlying cardiopulmonary diseases, obesity, and smoking, are relatively uncommon in children. Social factors, including home quarantine and timely closure of schools, may help to reduce the infection rate in children. However, children with immunodeficiency are a high-risk population and should be closely monitored. Further studies are needed to investigate the immune and protection mechanisms against COVID-19 in children.

How to Train Your Dragon: Harnessing Gamma Delta T Cells Antiviral Functions and Trained Immunity in a Pandemic Era

The emergence of viruses with pandemic potential such as the SARS-CoV-2 coronavirus causing COVID-19 poses a global health challenge. There is remarkable progress in vaccine technology in response to this threat, but their design often overlooks the innate arm of immunity. Gamma Delta (γδ) T cells are a subset of T cells with unique features that gives them a key role in the innate immune response to a variety of homeostatic alterations, from cancer to microbial infections. In the context of viral infection, a growing body of evidence shows that γδ T cells are particularly equipped for early virus detection, which triggers their subsequent activation, expansion and the fast deployment of antiviral functions such as direct cytotoxic pathways, secretion of cytokines, recruitment and activation of other immune cells and mobilization of a trained immunity memory program. As such, γδ T cells represent an attractive target to stimulate for a rapid and effective resolution of viral infections. Here, we review the known aspects of γδ T cells that make them crucial component of the immune response to viruses, and the ways that their antiviral potential can be harnessed to prevent or treat viral infection.

TANK-Binding Kinase 1 (TBK1) Serves as a Potential Target for Hepatocellular Carcinoma by Enhancing Tumor Immune Infiltration

BACKGROUND

Numerous cancer types present the aberrant TANK-binding kinase 1 (TBK1) expression, which plays an important role in driving inflammation and innate immunity. However, the prognostic role of TBK1 and its relationship with immune cell infiltration in hepatocellular carcinoma (HCC) remain unclear.

METHODS

The expression and prognostic value of TBK1 was analyzed by Tumor Immune Estimation Resource (TIMER), Kaplan-Meier plotter and Gene Expression Profiling Interactive Analysis (GEPIA), Clinical Proteomic Tumor Analysis Consortium (CPTAC) and further confirmed in the present cohort of patients with HCC. The association between TBK1 and HCC immune infiltrates, and its potential mechanism were investigated via analyses of the Tumor Immune Estimation Resource, tumor-immune system interactions database (TISIDB), CIBERSORT, STRING, and Metascape. The effect of TBK1 on immune infiltrates and the therapeutic value of targeting TBK1 were further investigated in a HCC mouse model by treatment with a TBK1 antagonist.

RESULTS

The level of TBK1 expression in HCC was higher than that measured in normal tissues, and associated with poorer overall survival (GEPIA: hazard ratio [HR]=1.80, P=0.038; Kaplan-Meier plotter: HR=1.87, P<0.001; CPTAC: HR=2.23, P=0.007; Our cohort: HR=2.92, P=0.002). In addition, high TBK1 expression was found in HCC with advanced TNM stage and identified as an independent poor prognostic factor for overall survival among patients with HCC. In terms of immune infiltration, tumor tissues from HCC patients with high TBK1 expression had a low proportion of CD8+ T cells, and TBK1 expression did not show prognostic value in HCC patients with enriched CD8+ T cells. Furthermore, TBK1 expression was positively correlated with the markers of T cell exhaustion and immunosuppressive cells in the HCC microenvironment. Mechanistically, the promotion of HCC immunosuppression by TBK1 was involved in the regulation of inflammatory cytokines. In vivo experiments revealed that treatment with a TBK1 antagonist delayed HCC growth by increasing the number of tumor-infiltrating CD8+ T cells.

CONCLUSIONS

The up-regulated expression of TBK1 may be useful in predicting poor prognosis of patients with HCC. In addition, TBK1, which promotes the HCC immunosuppressive microenvironment, may be a potential immunotherapeutic target for patients with HCC.

The younger the milder clinical course of COVID-19: Even in newborns?

BACKGROUND

Milder symptoms were observed in children with COVID-19. However, whether this also holds true for neonates is not known.

METHODS

The clinical data of a total of 3213 patients aged 2 years or below, including 749 neonates, in Brazil nationwide were studied. Comparisons were made between neonate and infant patients by conducting statistical tests.

RESULTS

Neonates appeared to bear more severe clinical courses. In addition to higher case fatality rates, newborns with COVID-19 had much shorter time from symptom onset to death and longer time from symptom onset to discharge. Dyspnoea, sore throat and cough were more prominent in neonate patients, suggestive of both upper and lower respiratory tract infection, as opposed to upper respiratory tract symptoms mostly observed in children.

CONCLUSION

Findings suggested that trained immunity provides a possible explanation because the innate immune system in newborns is not "well-trained" while that in adult tends to hyperactive.

Dynamic progression of the calf's microbiome and its influence on host health

The first year of a calf's life is a critical phase as its digestive system and immunity are underdeveloped. A high level of stress caused by separation from mothers, transportation, antibiotic treatments, dietary shifts, and weaning can have long-lasting health effects, which can reduce future production parameters, such as milk yield and reproduction, or even increase the mortality of calves. The early succession of microbes throughout the gastrointestinal tract of neonatal calves follows a sequential pattern of colonisation and is greatly influenced by their physiological state, age, diet, and environmental factors; this leads to the establishment of region- and site-specific microbial communities. This review summarises the current information on the various potential factors that may affect the early life microbial colonisation pattern in the gastrointestinal tract of calves. The possible role of host-microbe interactions in the development and maturation of host gut, immune system, and health are described. Additionally, the possibility of improving the health of calves through gut microbiome modulation and using antimicrobial alternatives is discussed. Finally, the trends, challenges, and limitations of the current research are summarised and prospective directions for future studies are highlighted.

Integrated analyses of the microbiological, immunological and ontological transitions in the calf ileum during early life

Aberdeen Angus calves were sacrificed from immediately post-birth up to 96 days of age (DOA) and ileal samples were collected for microbial, histological and immunological analyses. Firmicutes bacteria were established immediately in the ileum of calves after birth and remained the dominant phyla at all time points from birth until 96 DOA. Temporal shifts in phyla reflected significantly increased Bacteroidetes at birth followed by temporal increases in Actinobacteria abundance over time. At a cellular level, a significant increase in cell density was detected in the ileal villi over time. The innate cell compartment at birth was composed primarily of eosinophils and macrophages with a low proportion of adaptive T lymphocytes; whereas an increase in the relative abundance of T cells (including those in the intra-epithelial layer) was observed over time. The ileal intestinal cells were immunologically competent as assessed by expression levels of genes encoding the inflammasome sensor NLRP3, and inflammatory cytokines IL1A, IL1B and IL33-all of which significantly increased from birth. In contrast, a temporal reduction in genes encoding anti-inflammatory cytokine IL10 was detected from birth. This study provides an integrated baseline of microbiological, histological and immunological data on the immune adaptation of the neonatal ileum to microbial colonisation in calves.

Lessons From COVID-19 in Children: Key Hypotheses to Guide Preventative and Therapeutic Strategies

The current pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), reveals a peculiar trend of milder disease and lower case fatality in children compared with adults. Consistent epidemiologic evidence of reduced severity of infection in children across different populations and countries suggests there are underlying biological differences between children and adults that mediate differential disease pathogenesis. This presents a unique opportunity to learn about disease-modifying host factors from pediatric populations. Our review summarizes the current knowledge of pediatric clinical disease, role in transmission, risks for severe disease, protective immunity, as well as novel therapies and vaccine trials for children. We then define key hypotheses and areas for future research that can use the pediatric model of disease, transmission, and immunity to develop preventive and therapeutic strategies for people of all age groups.

A Cell for the Ages: Human γδ T Cells across the Lifespan

The complexity of the human immune system is exacerbated by age-related changes to immune cell functionality. Many of these age-related effects remain undescribed or driven by mechanisms that are poorly understood. γδ T cells, while considered an adaptive subset based on immunological ontogeny, retain both innate-like and adaptive-like characteristics. This T cell population is small but mighty, and has been implicated in both homeostatic and disease-induced immunity within tissues and throughout the periphery. In this review, we outline what is known about the effect of age on human peripheral γδ T cells, and call attention to areas of the field where further research is needed.

Pathophysiology of COVID-19: Why Children Fare Better than Adults?

The world is facing Coronavirus Disease-2019 (COVID-19) pandemic, which is causing a large number of deaths and burden on intensive care facilities. It is caused by Severe Acute Respiratory Syndrome coronavirus-2 (SARS-CoV-2) originating in Wuhan, China. It has been seen that fewer children contract COVID-19 and among infected, children have less severe disease. Insights in pathophysiological mechanisms of less severity in children could be important for devising therapeutics for high-risk adults and elderly. Early closing of schools and day-care centers led to less frequent exposure and hence, lower infection rate in children. The expression of primary target receptor for SARS-CoV-2, i.e. angiotensin converting enzyme-2 (ACE-2), decreases with age. ACE-2 has lung protective effects by limiting angiotensin-2 mediated pulmonary capillary leak and inflammation. Severe COVID-19 disease is associated with high and persistent viral loads in adults. Children have strong innate immune response due to trained immunity (secondary to live-vaccines and frequent viral infections), leading to probably early control of infection at the site of entry. Adult patients show suppressed adaptive immunity and dysfunctional over-active innate immune response in severe infections, which is not seen in children. These could be related to immune-senescence in elderly. Excellent regeneration capacity of pediatric alveolar epithelium may be contributing to early recovery from COVID-19. Children, less frequently, have risk factors such as co-morbidities, smoking, and obesity. But young infants and children with pre-existing illnesses could be high risk groups and need careful monitoring. Studies describing immune-pathogenesis in COVID-19 are lacking in children and need urgent attention.

Increased T Cell Differentiation and Cytolytic Function in Bangladeshi Compared to American Children

During the first 5 years of life, children are especially vulnerable to infection-related morbidity and mortality. Conversely, the Hygiene Hypothesis suggests that a lack of exposure to infectious agents early in life could explain the increasing incidence of allergies and autoimmunity in high-income countries. Understanding these phenomena, however, is hampered by a lack of comprehensive, direct immune monitoring in children with differing degrees of microbial exposure. Using mass cytometry, we provide an in-depth profile of the peripheral blood mononuclear cells (PBMCs) of children in regions at the extremes of exposure: the San Francisco Bay Area, USA and an economically poor district of Dhaka, Bangladesh. Despite variability in clinical health, functional characteristics of PBMCs were similar in Bangladeshi and American children at 1 year of age. However, by 2–3 years of age, Bangladeshi children's immune cells often demonstrated altered activation and cytokine production profiles upon stimulation with PMA-ionomycin, with an overall immune trajectory more in line with American adults. Conversely, immune responses in children from the US remained steady. Using principal component analysis, donor location, ethnic background, and cytomegalovirus infection status were found to account for some of the variation identified among samples. Within Bangladeshi 1-year-olds, stunting (as measured by height-for-age z-scores) was found to be associated with IL-8 and TGFβ expression in PMA-ionomycin stimulated samples. Combined, these findings provide important insights into the immune systems of children in high vs. low microbial exposure environments and suggest an important role for IL-8 and TGFβ in mitigating the microbial challenges faced by the Bangladeshi children.

Soil-transmitted helminth parasites and allergy: Observations from Ecuador

There is considerable interest as to potential protective effects of soil-transmitted helminths (STH) against allergy and allergic diseases. Here, we discuss findings of studies done of the effects of STH parasites on atopy and allergic diseases in Ecuador. While cross-sectional studies have consistently shown a reduced prevalence of allergen skin prick test (SPT) reactivity among infected schoolchildren, the removal of these infections by repeated deworming did not affect SPT prevalence over the short-term (ie, 12 months) but may have increased SPT prevalence over the long-term (ie, 15-17 years). In the case of allergic symptoms, cross-sectional studies have generally not shown associations with STH and intervention studies showed no impact on prevalence. However, a birth cohort suggested that early STH infections might reduce wheeze by 5 years. Allergic sensitization to Ascaris, however, explained a significant proportion of wheezing among rural schoolchildren. Studies of the effects of STH on immune and inflammatory responses indicated a potential role of STH in contributing to more robust regulation. The effects of STH on allergy are likely to be determined by history of exposure over the life-course and by interactions with a wide variety of other infectious and non-infectious factors.

Age-related waning of immune responses to BCG in healthy children supports the need for a booster dose of BCG in TB endemic countries

In the absence of a more effective vaccine against TB and in the interest of developing one, it is essential to understand immune responses associated with BCG protection. We comprehensively characterized T cell populations in BCG-vaccinated children over time. Blood from 78 healthy, BCG-vaccinated children representing four age groups (<1 yr, ≥1 yr <2 yr, ≥2 yr <5 yr, ≥5 yr), was stimulated in vitro for 24 hours and 6 days with live BCG to induce effector and central memory responses. Antigen-specific CD4, CD8, γδ and regulatory T cell populations were phenotyped and intracellular and secreted cytokines measured by flow cytometry and multiplex ELISA respectively. Our results demonstrated that populations of naïve T cells predominated in infants, compared to older children. However, BCG-specific effector CD4 T cell responses were equivalent and antigen-specific CD4 T cell proliferative capacity was increased in infants compared to older children. Increases in innate immune responses including γδ T cell responses and secreted pro-inflammatory cytokines were noted with increasing age. In conclusion, we identified that the capacity to expand and differentiate effector T cells in response to BCG stimulation wanes with increasing age, which may indicate waning central memory immunity. Booster vaccination could be considered to maintain the antigen-specific central memory pool and possibly enhance the duration of protection.

CD58; leucocyte function adhesion-3 (LFA-3) could be used as a differentiating marker between immune and non-immune thyroid disorders

The link between Graves’ disease (GD) and Hashimoto^’s thyroiditis (HT) has been debated for decades due to the shared pathological and immunological components. Immune intolerance and inappropriate immune reaction against self-thyroid cells are distinctive features of both diseases, but definitive data for the clinical presentation of autoimmune thyroid disease remains unclear. To analyse the expression of T-regulatory cells, CD58, the CD4/CD8 ratio and the neutrophil/lymphocyte ratio and to determine if these parameters could be used as differentiating markers between auto- and non-immune thyroid diseases, 75 patients were enrolled in this study—40 with autoimmune thyroid disease (HT and GD ), 15 with non-immune thyroid disease, and 20 healthy controls. Multicolour flow cytometry was used to analyse CD58, T-regulatory cells (Treg) expressing CD4, CD25, HLA-DR and CD8 using different stained fluorescent labelled monoclonal antibodies. The neutrophils and lymphocyte ratio was also measured. Lower expression of Treg with higher expression of CD58 (LFA-3) was found in the autoimmune diseases when compared with the non-immune and control groups. ROC analysis showed that CD58 with sensitivity 88% and specificity 100% with cut-off value more than or equal to 29.9 indicates Hashimoto’s disease, while lower value indicates colloid goitre, and higher or equal to 29.84 indicates Graves’ disease and lower indicates colloid goitre with 100% sensitivity and specificity. CD58 could be used as differentiating marker between immune and non-immune thyroid disorders.

The expression and correlation of Hsp 70 and Hsp 27 in serous middle ear effusion fluids of pediatric patients-a preliminary study

OBJECTIVES

Several cytokines and innate immune-associated molecules are present in middle ear effusions, but damage-associated molecular patterns (DAMPs) in middle ear effusion have not been studied. Therefore, we evaluated the role of heat shock proteins (Hsps) in the development of otitis media with effusion (OME).

METHODS

Serous middle ear effusions from 22 pediatric patients who were diagnosed with OME and underwent ventilation tube insertion from June 2015 to March 2017 were evaluated in our study. The levels of Hsp 90, 70, 27, IL-8, and TNF-α in effusion fluids were evaluated by enzyme-linked immunosorbent assays. The associations between the levels of these molecules and the degree of tympanic membrane inflammation were statistically evaluated. Finally, the relationships among these molecules were also evaluated.

RESULTS

Hsp 70 and Hsp 27 were detected in all middle ear effusions, but Hsp 90 was detected in only five effusion fluid samples. IL-8 was also detected in all middle ear effusions, but TNF-α was detected in only four effusion fluid samples. When we compared the degree of tympanic membrane inflammation with the levels of Hsp 70, Hsp 27, and IL-8, which were detected in all effusion fluids, we could not find statistical significance. However, Hsp 70, Hsp 27, and IL-8 were significantly associated with each other (p < 0.05).

CONCLUSIONS

Hsp 70 and Hsp 27 were expressed in middle ear effusions. Furthermore, the levels of Hsp 70 and Hsp 27 were positively correlated with each other, and were also positively associated with the neutrophil chemoattractant, IL-8. Our findings suggested that Hsp 70 and Hsp 27 might be involved in the pathophysiology of pediatric OME.

Humoral immune responses during asthma and influenza co-morbidity in mice

Humoral immunity serve dual functions of direct pathogen neutralization and enhancement of leukocyte function. Antibody classes are determined by antigen triggers, and the resulting antibodies can contribute to disease pathogenesis and host defense. Although asthma and influenza are immunologically distinct diseases, since we have found that allergic asthma exacerbation promotes antiviral host responses to influenza A virus, we hypothesized that humoral immunity may contribute to allergic host protection during influenza. C57BL/6J mice sensitized and challenged with Aspergillus fumigatus (or not) were infected with pandemic influenza A/CA/04/2009 virus. Negative control groups included naïve mice, and mice with only 'asthma' or influenza. Concentrations of antibodies were quantified by ELISA, and in situ localization of IgA- and IgE-positive cells in the lungs was determined by immunohistochemistry. The number and phenotype of B cells in spleens and mediastinal lymph nodes were determined by flow cytometry at predetermined timepoints after virus infection until viral clearance. Mucosal and systemic antibodies remained elevated in mice with asthma and influenza with prominent production of IgE and IgA compared to influenza-only controls. B cell expansion was prominent in the mediastinal lymph nodes of allergic mice during influenza where most cells produced IgG₁ and IgA. Although allergy-skewed B cell responses dominated in mice with allergic airways inflammation during influenza virus infection, virus-specific antibodies were also induced. Future studies are required to identify the mechanisms involved with B cell activation and function in allergic hosts facing respiratory viral infections.

Natural and artificial feeding management before weaning promote different rumen microbial colonization but not differences in gene expression levels at the rumen epithelium of newborn goats

The aim of this work was to evaluate the effect of feeding management during the first month of life (natural with the mother, NAT, or artificial with milk replacer, ART) on the rumen microbial colonization and the host innate immune response. Thirty pregnant goats carrying two fetuses were used. At birth one kid was taken immediately away from the doe and fed milk replacer (ART) while the other remained with the mother (NAT). Kids from groups received colostrum during first 2 days of life. Groups of four kids (from ART and NAT experimental groups) were slaughtered at 1, 3, 7, 14, 21 and 28 days of life. On the sampling day, after slaughtering, the rumen content was sampled and epithelial rumen tissue was collected. Pyrosequencing analyses of the bacterial community structure on samples collected at 3, 7, 14 and 28 days showed that both systems promoted significantly different colonization patterns (P = 0.001). Diversity indices increased with age and were higher in NAT feeding system. Lower mRNA abundance was detected in TLR2, TLR8 and TLR10 in days 3 and 5 compared to the other days (7, 14, 21 and 28). Only TLR5 showed a significantly different level of expression according to the feeding system, presenting higher mRNA abundances in ART kids. PGLYRP1 showed significantly higher abundance levels in days 3, 5 and 7, and then experienced a decline independently of the feeding system. These observations confirmed a highly diverse microbial colonisation from the first day of life in the undeveloped rumen, and show that the colonization pattern substantially differs between pre-ruminants reared under natural or artificial milk feeding systems. However, the rumen epithelial immune development does not differentially respond to distinct microbial colonization patterns.

Postnatal Innate Immune Development: From Birth to Adulthood

It is well established that adaptive immune responses are deficient in early life, contributing to increased mortality and morbidity. The developmental trajectories of different components of innate immunity are only recently being explored. Individual molecules, cells, or pathways of innate recognition and signaling, within different compartments/anatomical sites, demonstrate variable maturation patterns. Despite some discrepancies among published data, valuable information is emerging, showing that the developmental pattern of cytokine responses during early life is age and toll-like receptor specific, and may be modified by genetic and environmental factors. Interestingly, specific environmental exposures have been linked both to innate function modifications and the occurrence of chronic inflammatory disorders, such as respiratory allergies. As these conditions are on the rise, our knowledge on innate immune development and its modulating factors needs to be expanded. Improved understanding of the sequence of events associated with disease onset and persistence will lead toward meaningful interventions. This review describes the state-of-the-art on normal postnatal innate immune ontogeny and highlights research areas that are currently explored or should be further addressed.

Understanding the gut microbiome of dairy calves: Opportunities to improve early-life gut health

Early gut microbiota plays a vital role in the long-term health of the host. However, understanding of these microbiota is very limited in livestock species, especially in dairy calves. Neonatal calves are highly susceptible to enteric infections, one of the major causes of calf death, so approaches to improving gut health and overall calf health are needed. An increasing number of studies are exploring the microbial composition of the gut, the mucosal immune system, and early dietary interventions to improve the health of dairy calves, revealing possibilities for effectively reducing the susceptibility of calves to enteric infections while promoting growth. Still, comprehensive understanding of the effect of dietary interventions on gut microbiota-one of the key aspects of gut health-is lacking. Such knowledge may provide in-depth understanding of the mechanisms behind functional changes in response to dietary interventions. Understanding of host-microbial interactions with dietary interventions and the role of the gut microbiota during pathogenesis at the site of infection in early life is vital for designing effective tools and techniques to improve calf gut health.

Influence of Age and Other Factors on Cytokine Expression Profiles in Healthy Children-A Systematic Review

Cytokines have attracted much attention as diagnostic biomarkers for infectious and inflammatory diseases in recent years. However, understanding of maturation and normal age-associated values is limited. This review summarizes evidence on the influence of age and other factors on expression profiles of soluble and intracellular cytokines in healthy children. IFN-γ, IL-6, IL-10, and TNF-α are the most frequently investigated cytokines, of which an age-associated increase was shown consistently for IFN-γ and TNF-α. An age-associated decrease of IL-13 was seen in resource-limited settings. For other cytokines, including IL-1RA, IL-2, and IL-10, uni- or bimodal curves have been described, and results were influenced by study setting. To conclude, despite limited current understanding of the development of cytokine expression, age clearly influences expression profiles in healthy children. Dynamics of cytokine expression in childhood need to be considered when these are measured in diagnostic assays or as biomarkers. In addition, cytokine-targeting agents may require adjustment for normal values when used in children.

Comparison of innate immunity mediators in peritoneal fluid and spleen between young and aged rats

BACKGROUND

Aging of the innate immune system can result in a wide array of decreasing biological function.

AIM

We investigated differences between young and old mice in the expression of the pattern-recognition receptors (PRRs).

METHODS

mRNA levels for PRRs were quantified and compared in peritoneal fluid and spleens from old (36 months old) and young (1 month old) Wistar white rats (n = 8/group) using real-time reverse transcription-polymerase chain reaction.

RESULTS

In old rats, TLR-5 and -7 were decreased in peritoneal fluid, whereas TLR 4/6/9 and Syk were increased in the spleen (p < 0.05). In young rats, TLR 2/4, dectin-1, and Trem-1 were increased in peritoneal fluid and decreased in the spleen (p < 0.05), but TLR 1/3/7/9/10 and Syk were vice versa (p < 0.05).

DISCUSSION

Several parameters related to innate immunity may change with aging.

CONCLUSION

Different expressions of mRNA for several PRRs are suggesting changes in innate immune responses in association with aging.

The Gut Microbiome and Its Potential Role in the Development and Function of Newborn Calf Gastrointestinal Tract

A diverse microbial population colonizes the sterile mammalian gastrointestinal tract during and after the birth. There is increasing evidence that this complex microbiome plays a crucial role in the development of the mucosal immune system and influences newborn health. Microbial colonization is a complex process influenced by a two-way interaction between host and microbes and a variety of external factors, including maternal microbiota, birth process, diet, and antibiotics. Following this initial colonization, continuous exposure to host-specific microbes is not only essential for development and maturation of the mucosal immune system but also the nutrition and health of the animal. Thus, it is important to understand host–microbiome interactions within the context of individual animal species and specific management practices. Data is now being generated revealing significant associations between the early microbiome, development of the mucosal immune system, and the growth and health of newborn calves. The current review focuses on recent information and discusses the limitation of current data and the potential challenges to better characterizing key host-specific microbial interactions. We also discuss potential strategies that may be used to manipulate the early microbiome to improve production and health during the time when newborn calves are most susceptible to enteric disease.

Effects of environment on human cytokine responses during childhood in the tropics: role of urban versus rural residence

BACKGROUND

Environment may have a key role in the development of the immune system in childhood and environmental exposures associated with rural residence may explain the low prevalence of allergic and autoimmune diseases in the rural tropics. We investigated the effects of urban versus rural residence on the adaptive immune response in children living in urban and rural areas in a tropical region of Latin America.

METHODS

We recruited school children in either rural communities in the Province of Esmeraldas or in urban neighborhoods in the city of Esmeraldas, Ecuador. We collected data on environmental exposures by questionnaire and on intestinal parasites by examination of stool samples. Peripheral blood leukocytes (PBLs) in whole blood were stimulated with superantigen, parasite antigens and aeroallergens and IFN-γ, IL-5, IL-10, IL-13, and IL-17 were measured in supernatants.

RESULTS

We evaluated 440 school children; 210 living in rural communities and 230 in the city of Esmeraldas. Overall, urban children had greater access to piped water (urban 98.7 % vs. rural 1.9 %), were more likely to have a household bathroom (urban 97.4 % vs. rural 54.8 %), and were less likely to be infected with soil-transmitted helminth infections (urban 20.9 % vs. rural 73.5 %). Generally, detectable levels of cytokines were more frequent in blood from children living in urban than rural areas. Urban residence was associated with a significantly greater frequency of IL-10 production spontaneously (adjusted OR 2.56, 95 % CI 1.05-6.24) and on stimulation with Ascaris (adj. OR 2.5, 95 % CI 1.09-5.79) and house dust mite (adj. 2.24, 95 % CI 1.07-4.70) antigens. Analysis of effects of environmental exposures on SEB-induced IL-10 production within urban and rural populations showed that some environmental exposures indicative of poor hygiene (urban - higher birth order, A. lumbricoides infection; rural - no bathroom, more peri-domiciliary animals, and living in a wood/bamboo house) were associated with elevated IL-10.

CONCLUSIONS

In our study population, the immune response of children living in an urban environment was associated more frequently with the production of the immune regulatory cytokine, IL-10. Some factors related to poor hygiene and living conditions were associated with elevated IL-10 production within urban and rural populations.

Age-dependent changes in pattern recognition receptor and cytokine mRNA expression in children with otitis media with effusion

OBJECTIVE

To investigate age-dependent changes in expression of pattern recognition receptors (PRRs) and cytokines in pediatric OME.

MATERIALS AND METHODS

Ninety five pediatric patients with OME were divided into 4 age groups: 0-2, 2-4, 4-7, and over 7 years. The presence of bacteria, and the levels of expression of mRNAs encoding Toll-like receptor (TLRs), NOD like receptors (NLRs) and cytokines in middle ear fluid were assessed, as were their correlations with age, gender, presence of bacteria and accompanying disease.

RESULTS

Bacteria were detected in 32.6% of patients. The levels of expression of PRR and cytokine mRNAs tended to be lower in children aged 2-4 and 4-7 years. The levels of expression of TLR-2, TLR-9, NOD-1, NOD-2, IL-1, IL-6, and TNF-α mRNAs in effusion fluid were significantly lower in these two groups than in children aged 0-2 and over 7 years (p<0.05 each). The levels of expression of TLR-4, TLR-5, TLR-9, and NOD-1 mRNAs were significantly lower in culture positive than in culture negative patients (p<0.05 each). However, the expression levels of PRR and cytokine mRNAs were unrelated to gender and accompanying disease (p>0.05 each).

CONCLUSIONS

The levels of expression of PRR and cytokine mRNAs differed by age in children with OME.

Leg length is associated with lower values of inflammatory markers in older Chinese: The Guangzhou Biobank Cohort Study

BACKGROUND

In developed western populations, longer legs are a biomarker of better childhood conditions and negatively associated with cardiovascular disease risk factors. These associations are less obvious in non-western settings. However, early life is also a key immune system development phase.

AIM

To examine the associations of height, leg length, sitting height and leg length/sitting height ratio with inflammatory markers (white blood, lymphocyte and granulocyte cell counts and C-reactive protein (CRP)) in a developing population of southern China.

SUBJECTS AND METHODS

This study used multivariable linear regression to examine the adjusted associations in 30,499 Chinese (50+ years).

RESULTS

Height z-score was associated with lower white blood, lymphocyte and granulocyte cell counts. Leg length z-score was associated with lower white blood, lymphocyte and granulocyte cell counts and CRP. Sitting height z-score was associated with lower white blood and granulocyte cell counts, but not with lymphocyte cell count or CRP. Leg length/sitting height ratio z-score was associated with lower white blood, lymphocyte and granulocyte cell counts and CRP.

CONCLUSION

Factors enabling more early growth may also lead to changes in immunity that are associated with reduced CVD risk.

Cohort Profile: The Ecuador Life (ECUAVIDA) study in Esmeraldas Province, Ecuador

The ECUAVIDA birth cohort is studying the impact of exposures to soil-transmitted helminth (STH) parasites and early-life microbial exposures on the development of atopy, allergic diseases and immune responses in childhood. A total of 2404 newborns were recruited between 2006 and 2009 in a public hospital serving the rural district of Quininde, Esmeraldas Province, in a tropical region of coastal Ecuador. Detailed measurements were done around the time of the birth, at 7 and 13 months and at 2 and 3 years, and data collection is ongoing at 5 and 8 years. Data being collected include questionnaires for: sociodemographic, lifestyle, psychosocial (at 4-6 years only) and dietary (at 6-7 years only) factors; childhood morbidity and clinical outcomes; stool samples for parasites; blood samples for DNA, measurements of vaccine responses and other measures of immune function/inflammation; and anthropometrics. Allergen skin prick test reactivity is done from 2 years and measures of airway function and inflammation at 8 years.

Altered innate immune development in HIV-exposed uninfected infants

BACKGROUND

Early in life, HIV-exposed uninfected (HEU) infants are at an increased risk of morbidity and mortality from infectious disease compared with HIV-unexposed (UE) infants. To improve our understanding of the mechanisms underlying their increased risk, we contrasted innate immune development between HEU and UE infants in a developing world setting, where early life infectious disease risk is exceptionally high.

METHODS

A prospective longitudinal cohort of HEU and UE newborns was established, and the most detailed characterization to date of HEU infant immune development was performed. Single-cell cytokine production was analyzed by flow cytometry after stimulation of whole blood with pathogen-associated molecular patterns (PAMPs).

RESULTS

Monocyte, classical dendritic cell, and plasmacytoid dendritic cell composition was similar between HEU and UE infants throughout the first year of life. However, HEU mononuclear cells mounted an enhanced pro-inflammatory response to PAMP stimulation, both in quantity of cytokine produced per cell and in proportion of responder cells. Significant differences in cytokine production were detected on the single-cell level in a PAMP-specific pattern, but only at 2 and 6 weeks of age; all differences normalized by 12 months of age.

CONCLUSIONS

This time course of innate immune deviation early in life corresponds to the clinical window of vulnerability to infections in HEU infants and may be at least partially responsible for their increased morbidity and mortality from infectious disease.

Pattern recognition receptor-mediated cytokine response in infants across 4 continents

Background

Susceptibility to infection as well as response to vaccination varies among populations. To date, the underlying mechanisms responsible for these clinical observations have not been fully delineated. Because innate immunity instructs adaptive immunity, we hypothesized that differences between populations in innate immune responses may represent a mechanistic link to variation in susceptibility to infection or response to vaccination.

Objective

Determine whether differences in innate immune responses exist among infants from different continents of the world.

Methods

We determined the innate cytokine response following pattern recognition receptor (PRR) stimulation of whole blood from 2-year-old infants across 4 continents (Africa, North America, South America, and Europe).

Results

We found that despite the many possible genetic and environmental exposure differences in infants across 4 continents, innate cytokine responses were similar for infants from North America, South America, and Europe. However, cells from South African infants secreted significantly lower levels of cytokines than did cells from infants from the 3 other sites, and did so following stimulation of extracellular and endosomal but not cytosolic PRRs.

Conclusions

Substantial differences in innate cytokine responses to PRR stimulation exist among different populations of infants that could not have been predicted. Delineating the underlying mechanism(s) for these differences will not only aid in improving vaccine-mediated protection but possibly also provide clues for the susceptibility to infection in different regions of the world.

Longitudinal trajectory of vitamin D status from birth to early childhood in the development of food sensitization

BACKGROUND

Increasing evidence supports the immunomodulatory effect of vitamin D on allergic diseases. The combined role of prenatal and postnatal vitamin D status in the development of food sensitization (FS) and food allergy remains understudied.

METHODS

Plasma 25-hydroxyvitamin D (25(OH)D) levels of 460 children in the Boston Birth Cohort (BBC) were measured at birth and early childhood, and the subjects were genotyped for rs2243250 (C-590T) in the IL4 gene. We defined FS as specific IgE levels of ≥0.35 kUA/l to any of eight common food allergens; we defined persistently low vitamin D status as cord blood 25(OH)D <11 ng/ml and postnatal 25(OH)D <30 ng/ml.

RESULTS

We observed a moderate correlation between cord blood 25(OH)D at birth and venous blood 25(OH)D measured at 2-3 y (r = 0.63), but a weak correlation at <1 y (r = 0.28). There was no association between low vitamin D status and FS at any single time point alone. However, in combination, persistence of low vitamin D status at birth and in early childhood increased the risk of FS (odds ratio (OR) = 2.03, 95% confidence interval (CI): 1.02-4.04), particularly among children carrying the C allele of rs2243250 (OR = 3.23, 95% CI: 1.37-7.60).

CONCLUSION

Prenatal and early postnatal vitamin D levels, along with individual genetic susceptibility, should be considered in assessing the role of vitamin D in the development of FS and food allergy.

Development of monocyte Toll-like receptor 2 and Toll-like receptor 4 in preterm newborns during the first few months of life

BACKGROUND

Although the immaturity of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) at birth in preterm newborns is known, their development during the first few months of life remains unclear.

METHODS

Blood monocytes of preterm newborns (gestational age: 24-36 wk) were obtained every 2 wk when possible in order to perform serial measurements of TLR2 and TLR4 surface expression, as well as lipopolysaccharide (LPS)-induced cytokine production. Measurements using monocytes from term newborns and adults were also performed.

RESULTS

The monocytes of preterm newborns obtained at birth displayed reduced surface expression of TLR2 and TLR4, and diminished responses of tumor necrosis factor-α (TNF-α) and interleukin (IL)-8 to LPS stimulation. Regardless of gestational age, monocyte expression of TLR2 and TLR4 in preterm newborns increased rapidly within the first 2 wk after birth, quickly reaching those of term newborns. These increases continued for the following 4-6 wk, although the increase began to plateau. By contrast, LPS-induced production of TNF-α and IL-8 did not elevate over this period in preterm newborns.

CONCLUSION

The blood monocytes of preterm newborns display rapid increase in TLR2 and TLR4 expression during the first few months of life, whereas LPS-induced cytokine production functionality did not improve in parallel.

Vitamin A deficiency alters airway resistance in children with acute upper respiratory infection

OBJECTIVE

To assess whether vitamin A deficiency alters the recovery of total respiratory resistance (TRR) following acute upper respiratory tract infection (URI).

METHODS

This is a case control study of children, age 4-6 years and grouped as: URI, (n = 74), URI and wheezing, (URI-wheezing, n = 52), and healthy controls (n = 51). Vitamin A and total respiratory resistance (TRR) were assessed using the modified relative dose response (MRDR) and forced oscillometry, respectively.

RESULTS

Children with URI and URI-wheezing had lower retinol, 32.4 ± 13.12 and 18.3 ± 6.83 µg/dl respectively, compared to controls, 56.9 ± 29.82 µg/dl (ANOVA, P < 0.001). The MRDR was elevated in children in the URI or URI-wheezing groups 0.066 ± 0.045 and 0.021 ± 0.021, respectively, compared to controls 0.007 ± 0.006 (ANOVA, P < 0.0001). The TRR in the URI and URI-wheezing groups differed from controls. During convalescence, the TRR failed to decline in the URI-group only when the MRDR was >0.06. In the URI-wheezing group, TRR declined independently of retinol and MRDR.

CONCLUSION

Vitamin A contributes to preservation of airway function during and in recovery after upper respiratory infection in children.

Variation between Populations in the Innate Immune Response to Vaccine Adjuvants

The success of the World Health Organization recommended “Expanded Program of Immunization” (EPI) and similar regional or national programs has been astounding. However, infectious threats currently not covered by these programs continue to infect millions of infants around the world. Furthermore, many infants do not receive existing vaccines either on time or for the required number of doses to provide optimal protection. Nor do all infants around the world develop the same protective immune response to the same vaccine. As a result approximately three million infants die every year from vaccine preventable infections. To tackle these issues, new vaccines need to be developed as well as existing ones made easier to administer. This requires identification of age-optimized vaccine schedules and formulations. In order to be most effective this approach will need to take population-based differences in response to vaccines and adjuvants into account. This review summarizes what is currently known about differences between populations around the world in the innate immune response to existing as well as new and promising vaccine adjuvants.

Can brucellosis influence the course of chronic hepatitis C in dual infection?

Hepatitis C and brucellosis are infectious diseases that occur worldwide, and both are endemic in Egypt. Co-infection with both agents is possible, and this can involve the liver in various ways. In this study, we investigated serum tissue inhibitor metalloproteinase-1 (TIMP-1), viral load, and liver functions in patients co-infected with hepatitis C virus (HCV) before and after brucellosis treatment. Over 3 years, 241 consecutive HCV patients (before interferon therapy was received) with recurrent fever who had occupational contact with animals were tested for brucellosis co-infection by a standard tube agglutination test. In patients with dual infection, viraemia (RT-PCR), TIMP-1 measured by ELISA, and liver functions were assessed and re-evaluated 2 months after brucellosis treatment. The number of patients with HCV/brucellosis co-infection was 32 out of 241 (13.3%). TIMP-1, viraemia, AST, ALT and bilirubin showed significant decrease (improvement) after brucellosis treatment (p < 0.001) but an insignificant difference (p > 0.05) with regard to serum albumin and prothrombin concentration. The study revealed that brucellosis is an important infection in HCV-infected patients and can aggravate the course of disease, suggesting that early treatment and prevention are important.

Ontogeny of Toll-like receptor mediated cytokine responses of South African infants throughout the first year of life

The first year of life represents a time of marked susceptibility to infections; this is particularly true for regions in sub-Saharan Africa. As innate immunity directs the adaptive immune response, the observed increased risk for infection as well as a suboptimal response to vaccination in early life may be due to less effective innate immune function. In this study, we followed a longitudinal cohort of infants born and raised in South Africa over the first year of life, employing the most comprehensive analysis of innate immune response to stimulation published to date. Our findings reveal rapid changes in innate immune development over the first year of life. This is the first report depicting dramatic differences in innate immune ontogeny between different populations in the world, with important implications for global vaccination strategies.

Antigen-specific memory T cell responses after vaccination with an oral killed cholera vaccine in Bangladeshi children and comparison to responses in patients with naturally acquired cholera

Young children, older children, and adults develop comparable levels and durations of immunity following cholera. In comparison, young children receiving oral killed cholera vaccines (OCV) develop a lower level and shorter duration of protection than those of older children and adults. The reasons for this are unclear. We investigated OCV-induced memory T cell responses in younger and older children and compared responses to those in children with cholera. We found that patients with cholera developed significant levels of toxin-specific effector memory T cells (T(EM)) with follicular helper and gut-homing characteristics. Older children (6 to 14 years of age) receiving two doses of OCV containing recombinant cholera toxin B subunit (rCTB) had more modest T(EM) responses with follicular helper and gut-homing characteristics, but younger vaccinees (24 to 71 months of age) did not develop T(EM) responses. The T(EM) response correlated positively with subsequent IgG memory B cell responses specific to rCTB in older vaccinees. Cytokine analyses indicated that cholera patients developed significant Th1, Th17, and Th2 responses, while older children receiving vaccine developed more modest increases in Th1 and Th17 cells. Younger vaccinees had no increase in Th1 cells, a decrease in Th17 cells, and an increase in regulatory T (Treg) cells. Our findings suggest that T cell memory responses are markedly diminished in children receiving OCV, especially young children, compared to responses following naturally acquired cholera, and that these differences affect subsequent development of memory B cell responses. These findings may explain the lower efficacy and shorter duration of protection afforded by OCV in young children.

Individual variation and longitudinal pattern of genome-wide DNA methylation from birth to the first two years of life

Prenatal development and early childhood are critical periods for establishing the tissue-specific epigenome, and may have a profound impact on health and disease in later life. However, epigenomic profiles at birth and in early childhood remain largely unexplored. The focus of this report is to examine the individual variation and longitudinal pattern of genome-wide DNA methylation levels from birth through the first two years of life in 105 Black children (59 males and 46 females) enrolled at the Boston Medical Center. We performed epigenomic mapping of cord blood at birth and venous blood samples from the same set of children within the first two years of life using Illumina Infinium Humanmethylation27 BeadChip. We observed a wide range of inter-individual variations in genome-wide methylation at each time point including lower levels at CpG islands, TSS200, 5'UTR and 1st Exon locations, but significantly higher levels in CpG shores, shelves, TSS1500, gene body and 3'UTR. We identified CpG sites with significant intra-individual longitudinal changes in the first two years of life throughout the genome. Specifically, we identified 159 CpG sites in males and 149 CpG sites in females with significant longitudinal changes defined by both statistical significance and magnitude of changes. These significant CpG sites appeared to be located within genes with important biological functions including immunity and inflammation. Further studies are needed to replicate our findings, including analysis by specific cell types, and link those individual variations and longitudinal changes with specific health outcomes in early childhood and later life.

Thymopoiesis and regulatory T cells in healthy children and adolescents

OBJECTIVES

The purpose of this study was to investigate the association between T cell receptor excision circle levels in peripheral blood mononuclear cells and regulatory T cells that co-express CD25 and Foxp3 in healthy children and adolescents of different ages.

MATERIALS AND METHODS

The quantification of signal-joint T-cell receptor excision circle levels in the genomic DNA of peripheral blood mononuclear cells was performed using real-time quantitative PCR. The analysis of CD4, CD8, CD25, and Foxp3 expression was performed using flow cytometry.

RESULTS

Ninety-five healthy controls (46 females and 49 males) ranging in age from 1 to 18 years were analyzed. The mean T-cell receptor excision circle count in all individuals was 89.095 ± 36.790 T-cell receptor excision circles per microgram of DNA. There was an inverse correlation between T-cell receptor excision circles counts and age (r = -0.846; p<0.001) as well as between the proportion of CD4(+)CD25(+)Foxp3(+) T cells and age (r = -0.467; p = 0.04). In addition, we observed a positive correlation between the amount of CD4(+)CD25(+)Foxp3(+) T cells and the amount of T-cell receptor excision circles per microgram of DNA in individuals of all ages (r = -0.529; p = 0.02).

CONCLUSIONS

In this study, we observed a decrease in the thymic function with age based on the fact that the level of T-cell receptor excision circles in the peripheral blood positively correlated with the proportion of regulatory T cells in healthy children and adolescents. These findings indicate that although T-cell receptor excision circles and regulatory T cells levels decrease with age, homeostasis of the immune system and relative regulatory T cells population levels are maintained in the peripheral blood.

Restricting microbial exposure in early life negates the immune benefits associated with gut colonization in environments of high microbial diversity

Background

Acquisition of the intestinal microbiota in early life corresponds with the development of the mucosal immune system. Recent work on caesarean-delivered infants revealed that early microbial composition is influenced by birthing method and environment. Furthermore, we have confirmed that early-life environment strongly influences both the adult gut microbiota and development of the gut immune system. Here, we address the impact of limiting microbial exposure after initial colonization on the development of adult gut immunity.

Methodology/Principal Findings

Piglets were born in indoor or outdoor rearing units, allowing natural colonization in the immediate period after birth, prior to transfer to high-health status isolators. Strikingly, gut closure and morphological development were strongly affected by isolator-rearing, independent of indoor or outdoor origins of piglets. Isolator-reared animals showed extensive vacuolation and disorganization of the gut epithelium, inferring that normal gut closure requires maturation factors present in maternal milk. Although morphological maturation and gut closure were delayed in isolator-reared animals, these hard-wired events occurred later in development. Type I IFN, IL-22, IL-23 and Th17 pathways were increased in indoor-isolator compared to outdoor-isolator animals during early life, indicating greater immune activation in pigs originating from indoor environments reflecting differences in the early microbiota. This difference was less apparent later in development due to enhanced immune activation and convergence of the microbiota in all isolator-reared animals. This correlated with elevation of Type I IFN pathways in both groups, although T cell pathways were still more affected in indoor-reared animals.

Conclusions/Significance

Environmental factors, in particular microbial exposure, influence expression of a large number of immune-related genes. However, the homeostatic effects of microbial colonization in outdoor environments require sustained microbial exposure throughout development. Gut development in high-hygiene environments negatively impacts on normal succession of the gut microbiota and promotes innate immune activation which may impair immune homeostasis.

Impact of early life exposures to geohelminth infections on the development of vaccine immunity, allergic sensitization, and allergic inflammatory diseases in children living in tropical Ecuador: the ECUAVIDA birth cohort study

Background

Geohelminth infections are highly prevalent infectious diseases of childhood in many regions of the Tropics, and are associated with significant morbidity especially among pre-school and school-age children. There is growing concern that geohelminth infections, particularly exposures occurring during early life in utero through maternal infections or during infancy, may affect vaccine immunogenicity in populations among whom these infections are endemic. Further, the low prevalence of allergic disease in the rural Tropics has been attributed to the immune modulatory effects of these infections and there is concern that widespread use of anthelmintic treatment in high-risk groups may be associated with an increase in the prevalence of allergic diseases. Because the most widely used vaccines are administered during the first year of life and the antecedents of allergic disease are considered to occur in early childhood, the present study has been designed to investigate the impact of early exposures to geohelminths on the development of protective immunity to vaccines, allergic sensitization, and allergic disease.

Methods/Design

A cohort of 2,403 neonates followed up to 8 years of age. Primary exposures are infections with geohelminth parasites during the last trimester of pregnancy and the first 2 years of life. Primary study outcomes are the development of protective immunity to common childhood vaccines (i.e. rotavirus, Haemophilus influenzae type B, Hepatitis B, tetanus toxoid, and oral poliovirus type 3) during the first 5 years of life, the development of eczema by 3 years of age, the development of allergen skin test reactivity at 5 years of age, and the development of asthma at 5 and 8 years of age. Potential immunological mechanisms by which geohelminth infections may affect the study outcomes will be investigated also.

Discussion

The study will provide information on the potential effects of early exposures to geohelminths (during pregnancy and the first 2 years of life) on the development of vaccine immunity and allergy. The data will inform an ongoing debate of potential effects of geohelminths on child health and will contribute to policy decisions on new interventions designed to improve vaccine immunogenicity and protect against the development of allergic diseases.

Trial registration

Current Controlled Trials ISRCTN41239086.