Th1/Th2 balance in infection

Multilayer Adjuvanted Influenza Protein Nanoparticles Improve Intranasal Delivery and Antigen-Specific Immunity

Intranasal vaccination is a desired route for protection against influenza viruses by mucosal and systemic immunity. However, the nasal mucosa impedes the intranasal delivery of vaccines. Here, we formulated layer-by-layer (LBL) influenza vaccine nanoparticles for effective intranasal delivery by coating them with alternating mucoadhesive cationic chitosan and muco-inert anionic CpG adjuvants. The nanoparticle cores were formed by desolvating influenza M2e antigen and coating it with hemagglutinin (HA) antigen via biotin-streptavidin conjugation. LBL modification promoted nasal delivery and interaction with the resident immune cells. Intranasal administration with LBL nanoparticles significantly improved cellular and humoral immune responses against HA and M2e including high IgA titers, a hallmark of potent mucosal immunity and persistence of immune responses. Distinct trends for antigen-specific immune responses were observed for different routes of vaccination. The enhanced immune responses conferred mice protection against the influenza challenge and prominently reduced viral titers, demonstrating the effectiveness of intranasal LBL vaccine nanoparticles.

Chitooligosaccharides suppress airway inflammation, fibrosis, and mucus hypersecretion in a house dust mite-induced allergy model

Background

Respiratory allergy is a serious respiratory disorder characterized by inflammation, mucus hypersecretion, and airway tissue sclerosis. Disruption of the T helper 1 (Th1) and T helper 2 (Th2) immune systems by stimuli induced by house dust mites (HDM) and fine particulate matter leads to the secretion of various inflammatory cytokines, resulting in immune respiratory diseases characterized by airway inflammation. Chitooligosaccharides (COS) are known for their antioxidant and anti-inflammatory properties.

Methods

Human airway epithelial cells (BEAS-2B) were cultured in DMEM/F12 medium containing COS at concentrations of 25-100 µg/ml for 24 h. No intracellular toxicity was observed up to 1,000 µg/ml. Cell experiments were conducted at COS concentrations below 100 µg/ml, while animal experiments were performed at concentrations below 100 mg/kg body weight for 4 weeks. Samples of right lung tissue obtained from the experimental animals were used for gene and protein expression analysis, whereas samples of contralateral lung tissue were used for immunohistochemical analysis.

Results

COS regulated Th1 immunity by inhibiting major cytokines, including inflammatory tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), in BEAS-2B cells. In the HDM-induced allergic respiratory model, COS suppressed the infiltration of inflammatory cells around the airways and inhibited the mRNA expression of Th1 immune cytokines in lung tissues, while also reducing the expression of nuclear factor kappa B (NF-κB)-related proteins. Furthermore, the results confirmed the suppression of the levels of immunoglobulin E (IgE) in the blood secreted by mast cells activated by HDM, which led to a reduction in allergic mucus hypersecretion and airway sclerosis.

Conclusion

In summary, COS are thought to improve airway resistance by alleviating inflammatory allergic respiratory diseases caused by HDM and are regarded as substances that regulate the balance of the Th1 and Th2 immune systems in epithelial cells affected by mucus hypersecretion.

Impact of diabetes mellitus on tuberculosis prevention, diagnosis, and treatment from an immunologic perspective

The coexistence of diabetes mellitus (DM) and tuberculosis (TB) presents a significant global burden, with DM being recognized as a major risk factor for TB. This review comprehensively analyzes the immunological aspects of DM-TB comorbidity, shedding light on the impact of DM on TB pathogenesis and immune responses. It reveals that high blood glucose levels in TB patients contribute to reduced innate immune cell count, compromised phagocytic function, and delayed antigen presentation. These factors ultimately impair the clearance of Mycobacterium tuberculosis (MTB) and delay adaptive immune responses. With the interaction between TB and DM, there is an increase in inflammation and elevated secretion of pro-inflammatory cytokines by immune cells. This exacerbates the inflammatory response and contributes to poor treatment outcomes in TB. Moreover, the review explores the effects of DM on TB prevention, diagnosis, and treatment. It highlights how poor glycemic control, insulin resistance (IR), DM complications, and genetic factors increase the risk of MTB infection in individuals with DM. Additionally, DM-related immune suppression adversely affects the sensitivity of traditional diagnostic tests for TB, potentially resulting in underdiagnosis and delayed intervention. To mitigate the burden of TB in DM patients, the review emphasizes the need for further research on the mechanisms underlying DM reactivation in latent TB infection (LTBI). It shows how important it is to find and treat LTBI in DM patients as soon as possible and suggests looking into biomarkers that are specific to DM to make diagnosis more accurate.

Saponin nanoparticle adjuvants incorporating Toll-like receptor agonists drive distinct immune signatures and potent vaccine responses

Over the past few decades, the development of potent and safe immune-activating adjuvant technologies has become the heart of intensive research in the constant fight against highly mutative and immune evasive viruses such as influenza, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and human immunodeficiency virus (HIV). Herein, we developed a highly modular saponin-based nanoparticle platform incorporating Toll-like receptor agonists (TLRas) including TLR1/2a, TLR4a, and TLR7/8a adjuvants and their mixtures. These various TLRa-saponin nanoparticle adjuvant constructs induce unique acute cytokine and immune-signaling profiles, leading to specific T helper responses that could be of interest depending on the target disease for prevention. In a murine vaccine study, the adjuvants greatly improved the potency, durability, breadth, and neutralization of both COVID-19 and HIV vaccine candidates, suggesting the potential broad application of these adjuvant constructs to a range of different antigens. Overall, this work demonstrates a modular TLRa-SNP adjuvant platform that could improve the design of vaccines and affect modern vaccine development.

The Th1/Th2 paradigm: A misrepresentation of helper T cell plasticity

For decades, the Th1/2 paradigm has been used to classify immune responses as either Th1 or Th2-biased. However, in recent years, a staggering amount of evidence has emerged to support rejection of the classical Th1/Th2 paradigm, such as the discoveries of new helper T cell subsets, helper T cell plasticity and protective mixed-Th1/Th2 responses. This opinion piece investigates the shortcomings of classical Th1/Th2 paradigm in the context of recent works, with the goal of facilitating the development of newer models to represent the diversity of Th cells.

Saponin Nanoparticle Adjuvants Incorporating Toll-Like Receptor Agonists Drive Distinct Immune Signatures and Potent Vaccine Responses

Over the past few decades, the development of potent and safe immune-activating adjuvant technologies has become the heart of intensive research in the constant fight against highly mutative and immune evasive viruses such as influenza, SARS-CoV-2, and HIV. Herein, we developed a highly modular saponin-based nanoparticle platform incorporating toll-like receptor agonists (TLRas) including TLR1/2a, TLR4a, TLR7/8a adjuvants and their mixtures. These various TLRa-SNP adjuvant constructs induce unique acute cytokine and immune-signaling profiles, leading to specific Th-responses that could be of interest depending on the target disease for prevention. In a murine vaccine study, the adjuvants greatly improved the potency, durability, breadth, and neutralization of both COVID-19 and HIV vaccine candidates, suggesting the potential broad application of these adjuvant constructs to a range of different antigens. Overall, this work demonstrates a modular TLRa-SNP adjuvant platform which could improve the design of vaccines for and dramatically impact modern vaccine development.

Teaser

Saponin-TLRa nanoadjuvants provide distinct immune signatures and drive potent, broad, durable COVID-19 and HIV vaccine responses.

From immunology to artificial intelligence: revolutionizing latent tuberculosis infection diagnosis with machine learning

Latent tuberculosis infection (LTBI) has become a major source of active tuberculosis (ATB). Although the tuberculin skin test and interferon-gamma release assay can be used to diagnose LTBI, these methods can only differentiate infected individuals from healthy ones but cannot discriminate between LTBI and ATB. Thus, the diagnosis of LTBI faces many challenges, such as the lack of effective biomarkers from Mycobacterium tuberculosis (MTB) for distinguishing LTBI, the low diagnostic efficacy of biomarkers derived from the human host, and the absence of a gold standard to differentiate between LTBI and ATB. Sputum culture, as the gold standard for diagnosing tuberculosis, is time-consuming and cannot distinguish between ATB and LTBI. In this article, we review the pathogenesis of MTB and the immune mechanisms of the host in LTBI, including the innate and adaptive immune responses, multiple immune evasion mechanisms of MTB, and epigenetic regulation. Based on this knowledge, we summarize the current status and challenges in diagnosing LTBI and present the application of machine learning (ML) in LTBI diagnosis, as well as the advantages and limitations of ML in this context. Finally, we discuss the future development directions of ML applied to LTBI diagnosis.

Sex-Specific Immune Responses to Seasonal Influenza Vaccination in Diabetic Individuals: Implications for Vaccine Efficacy

Seasonal influenza vaccination has different implications on the immune response depending on the comorbidities. Diabetes is one such critical disease that increases the patient's susceptibility to influenza and suppresses vaccine efficacy and immunity. The sex of the individuals also plays a definitive role in the immune responses to both the vaccine and the infection. This study aims to understand the efficacy of the seasonal vaccine against influenza in diabetic groups and undergoing immune mechanisms in different sexes (females and males). In this study, we are reporting about a switching of the immune response of the infected and vaccinated diabetic females towards stronger Th1/Th17 responses with suppressed humoral immunity. They show increased cDC1, enhanced proinflammatory activities within T cells, CD8T activation, Th17 proliferation, and the majority of IgG2 antibody subtypes with reduced neutralization potential. Males with diabetes exhibit enhanced humoral Th2-immunity than the nondiabetic group. They exhibit higher cDC2, and DEC205 levels within them with an increase in plasma B lymphocytes, higher IgG1 subtypes in plasma cells, and influenza-hemagglutinin-specific IgG titer with stronger virus neutralization potential. Males with diabetes recovered better than the females as observed from the changes in their body weight. This study highlights the critical immune mechanisms and sex-specific swapping of their preferred immune response pathways against influenza after vaccination during diabetes. We propose a need for a sex-specific customized vaccine regimen to be implemented against influenza for individuals having diabetes to exploit the manifested strength and weakness in their protective immunity.

Self-Adjuvanting Calcium-Phosphate-Coated Microcrystal-Based Vaccines Induce Pyroptosis in Human and Livestock Immune Cells

Successful vaccines require adjuvants able to activate the innate immune system, eliciting antigen-specific immune responses and B-cell-mediated antibody production. However, unwanted secondary effects and the lack of effectiveness of traditional adjuvants has prompted investigation into novel adjuvants in recent years. Protein-coated microcrystals modified with calcium phosphate (CaP-PCMCs) in which vaccine antigens are co-immobilised within amino acid crystals represent one of these promising self-adjuvanting vaccine delivery systems. CaP-PCMCs has been shown to enhance antigen-specific IgG responses in mouse models; however, the exact mechanism of action of these microcrystals is currently unclear. Here, we set out to investigate this mechanism by studying the interaction between CaP-PCMCs and mammalian immune cells in an in vitro system. Incubation of cells with CaP-PCMCs induced rapid pyroptosis of peripheral blood mononuclear cells and monocyte-derived dendritic cells from cattle, sheep and humans, which was accompanied by the release of interleukin-1β and the activation of Caspase-1. We show that this pyroptotic event was cell-CaP-PCMCs contact dependent, and neither soluble calcium nor microcrystals without CaP (soluble PCMCs) induced pyroptosis. Our results corroborate CaP-PCMCs as a promising delivery system for vaccine antigens, showing great potential for subunit vaccines where the enhancement or find tuning of adaptive immunity is required.

T cells in health and disease

T cells are crucial for immune functions to maintain health and prevent disease. T cell development occurs in a stepwise process in the thymus and mainly generates CD4+ and CD8+ T cell subsets. Upon antigen stimulation, naïve T cells differentiate into CD4+ helper and CD8+ cytotoxic effector and memory cells, mediating direct killing, diverse immune regulatory function, and long-term protection. In response to acute and chronic infections and tumors, T cells adopt distinct differentiation trajectories and develop into a range of heterogeneous populations with various phenotype, differentiation potential, and functionality under precise and elaborate regulations of transcriptional and epigenetic programs. Abnormal T-cell immunity can initiate and promote the pathogenesis of autoimmune diseases. In this review, we summarize the current understanding of T cell development, CD4+ and CD8+ T cell classification, and differentiation in physiological settings. We further elaborate the heterogeneity, differentiation, functionality, and regulation network of CD4+ and CD8+ T cells in infectious disease, chronic infection and tumor, and autoimmune disease, highlighting the exhausted CD8+ T cell differentiation trajectory, CD4+ T cell helper function, T cell contributions to immunotherapy and autoimmune pathogenesis. We also discuss the development and function of γδ T cells in tissue surveillance, infection, and tumor immunity. Finally, we summarized current T-cell-based immunotherapies in both cancer and autoimmune diseases, with an emphasis on their clinical applications. A better understanding of T cell immunity provides insight into developing novel prophylactic and therapeutic strategies in human diseases.

Invited review: From heat stress to disease-Immune response and candidate genes involved in cattle thermotolerance

Heat stress implies unfavorable effects on primary and functional traits in dairy cattle and, in consequence, on the profitability of the whole production system. The increasing number of days with extreme hot temperatures suggests that it is imperative to detect the heat stress status of animals based on adequate measures. However, confirming the heat stress status of an individual is still challenging, and, in consequence, the identification of novel heat stress biomarkers, including molecular biomarkers, remains a very relevant issue. Currently, it is known that heat stress seems to have unfavorable effects on immune system mechanisms, but this information is of limited use in the context of heat stress phenotyping. In addition, there is a lack of knowledge addressing the molecular mechanisms linking the relevant genes to the observed phenotype. In this review, we explored the potential molecular mechanisms explaining how heat stress affects the immune system and, therefore, increases the occurrence of immune-related diseases in cattle. In this regard, 2 relatively opposite hypotheses are under focus: the immunosuppressive action of cortisol, and the proinflammatory effect of heat stress. In both hypotheses, the modulation of the immune response during heat stress is highlighted. Moreover, it is possible to link candidate genes to these potential mechanisms. In this context, immune markers are very valuable indicators for the detection of heat stress in dairy cattle, broadening the portfolio of potential biomarkers for heat stress.

CpG 684: an effective adjuvant for the inactivated COVID-19 vaccine in mice

Aim

This study used CpG 684 as adjuvant of inactivated COVID-19 vaccine to detect a humoral and cellular immune response in mice.

Materials & methods

We used 10 and 20 µg CpG 684 as adjuvants of an inactivated COVID-19 vaccine to immunize mice. IgG, IgG1, IgG2a, IgG2b and IgM binding antibodies were detected in serum by ELISA. The IFN-γ cytokine was detected by ELISPOT.

Results

CpG 684 improved spike-specific IgG and IgM subtype binding antibodies and increased the neutralizing antibody titer against prototype, Delta and Beta strains. CpG 684 also improved cellular immune response.

Conclusion

CpG 684 is an effective adjuvant for inactivated COVID-19 vaccine.

Pulmonary immune profiling of SIDS: impaired immune maturation and age-related cytokine imbalance

BACKGROUND

For sudden infant death syndrome (SIDS), an impaired immunocompetence has been discussed for a long time. Cytokines and chemokines are soluble immune mediators (SIM) whose balance is essential for the immune status. We hypothesized that an imbalanced immune response might contribute to the etiology of SIDS.

METHODS

We investigated 27 cytokines, chemokines, and growth factors in protein lysates of lungs derived from 29 SIDS cases and 15 control children deceased for other reasons.

RESULTS

Except for the CCL5, no significant differences were detected in the lungs between SIDS cases with and without mild upper respiratory tract infections. In contrast, IL-1RA, IL-7, IL-13, and G-CSF were decreased in the merged SIDS cases compared to control cases without evidence of infection. Plotting SIM concentrations against infant age resulted in increasing concentrations in control but not in SIDS lungs, indicating a disturbed immune maturation. Moreover, an age-dependent shift towards a Th2-related pattern was observed in SIDS.

CONCLUSIONS

Our findings suggest that an impaired maturation of the immune system, an insufficient response to respiratory pathogens, and an immune response modulated by Th1/Th2 imbalance might play a possible role in triggering SIDS. These findings might in part be explained by chronic stress.

IMPACT

Maturation of the cytokine and chemokine network may be impaired in SIDS. An imbalance between Th1- and Th2-related cytokines, which may reflect a state of chronic stress causing a more Th2 shift. An impaired immune maturation, an insufficient response to respiratory pathogens, and an immune response modulated by Th1/Th2 imbalance might play a possible role in SIDS.

Effect of IL-10 in the pathogenesis of HIV/AIDS patients with cryptococcal meningitis

This study aimed to explore the role of IL-10 in the pathogenesis of HIV/AIDS patients with cryptococcal meningitis (CM).Patients were assigned into 4 groups (n = 40/group): group A (HIV/AIDS with CM), group B (HIV/AIDS with tuberculosis), group C (HIV/AIDS), and group D (CM). The levels of IL-10 and associated indicators were measured and the correlations were analyzed by Pearson correlation and partial correlation method. In plasma and cerebrospinal fluid (CSF), no significant difference was observed on IL-10 level between group A and other groups (P > 0.050). R values for IL-10 and relevant indicators in blood were as follows (P < 0.050): group A, IFN-γ (-0.377), IL-12 (0.743), IL-4 (0.881), and IL-6 (0.843); group B, IL-12 (0.740), IL-4 (0.573), and IL-6 (0.900); group C, IL-12 (0.402) and IL-4 (0.896); group D, IL-12 (0.575), IL-4 (0.852), and CD8 (0.325). R values for IL-10 and related indicators in CSF were as follows (P < 0.050): group A, TNF-α (0.664), IL-4 (0.852), white blood cells (WBCs, 0.321) and total protein (TP, 0.330); group B, TNF-α (0.566), IL-4 (0.702), and lactate dehydrogenase (LDH, 0.382); group D, IFN-γ (0.807) and IL-4 (0.441). IL-10 level was positively correlated with IL-4, IL-6, IL-12, TNF-α, WBC, and TP in blood or CSF, and negatively correlated with IFN-γ in blood, suggesting that IL-10 affected both pro-inflammatory and anti-inflammatory activities in the pathogenesis of HIV/AIDS with CM.

Longevity of memory B cells and antibodies, as well as the polarization of effector memory helper T cells, are associated with disease severity in patients with COVID-19 in Bangladesh

The longevity of immune responses induced by different degrees of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection provides information important to understanding protection against coronavirus disease 2019 (COVID-19). Here, we report the persistence of SARS-CoV-2 spike receptor-binding domain (RBD) specific antibodies and memory B cells recognizing this antigen in sequential samples from patients in Bangladesh with asymptomatic, mild, moderate and severe COVID-19 out to six months following infection. Since the development of long-lived memory B cells, as well as antibody production, is likely to be dependent on T helper (Th) cells, we also investigated the phenotypic changes of Th cells in COVID-19 patients over time following infection. Our results show that patients with moderate to severe COVID-19 mounted significant levels of IgG antibodies out to six months following infection, while patients with asymptomatic or mild disease had significant levels of IgG antibodies out to 3 months following infection, but these then fell more rapidly at 6 months than in patients with higher disease severity. Patients from all severity groups developed circulating memory B cells (MBCs) specific to SARS-CoV-2 spike RBD by 3 months following infection, and these persisted until the last timepoint measured at 6 months. A T helper cell response with an effector memory phenotype was observed following infection in all symptomatic patients, while patients with asymptomatic infection had no significant increases in effector Th1, Th2 and Th17 effector memory cell responses. Our results suggest that the strength and magnitude of antibody and memory B cells induced following SARS-CoV-2 infection depend on the severity of the disease. Polarization of the Th cell response, with an increase in Th effector memory cells, occurs in symptomatic patients by day 7 following infection, with increases seen in Th1, Th2, Th17 and follicular helper T cell subsets.

Genetic resilience in chickens against bacterial, viral and protozoal pathogens

The genome contributes to the uniqueness of an individual breed, and enables distinctive characteristics to be passed from one generation to the next. The allelic heterogeneity of a certain breed results in a different response to a pathogen with different genomic expression. Disease resistance in chicken is a polygenic trait that involves different genes that confer resistance against pathogens. Such resistance also involves major histocompatibility (MHC) molecules, immunoglobulins, cytokines, interleukins, T and B cells, and CD4+ and CD8+ T lymphocytes, which are involved in host protection. The MHC is associated with antigen presentation, antibody production, and cytokine stimulation, which highlight its role in disease resistance. The natural resistance-associated macrophage protein 1 (Nramp-1), interferon (IFN), myxovirus-resistance gene, myeloid differentiation primary response 88 (MyD88), receptor-interacting serine/threonine kinase 2 (RIP2), and heterophile cells are involved in disease resistance and susceptibility of chicken. Studies related to disease resistance genetics, epigenetics, and quantitative trait loci would enable the identification of resistance markers and the development of disease resistance breeds. Microbial infections are responsible for significant outbreaks and have blighted the poultry industry. Breeding disease-resistant chicken strains may be helpful in tackling pathogens and increasing the current understanding on host genetics in the fight against communicable diseases. Advanced technologies, such as the CRISPR/Cas9 system, whole genome sequencing, RNA sequencing, and high-density single nucleotide polymorphism (SNP) genotyping, aid the development of resistant breeds, which would significantly decrease the use of antibiotics and vaccination in poultry. In this review, we aimed to reveal the recent genetic basis of infection and genomic modification that increase resistance against different pathogens in chickens.

Immune Response to Conjugates of Fragments of the Type K9 Capsular Polysaccharide of Acinetobacter baumannii with Carrier Proteins

The clonal bacterial species Acinetobacter baumannii is an emerging multidrug-resistant pathogen which causes high-lethality infections. Cells of A. baumannii are surrounded by the type-specific capsular polysaccharide (CPS), which provides resistance to the protective mechanisms of the host and is considered a target for immunization. The conjugates of three inert carrier proteins and A. baumannii type K9 CPS fragments, which contained various numbers of oligosaccharide repeats (K-units), were synthesized by periodate oxidation and squaric acid chemistry. The conjugates were applied to immunize mice, and chemical synthesis by squaric acid was shown to significantly improve the immunogenic properties of glycoconjugate. In BALB/c mice, IgG antibodies were predominant among type K9 CPS reactive antibodies, and their total content was several times higher than that of IgM. Immune sera were characterized by their opsonization ability during practically the entire lives of the experimental mice. The sera were cross-reactive, but the highest specificity was observed against the antigen (type K9 CPS) used for immunization. The immunization of BALB/c and ICR-1 mice with a glycoconjugate without adjuvants led to varying degrees of stimulation of IL-10, IL-17A, and TNF-α production, but not IL-4 production in the ICR-1 mice. This is in contrast to the BALB/c mice, in which γ-IFN production was also activated. The protective effectiveness of the glycoconjugates obtained by squaric acid chemistry was demonstrated by experiments that involved challenging immunized and nonimmunized animals with a lethal dose of A. baumannii K9. IMPORTANCE Immunization by glycoconjugates with A. baumannii type K9 CPS fragments induced a high level of antibodies (predominantly IgG) in sera, which reacted specifically with the CPS of A. baumannii type K9, as well as a long immunological memory. The sera of immunized animals efficiently opsonized A. baumannii type K9. Immunization resulted in the balanced production of pro/anti-inflammatory lymphokines and protective antibodies to ensure the survival of the mice infected with A. baumannii. The level of specific antibodies was sufficient to provide protective immunity against the challenge by A. baumannii, making this approach applicable in the development of vaccine preparations.

Tim-3/Galectin-9 signaling pathway is involved in the cytokine changes in mice with alveolar echinococcosis

BACKGROUND

Tim-3/Galectin-9 is involved in the immune escape of many pathogens. However, the role of Tim-3/Galectin-9 in persistent infection of Echinococcus multilocularis (Em), which is related to immune escape, is still unclear.

OBJECTIVE

To investigate the role of Tim-3/Galectin-9 and related cytokines in mice with persistent infection of Em.

METHODS

Em infection model was established by injecting the protoscoleces. Serum was collected at days 2, 8, 30, 60, 90, 180 and 270 after infection. Lymphocytes were isolated from liver tissue samples with Ficoll. Tim-3 + CD4 + T percentage was analyzed by flow cytometry. CD4 + T cells were isolated from liver tissues of Em infected mice and cultured in vitro. The mRNA levels of Tim-3, Galectin-9, IFN-γ and IL-4 were detected by qRT-PCR. Cytokine levels in serum and culture supernatant (IFN-γ and IL-4) were analyzed by cytometric bead array.

RESULTS

The expression of Tim-3 and Galectin-9 mRNA significantly increased after 30 days of infection, reached peak on day 90, and then decreased slightly on days 180-270. The expression of IFN-γ mRNA, increased on day 2 and 8 after infection, slightly decreased on days 30-60, and obvious decreased on days 90-270, but were still higher than those of the control group. The expression of IL-4 mRNA gradually increased along with the time of infection. In serum of Em infected mice, level of IFN-γ peaked at day 30 and then gradually decreased; whereas IL-4 level peaked at day 90 and then gradually decreased. In vitro experiment found that Tim-3/Galectin-9 directly caused the changes in the levels of IFN-γ and IL-4.

CONCLUSIONS

Tim-3/Galectin-9 signaling pathway may be involved in the development of persistent infection of Em by regulating the production of Th1 and Th2 cytokines.

T Cell Metabolism in Infection

T lymphocytes (T cells) are divided into two functionally different subgroups the CD4+ T helper cells (Th) and the CD8+ cytotoxic T lymphocytes (CTL). Adequate CD4 and CD8 T cell activation to proliferation, clonal expansion and effector function is crucial for efficient clearance of infection by pathogens. Failure to do so may lead to T cell exhaustion. Upon activation by antigen presenting cells, T cells undergo metabolic reprograming that support effector functions. In this review we will discuss how metabolic reprograming dictates functionality during viral infections using severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human immunodeficiency virus (HIV) as examples. Moreover, we will briefly discuss T cell metabolic programs during bacterial infections exemplified by Mycobacterium tuberculosis (MT) infection.

An Early Th1 Response Is a Key Factor for a Favorable COVID-19 Evolution

The Th1/Th2 balance plays a crucial role in the progression of different pathologies and is a determining factor in the evolution of infectious diseases. This work has aimed to evaluate the early, or on diagnosis, T-cell compartment response, T-helper subsets and anti-SARS-CoV-2 antibody specificity in COVID-19 patients and to classify them according to evolution based on infection severity. A unicenter, randomized group of 146 COVID-19 patients was divided into four groups in accordance with the most critical events during the course of disease. The immunophenotype and T-helper subsets were analyzed by flow cytometry. Asymptomatic SARS-CoV-2 infected individuals showed a potent and robust Th1 immunity, with a lower Th17 and less activated T-cells at the time of sample acquisition compared not only with symptomatic patients, but also with healthy controls. Conversely, severe COVID-19 patients presented with Th17-skewed immunity, fewer Th1 responses and more activated T-cells. The multivariate analysis of the immunological and inflammatory parameters, together with the comorbidities, showed that the Th1 response was an independent protective factor for the prevention of hospitalization (OR 0.17, 95% CI 0.03–0.81), with an AUC of 0.844. Likewise, the Th1 response was found to be an independent protective factor for severe forms of the disease (OR 0.09, 95% CI: 0.01–0.63, p = 0.015, AUC: 0.873). In conclusion, a predominant Th1 immune response in the acute phase of the SARS-CoV-2 infection could be used as a tool to identify patients who might have a good disease evolution.

Antenatal and postpartum immunological markers levels in women with HIV infection and malnutrition in a low resource setting: A pilot study

Objectives: Both, Human Immunodeficiency Virus (HIV) infection and malnutrition are major challenges in pregnancy and postpartum in low-resource settings and the respective cytokine levels remain poorly described. The main objectives of this study were to find immune markers that are associated with HIV infection and malnutrition in pregnant women and to determine how these would change at 14 weeks postpartum.Method: Pregnant women of at least 20 weeks gestational age were enrolled into this longitudinal observational single centre pilot study at 4 primary health clinics in high-density areas around Harare, Zimbabwe. Socio-demographic and clinical data including plasma samples were collected in pregnancy and 14 weeks postpartum (PP). Mid-upper-arm circumference (MUAC) ≤23 cm was used as an indicator for malnourishment. Fifty-six cytokines and chemokines were assayed in plasma using the Mesoscale multiplex assay. We determined cytokine/chemokine levels including markers for vascular injury in HIV-infection and malnutrition. Associations remaining significant after multiple test correction were confirmed in multivariable analyses after controlling for confounders.Results: Ninety-seven pregnant women were recruited for this study and from these, 44 were randomly selected for cytokine assaying of which 20 HIV infected, 15 malnourished, and 9 well-nourished HIV uninfected participants. HIV infection was associated with significantly higher interleukin (IL)-4 ( q < 0.05) and IL-10 ( q < 0.001) in pregnancy. Longitudinally, IL-4 ( q < 0.01) and IL-10 ( q < 0.001) significantly increased in HIV uninfected women whilst in the HIV-infected both were non-significantly decreased. IL-8 (q < 0.05) levels significantly increased in HIV-infected women from pregnancy to 14 weeks PP. Vascular Cell Adhesion Molecule 1 (VCAM-1) ( q < 0.05) and interleukin-1 receptor antagonist (IL-1RA) ( q < 0.05) were significantly lower in malnourished women in pregnancy and 14 weeks PP, respectively. Conclusions: IL-4, IL-8, IL-10, and VCAM-1 are potential biomarkers for monitoring immune functioning in HIV-infected pregnant women and malnutrition. However, studies with larger sample size are warranted to confirm these findings.

IL-6 and IL-10 Are Associated With Gram-Negative and Gram-Positive Bacteria Infection in Lymphoma

To investigate the Th1/Th2 cytokine profile in patients with lymphoma during the myelosuppression stage of infection. 52 patients with gram-negative bacterial infection (G- group), 49 patients with gram-positive bacterial infection (G+ group), 51 uninfected patients with lymphoma (uninfected group) and 20 healthy controls (healthy group) were enrolled in this study. We evaluated the quantification of Th1/Th2 cytokines with flow cytometry bead assay (CBA) in the sera to explore a rapid diagnostic method to determine the type of infection and anti-infective effect. The levels of procalcitonin (PCT) were also detected simultaneously. The four groups did not differ with regard to IL-2 and IL-4 (P>0.05). The IFN-γ and TNF-α levels of patients with lymphoma were higher than those of healthy controls (P<0.05). There was significantly upregulated IL-6 and IL-10 expression in the G- group (P<0.001). A similar trend was reflected in the IL-6 of the G+ group, which was significantly increased (P<0.001). However, no significant upregulation was observed for IL-10 in the G+ group. According to the different degrees of increased IL-6 and IL-10 levels, We proposed to use the G- Bacterial Infection Cytokine Profile (G- BICP) and the G+ Bacterial Infection Cytokine Profile (G+ BICP) for the first time to differentiate between Gram-negative and Gram-positive (G-/G+) bacterial infection in adults with lymphoma in the myelosuppression stage after chemotherapy. The IL-6, IL-10 and PCT in the G- group and the IL-6, PCT in the G+ group were significantly decreased at day 4 and day 8 compared with those at day 1. IL-6 and IL-10 are closely associated with the severity and treatment efficacy in adults with lymphomas who develop infections after chemotherapy and can help distinguish between G- and G+ bacterial infections at an early stage.

Loss of Interleukin-6 Influences Transcriptional Immune Signatures and Alters Bacterial Colonization in the Skin

The skin functions as a protective barrier to inhibit the entry of foreign pathogens, all the while hosting a diverse milieu of microorganisms. Over time, skin cells, immune cells, cytokines, and microbes interact to integrate the processes of maintaining the skin's physical and immune barrier. In the present study, the basal expression of two immunologically divergent mouse strains C57BL/6 and BALB/c, as well as a strain on the C57 background lacking IL-6, was characterized. Additionally, cutaneous antimicrobial gene expression profiles and skin bacterial microbiome were assessed between strains. Total RNA sequencing was performed on untreated C57BL/6 (control), BALB/c, and IL-6-deficient skin samples and found over 3,400 genes differentially modulated between strains. It was found that each strain modulated its own transcriptional "profile" associated with skin homeostasis and also influenced the overall bacterial colonization as indicated by the differential phyla present on each strain. Together, these data not only provide a comprehensive view of the transcriptional changes in homeostatic skin of different mouse strains but also highlight the possible influence of the strain differences (e.g., Th1/Th2 balance) as well as a role for IL-6 in overall skin immunity and resident microbial populations.

Association of gastrointestinal parasite burden, serum cytokines and hormones concentrations, and pregnancy in Angus-cross beef cows

The objective was to elucidate the relationships among gastrointestinal (GI) parasite load, serum cytokines (Th 1 - Interleukin (IL) 2, Interferon (IFN) γ and Tumor necrosis factor (TNF) α; Th 2- IL4, IL6, and IL10) levels, hormones (progesterone, cortisol, 8-epi-prostaglandin F2 alpha (isoprostane), prolactin, substance-p, and prostaglandin F metabolites) concentrations, and pregnancy in beef cattle. Angus-cross beef cows (n = 700; age, 3-8 y) were blocked by age and body condition score (BCS, 1-9), and were randomly assigned to treatment (n = 350, TRT, 50 mg of eprinomectin/50 kg BW, im) or control (n = 350, CON, no treatment) on Day -30. Cows were synchronized using Controlled Internal Drug Release insert (CIDR) + CO-Synch protocol and artificially inseminated at a fixed time on Day 0 (66 h after CIDR removal). Fecal samples were collected to determine fecal egg count per gram (FEG, McMaster method) on Days -30, -23, -16, -7, 7, 0, 16 and 23, and blood samples were collected on Days -7, 0, 7, 16 and 23. Serum cytokines were determined on Days -7, 0, 7, 16 and 23, and circulating hormones were measured on Day 16. BCS were recorded on Day 16 following artificial insemination (AI), and pregnancy status was diagnosed on Day 30 and 60. Pregnancy/AI varied among treatment groups on Day 30 [TRT, 62.0% (217/350); CON, 54.9% (192/350) (P = 0.05)] and Day 60 [TRT, 60.9% (213/350); CON, 51.7% (181/350) (P < 0.05)]. Pregnancy loss between 30 and 60 days for TRT and CON groups were 1.8% (4/217) and 5.7% (11/192), respectively (P < 0.05). The BCS on Day 16 did not differ among treatment groups (P> 0.1). Four groups of 40 cows were selected based on their pregnancy status and treatment: pregnant, TRT; non-pregnant, TRT; pregnant, CON; and non-pregnant, CON to compare the mean FEG, cytokines, and hormones levels. The FEG and cytokine concentrations were significantly (P < 0.05) influenced by treatment, pregnancy status, day, treatment by pregnancy status, and treatment by day. Day 16 hormone concentrations were considerably influenced by treatment, pregnancy status, and treatment by pregnancy. Although FEG on Day -30 did not differ among the groups (P> 0.1), it was lower in treated, pregnant cows compared with cows in other three groups from Day -23 onwards (P < 0.05). Overall and pairwise comparisons showed that serum concentrations of Type 1 cytokines, IL2, IFNγ, and TNFα were lower (P < 0.05) from gestational Day 7 onwards in treated, pregnant cows compared with cows in other three groups. In contrast, serum concentrations of Type 2 cytokines, IL4, IL6 and IL10 were greater (P < 0.05) from gestational Day 7 onwards in treated, pregnant cows compared with cows in other groups. Serum concentrations of progesterone was greater and other hormones were lower for pregnant cows in TRT group compared to cows in other groups on gestational Day 16. In conclusion, GI parasite load was reduced; Th 1 cytokines levels were decreased; Th 2 cytokines concentrations were increased; progesterone level was increased; and cortisol, substance-P, prolactin, isoprostane, and PGFM were decreased in pregnant, TRT cows. These changes also resulted in an increase in P/AI. It is plausible that direct and bidirectional host-parasite interactions mediated by cytokines and hormones may have promoted maternal tolerance of an immunologically diverse conceptus and the establishment of pregnancy.

Quantification of Cytokine Storms During Virus Infections

Highly pathogenic virus infections usually trigger cytokine storms, which may have adverse effects on vital organs and result in high mortalities. The two cytokines interleukin (IL)-4 and interferon (IFN)-γ play key roles in the generation and regulation of cytokine storms. However, it is still unclear whether the cytokine with the largest induction amplitude is the same under different virus infections. It is unknown which is the most critical and whether there are any mathematical formulas that can fit the changing rules of cytokines. Three coronaviruses (SARS-CoV, MERS-CoV, and SARS-CoV-2), three influenza viruses (2009H1N1, H5N1 and H7N9), Ebola virus, human immunodeficiency virus, dengue virus, Zika virus, West Nile virus, hepatitis B virus, hepatitis C virus, and enterovirus 71 were included in this analysis. We retrieved the cytokine fold change (FC), viral load, and clearance rate data from these highly pathogenic virus infections in humans and analyzed the correlations among them. Our analysis showed that interferon-inducible protein (IP)-10, IL-6, IL-8 and IL-17 are the most common cytokines with the largest induction amplitudes. Equations were obtained: the maximum induced cytokine (max) FC = IFN-γ FC × (IFN-γ FC/IL-4 FC) (if IFN-γ FC/IL-4 FC > 1); max FC = IL-4 FC (if IFN-γ FC/IL-4 FC < 1). For IFN-γ-inducible infections, 1.30 × log2 (IFN-γ FC) = log10 (viral load) − 2.48 − 2.83 × (clearance rate). The clinical relevance of cytokines and their antagonists is also discussed.

T-Helper Cell Subset Response Is a Determining Factor in COVID-19 Progression

The immune response type organized against viral infection is determinant in the prognosis of some infections. This work has aimed to study Th polarization in acute COVID-19 and its possible association with the outcome through an observational prospective study. Fifty-eight COVID-19 patients were recruited in the Medicine Department of the hospital “12 de Octubre,” 55 patients remaining after losses to follow-up. Four groups were established according to maximum degree of disease progression. T-helper cell percentages and phenotypes, analyzed by flow cytometer, and serum cytokines levels, analyzed by Luminex, were evaluated when the microbiological diagnosis (acute phase) of the disease was obtained. Our study found a significant reduction of %Th1 and %Th17 cells with higher activated %Th2 cells in the COVID-19 patients compared with reference population. A higher percent of senescent Th2 cells was found in the patients who died than in those who survived. Senescent Th2 cell percentage was an independent risk factor for death (OR: 13.88) accompanied by the numbers of total lymphocytes (OR: 0.15) with an AUC of 0.879. COVID-19 patients showed a profile of pro-inflammatory serum cytokines compared to controls, with higher levels of IL-2, IL-6, IL-15, and IP-10. IL-10 and IL-13 were also elevated in patients compared to controls. Patients who did not survive presented significantly higher levels of IL-15 than those who recovered. No significant differences were observed according to disease progression groups. The study has shown that increased levels of IL-15 and a high Th2 response are associated with a fatal outcome of the disease.

Sex Differences and COVID-19

Biological sex and psychosocial gender both play a role in many disease outcomes, and the novel coronavirus disease (COVID-19) is no different. Clinical observations in COVID-19 patient data delineate clear disparities between males and females, indicating males are at a higher risk for poorer disease outcomes. Although we are yet to understand the sex and gender-based disparities specific to COVID-19, there is evidence for sex-based differences in the endocrine, immune and renin-angiotensin system, all systems implicated in COVID-19 outcomes. Such disparities are largely thought to be driven by sex chromosomes and modulating sex hormones, which are known to vary between sex, and across the reproductive lifespan. Understanding and exploiting these driving factors are critical to understanding the pathobiology of SARS-CoV-2 virus and may lead to the development of novel therapies and increase the efficacy of preventative vaccine strategies currently under development. This chapter focuses on the endocrine, immune and renin-angiotensin system and genetic sex-based differences that could account for the meaningful differences observed in the outcomes of the SARS-CoV-2 infection.

The Impact of Helminth Infection on the Incidence of Metabolic Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

There are a growing number of publications that report an absence of inflammatory based disease among populations that are endemic to parasitic worms (helminths) demonstrating the ability of these parasites to potentially regulate human immune responses. The aim of this systematic review and meta-analysis was to determine the impact of helminth infection on metabolic outcomes in human populations.

METHODS

Using PRISMA guidelines, six databases were searched for studies published up to August 2020. Random effects meta-analysis was performed to estimate pooled proportions with 95% confidence intervals using the Review Manager Software version 5.4.1.

RESULTS

Fourteen studies were included in the review. Fasting blood glucose was significantly lower in persons with infection (MD -0.22, 95% CI -0.40- -0.04, P=0.02), HbA1c levels were lower, although not significantly, and prevalence of the metabolic syndrome (P=0.001) and type 2 diabetes was lower (OR 1.03, 95% CI 0.34-3.09, P<0.0001). Infection was negatively associated with type 2 diabetes when comparing person with diabetes to the group without diabetes (OR 0.44, 95% CI 0.29-0.67, P=0.0001).

CONCLUSIONS

While infection with helminths was generally associated with improved metabolic function, there were notable differences in efficacy between parasite species. Based on the data assessed, live infection with S. mansoni resulted in the most significant positive changes to metabolic outcomes.

SYSTEMATIC REVIEW REGISTRATION

Website: PROSPERO Identified: CRD42021227619.

IL-2-Agonist-Induced IFN-γ Exacerbates Systemic Anaphylaxis in Food Allergen-Sensitized Mice

Food allergies are common, costly and potentially life-threatening disorders. They are driven by Th2, but inhibited by Th1 reactions. There is also evidence indicating that IL-2 agonist treatment inhibits allergic sensitization through expansion of regulatory T cells. Here, we tested the impact of an IL-2 agonist in a novel model for food allergy to hen´s egg in mice sensitized without artificial adjuvants. Prophylactic IL-2 agonist treatment expanded Treg populations and inhibited allergen-specific sensitization. However, IL-2 agonist treatment of already sensitized mice increased mast cell responses and allergic anaphylaxis upon allergen re-challenge. These effects depended on allergen-specific IgE and were mediated through IFN-γ, as shown by IgE transfer and blockade of IFN-γ with monoclonal antibodies. These results suggest that although shifting the allergic reaction toward a Treg/Th1 response inhibits allergic sensitization, the prototypic Th1 cytokine IFN-γ promotes mast cell activation and allergen-induced anaphylaxis in individuals that are already IgE-sensitized. Hence, while a Th1 response can prevent the development of food allergy, IFN-γ has the ability to exacerbate already established food allergy.

Immunostimulating RNA Delivered by P1500 PEGylated Cationic Liposomes Limits Influenza Infection in C57Bl/6 Mice

The emergence of highly pathogenic viruses and a high speed of infection spread put forward the problem of the development of novel antivirals and their delivery vehicles. In this study, we investigated the antiviral effect of the previously identified immunostimulatory 19-bp dsRNA (isRNA) with 3'-nucleotide overhangs, which stimulates interferon α synthesis when delivered using cationic liposomes consisting of 1,26-bis(cholest-5-en-3β-yloxycarbonylamino)-7,11,16,20-tetraazahexacosan tetrahydrochloride and lipid-helper dioleoylphosphatidylethanolamine and its PEGylated formulation P1500 in vitro and in vivo. In vitro data showed that isRNA/2X3-DOPE complexes protected L929 cells from encephalomyocarditis virus infection, while isRNA/P1500 complexes were not active, which correlates with their lower transfection activity in cell culture. Comparison of the interferon-inducing activity of isRNA in BALB/c, CBA and C57Bl/6 mice showed that PEGylated liposomes significantly enhance the interferon-inducing activity of isRNA in vivo. The antiviral efficacy of the isRNA in vivo was considerably affected by the delivery system. The cationic liposomes 2X3-DOPE did not enhance the antiviral properties of isRNA in vivo. Similar liposomes equipped with a PEGylated lipoconjugate provided a pronounced anti-influenza effect of the isRNA in vivo. Administration of isRNA to C57Bl/6 led to a decrease in virus titers in the lungs and a significant decrease in the severity of the infection. Administration of a similar formulation to BALB/c mice caused only a mild antiviral effect at the initial stages of the infection. The data show that isRNA in combination with the PEGylated delivery system can be considered an effective means of suppressing influenza A infection.

Cytokines in inflammatory bowel diseases - Update 2020

Inflammatory Bowel Diseases (IBD), namely Crohn's Disease and Ulcerative Colitis, cause a significant disease burden in modern civilization. Ever since the introduction of anti-TNF-directed therapies 20 years ago, cytokines have attracted a lot of research attention and several cytokine-directed therapies have been implemented in the clinical treatment of these diseases. The research progress in these past years has underlined the importance of both myeloid and lymphoid elements of the immune system in the pathogenesis of IBD and their cytokine-mediated interplay. The conceptual framework of the mucosal cytokine network has shifted during these years from a T helper (Th) dichotomy (Th1/Th2) to the effector/regulatory T cell balance, while nowadays, the importance of myeloid cell instruction of lymphocytes, namely by IL-12 and IL-23, is increasingly recognized. Anti-IL-12p40 agents, like ustekinumab, groundbreakingly changed patient care, and anti-IL23p19-directed approaches are on the verge of grand success. In this review we present a modular approach to understand the cytokine network and put it into the context of the pathogenesis of IBD with a special focus on publications since 2014.

BCG stimulation promotes dendritic cell proliferation and expression of VDR and CYP27B1 in vitamin D‑deficient mice

Vitamin D deficiency may lead to an increased risk of tuberculosis. In the present study, the effects of Mycobacterium tuberculosis (Mtb) infection on dendritic cells (DCs) derived from vitamin D‑deficient mice or normal control mice were investigated. A vitamin D‑deficient mouse model was established, and bone marrow‑derived DCs (BMDCs) were isolated and treated with GM‑CSF and interleukin (IL)‑4 for 6 days, followed by an additional 24 h of treatment with Bacillus Calmette‑Guérin (BCG). The expression levels of surface molecules of DCs, including integrin alpha‑X and T‑lymphocyte activation antigen CD86, were significantly increased by BCG in the vitamin D‑deficient mice model group compared with the control group, while those of T‑lymphocyte activation antigen CD80, major histocompatibility complex class I and major histocompatibility complex class II were significantly decreased. These changes were BCG concentration‑dependent. In addition, the levels of IL‑4, IL‑6 and IL‑10 in the BMDCs from the vitamin D‑deficient mice were significantly decreased compared with the control mice, while the levels of tumor necrosis factor‑α, IL‑5, IL‑2, IL‑12 and interferon‑γ were significantly increased. Furthermore, the expression levels of vitamin D receptor (VDR) and CYP27B1 protein in the BMDCs from the vitamin D‑deficient mice were decreased compared with the control. BCG significantly increased the expression levels of VDR and CYP27B1 in the BMDCs. The DCs treated with BCG significantly induced the viability of CD4+ T lymphocytes. Therefore, BCG increases DCs and may enhance immunofunction, which may assist in preventing the risk of tuberculosis in patients with a vitamin D deficiency.

Tuberculosis: Smart manipulation of a lethal host

Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a global threat to human health. Development of drug resistance and co-infection with HIV has increased the morbidity and mortality caused by TB. Macrophages serve as primary defense against microbial infections, including TB. Upon recognition and uptake of mycobacteria, macrophages initiate a series of events designed to lead to generation of effective immune responses and clearance of infection. However, pathogenic mycobacteria utilize multiple mechanisms for manipulating macrophage responses to protect itself from being killed and to survive within these cells that are designed to kill them. The outcomes of mycobacterial infection are determined by several host- and pathogen-related factors. Significant advancements in understanding mycobacterial pathogenesis have been made in recent years. In this review, some of the important factors/mechanisms regulating mycobacterial survival inside macrophages are discussed.

T Cell Profile was Altered in Pulmonary Tuberculosis Patients with Type 2 Diabetes

Background

Studies have suggested that type 2 diabetes (T2D) increases the risk of active pulmonary tuberculosis (TB) infection. T2D might exacerbate TB severity and adversely impact the treatment of TB patients by suppressing the immune response of TB. However, how the immune cell profiles are changed in Chinese TB patients with coincident of T2D compared with TB patients without T2D is still unclear.

Material/Methods

To explore the immune cell profile alteration in TB patients with T2D, we collected blood samples from 46 TB patients with or without T2D and measured the profiles of T cell subsets.

Results

We found TB patients with coincident of T2D had higher percentages of Th2 and Th17 cells after TB antigens stimulation, while they had unchanged Th1 cells and decreased CD8⁺ cytotoxic T cells compared to TB patients without T2D. However, no significant difference in baseline percentages of these T cells subsets was observed.

Conclusions

T2D has important impacts on regulating anti-TB immunity by increasing Th2 and Th17 cell differentiation, but reducing the activity of CD8⁺ T cells. Our study supports the need to perform longitudinal studies to evaluate the roles of immunological interaction between T2D and TB in TB development.

Dynamic expression of cytokine and transcription factor genes during experimental Fasciola gigantica infection in buffaloes

BACKGROUND

Determining the mechanisms involved in the immune-pathogenesis of the tropical liver fluke, Fasciola gigantica, is crucial to the development of any effective therapeutic intervention. Here, we examined the differential gene expression of cytokines and transcription factors in the liver of F. gigantica-infected buffaloes, over the course of infection.

METHODS

Water buffaloes (swamp type) were infected orally with 500 F. gigantica encysted metacercariae. Liver tissue samples were collected 3, 10, 28, 42, 70 and 98 days post-infection (dpi). Levels of gene expression of nine cytokines (IFN-γ, TGF-β, IL-1β, IL-4, IL-6, IL-10, IL-12B, IL-13 and IL-17A) and four transcription factors (T-bet, GATA-3, Foxp3 and ROR-γτ) were determined using quantitative real-time PCR (qRT-PCR). We evaluated any correlation between gene expression of these immune-regulatory factors and the severity of liver pathology.

RESULTS

Histopathological examination revealed that cellular infiltration, hemorrhage and fibrosis without calcification in the liver parenchyma of infected buffaloes, increased over the course of infection. This progressive pathology was attributed to dysregulated and excessive inflammatory responses induced by infection. The early infection phase (3-10 dpi) was marked by a generalized immunosuppression and elevated TGF-β expression in order to facilitate parasite colonization. A mixed Th1/Th2 immune response was dominant from 28 to 70 dpi, to promote parasite survival while minimizing host tissue damage. During late infection (98 dpi), the response was biased towards Th1/Treg in order to inhibit the host's Th2 protective response and promote chronic infection. Both IL-10 and IL-17A and the Th17/Treg balance, played key roles in mediating the inflammatory and immunoregulatory mechanisms in the liver during chronic fasciolosis.

CONCLUSIONS

Our data showed distinct CD4⁺ T helper (Th) polarization and cytokine dysregulation in response to F. gigantica infection in water buffaloes over the course of infection. Characterizing the temporal expression profiles for host immune genes during infection should provide important information for defining how F. gigantica adapts and survives in the liver of buffaloes and how host immune responses influence F. gigantica pathogenicity.

Clinical improvement in feline herpesvirus 1 infected cats by oral low dose of interleukin-12 plus interferon-gamma

Feline herpesvirus 1 (FHV-1) is a widespread cat pathogen inducing rhinitis, conjunctivitis and corneal ulcers. To alleviate acute FHV-1-induced disease, antiviral agents are used often with antibiotics. But sometimes, these treatments, as well as conventional doses of cytokines have moderate efficacy and/or collateral effects. Herein we have investigated the effects of low dose interleukin (IL)-12 plus interferon (IFN)-gamma, prepared by Sequential Kinetic Activated (SKA), on the treatment of FHV-1 infection. Twenty-five, unvaccinated FHV-1-positive cats were recruited into a prospective, randomized, placebo-controlled, double-blinded clinical trial. Fifteen cats were treated for 6 months with oral low doses of SKA IL-12 plus IFN-gamma and 10 cats were treated with placebo. At 1, 6 and 12 months (follow-up) after the beginning of treatment, clinical assessment, PCR assay and blood count were carried out. At follow-up, in treated group, we observed significant (p<0.05) improvements in clinical signs and PCR became negative in 12/15 cats (80%). In placebo, 10/10 cats were PCR-positive, with improvements (30%) or worsening (70%) in clinical signs. Blood values were normal in both groups. Our results show that the low dose therapy, based on activated solutions of IL-12 plus IFN-gamma, represents a novel approach to treat FHV-1 infection in cats.

Increased soluble and membrane-bound PD-L1 contributes to immune regulation and disease progression in patients with tuberculous pleural effusion

Soluble and membrane-bound programmed death ligand-1 (sPD-L1 and mPD-L1, respectively) have been demonstrated to participate in the immune suppression of non-small cell lung cancer. However, the contribution of sPD-L1 and mPD-L1 to immune regulation and disease progression in patients with pleural effusions remains unknown. The present study evaluated the levels of sPD-L1 and membrane-bound PD-1/PD-L1 in the peripheral blood and pleural effusions of patients with tuberculous pleural effusion (TPE), malignant pleural effusion (MPE) and non-tuberculous non-malignant pleural effusion (n-TB n-M). Furthermore, selected T lymphocytes and cluster of differentiation (CD)14⁺ monocytes were co-cultured to investigate the potential effect of the PD-1/PD-L1 pathway in TPE. Levels of sPD-L1 and PD-L1 on CD14⁺ monocytes were increased in the TPE group, as compared with the MPE and n-TB n-M groups. Furthermore, sPD-L1 levels and the expression levels of PD-L1 on CD14⁺ monocytes were demonstrated to be positively correlated with interferon (IFN)-γ concentration in pleural effusions. Therefore, IFN-γ may increase the expression of PD-L1 on CD14⁺ monocytes in vitro. Cell counting kit-8 analysis demonstrated that anti-PD-L1 antibody was able to partially reverse the proliferation of T lymphocytes in the co-culture system. The results of the present study indicated that sPD-L1 or mPD-L1 are associated with the immune regulation and disease progression of TPE, and may serve as possible biomarkers of TPE. Furthermore, sPD-L1 and the PD-1/PD-L1 pathway of TPE may be associated with the Th1 immune response; therefore, an anti-PD-1/PD-L1 pathway suggests a potential immune therapy strategy for the treatment of TPE.

Aggravation of Helicobacter pylori stomach infections in stressed military recruits

Objective

To investigate the effect of military stress on immune response and Helicobacter pylori stomach infections.

Methods

In this prospective, observational study, the Symptom Checklist-90 questionnaire was completed by military recruits before and following a 3-month basic training programme. H. pylori immunoglobulin (Ig)G levels, C¹⁴-urea breath-test values and levels of cortisol, catecholamine, and certain humoral and cellular immune responses were measured before and after the basic training.

Results

For 60 military recruits, somatization, depression and paranoid ideation scores were significantly increased after, compared with before, basic training. Post-training H. pylori IgG detection revealed three additional cases of H. pylori infection. Post-training C¹⁴-urea breath-test values were significantly higher compared with before training – thus suggesting higher levels of H. pylori colonization in the stomach. Post-training cortisol and catecholamine levels were increased, while serum IgG levels were decreased; complement component (C)3 and C4 levels remained unchanged. Post-training CD4⁺ and CD8⁺ T-cell percentages and the CD4⁺/CD8⁺ ratio were significantly reduced compared with before training. Serum interleukin (IL)-2 levels were lower and IL-10 levels were higher following training and there was a significant decrease in the IL-2/IL-10 ratio.

Conclusion

Military stress may reduce humoral and cellular immune responses and may aggravate the severity of H. pylori infection.

Profiling the human immune response to Mycobacterium tuberculosis by human cytokine array

OBJECT

Tuberculosis (TB) continues to be one of the most serious infectious diseases in the world, however, no effective biomarkers can be used for rapid screening of latent tuberculosis infection (LTBI) and active TB. In this study, serum cytokines were screened and tested as potential biomarker for TB diagnosis.

METHOD

Cytokine array was used to track the cytokine profile and its dynamic change after TB infection. The different expressions of cytokines were confirmed by ELISA assay. ROC curve analyses were used to evaluate the efficacy of a cytokine or cytokine combination for diagnosis.

RESULTS

Eotaxin-2, ICAM-1, MCSF, IL-12p70, and IL-11 were significantly higher in the LTBI individuals. I-309, MIG, Eotaxin-2, IL-8, ICAM-1, IL-6sR, and Eotaxin were significantly higher in active TB patients. ROC curve analyses gave AUCs of 0.843, 0.898, and 0.888 for I-309, MIG, and IL-8, respectively, and 0.894 for the combination panel in active TB diagnosis. IFN-γ/IL-4 and IL-2/TNF-α ratios exhibit dynamic changes in the healthy control and LTBI to different stages of active TB.

CONCLUSIONS

Serum cytokines, including I-309 and MIG, IL-8, Extoxin-2, ICAM-1 and combinations of cytokines, including IFN-γ/IL-4 and IL-2/TNF-α, can be used as serum biomarkers for LTBI and active TB screening, thus indicating prospective clinical applications.

Protein kinase Cθ: the pleiotropic T-cell signalling intermediate

Activating as well as inhibitory circuits tightly regulate T-cell activation thresholds and effector differentiation processes enabling proper immune response outcomes. Recently, an additional molecular link between T-cell receptor signalling and CD4⁺ Th17 cell skewing has been reported, namely that protein kinase C (PKC) θ critically regulates Th17/Th1 phenotypic differentiation and plasticity in CD4⁺ T-cells by selectively acting as a 'reprogramming element' that suppresses Th1-typical genes during Th17-mediated immune activation in order to stabilize a Th17 cell phenotype.

Bovine IgG subclasses and fertility of Echinococcus granulosus hydatid cysts

Hydatidosis is an important zoonotic disease of worldwide distribution, causing important health problems to humans and major economical losses in infected livestock. Echinococcus granulosus, the etiological agent of hydatid disease, induces a humoral immune response in the intermediate host (human and herbivorous) against hydatid cyst antigens. Specifically, IgGs are found in the laminar and germinal layers and inside the lumen of fertile and infertile hydatid cysts. In the germinal layer of infertile cysts IgGs are found in an order of magnitude greater than in the germinal layer of fertile cysts; a fraction of those IgGs are associated with high affinity to germinal layer proteins, suggesting their binding to specific parasite antigens. We have previously shown that those immunoglobulins, bound with high affinity to the germinal layer of hydatid cysts, induce apoptosis leading to cyst infertility. In the present work the presence of IgG1 and IgG2 subclasses in the germinal layer of both fertile and infertile hydatid cysts is reported. IgG1 is the most relevant immunoglobulin subclass present in the germinal layer of infertile cysts and bound with high affinity to that parasite structure. Contrarily, though the IgG2 subclass was also found in the germinal and adventitial layers, those immunoglobulins show low affinity to parasite antigens. We propose that the binding of an IgG1 subclass to parasite antigens present in the germinal layer is involved in the mechanism of cyst infertility.

Regulation of the Anti-Inflammatory Cytokines Interleukin-4 and Interleukin-10 during Pregnancy

Inflammation mediated by both innate and adaptive immune cells is necessary for several important processes during pregnancy. Pro-inflammatory immune cell activation plays a critical role in embryo implantation, placentation, and parturition; however dysregulation of these cells can lead to detrimental pregnancy outcomes including spontaneous abortion, fetal growth restriction, maternal pathology including hypertensive disorders, or fetal and maternal death. The resolution of inflammation plays an important role throughout pregnancy and is largely mediated by immune cells that produce interleukin (IL)-4 and IL-10. The temporal and spatial aspects of reducing inflammation during pregnancy represent a complex process that if not functioning optimally can lead to persistent inflammation and pregnancy complications. In this review, we examine how immune cells that produce IL-4 and IL-10 are regulated throughout pregnancy as well as the effects that reduced IL-4 and IL-10 signaling has on fetal and maternal physiology.

Involvement of IL-18 in the expansion of unique hepatic T cells with unconventional cytokine profiles during Schistosoma mansoni infection

Infection with schistosomes invokes severe fibrotic granulomatous responses in the liver of the host. Schistosoma mansoni infection induces dramatic fluctuations in Th1 or Th2 cytokine responses systemically; Th1 reactions are provoked in the early phase, whilst Th2 responses become dominant after oviposition begins. In the liver, various unique immune cells distinct from those of conventional immune competent organs or tissues exist, resulting in a unique immunological environment. Recently, we demonstrated that S. mansoni infection induces unique CD4⁺ T cell populations exhibiting unconventional cytokine profiles in the liver of mice during the period between Th1- and Th2-phases, which we term the transition phase. They produce both IFN-γ and IL-4 or both IFN-γ and IL-13 simultaneously. Moreover, T cells secreting triple cytokines IFN-γ, IL-13 and IL-4 were also induced. We term these cells Multiple Cytokine Producing Hepatic T cells (MCPHT cells). During the transition phase, when MCPHT cells increase, IL-18 secretion was up-regulated in the liver and sera. In S. mansoni-infected IL-18-deficient mice, expansion of MCPHT cells was curtailed. Thus our data suggest that IL-18 produced during S. mansoni infection play a role in the expansion of MCPHT cells.

In vitro polarization of T-helper cells

In vitro polarization of CD4(+) T cells along distinct T-helper (Th) lineages is critical for defining the factors and properties that determine the differentiation, stability, and effector functions of each Th subset. Furthermore, polarized cells can be transferred into naïve syngeneic mice to investigate their trafficking patterns and pathological or therapeutic roles in the setting of infection, autoimmunity, and neoplasia. In this chapter, we describe methods for generating and characterizing a spectrum of CD4(+) Th cell lines in vitro. Protocols are provided that use naïve wild-type or T cell receptor (TCR) transgenic CD4+ T cells, or a polyclonal population of primed CD4+ T cells from immunized mice.

25(OH)D(3) affects the maturation and function of mouse bone marrow-derived dendritic cells stimulated by Mycobacterium bovis BCG

It has been shown that vitamin D deficiency increases an individual's susceptibility to tuberculosis (TB). However, very little is known about the effect of vitamin D on the immune response to Mycobacterium tuberculosis (M. tb) in dendritic cells (DCs). Because DCs play an important role in TB infection, we investigated the phenotypic characteristics and functional capabilities of mouse bone marrow-derived dendritic cells (BMDCs) after stimulation with Bacillus Calmette-Guérin (BCG) in the presence or absence of 25(OH)D(3)(100 nM). Bone marrow cells from mice were cultured with GM-CSF (20 ng/ml) and were then treated with 25(OH)D(3) for 7 days. On day 6, 5 µg/ml of BCG (≥1.0×10(6) CFU/mg) was added to the cells for 24 hours, and on day 7, the non-adherent cells were harvested for phenotypic and functional analyses. After incubation with 25(OH)D(3), the expression levels of MHC-II and CD86 on the surface of the dendritic cells (DCs) and the ability of the DCs to stimulate proliferation of allogeneic mixed lymphocytes were lower than control cells (p<0.05). Furthermore, the level of Interleukin (IL) -4 secreted by the BMDCs in the 25(OH)D(3) culture was lower than that in the control culture (p<0.01). However, the BMDCs cultured with 25(OH)D(3) produced significantly higher levels of IL-2, IL-6, IL-10 and interferon gamma(IFN-γ) than those in the control culture (p<0.05). These findings suggest that 25(OH)D(3) modulates the immune response during mycobacterial infection by affecting the maturation and function of DCs.

The Th1:th2 dichotomy of pregnancy and preterm labour

Pregnancy is a unique immunological state in which a balance of immune tolerance and suppression is needed to protect the fetus without compromising the mother. It has long been established that a bias from the T helper 1 cytokine profile towards the T helper 2 profile contributes towards successful pregnancy maintenance. The majority of publications that report on aberrant Th1:Th2 balance focus on early pregnancy loss and preeclampsia. Over the last few decades, there has been an increased awareness of the role of infection and inflammation in preterm labour, and the search for new biomarkers to predict preterm labour continues. In this paper, we explore the evidence for an aberrant Th1:Th2 profile associated with preterm labour. We also consider the potential for its use in screening women at high risk of preterm labour and for prophylactic therapeutic measures for the prevention of preterm labour and associated neonatal adverse outcomes.

Characterization of Th1- and Th2-type immune response in human multidrug-resistant tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) has become a lethal global threat. Insights into the immune regulation of MDR-TB are urgently needed for the development of new treatments; however, the T cell response to an MDR-TB infection in human remains unclear. In the present study, the proportion of Th1 and Th2 cell subsets and the level of related T cell subset cytokines in peripheral blood were investigated. We detected that an MDR-TB infection resulted in suppressed Th1 and Th2 cell activation, which was more remarkable in patients with MDR-TB than that in drug-sensitive tuberculosis (DS-TB) sufferers when compared to healthy controls (HCs). In addition, MDR-TB infection down-regulated the expression of IFN-γ, IL-2, and IL-10, and up-regulated IL-4, IL-6, and TNF-α expression. Our data suggest that the disturbance between protective and pathogenic effects induced by the immunosuppression of Th1- and Th2-type responses is a substantial characteristic of MDR-TB infections.

Blood stage merozoite surface protein conjugated to nanoparticles induce potent parasite inhibitory antibodies

In this proof-of-concept study we report the use of <15 nm, water soluble, inorganic nanoparticles as a vaccine delivery system for a blood stage malaria vaccine. The recombinant malarial antigen, Merozoite Surface Protein 1 (rMSP1) of Plasmodium falciparum served as the model vaccine. The rMSP1 was covalently conjugated to polymer-coated quantum dot CdSe/ZnS nanoparticles (QDs) via surface carboxyl groups, forming rMSP1-QDs. Anti-MSP1 antibody responses induced by rMSP1-QDs were found to have 2-3 log higher titers than those obtained with rMSP1 administered with the conventional adjuvants, Montanide ISA51 and CFA. Moreover, the immune responsiveness and the induction of parasite inhibitory antibodies were significantly superior in mice injected with rMSP1-QDs. The rMSP1-QDs delivered via intra-peritoneal (i.p.), intra-muscular (i.m.), and subcutaneous (s.c.) routes were equally efficacious. The high level of immunogenicity exhibited by the rMSP1-QDs was achieved without further addition of other adjuvant components. Bone marrow derived dendritic cells were shown to efficiently take up the nanoparticles leading to their activation and the expression/secretion of key cytokines, suggesting that this may be a mode of action for the enhanced immunogenicity. This study provides promising results for the use of water soluble, inorganic nanoparticles (<15 nm) as potent vehicles/platforms to enhance the immunogenicity of polypeptide antigens in adjuvant-free immunizations.

New insight into immunity and immunopathology of Rickettsial diseases

Human rickettsial diseases comprise a variety of clinical entities caused by microorganisms belonging to the genera Rickettsia, Orientia, Ehrlichia, and Anaplasma. These microorganisms are characterized by a strictly intracellular location which has, for long, impaired their detailed study. In this paper, the critical steps taken by these microorganisms to play their pathogenic roles are discussed in detail on the basis of recent advances in our understanding of molecular Rickettsia-host interactions, preferential target cells, virulence mechanisms, three-dimensional structures of bacteria effector proteins, upstream signalling pathways and signal transduction systems, and modulation of gene expression. The roles of innate and adaptive immune responses are discussed, and potential new targets for therapies to block host-pathogen interactions and pathogen virulence mechanisms are considered.