Cytokines acting on or secreted by macrophages during intracellular infection (IL-10, IL-12, IFN-gamma)

hsa-miR-330-5p regulates serine palmitoyltransferase long chain base subunit 1 and augments host protective immune response against Leishmania donovani infection

Leishmaniasis, caused by the protozoan parasites of the genus Leishmania, poses a significant global health challenge, particularly in the resource-limited regions where it causes high mortality. Regardless in the progress of treatment strategies, the emergence of drug resistance and limited efficacy requires the search of novel therapy and therapeutic targets. MicroRNAs, the crucial post-transcriptional regulators of gene expression, play critical roles in host-pathogen interactions. Here, we screened the miRNAs dysregulated during Leishmania donovani infection through literature search. hsa-miR-330-5p, one of the miRNAs which through human KEGG 2021 and Human Cyc 2016 analysis was found to be involved in multiple pathways including sphingolipid signaling pathway. Sphingolipids are important class of lipids involved in different cellular processes and therefore are the targets of many pathogens including Leishmania. hsa-miR-330-5p was found downregulated after 24 h of Leishmania donovani infection in THP-1 derived human macrophages. Target prediction of sphingolipid biosynthetic genes through in silico prediction tools showed 3/ UTR of serine palmitoyltransferase long chain base subunit 1 to be a target of hsa-miR-330-5p. The in silico target prediction of hsa-miR-330-5p was validated by cloning the 3/ UTR target sequence of gene, transfecting and performing luciferase assay in HEK 293 T cell line. Transfection of mimic of hsa-miR-330-5p reduced the luciferase activity which validated the in silico target prediction. Further, mimic of hsa-miR-330-5p inhibited the expression of the target gene, serine palmitoyltransferase long chain base subunit 1 and augmented the expression of pro-inflammatory cytokines in L. donovani infected THP-1 derived macrophages. Mimic of hsa-miR-330-5p also led to a significant reduction in the intracellular parasite burden in both THP-1 derived as well as primary human macrophages. This study has not only identified the sphingolipid biosynthesis regulatory miRNA but will also help in the development of novel and effective treatment strategy against leishmaniasis in future.

Coexisting Th1 and Th2 cytokines in patients with collagenous gastritis and implications for its pathogenesis

OBJECTIVES

Collagenous gastritis (CG) is a rare cause of refractory dyspepsia and anemia that frequently affects children and young adults and whose histological hallmark is chronic mucosal inflammation with a subepithelial collagen band. The etiology remains obscure, and no established treatments exist. We investigated the pathogenesis of CG by determining the expression profiles of genes related to immunity and inflammation in index biopsies.

METHODS

Gastric biopsies from 10 newly diagnosed patients with CG were evaluated using the NanoString nCounter assay. Gastric biopsies from 14 normal individuals served as controls. The gene expression ratios for CG versus controls were determined in pooled samples and confirmed in individual samples by quantitative reverse transcription polymerase chain reaction. The results were compared with previously reported expression data from a cohort of patients with collagenous colitis, a colonic disorder with similar morphology, including subepithelial collagen band.

RESULTS

CG biopsies featured enhanced expression of key genes encoding both Th1 (IFNγ, TNF-α, IL-2, IL-10, IL-12A, IL-12B, and IL-18) and Th2 cytokines (IL-3, IL-4, IL-5, IL-6, and IL-13). In contrast, biopsies from patients with CC exhibited upregulated Th1 cytokines only.

CONCLUSIONS

We show in this first published gene expression profiling study that CG involves simultaneous upregulation of Th1 and Th2 cytokines. This finding is unique, contrasting with other types of chronic gastritis as well as with collagenous colitis, which shares the presence of a collagen band. Involvement of Th2 immunity in CG would support further investigation of potential dietary, environmental, or allergic factors to guide future therapeutic trials.

MCP-1/IL-12 ratio expressions correlated with adventitial collagen depositions in renal vessels and IL-4/IFN-γ expression correlated with interstitial collagen depositions in the kidneys of dogs with canine leishmaniasis

Collagen deposition is a common event in chronic inflammation, and canine Leishmaniosis (CanL) is generally associated with a long and chronic evolution. Considering that the kidney shows fibrinogenic changes during CanL, and the balance of cytokines/chemokines regulates the profibrinogenic and antifibrinogenic immune responses differently, it can be hypothesized that the balance of cytokines/chemokines can be differentially expressed in the renal tissue in order to determine the expression of collagen depositions in the kidneys. This study aimed to measure collagen deposition and to evaluate cytokine/chemokine expressions in the kidney by means of qRT-PCR in sixteen Leishmania-infected dogs and six uninfected controls. Kidney fragments were stained with hematoxylin & eosin (H&E), Masson's Trichrome, Picrosirius Red, and Gomori's reticulin. Intertubular and adventitial collagen depositions were evaluated by the morphometric approach. Cytokine RNA expressions were measured by means of qRT-PCR to identify molecules involved in chronic collagen depositions in kidneys with CanL. Collagen depositions were related to the presence of clinical signs, and more intense intertubular collagen depositions occurred in infected dogs. Adventitial collagen deposition, as morphometrically measured by the average area of the collagen, was more intense in clinically affected dogs than in subclinically infected dogs. TNF-α/TGF-β, MCP1/IL-12, CCL5/IL-12, IL-4/IFN-γ, and IL-12/TGF-β expressions were associated with clinical manifestations in dogs with CanL. The IL-4/IFN-α ratio was more commonly expressed and upregulated in clinically affected dogs, and downregulated in subclinically infected dogs. Furthermore, MCP-1/IL-12 and CCL5/IL-12 were more commonly expressed in subclinically infected dogs. Strong positive correlations were detected between morphometric values of interstitial collagen depositions and MCP-1/IL-12, IL-12, and IL-4 mRNA expression levels in the renal tissues. Adventitial collagen deposition was correlated with TGF-β, IL-4/IFN-γ, and TNF-α/TGF-β. In conclusion, our results showed the association of MCP-1/IL-12 and CCL5/IL-12 ratios with an absence of clinical signs, as well as an IL-4/IFN-α ratio with adventitial and intertubular collagen depositions in dogs with visceral leishmaniosis.

Biflavones from Platonia insignis Mart. Flowers Promote In Vitro Antileishmanial and Immunomodulatory Effects against Internalized Amastigote Forms of Leishmania amazonensis

Leishmaniasis is an infectious disease that affects millions of people worldwide, making the search essential for more accessible treatments. The species Platonia insignis Mart. (Clusiaceae) has been extensively studied and has gained prominence for its pharmacological potential. The objective of this work was to evaluate the antileishmania activity, cytotoxic effect and activation patterns of macrophages of hydroalcoholic extract (EHPi), ethyl acetate fractions (FAcOEt) and morelloflavone/volkensiflavone mixture (MB) from P. insignis flowers. EHPi, FAcOEt and MB demonstrated concentration-dependent antileishmania activity, with inhibition of parasite growth in all analyzed concentrations. EHPi exhibited maximum effect at 800 μg/mL, while FAcOEt and MB reduced the growth of the parasite by 94.62% at 800 μg/mL. EHPi, FAcOEt and MB showed low cytotoxic effects for macrophages at 81.78, 159.67 and 134.28 μg/mL, respectively. EHPi (11.25 µg/mL), FAcOEt (11.25 and 22.5 µg/mL) and MB (22.5 µg/mL) characterized the increase in lysosomal activity, suggesting a possible modulating effect. These findings open for the application of flowers from a P. insignis flowers and biflavones mixture thereof in the promising treatment of leishmaniasis.

Relative virulence of Staphylococcus aureus bovine mastitis strains representing the main Canadian spa types and clonal complexes as determined using in vitro and in vivo mastitis models

Staphylococcus aureus is one of the main pathogens leading to both clinical and subclinical bovine mastitis in dairy cattle. Prediction of disease evolution based on the characteristics of Staph. aureus isolates that cause intramammary infections and understanding the host-pathogen interactions may improve management of mastitis in dairy herds. For this study, several strains were selected from each of the 6 major Canadian spa types associated with mastitis (t267, t359, t529, t605, t2445, and t13401). Adherence to host cells and intracellular persistence of these strains were studied using a bovine mammary gland epithelial cell line (MAC-T). Additionally, relative virulence and host response (cytokines production) were also studied in vivo using a mouse model of mastitis. Whole-genome sequencing was performed on all strains and associations between clonal complex, sequence type, and presence of certain virulence factors were also investigated. Results show that spa type t2445 was correlated with persistence in MAC-T cells. Strains from spa t359 and t529 showed better ability to colonize mouse mammary glands. The exception was strain sa3154 (spa t529), which showed less colonization of glands compared with other t359 and t529 strains but possessed the highest number of superantigen genes including tst. All strains possessed hemolysins, but spa types t529 and t2445 showed the largest diameter of β-hemolysis on blood agar plates. Although several spa types possessed 2 or 3 serine-aspartate rich proteins (Sdr) believed to be involved in many pathogenic processes, most t529 strains expressed only an allelic variant of sdrE. The spa types t605 (positive for the biofilm associated protein gene; bap+) and t13401 (bap-), that produced the largest amounts of biofilm in vitro, were the least virulent in vivo. Finally, strains from spa type t529 (ST151) elicited a cytokine expression profile (TNF-α, IL-1β and IL-12) that suggests a potential for severe inflammation. This study suggests that determination of the spa type may help predict the severity of the disease and the ability of the immune system to eliminate intramammary infections caused by Staph. aureus.

CRISPR/Cas9-mediated genome editing of Schistosoma mansoni acetylcholinesterase

CRISPR/Cas9-mediated genome editing shows cogent potential for the genetic modification of helminth parasites. We report successful gene knock-in (KI) into the genome of the egg of Schistosoma mansoni by combining CRISPR/Cas9 with single-stranded oligodeoxynucleotides (ssODNs). We edited the acetylcholinesterase (AChE) gene of S. mansoni targeting two guide RNAs (gRNAs), X5 and X7, located on exon 5 and exon 7 of Smp_154600, respectively. Eggs recovered from livers of experimentally infected mice were transfected by electroporation with a CRISPR/Cas9-vector encoding gRNA X5 or X7 combining with/ without a ssODN donor. Next generation sequencing analysis of reads of amplicon libraries spanning targeted regions revealed that the major modifications induced by CRISPR/Cas9 in the eggs were generated by homology directed repair (HDR). Furthermore, soluble egg antigen from AChE-edited eggs exhibited markedly reduced AChE activity, indicative that programed Cas9 cleavage mutated the AChE gene. Following injection of AChE-edited schistosome eggs into the tail veins of mice, an significantly enhanced Th2 response involving IL-4, -5, -10, and-13 was detected in lung cells and splenocytes in mice injected with X5-KI eggs in comparison to control mice injected with unmutated eggs. A Th2-predominant response, with increased levels of IL-4, -13, and GATA3, also was induced by X5 KI eggs in small intestine-draining mesenteric lymph node cells when the gene-edited eggs were introduced into the subserosa of the ileum of the mice. These findings confirmed the potential and the utility of CRISPR/Cas9-mediated genome editing for functional genomics in schistosomes.

Phenotypic and Functional Heterogeneity of Low-Density and High-Density Human Lung Macrophages

BACKGROUND

Pulmonary macrophages are a highly heterogeneous cell population distributed in different lung compartments.

METHODS

We separated two subpopulations of macrophages from human lung parenchyma according to flotation over density gradients.

RESULTS

Two-thirds 65.4% of the lung macrophages have a density between 1.065 and 1.078 (high-density macrophages: HDMs), and the remaining one-third (34.6) had a density between 1.039 and 1.052 (low-density macrophages: LDMs). LDMs had a larger area (691 vs. 462 μm²) and cell perimeter (94 vs. 77 μm) compared to HDMs. A significantly higher percentage of HDMs expressed CD40, CD45, and CD86 compared to LDMs. In contrast, a higher percentage of LDMs expressed the activation markers CD63 and CD64. The release of TNF-α, IL-6, IL-10 and IL-12 induced by lipopolysaccharide (LPS) was significantly higher in HDMs than in LDMs.

CONCLUSION

The human lung contains two subpopulations of macrophages that differ in buoyancy, morphometric parameters, surface marker expression and response to LPS. These subpopulations of macrophages probably play distinct roles in lung inflammation and immune responses.

Human Immune Responses to Melioidosis and Cross-Reactivity to Low-Virulence Burkholderia Species, Thailand1

Melioidosis is a neglected tropical disease with an estimated annual mortality rate of 89,000 in 45 countries across tropical regions. The causative agent is Burkholderia pseudomallei, a gram-negative soil-dwelling bacterium. In Thailand, B. pseudomallei can be found across multiple regions, along with the low-virulence B. thailandensis and the recently discovered B. thailandensis variant (BTCV), which expresses B. pseudomallei-like capsular polysaccharide. Comprehensive studies of human immune responses to B. thailandensis variants and cross-reactivity to B. pseudomallei are not complete. We evaluated human immune responses to B. pseudomallei, B. thailandensis, and BTCV in melioidosis patients and healthy persons in B. pseudomallei-endemic areas using a range of humoral and cellular immune assays. We found immune cross-reactivity to be strong for both humoral and cellular immunity among B. pseudomallei, B. thailandensis, and BTCV. Our findings suggest that environmental exposure to low-virulence strains may build cellular immunity to B. pseudomallei.

Nrf2 Regulates Granuloma Formation and Macrophage Activation during Mycobacterium avium Infection via Mediating Nramp1 and HO-1 Expressions

Nontuberculous mycobacteria (NTM) are an important cause of morbidity and mortality in pulmonary infections. Among them, Mycobacterium avium complex (MAC) is the most common cause of pulmonary NTM disease worldwide.

Nrf2 is a redox-sensitive transcription factor that is thought to be important in protection against intracellular pathogens. To determine the protective role of Nrf2 in the host defense against Mycobacterium avium complex (MAC), both wild-type and Nrf2-deficient mice were intranasally infected with MAC bacteria. Nrf2-deficient mice were highly susceptible to MAC bacteria compared with wild-type mice. There were no significant changes in the levels of oxidative stress and Th1 cytokine production between genotypes. Comprehensive transcriptome analysis showed that the expressions of Nramp1 and HO-1 were much lower in the infected lungs, and the expression of Nramp1 was especially lower in alveolar macrophages of Nrf2-deficient mice than of wild-type mice. Electron microscopy showed that many infected alveolar macrophages from Nrf2-deficient mice contained a large number of intracellular MAC bacteria with little formation of phagolysosomes, compared with those from wild-type mice. Treatment with sulforaphane, an activator of Nrf2, increased resistance to MAC with increased lung expression of Nramp1 and HO-1 in wild-type mice. These results indicate that Nramp1 and HO-1, regulated by Nrf2, are essential in defending against MAC infection due to the promotion of phagolysosome fusion and granuloma formation, respectively. Thus, Nrf2 is thought to be a critical determinant of host resistance to MAC infection.

Antimicrobial Peptides and Cell-Penetrating Peptides for Treating Intracellular Bacterial Infections

Bacterial infections caused by intracellular pathogens are difficult to control. Conventional antibiotic therapies are often ineffective, as high doses are needed to increase the number of antibiotics that will cross the host cell membrane to act on the intracellular bacterium. Moreover, higher doses of antibiotics may lead to elevated severe toxic effects against host cells. In this context, antimicrobial peptides (AMPs) and cell-penetrating peptides (CPPs) have shown great potential to treat such infections by acting directly on the intracellular pathogenic bacterium or performing the delivery of cargos with antibacterial activities. Therefore, in this mini-review, we cover the main AMPs and CPPs described to date, aiming at intracellular bacterial infection treatment. Moreover, we discuss some of the proposed mechanisms of action for these peptide classes and their conjugation with other antimicrobials.

Dendritic cell engineered cTXN as new vaccine prospect against L. donovani

Dendritic cells (DCs), as antigen-presenting cells, can reportedly be infected withLeishmaniaparasites and hence provide a better option to trigger T-cell primary immune responses and immunological memory. We consistently primed DCs during culture with purified recombinant cytosolic tryparedoxin (rcTXN) and then evaluated the vaccine prospect of presentation of rcTXN against VL in BALB/c mice. We reported earlier the immunogenic properties of cTXN antigen derived fromL. donovani when anti-cTXN antibody was detected in the sera of kala-azar patients. It was observed that cTXN antigen, when used as an immunogen with murine DCs acting as a vehicle, was able to induce complete protection against VL in an infected group of immunized mice. This vaccination triggered splenic macrophages to produce more IL-12 and GM-CSF, and restricted IL-10 release to a minimum in an immunized group of infected animals. Concomitant changes in T-cell responses against cTXN antigen were also noticed, which increased the release of protective cytokine-like IFN-γ under the influence of NF-κβ in the indicated vaccinated group of animals. All cTXN-DCs-vaccinated BALB/c mice survived during the experimental period of 120 days. The results obtained in our study suggest that DCs primed with cTXN can be used as a vaccine prospect for the control of visceral leishmaniasis.

Antileishmanial Drugs Modulate IL-12 Expression and Inflammasome Activation in Primary Human Cells

Leishmaniases are neglected tropical diseases. The treatment of leishmaniasis relies exclusively on chemotherapy including amphotericin B (AmB), miltefosine (hexadecylphosphocholine), and pentamidine. Besides the fact that these molecules are harmful for patients, little is known about the impact of such antileishmanial drugs on primary human cells in relation to immune function. The present study demonstrates that all antileishmanial drugs inhibit CD4 and CD8 T cell proliferation at the doses that are not related to increased cell death. Our results highlight that antileishmanial drugs have an impact on monocytes by altering the expression of IL-12 induced by LPS, whereas only AmB induced IL-10 secretion; both cytokines are essential in regulating Th1 cell-mediated immunity. Interestingly, IL-12 and anti-IL-10 Abs improved T cell proliferation inhibited by AmB. Furthermore, our results show that in contrast to hexadecylphosphocholine and pentamidine, AmB induced gene expression of the inflammasome pathway. Thus, AmB induced IL-1β and IL-18 secretions, which are reduced by specific inhibitors of caspase activation (Q-VD) and NLRP3 activation (MCC950). Our results reveal previously underestimated effects of antileishmanial drugs on primary human cells.

A comparison of Chikungunya virus infection, progression, and cytokine profiles in human PMA-differentiated U937 and murine RAW264.7 monocyte derived macrophages

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes rash, fever and severe polyarthritis that can last for years in humans. Murine models display inflammation and macrophage infiltration only in the adjacent tissues at the site of inoculation, showing no signs of systemic polyarthritis. Monocyte-derived macrophages are one cell type suspected to contribute to a systemic CHIKV infection. The purpose of this study was to analyze differences in CHIKV infection in two different cell lines, human U937 and murine RAW264.7 monocyte derived macrophages. PMA-differentiated U937 and RAW264.7 macrophages were infected with CHIKV, and infectious virus production was measured by plaque assay and by reverse transcriptase quantitative PCR at various time points. Secreted cytokines in the supernatants were measured using cytometric bead arrays. Cytokine mRNA levels were also measured to supplement expression data. Here we show that CHIKV replicates more efficiently in human macrophages compared to murine macrophages. In addition, infected human macrophages produced around 10-fold higher levels of infectious virus when compared to murine macrophages. Cytokine induction by CHIKV infection differed between human and murine macrophages; IL-1, IL-6, IFN-γ, and TNF were significantly upregulated in human macrophages. This evidence suggests that CHIKV replicates more efficiently and induces a much greater pro-inflammatory cytokine profile in human macrophages, when compared to murine macrophages. This may shed light on the critical role that macrophages play in the CHIKV inflammatory response.

Garcinielliptone FC: Selective anti-amastigote and immunomodulatory effects on macrophages infected by Leishmania amazonensis

The present study was directed to the in vitro antileishmanial, cytotoxic and immunomodulatory effects of Garcinielliptone FC (GFC) against promastigote and macrophage-internalized amastigote forms of Leishmania amazonensis. GFC showed in vitro cytotoxicity against BALB/c peritoneal macrophages with CC₅₀ of 74.90 μM. The hemolytic activity against sheep erythrocytes only demonstrated a decrease of 20.42% in cell viability at the highest tested concentration tested (1326.0 μM). GFC promoted in vitro growth inhibition of both promastigote and intracellular amastigotes with IC₅₀ values of 14.06 and 1.91 μM, respectively, with 7.3-fold higher Selectivity Index (SI) for intracellular amastigotes (SI = 39.21) than for promastigotes (SI = 5.33). Interestingly, the pre-treatment of macrophages or promastigotes with GFC promoted decrease of infected macrophages and number of recovered amastigotes, respectively. Also, GFC was able to markedly promote macrophages activation by increase of phagocytic capability and nitrite production at concentrations able to solve infection of macrophages by L. amazonensis, suggesting the possible involvement of immunomodulatory modulation of macrophages leading to solve the infection. GFC is an emerging and promising chemical compound for the studies focused on the assessment of its therapeutic potential on in vivo experimental models of leishmaniasis.

Rough Brucella neotomae provides protection against Brucella suis challenge in mice

Brucellosis is one of the most common zoonotic diseases worldwide. Almost 500,000 new human cases occur each year; yet there is no vaccine for human use. Moreover, there is no universal Brucella vaccine that would provide protection against all pathogenic species of Brucella. We generated a rough, live-attenuated B. neotomae strain by deleting the wboA gene encoding a glycosyltransferase. This strain lacks the O-side chain in its lipopolysaccharide (LPS) and thus the vaccinated animals can be differentiated serologically from the field-infected animals. We tested the efficacy of rough B. neotomae strain to stimulate dendritic cells compared to the smooth wild type strain. Based on TNF-α production, our data suggests that a significantly higher stimulation was obtained when dendritic cells were stimulated with the rough vaccine strain compared to the smooth wild type B. neotomae. Furthermore, the rough mutant was cleared from mice within 6 weeks even at a dose as high as 2 x 10⁸ CFU. Vaccinated mice showed significantly higher level of protection against a virulent B. suis 1330 challenge compared to the control mice. Antibody titers in the mice and cytokine production by the splenocytes from the vaccinated mice showed a Th1 mediated immune response that correlated with the protection.

Detection of post-vaccination enhanced dengue virus infection in macaques: An improved model for early assessment of dengue vaccines

The need for improved dengue vaccines remains since the only licensed vaccine, Dengvaxia, shows variable efficacy depending on the infecting dengue virus (DENV) type, and increases the risk of hospitalization for severe dengue in children not exposed to DENV before vaccination. Here, we developed a tetravalent dengue purified and inactivated vaccine (DPIV) candidate and characterized, in rhesus macaques, its immunogenicity and efficacy to control DENV infection by analyzing, after challenge, both viral replication and changes in biological markers associated with dengue in humans. Although DPIV elicited cross-type and long-lasting DENV-neutralizing antibody responses, it failed to control DENV infection. Increased levels of viremia/RNAemia (correlating with serum capacity at enhancing DENV infection in vitro), AST, IL-10, IL-18 and IFN-γ, and decreased levels of IL-12 were detected in some vaccinated compared to non-vaccinated monkeys, indicating the vaccination may have triggered antibody-dependent enhancement of DENV infection. The dengue macaque model has been considered imperfect due to the lack of DENV-associated clinical signs. However, here we show that post-vaccination enhanced DENV infection can be detected in this model when integrating several parameters, including characterization of DENV-enhancing antibodies, viremia/RNAemia, and biomarkers relevant to dengue in humans. This improved dengue macaque model may be crucial for early assessment of efficacy and safety of future dengue vaccines.

Dengue virus (DENV) is responsible for the most widespread arboviral disease affecting humans. A pre-existing suboptimal immunity to DENV is accepted as being the major risk factor for severe dengue. Thus, if vaccination does not elicit optimal DENV-specific immunity, a vaccine might, instead, increase the risk of severe dengue in vaccinated individuals, as seen with the only licensed vaccine (Dengvaxia) in children naïve to DENV at vaccination. It is thus crucial to assess dengue vaccine safety at the earliest development stages, ideally in the preclinical stage. The dengue macaque model has been used to assess preclinical efficacy of dengue vaccines, with post-challenge DENV replication as the sole efficacy endpoint. However, this model had not predicted the Dengvaxia-associated safety signals. Here we characterized, in macaques, a dengue purified and inactivated vaccine (DPIV) candidate for its immunogenicity and efficacy/safety. Using a multiparameter approach, including characterization of viral replication and biomarkers relevant to dengue/severe dengue in humans, we were able to detect vaccine-associated safety signals in this model. While these results enabled us to discontinue at an early stage the DPIV development, this improved dengue macaque model may also be instrumental for early assessment of efficacy/safety of future dengue vaccines.

Overexpression of wbkF gene in Brucella abortus RB51WboA leads to increased O-polysaccharide expression and enhanced vaccine efficacy against B. abortus 2308, B. melitensis 16M, and B. suis 1330 in a murine brucellosis model

Brucella abortus RB51 is an attenuated, stable, spontaneous rough mutant derived in the laboratory from the virulent strain B. abortus 2308. Previous studies discovered that the wboA gene, which encodes a glycosyltransferase required for synthesis of the O-polysaccharide, is disrupted in strain RB51 by an IS711 element. However, complementation of strain RB51 with a functional wboA gene (strain RB51WboA) does not confer it a smooth phenotype but results in low levels of cytoplasmic O-polysaccharide synthesis. In this study, we asked if increasing the potential availability of bactoprenol priming precursors in strain RB51WboA would increase the levels of O-polysaccharide synthesis and enhance the protective efficacy against virulent Brucella challenge. To achieve this, we overexpressed the wbkF gene, which encodes a putative undecaprenyl-glycosyltransferase involved in bactoprenol priming for O-polysaccharide polymerization, in strain RB51WboA to generate strain RB51WboAKF. In comparison to strain RB51WboA, strain RB51WboAKF expressed higher levels of O-polysaccharide, but was still attenuated and remained phenotypically rough. Mice immunized with strain RB51WboAKF developed increased levels of smooth LPS-specific serum antibodies, primarily of IgG2a and IgG3 isotype. Splenocytes from mice vaccinated with strain RB51WboAKF secreted higher levels of antigen-specific IFN-γ and TNF-α and contained more numbers of antigen-specific IFN-γ secreting CD4⁺ and CD8⁺ T lymphocytes when compared to those of the RB51 or RB51WboA vaccinated groups. Immunization with strain RB51WboAKF conferred enhanced protection against virulent B. abortus 2308, B. melitensis 16M and B. suis 1330 challenge when compared to the currently used vaccine strains. Our results suggest that strain RB51WboAKF has the potential to be a more efficacious vaccine than its parent strain in natural hosts.

Exploring immunomodulation by endocrine changes in Lady Windermere syndrome

Lung disease due to nontuberculous mycobacteria (NTM) occurs with disproportionate frequency in postmenopausal women with a unique phenotype and without clinically apparent predisposing factors. Dubbed 'Lady Windermere syndrome', the phenotype includes low body mass index (BMI), tall stature and higher than normal prevalence of scoliosis, pectus excavatum and mitral valve prolapse. Although the pathomechanism for susceptibility to NTM lung disease in these patients remains uncertain, it is likely to be multi-factorial. A role for the immunomodulatory consequences of oestrogen deficiency and altered adipokine production has been postulated. Altered levels of adipokines and dehydroepiandrosterone have been demonstrated in patients with NTM lung disease. Case reports of NTM lung disease in patients with hypopituitarism support the possibility that altered endocrine function influences disease susceptibility. This paper catalogues the evidence for immunomodulatory consequences of predicted endocrine changes in Lady Windermere syndrome, with emphasis on the immune response to NTM. Collectively, the data warrant further exploration of an endocrine link to disease susceptibility in Lady Windermere syndrome.

AcSDKP is down-regulated in anaemia induced by Trypanosoma brucei infection in mice

Background

Anaemia commonly results from destruction of erythrocytes in the peripheral blood and failure of the bone marrow haematopoietic cells to replenish the erythrocytes. The mechanisms involved in trypanosoma-induced anaemia, including the role of the bone marrow haematopoietic cells are incompletely understood. We studied the responses of a tetrapeptide, AcSDKP, and IL-10, and their association with bone marrow nucleated cells in a Trypanosoma brucei brucei GVR35 experimental infection model.

Methods

Mouse infection was done intraperitoneally with 1 × 10³ trypanosomes/mL. Mice were either infected or left uninfected (N = 100). At days 0, 9, 16, 23, 30, 37, and 44 post-infection, mice were euthanised and blood was collected by cardiac puncture to examine for parasitaemia and packed cell volume (PCV) and then centrifuged for plasma, which was used for cytokine ELISA. The mice's femurs were also dissected and bone marrow was collected for femur cellularity.

Results

PCV dropped from 39.6% to 27% in infected animals by day 9 and remained low (relative to uninfected mice) for the duration of the experiment. AcSDKP levels decreased from day 0 (11.5 × 104 pg/mL) to day 16 (10 × 104), and increased by day 30 (12.6 × 104). There was a significant difference at day 16 (P = 0.023) between the infected and uninfected groups. By contrast, expression of IL-10 markedly increased between day 0 (18.6 pg/mL) and day 16 (145 pg/mL) and decreased by day 30 (42.8 pg/mL). There was also a significant difference in IL-10 expression between infected and uninfected mice at day 16 (P < 0.001). Bone marrow nucleated cells were significantly reduced during periods of low plasma AcSDKP and high plasma IL-10 concentrations (5.4 × 106 infected vs 6.2 × 106 on day 0 and 4.9 × 106 infected vs 10 × 106 uninfected on day 16).

Conclusions

These data unravel a possible negative feedback interaction between AcSDKP and IL-10 in trypanosome infection. More importantly, this study implicates an IL-10/AcSDKP cytokine network in the regulation of bone marrow nucleated cells and provides a new potential mechanism in the pathogenesis of trypanosoma-induced anaemia. Further mechanistic blocking experiments on AcSDKP and IL-10 are recommended to further clarify understanding of the interaction.

Interleukin 23/interleukin 17 axis activated by Mycobacterium avium complex (MAC) is attenuated in patients with MAC-lung disease

BACKGROUND

Mycobacterium avium complex (MAC)-lung disease (LD) is increasing in patients without human immunodeficiency virus infection. However, data on host vulnerability to MAC-related immune responses, and in particular the interleukin (IL)-23/IL-17 axis, are lacking.

METHODS

We enrolled 50 patients with MAC-LD, 25 age-matched patients with tuberculosis (TB) and 25 controls. We measured levels of plasma cytokines, and studied IL-12/IL-17 responses in macrophage and lymphocyte activation to MAC.

RESULTS

The plasma level of IL-17 in the MAC group was higher than in the TB and control groups. In in-vitro macrophage stimulation, the expression of IL-23 in macrophages was similar in the patients with MAC-LD and controls, although the expression of IL-12 p40 was lower in the patients with MAC-LD. In assays of lymphocyte activation, IL-17 was induced by MAC-primed macrophages, but its level was lower in the patients with MAC-LD and TB than in the controls. The expression of programmed death (PD)-1 receptor was higher in CD4⁺IL17A⁺ lymphocytes in the patients with MAC-LD, and the production of IL-17 was significantly increased by blockade of PD-1 and PD-ligand 1.

CONCLUSIONS

MAC induced a similar expression of IL-23 from macrophages in the patients with MAC-LD compared to the controls, but a lower expression of IL-17 from lymphocytes, which may be through an increased expression of PD-1. The macrophage response of IL-12 p40 was stronger than that of IL-12 p70, and higher in the controls during MAC disease, which may suggest another kind of MAC-related immune evasion.

Could age and aging change the host response to systemic parasitic infections? A systematic review of preclinical evidence

The impact of age and aging in the evolution of systemic parasitic infections remains poorly understood. We conducted a systematic review from preclinical models of Chagas disease, leishmaniasis, malaria, sleeping sickness and toxoplasmosis. From a structured and comprehensive search in electronic databases, 29 studies were recovered and included in the review. Beyond the characteristics of the experimental models, parasitological and immunological outcomes, we also discussed the quality of current evidence. Our findings indicated that throughout aging, parasitemia and mortality were consistently reduced in Chagas disease and malaria, but were similar or increased in leishmaniasis and highly variable in toxoplasmosis. While a marked humoral response in older animals was related to the anti-T. cruzi protective phenotype, cellular responses mediated by a polarized Th1 phenotype were associated with a more effective defense against Plasmodium infection. Conversely, in leishmaniasis, severe infections and high mortality rates were potentially related to attenuation of humoral response and an imbalance between Th1 and Th2 phenotypes. Due to the heterogeneous parasitological outcomes and limited immunological data, the role of aging on toxoplasmosis evolution remains unclear. From a detailed description of the methodological bias, more controlled researches could avoid the systematic reproduction of inconsistent and poorly reproducible experimental designs.

In vitro anti-inflammatory and skin protective properties of Virgin coconut oil

Virgin coconut oil (VCO) has been traditionally used as moisturizer since centuries by people in the tropical region. Clinical studies have revealed that VCO improves the symptoms of skin disorders by moisturizing and soothing the skin. However, the mechanistic action of VCO and its benefits on skin has not been elucidated in vitro. The cytotoxicity (CTC₅₀) of VCO was 706.53 ± 2.1 and 787.15 ± 1.1 μg/mL in THP-1 (Human monocytes) and HaCaT (Human keratinocytes) cells respectively. VCO inhibited TNF-α (62.34 ± 3.2 %), IFN-γ (42.66 ± 2.9 %), IL-6 (52.07 ± 2.0 %), IL-8 (53.98 ± 1.8 %) and IL-5 (51.57 ± 2.6 %) respectively in THP-1 cells. Involucrin (INV) and filaggrin (FLG) content increased by 47.53 ± 2.1 % and 40.45 ± 1.2 % respectively in HaCaT cells. VCO increased the expression of Aquaporin-3 (AQP3), involucrin (INV) and filaggrin (FLG) and showed moderate UV protection in HaCaT cells. In vitro skin irritation studies in Reconstructed human epidermis (RHE) and NIH3T3 cells showed that VCO is a non skin irritant (IC₅₀ > 1000 μg/mL) and non phototoxic (PIF < 2). Our study demonstrated the anti inflammatory activity of VCO by suppressing inflammatory markers and protecting the skin by enhancing skin barrier function. This is the first report on anti-inflammatory and skin protective benefits of VCO in vitro. Overall, the results warrant the use of VCO in skin care formulations.

Effect of peste des petits ruminants virus (PPRV) infection on the host immune response in naturally infected goats

Toll like receptors (TLRs) expressed by various immune cells and tissues are known to play an important role in recognising the pathogens by the host. The study was carried out to envisage the expression of virus-recognising-TLRs like TLR-3, TLR-7 and TLR-8 as well as the Th1 and Th2 cytokines in the serum of naturally Peste des petits ruminants virus (PPRV) infected goats. Goat serum samples, collected from three districts of Asom (Kamrup, Nalbari, Darrang), were screened for Peste des petits ruminants virus (PPRV) antibody by Complementary-ELISA. Out of 227 samples screened, 72 samples showed presence of PPR viral antibody with a percentage prevalence of 31.72%. Out of the positive samples, 39 were selected randomly for testing the TLR and cytokine response after PPRV infection. The study indicated TLR-8 to have an enhanced expression in serum of PPRV infected goats alongwith IL-12 and IFN-γ of the Th1 pathway. Further, in infected group, a significant correlation was registered between IL-12 and IFN-γ. The present study showed the involvement of the Th-1 pathway in host immune response after PPRV natural infection which may help in proper disease management and control strategies.

Vitamin E-rich Nanoemulsion Enhances the Antitumor Efficacy of Low-Dose Paclitaxel by Driving Th1 Immune Response

PURPOSE

To overcome the drawbacks of high dose regimen and improve the outcomes of chemotherapy at a low dose, an immunotherapeutic nanoemulsion based combination of chemotherapeutic agent (paclitaxel) with immunomodulatory agent (vitamin E) was developed and evaluated for their antitumor effect against breast cancer.

METHODS

A total of five nanoemulsions loaded with various content of vitamin E were prepared and characterized. The immunoregulatory effects of vitamin E along with the overall antitumor efficacy of vitamin E-rich nanoemulsion with a low dose of paclitaxel were investigated through in vitro and in vivo experiments.

RESULTS

Vitamin E-rich nanoemulsion exhibited relatively narrow size distribution, high entrapment efficiency and controlled in vitro release profile. In RAW264.7 cells, vitamin E-rich nanoemulsion significantly enhanced the secretion of Th1 cytokines and down-regulated the secretion of Th2 cytokine. In a co-culture system, vitamin E-rich nanoemulsion induced a high apoptosis rate in MDA-MB-231 cells as compared with vitamin E-low nanoemulsion. Furthermore, vitamin E-rich nanoemulsion exhibited superior in vivo antitumor efficacy in comparison with Taxol and vitamin E-low nanoemulsion at a paclitaxel dose of 4 mg/kg.

CONCLUSIONS

Vitamin E-rich nanoemulsion has great potential for the treatment of breast cancers with a low dose of paclitaxel via driving Th1 immune response.

Infrared spectroscopic characterization of monocytic microvesicles (microparticles) released upon lipopolysaccharide stimulation

Microvesicles (MVs) are involved in cell-cell interactions, including disease pathogenesis. Nondestructive Fourier-transform infrared (FTIR) spectra from MVs were assessed as a technique to provide new biochemical insights into a LPS-induced monocyte model of septic shock. FTIR spectroscopy provided a quick method to investigate relative differences in biomolecular content of different MV populations that was complementary to traditional semiquantitative omics approaches, with which it is difficult to provide information on relative changes between classes (proteins, lipids, nucleic acids, carbohydrates) or protein conformations. Time-dependent changes were detected in biomolecular contents of MVs and in the monocytes from which they were released. Differences in phosphatidylcholine and phosphatidylserine contents were observed in MVs released under stimulation, and higher relative concentrations of RNA and α-helical structured proteins were present in stimulated MVs compared with MVs from resting cells. FTIR spectra of stimulated monocytes displayed changes that were consistent with those observed in the corresponding MVs they released. LPS-stimulated monocytes had reduced concentrations of nucleic acids, α-helical structured proteins, and phosphatidylcholine compared with resting monocytes but had an increase in total lipids. FTIR spectra of MV biomolecular content will be important in shedding new light on the mechanisms of MVs and the different roles they play in physiology and disease pathogenesis.-Lee, J., Wen, B., Carter, E. A., Combes, V., Grau, G. E. R., Lay, P. A. Infrared spectroscopic characterization of monocytic microvesicles (microparticles) released upon lipopolysaccharide stimulation.

Expansion of CD11b+Ly-6C+ myeloid-derived suppressor cells (MDSCs) driven by galectin-9 attenuates CVB3-induced myocarditis

Galectin-9 is known to play a role in the modulation of innate and adaptive immunity to ameliorate CVB3-induced myocarditis. In the present study, we found that galectin-9 induced the expansion of CD11b⁺Ly-6C⁺ myeloid-derived suppressor cells (MDSCs) in the heart from CVB3-infected mice. Adoptive transfer of CD11b⁺Ly-6C⁺ MDSCs significantly alleviated myocarditis accompanied by increased Th2 and Treg frequency and anti-inflammatory cytokines expression in the heart tissue. Moreover, Ly6C⁺ MDSCs, but not Ly6G⁺ cells, expressed Arg-1 and NOS2, and suppressed CD4⁺ T cell proliferation in vitro in an Arg-1-dependent mechanism; an event that was reversed with treatment of either an Arg-1 inhibitor or addition of excess l-arginine. Furthermore, Ly6C⁺ MDSCs co-expressed higher levels of F4/80, Tim-3, and IL-4Rα, and had the plasticity to up-regulate NOS2 or Arg-1 in response to IFN-γ or IL-4 treatment. The present results indicate that galectin-9 expands CD11b⁺Ly-6C⁺ MDSCs to ameliorate CVB3-induced myocarditis.

Regulation of Viral Replication, Apoptosis and Pro-Inflammatory Responses by 17-AAG during Chikungunya Virus Infection in Macrophages

Chikungunya virus (CHIKV) infection has re-emerged as a major public health concern due to its recent worldwide epidemics and lack of control measures. Although CHIKV is known to infect macrophages, regulation of CHIKV replication, apoptosis and immune responses towards macrophages are not well understood. Accordingly, the Raw264.7 cells, a mouse macrophage cell line, were infected with CHIKV and viral replication as well as new viral progeny release was assessed by flow cytometry and plaque assay, respectively. Moreover, host immune modulation and apoptosis were studied through flow cytometry, Western blot and ELISA. Our current findings suggest that expression of CHIKV proteins were maximum at 8 hpi and the release of new viral progenies were remarkably increased around 12 hpi. The induction of Annexin V binding, cleaved caspase-3, cleaved caspase-9 and cleaved caspase-8 in CHIKV infected macrophages suggests activation of apoptosis through both intrinsic and extrinsic pathways. The pro-inflammatory mediators (TNF and IL-6) MHC-I/II and B7.2 (CD86) were also up-regulated during infection over time. Further, 17-AAG, a potential HSP90 inhibitor, was found to regulate CHIKV infection, apoptosis and pro-inflammatory cytokine/chemokine productions of host macrophages significantly. Hence, the present findings might bring new insight into the therapeutic implication in CHIKV disease biology.

Staphylococcus aureus bacteremia with iliac artery endarteritis in a patient receiving ustekinumab

BACKGROUND

Ustekinumab (Stelara®), a human monoclonal antibody targeting the p40-subunit of interleukin (IL)-12 and IL-23, is indicated for moderate to severe plaque psoriasis and psoriatic arthritis. In large multicenter, prospective trials assessing efficacy and safety of ustekinumab increased rates of severe infections have not been observed so far.

CASE PRESENTATION

Here, we report the case of a 64-year old woman presenting with chills, pain and swelling of her right foot with dark maculae at the sole, and elevated inflammatory markers. She had received a third dose of ustekinumab due to psoriatic arthritis three days before admission. Blood cultures revealed growth of Staphylococcus aureus and imaging showed a thickening of the aortic wall ventral the bifurcation above the right internal iliac artery, resembling an acute bacterial endarteritis. Without the evidence of aneurysms and in absence of foreign bodies, the decision for conservative management was made. The patient received four weeks of antibiotic therapy with intravenous flucloxacillin, followed by an oral regime with levofloxacin and rifampicin for an additional four weeks. Inflammatory markers resolved promptly and the patient was discharged in good health.

CONCLUSION

To our knowledge, this is the first report of a severe S. aureus infection in a patient receiving ustekinumab. Albeit ustekinumab is generally regarded as a safe drug, severe bacterial infections should always be included in the differential diagnosis of elevated inflammatory markers in patients receiving biologicals as these might present with nonspecific symptoms and fever might be absent. Any effort to detect deep-seated or metastatic infections should be made to prevent complications and to secure appropriate treatment. Although other risk factors for an invasive staphylococcal infection like psoriasis, recent corticosteroid injection, or prior hospitalisations were present, and therefore a directive causative link between the S. aureus bacteraemia and ustekinumab can not be drawn, we considered the reporting of this case worthwhile to alert clinicians as we believe that ongoing pharmacovigilance to detect increased risks for rare but severe infections beyond phase II and phase III trials in patients treated with biologicals is essential.

Effect of a Synthetic Immunomodulator on the Regulation of Gamma Interferon and Interleukin-10 Production during Salmonella Sepsis in Itys Mice

The present study examined the in vivo capacity of diHDA-glycerol, a new chemically defined compound that we synthesized, to enhance nonspecific resistance of Itys mice to a virulent Salmonella typhimurium challenge (>LD50). This compound derives from (E)-10 hydroxy-2 decenoic acid (10-HDA), a fatty acid isolated from Royal Jelly. Bacterial growth rate within the spleen, interferon-gamma (IFN-γ), interleukin-10 (IL-10), and nitric oxide (NO) levels were measured in splenocyte cultures from diHDA-glycerol-pretreated mice or saline infected controls, at various time intervals after infectious challenge. Repeated administration of diHDA-glycerol before bacterial inoculation resulted in increased bacterial clearance from the spleen, starting in the second week of infection, whereas in control mice, bacterial proliferation led to death beyond day 13 after challenge. In addition, spleen cells from infected mice produced elevated levels of IFN-γ but failed to produce IL-10. In contrast, on the second week post challenge, the time course of cytokine responses was modified by the pretreatment. Spleen cells from diHDA-glycerol pretreated mice exhibited significantly lower levels of IFN-γ and significantlty higher levels of the anti-inflammatory cytokine IL-10, when compared with those in infected controls. Furthermore, on the second week post challenge, the restored functional capacity of splenocytes to produce nitric oxide (NO) was apparently linked with diHDA-glycerol pretreatment. These results suggest that diHDA-glycerol accelerates some macrophage functions resulting in a more adequate modulation of the balance of inflammatory mediators and consequently, in an enhanced host defense against Salmonella infection.

Impact of intensified training and carbohydrate supplementation on immunity and markers of overreaching in highly trained cyclists

Purpose

To determine effects of intensified training (IT) and carbohydrate supplementation on overreaching and immunity.

Methods

In a randomized, double-blind, crossover design, 13 male cyclists (age 25 ± 6 years, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}O_{2\hbox{max} }$$\end{document}V˙O2max 72 ± 5 ml/kg/min) completed two 8-day periods of IT. On one occasion, participants ingested 2 % carbohydrate (L-CHO) beverages before, during and after training sessions. On the second occasion, 6 % carbohydrate (H-CHO) solutions were ingested before, during and after training, with the addition of 20 g of protein in the post-exercise beverage. Blood samples were collected before and immediately after incremental exercise to fatigue on days 1 and 9.

Results

In both trials, IT resulted in decreased peak power (375 ± 37 vs. 391 ± 37 W, P < 0.001), maximal heart rate (179 ± 8 vs. 190 ± 10 bpm, P < 0.001) and haematocrit (39 ± 2 vs. 42 ± 2 %, P < 0.001), and increased plasma volume (P < 0.001). Resting plasma cortisol increased while plasma ACTH decreased following IT (P < 0.05), with no between-trial differences. Following IT, antigen-stimulated whole blood culture production of IL-1α was higher in L-CHO than H-CHO (0.70 (95 % CI 0.52–0.95) pg/ml versus 0.33 (0.24–0.45) pg/ml, P < 0.01), as was production of IL-1β (9.3 (95 % CI 7–10.4) pg/ml versus 6.0 (5.0–7.8) pg/ml, P < 0.05). Circulating total leukocytes (P < 0.05) and neutrophils (P < 0.01) at rest increased following IT, as did neutrophil:lymphocyte ratio and percentage CD4+ lymphocytes (P < 0.05), with no between-trial differences.

Conclusion

IT resulted in symptoms consistent with overreaching, although immunological changes were modest. Higher carbohydrate intake was not able to alleviate physiological/immunological disturbances.

Overexpression of RORγt Enhances Pulmonary Inflammation after Infection with Mycobacterium Avium

Mycobacterium avium complex (MAC) is the most common cause of nontuberculous mycobacterial disease in humans. The role of Th17 immunity in the pathogenesis of intracellular bacteria, such as MAC, is not currently understood. Transcription factor RAR-related orphan receptor gamma t (RORγt) is known as the master regulator for Th17 cell development. Here, we investigated the role of RORγt in host responses against MAC infection. Wild-type (WT) mice and RORγt-overexpressing mice were infected with MAC via intratracheal inoculation. Systemic MAC growth was not different between WT mice and RORγt-overexpressing mice. However, neutrophilic pulmonary inflammation following MAC infection was enhanced in RORγt-overexpressing mice compared with that in WT mice. The cytokine expression shifted toward a Th17 phenotype in the lungs of RORγt-overexpressing mice following MAC infection; the levels of IL-6 and IL-17 were significantly higher in the lung of these mice than in WT mice. In addition to the increase in IL-17 single-positive T cells, T cells producing both IL-17 and interferon-γ were elevated in the lung of RORγt-overexpressing mice following MAC infection. These findings suggest that RORγt overexpression-mediated Th17 bias contributes to local inflammation rather than systemic responses, by regulating neutrophil recruitment into the sites of infection during MAC infection.

Liposomal Glutathione Supplementation Restores TH1 Cytokine Response to Mycobacterium tuberculosis Infection in HIV-Infected Individuals

Cytokines are signaling biomolecules that serve as key regulators of our immune system. CD4⁺ T-cells can be grouped into 2 major categories based on their cytokine profile: T-helper 1 (T_H1) subset and T-helper 2 (T_H2) subset. Protective immunity against HIV infection requires T_H1-directed CD4 T-cell responses, mediated by cytokines, such as interleukin-1β (IL-1β), IL-12, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α). Cytokines released by the T_H1 subset of CD4 T-cells are considered important for mediating effective immune responses against intracellular pathogens such as Mycobacterium tuberculosis (M. tb). Oxidative stress and redox imbalance that occur during HIV infection often lead to inappropriate immune responses. Glutathione (GSH) is an antioxidant present in nearly all cells and is recognized for its function in maintaining redox homeostasis. Our laboratory previously reported that individuals with HIV infection have lower levels of GSH. In this study, we report a link between lower levels of GSH and dysregulation of T_H1- and T_H2-associated cytokines in the plasma samples of HIV-positive subjects. Furthermore, we demonstrate that supplementing individuals with HIV infection for 13 weeks with liposomal GSH (lGSH) resulted in a significant increase in the levels of T_H1 cytokines, IL-1β, IL-12, IFN-γ, and TNF-α. lGSH supplementation in individuals with HIV infection also resulted in a substantial decrease in the levels of free radicals and immunosuppressive cytokines, IL-10 and TGF-β, relative to those in a placebo-controlled cohort. Finally, we determined the effects of lGSH supplementation in improving the functions of immune cells to control M. tb infection by conducting in vitro assays using peripheral blood mononuclear cells collected from HIV-positive individuals at post-GSH supplementation. Our studies establish a correlation between low levels of GSH and increased susceptibility to M. tb infection through T_H2-directed response, which may be relieved with lGSH supplementation enhancing the T_H1 response.

Expression of immune-related genes of common carp during cyprinid herpesvirus 3 infection

Fish herpesviruses and their hosts may have coevolved for 400 to 450 million yr. During this coexistence, the hosts have equipped themselves with an elaborate immune system to defend themselves from invading viruses, whereas the viruses have developed strategies to evade host immunity, including the expression of cytokine genes that have been captured from the host. Taking advantage of our experimental model for cyprinid herpesvirus 3 (CyHV-3) persistence in carp, we studied the gene expression of host and virus immune-related genes in each stage of infection: acute, persistent and reactivation phases. IFNγ-1, IFNγ-2, IL-12 and IL-10 host genes, and the CyHV-3 vIL-10 gene (khvIL-10) were highly significantly up-regulated in different phases of CyHV-3 infection. Similarly, host IL-1β was up-regulated in the acute phase of CyHV-3 infection. There was no significant difference in the expression of host TNFα-1 and MHC-II genes during all phases of CyHV-3 infection. Based on the expression profile of carp immune-related genes in each stage of CyHV-3 infection, we propose a possible interaction between carp IL-12, carp IL-10 and khvIL-10 during the course of viral infection. To our knowledge, this is the first report on the expression of cytokine genes during all phases (acute, persistent and reactivation) of CyHV-3 infection.

The Immunology of Mammary Gland of Dairy Ruminants between Healthy and Inflammatory Conditions

The health of dairy animals, particularly the milk-producing mammary glands, is essential to the dairy industry because of the crucial hygienic and economic aspects of ensuring production of high quality milk. Due to its high prevalence, mastitis is considered the most important threat to dairy industry, due to its impacts on animal health and milk production and thus on economic benefits. The MG is protected by several defence mechanisms that prevent microbial penetration and surveillance. However, several factors can attenuate the host immune response (IR), and the possession of various virulence and resistance factors by different mastitis-causing microorganisms greatly limits immune defences and promotes establishment of intramammary infections (IMIs). A comprehensive understanding of MG immunity in both healthy and inflammatory conditions will be an important key to understand the nature of IMIs caused by specific pathogens and greatly contributes to the development of effective control methods and appropriate detection techniques. Consequently, this review aims to provide a detailed overview of antimicrobial defences in the MG under healthy and inflammatory conditions. In this sense, we will focus on pathogen-dependent variations in IRs mounted by the host during IMI and discuss the potential ramifications of these variations.

Variable transcription of pro- and anti-inflammatory cytokines in phocine lymphocytes following canine distemper virus infection

Canine distemper virus (CDV) is a highly contagious viral pathogen. Domesticated dogs are the main reservoir of CDV. Although phocine distemper virus was responsible for the recent epidemics in seals in the North and Baltic Seas, most devastating epidemics in seals were also caused by CDV. To further study the pathogenesis of CDV infection in seals, it was the aim of the present study to investigate the mechanisms of CDV induced immunosuppression in seals by analyzing the gene transcription of different pro- and anti-inflammatory cytokines in Concanavalin A (Con A) stimulated and non-stimulated phocine lymphocytes in vitro following infection with the CDV Onderstepoort (CDV-OND) strain. Phocine lymphocytes were isolated via density gradient centrifugation. The addition of 1 μg/ml Con A and virus was either performed simultaneously or lymphocytes were stimulated for 48 h with Con A prior to virus infection. Gene transcription of interleukin (IL)-6, IL-12 and tumor necrosis factor alpha (TNFα) as pro-inflammatory cytokines and IL-4, IL-10 and transforming growth factor beta (TGFβ) as anti-inflammatory cytokines were determined by using RT-qPCR. CDV-OND infection caused an initial increase of pro-inflammatory phocine cytokines mRNA 24h after infection, followed by a decrease in gene transcription after 48 h. A strong increase in the transcription of IL-4 and TGFβ was detected after 48 h when virus and mitogen were added simultaneously. An increased IL-10 production occurred only when stimulation and infection were performed simultaneously. Furthermore, an inhibition of IL-12 on IL-4 was noticed in phocine lymphocytes which were stimulated for 48 h prior to infection. In summary, the duration of the stimulation or the lymphocytes seem to have an important influence on the cytokine transcription and indicates that the outcome of CDV infection is dependent on various factors that might sensitize lymphocytes or make them more susceptible or reactive to CDV infection.

Immunotherapy and Immunochemotherapy in Visceral Leishmaniasis: Promising Treatments for this Neglected Disease

Leishmaniasis has several clinical forms: self-healing or chronic cutaneous leishmaniasis or post-kala-azar dermal leishmaniasis; mucosal leishmaniasis; visceral leishmaniasis (VL), which is fatal if left untreated. The epidemiology and clinical features of VL vary greatly due to the interaction of multiple factors including parasite strains, vectors, host genetics, and the environment. Human immunodeficiency virus infection augments the severity of VL increasing the risk of developing active disease by 100–2320 times. An effective vaccine for humans is not yet available. Resistance to chemotherapy is a growing problem in many regions, and the costs associated with drug identification and development, make commercial production for leishmaniasis, unattractive. The toxicity of currently drugs, their long treatment course, and limited efficacy are significant concerns. For cutaneous disease, many studies have shown promising results with immunotherapy/immunochemotherapy, aimed to modulate and activate the immune response to obtain a therapeutic cure. Nowadays, the focus of many groups centers on treating canine VL by using vaccines and immunomodulators with or without chemotherapy. In human disease, the use of cytokines like interferon-γ associated with pentavalent antimonials demonstrated promising results in patients that did not respond to conventional treatment. In mice, immunomodulation based on monoclonal antibodies to remove endogenous immunosuppressive cytokines (interleukin-10) or block their receptors, antigen-pulsed syngeneic dendritic cells, or biological products like Pam3Cys (TLR ligand) has already been shown as a prospective treatment of the disease. This review addresses VL treatment, particularly immunotherapy and/or immunochemotherapy as an alternative to conventional drug treatment in experimental models, canine VL, and human disease.

Influence of Hydration Status on Changes in Plasma Cortisol, Leukocytes, and Antigen-Stimulated Cytokine Production by Whole Blood Culture following Prolonged Exercise

Elevated antigen-stimulated anti-inflammatory cytokine production appears to be a risk factor for upper respiratory tract illness in athletes. The purpose of this study was to determine the effects of prolonged exercise and hydration on antigen-stimulated cytokine production. Twelve healthy males cycled for 120 min at 60% V˙O2max⁡ on two occasions, either euhydrated or moderately hypohydrated (induced by fluid restriction for 24 h). Blood samples were collected before and after exercise and following 2 h recovery for determination of cell counts, plasma cortisol, and in vitro antigen-stimulated cytokine production by whole blood culture. Fluid restriction resulted in mean body mass loss of 1.3% and 3.9% before and after exercise, respectively. Exercise elicited a significant leukocytosis and elevated plasma cortisol, with no differences between trials. IL-6 production was significantly reduced 2 h postexercise (P < 0.05), while IL-10 production was elevated postexercise (P < 0.05). IFN-γ and IL-2 production tended to decrease postexercise. No significant effect of hydration status was observed for the measured variables. Prolonged exercise appears to result in augmented anti-inflammatory cytokine release in response to antigen challenge, possibly coupled with acute suppression of proinflammatory cytokine production, corresponding with studies using mitogen or endotoxin as stimulant. Moderate hypohydration does not appear to influence these changes.

The role of osteoimmunology in periodontal disease

Periodontal disease is a pathological condition that involves inflammation of the tooth supporting structures. It occurs in response to the presence of bacterial plaque on the tooth structure. The host defense system, including innate and adaptive immunity, is responsible for combating the pathologic bacteria invading the periodontal tissue. Failure to eradicate the invading pathogens will result in a continuous state of inflammation where inflammatory cells such as lymphocytes, PMNs, and macrophages will continue to produce inflammatory mediators in an effort to destroy the invaders. Unfortunately, these inflammatory mediators have a deleterious effect on the host tissue as well as foreign microbes. One of the effects of these mediators on the host is the induction of matrix degradation and bone resorption through activation of proteases and other inflammatory mediators that activate osteoclasts.

Role of Th17 cells in the pathogenesis of CNS inflammatory demyelination

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS). The etiology of MS is not well understood, but it is believed that myelin-specific CD4(+) T cells play a central role in initiating and orchestrating CNS inflammation. In this scenario, CD4(+) T cells, activated in the periphery, infiltrate the CNS, where, by secreting cytokines and chemokines, they start an inflammatory cascade. Given the central role of CD4(+) T cells in CNS autoimmunity, they have been studied extensively, principally by using experimental autoimmune encephalomyelitis (EAE), an animal model of MS. In the late 1980s, CD4(+) T cells, based on their cytokine production, were divided into two helper lineages, Th1 and Th2 cells. It was postulated that Th1 cells, which produce IFN-γ, mediate inflammation of the CNS in MS/EAE, while Th2 cells, which produce IL-4, have a beneficial effect in disease, because of their antagonistic effect on Th1 cells. The Th1/Th2 paradigm remained the prevailing view of MS/EAE pathogenesis until 2005, when a new lineage, Th17, was discovered. In a relatively short period of time it became apparent that Th17 cells, named after their hallmark cytokine, IL-17A, play a crucial role in many inflammatory diseases, including EAE, and likely in MS as well. The Th17 paradigm developed rapidly, initiating the debate of whether Th1 cells contribute to EAE/MS pathogenesis at all, or if they might even have a protective role due to their antagonistic effects on Th17 cells. Numerous findings support the view that Th17 cells play an essential role in autoimmune CNS inflammation, perhaps mainly in the initial phases of disease. Th1 cells likely contribute to pathogenesis, with their role possibly more pronounced later in disease. Hence, the current view on the role of Th cells in MS/EAE pathogenesis can be called the Th17/Th1 paradigm. It is certain that Th17 cells will continue to be the focus of intense investigation aimed at elucidating the pathogenesis of CNS autoimmunity.

A cell permeable peptide inhibitor of NFAT inhibits macrophage cytokine expression and ameliorates experimental colitis

Nuclear factor of activated T cells (NFAT) plays a critical role in the development and function of immune and non-immune cells. Although NFAT is a central transcriptional regulator of T cell cytokines, its role in macrophage specific gene expression is less defined. Previous work from our group demonstrated that NFAT regulates Il12b gene expression in macrophages. Here, we further investigate NFAT function in murine macrophages and determined the effects of a cell permeable NFAT inhibitor peptide 11R-VIVIT on experimental colitis in mice. Treatment of bone marrow derived macrophages (BMDMs) with tacrolimus or 11R-VIVIT significantly inhibited LPS and LPS plus IFN-γ induced IL-12 p40 mRNA and protein expression. IL-12 p70 and IL-23 secretion were also decreased. NFAT nuclear translocation and binding to the IL-12 p40 promoter was reduced by NFAT inhibition. Experiments in BMDMs from IL-10 deficient (Il10^−/−) mice demonstrate that inhibition of IL-12 expression by 11R-VIVIT was independent of IL-10 expression. To test its therapeutic potential, 11R-VIVIT was administered systemically to Il10^−/− mice with piroxicam-induced colitis. 11R-VIVIT treated mice demonstrated significant improvement in colitis compared to mice treated with an inactive peptide. Moreover, decreased spontaneous secretion of IL-12 p40 and TNF in supernatants from colon explant cultures was demonstrated. In summary, NFAT, widely recognized for its role in T cell biology, also regulates important innate inflammatory pathways in macrophages. Selective blocking of NFAT via a cell permeable inhibitory peptide is a promising therapeutic strategy for the treatment of inflammatory bowel diseases.

A MATHEMATICAL MODEL OF IMMUNE RESPONSE IN CUTANEOUS LEISHMANIASIS

The TH1/TH2 paradigm has been largely used in the interpretation of several diseases, particularly in leishmaniasis. As far as we know there is no mathematical description of this model related to leishmaniasis. We have extended and modified a previous published set of equations1in order to adapt it to leishmanial disease particularities. The main modifications were: (1) the analysis of logistic and exponential parasite growth curves, (2) the assumption of the TH2 arm of the immune response having a positive action on parasite growth. The set of three simultaneous differential equations describing the TH1 arm, TH2 arm and parasite growth were analyzed for conditions of existence and stability of the solutions.

Stable solutions valid for the logistic and exponential parasite growth models, with its possible clinical correlations, were obtained in the following situations: (1) parasite and TH2 extinction [TH1 cure], (2) parasite extinction and TH1/TH2 co-existence [TH1/TH2 cure], (3) TH1 and parasite co-existence, TH2 extinction [stable TH1 infection], and (4) TH1, TH2 and parasite co-existence [stable TH1/TH2 infection]. TH2 and parasite co-existence associated to TH1 extinction [stable TH2 infection] was obtained only with the logistic growth model. The model also provides an alternative hypothesis for TH1 bias in resistant mice and emphazises the importance of natural immunity for the existence of chronic states.

Persistent arthralgia induced by Chikungunya virus infection is associated with interleukin-6 and granulocyte macrophage colony-stimulating factor

Background. Chikungunya virus (CHIKV) infection induces arthralgia. The involvement of inflammatory cytokines and chemokines has been suggested, but very little is known about their secretion profile in CHIKV-infected patients.

Methods. A case-control longitudinal study was performed that involved 30 adult patients with laboratory-confirmed Chikungunya fever. Their profiles of clinical disease, viral load, and immune mediators were investigated.

Results. When patients were segregated into high viral load and low viral load groups during the acute phase, those with high viremia had lymphopenia, lower levels of monocytes, neutrophilia, and signs of inflammation. The high viral load group was also characterized by a higher production of pro-inflammatory cytokines, such as interferon-α and interleukin (IL)–6, during the acute phase. As the disease progressed to the chronic phase, IL-17 became detectable. However, persistent arthralgia was associated with higher levels of IL-6 and granulocyte macrophage colony-stimulating factor, whereas patients who recovered fully had high levels of Eotaxin and hepatocyte growth factor.

Conclusions. The level of CHIKV viremia during the acute phase determined specific patterns of pro-inflammatory cytokines, which were associated with disease severity. At the chronic phase, levels of IL-6, and granulocyte macrophage colony-stimulating factor found to be associated with persistent arthralgia provide a possible explanation for the etiology of arthralgia that plagues numerous CHIKV-infected patients.

Areca-nut extract modulates antigen-specific immunity and augments inflammation in ovalbumin-sensitized mice

Areca-nut chewing has been linked to oral cancer and many other diseases, in which immune deterioration and tissue inflammation are plausibly involved. Recent studies reported that areca-nut extract (ANE) affected the functionality of lymphocytes and neutrophils in vitro. In the present study, we investigated the immunomodulatory effect of ANE in vivo. Ovalbumin (OVA)-sensitized mice were daily administered with ANE (5-50 mg/kg) for 10 doses by intraperitoneal injection from days 1 to 5 and from 8 to 12. The mice were systemically sensitized with OVA on day 3, and their footpads were challenged with OVA to induce delayed-type hypersensitivity (DTH) reactions on day 13. The serum level of OVA-specific IgM and IgG(1) was significantly attenuated by 5 and 25 mg/kg of ANE, whereas OVA-specific IgG(2a) was markedly enhanced by 50 mg/kg of ANE. The production of interferon (IFN)-γ by splenocytes reexposed to OVA in culture was markedly augmented by ANE (25 and 50 mg/kg). In addition, ANE (25 and 50 mg/kg) demonstrated an enhancing effect on DTH reactions, including the tissue swelling, the infiltration of CD3(+) and F4/80(+) cells, and the expression of IFN-γ and tumor necrosis factor (TNF)-α in the footpads challenged with OVA. The phagocytic activity and TNF-α production by the splenic CD11b(+) cells were also enhanced in ANE-treated groups. Taken together, these results demonstrated that ANE modulated antigen-specific immune responses and promoted inflammatory reactions in vivo, which may contribute to immune deregulation associated with areca-related diseases.