Elements Of Innate Immunity Research Articles

Human Intestinal Epithelial Cells Release Antiviral Factors That Inhibit HIV Infection of Macrophages.

As a rich source of CD4+ T cells and macrophages, the gastrointestinal (GI) tract is a major target site for HIV infection. The interplay between GI-resident macrophages and intestinal epithelial cells (IECs) constitutes an important element of GI innate immunity against pathogens. In this study, we investigated whether human IECs have the ability to produce antiviral factors that can inhibit HIV infection of macrophages. We demonstrated that IECs possess functional toll-like receptor 3 (TLR3), the activation of which resulted in induction of key interferon (IFN) regulatory factors (IRF3 and IRF7), IFN-β, IFN-λ, and CC chemokines (MIP-1α, MIP-1β, RANTES), the ligands of HIV entry co-receptor CCR5. In addition, TLR3-activated IECs release exosomes that contained the anti-HIV factors, including IFN-stimulated genes (ISGs: ISG15, ISG56, MxB, OAS-1, GBP5, and Viperin) and HIV restriction miRNAs (miRNA-17, miRNA-20, miRNA-28, miRNA-29 family members, and miRNA-125b). Importantly, treatment of macrophages with supernatant (SN) from the activated IEC cultures inhibited HIV replication. Further studies showed that IEC SN could also induce the expression of antiviral ISGs and cellular HIV restriction factors (Tetherin and APOBEC3G/3F) in HIV-infected macrophages. These findings indicated that IECs might act as an important element in GI innate immunity against HIV infection/replication.

Salmonella escapes antigen presentation through K63 ubiquitination mediated endosomal proteolysis of MHC II via modulation of endosomal acidification in dendritic cells.

CD4+ T-cell response is vital for successful clearance of Salmonella Typhimurium infection. Efficient antigen presentation is crucial for effective CD4+ T-cell response. Previous study has reported that Salmonella abrogates antigen presentation capacity of dendritic cells in order to escape host adaptive immune response. In this study, we have elucidated the mechanism of Salmonella-mediated downregulation of the total cellular Major Histocompatibility Complex (MHC) II pool in dendritic cells. Infected dendritic cells show upregulation of E3 ubiquitin ligase, MARCH1 expression and K63-linked ubiquitination of MHCII. Salmonella infection also enhances the internalisation of ubiquitin-tagged MHC II molecules that are subsequently degraded by endosomal proteases. In addition, Salmonella regulates the activation of endosomal proteases by lowering the pH of endosomes. In infected dendritic cells, Salmonella delays NOX2 recruitment to the phagosomes thereby preventing its alkalinisation. NOX2 is a significant part of innate immune response against pathogens as it is responsible for Reactive Oxygen Species (ROS) production. In this study, we have demonstrated how Salmonella evades MHC II-mediated adaptive immune response in dendritic cells through enhanced endosomal proteolysis. To escape host CD4+T response, Salmonella delays NOX2 recruitment, an innate immune response element to the phagosomes.

A hypothetical role for Notch signaling pathway in immunopathogenesis of leprosy

Leprosy is a chronic infectious disease caused by Mycobacterium leprae mainly affecting skin and peripheral nerves. Leprosy has a broad range of clinical manifestations that range from mild (tuberculoid leprosy) to severe (lepromatous leprosy) forms, and are highly dependent on the host’s immune response. Among the immune response elements involved in the pathogenesis of leprosy are the Toll-like receptors (TLRs), vitamin D receptor (VDR), natural killer cells (NK), and T cells. These innate and adaptive immune response elements may be related to the Notch signaling pathway, which is involved in immune cell growth, differentiation, and proliferation. We hypothesize that failure in Notch signaling in leprosy patients may be associated to: 1) compromising NK cell maturation, lysing of infected cells, and CD4+ Th1 differentiation. 2) VDR alterations and TLR polymorphisms may affect expression of Notch Delta-like ligands (DLL) in antigen presenting cells (APCs). 3) altered DLL expression by APCs could compromise CD4+ T cell differentiation towards the Th1 and Th17 effector phenotypes; and finally 4) expression of Notch Jagged ligands would induce CD4+ T cell differentiation towards Th2 effector phenotype and alternative activation of macrophages. Altogether, these signaling failures could favor proliferation of M. leprae in the host. Therefore, evidence of the proposed immunologic failures in leprosy patients would be essential for the better understanding of immunopathogenesis of this disease, and would ultimately enable detection of susceptible individuals, providing a valuable tool for prevention of this debilitating disease.

Differential regulation of the TLR4 signalling pathway in post-mortem prefrontal cortex and cerebellum in chronic schizophrenia: Relationship with SP transcription factors

Alterations in innate immunity may underlie the pathophysiology of schizophrenia (SZ). Toll-like receptor-4 (TLR4) is a master element of innate immunity. The specificity proteins (SPs), transcription factors recently implicated in SZ, are putative regulatory agents of this.This work was aimed at describing alterations in the TLR4 signalling pathway in postmortem brain prefrontal cortex (PFC) and cerebellum (CB) of 16 chronic SZ patients and 14 controls. The possible association of TLR4 pathway with SP1 and SP4 and SZ negative symptomatology is explored.In PFC, TLR4/myeloid differentiation factor 88 (MyD88)/inhibitory subunit of nuclear factor kappa B alpha (IκBα) protein levels were lower in SZ patients, while nuclear transcription factor-κB (NFκB) activity, cyclooxygenase-2 (COX-2) expression and the lipid peroxidation index malondialdehyde (MDA) appeared increased. The pattern of changes in CB is opposite, except for COX-2 expression that remained augmented and MDA levels unaltered.Network interaction analysis showed that TLR4/MyD88/IκBα/NFκB/COX-2 pathway was coupled in PFC and uncoupled in CB. SP4 co-expressed with TLR4 and NFκB in PFC and both SP1 and SP4 co-expressed with NFκB in CB. In PFC, correlation analysis found an inverse relationship between NFκB and negative symptoms.In summary, we found brain region-specific alterations in the TLR4 signalling pathway in chronic SZ, in which SP transcription factors could participate at different levels. Further studies are required to elucidate the regulatory mechanisms of innate immunity in SZ and its relationship with symptoms.

Targeting the permeability barrier and peptidoglycan recycling pathways to disarm Pseudomonas aeruginosa against the innate immune system.

Antimicrobial resistance is a continuously increasing threat that severely compromises our antibiotic arsenal and causes thousands of deaths due to hospital-acquired infections by pathogens such as Pseudomonas aeruginosa, situation further aggravated by the limited development of new antibiotics. Thus, alternative strategies such as those targeting bacterial resistance mechanisms, virulence or potentiating the activity of our immune system resources are urgently needed. We have recently shown that mutations simultaneously causing the peptidoglycan recycling blockage and the β-lactamase AmpC overexpression impair the virulence of P.aeruginosa. These findings suggested that peptidoglycan metabolism might be a good target not only for fighting antibiotic resistance, but also for the attenuation of virulence and/or potentiation of our innate immune weapons. Here we analyzed the activity of the innate immune elements peptidoglycan recognition proteins (PGRPs) and lysozyme against P. aeruginosa. We show that while lysozyme and PGRPs have a very modest basal effect over P. aeruginosa, their bactericidal activity is dramatically increased in the presence of subinhibitory concentrations of the permeabilizing agent colistin. We also show that the P. aeruginosa lysozyme inhibitors seem to play a very residual protective role even in permeabilizing conditions. In contrast, we demonstrate that, once the permeability barrier is overpassed, the activity of lysozyme and PGRPs is dramatically enhanced when inhibiting key peptidoglycan recycling components (such as the 3 AmpDs, AmpG or NagZ), indicating a decisive protective role for cell-wall recycling and that direct peptidoglycan-binding supports, at least partially, the activity of these enzymes. Finally, we show that recycling blockade when occurring simultaneously with AmpC overexpression determines a further decrease in the resistance against PGRP2 and lysozyme, linked to quantitative changes in the cell-wall. Thus, our results help to delineate new strategies against P. aeruginosa infections, simultaneously targeting β–lactam resistance, cell-wall metabolism and virulence, ultimately enhancing the activity of our innate immune weapons.

Abstract 5609: Macrophages in secondary lymphoid organs regulate t cell tolerance and immunosurveillance in pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease that shows striking resistance to standard therapies. Immunotherapy is an exciting new treatment strategy for PDAC, but has yet to reproducibly demonstrate clinical efficacy. This finding may reflect poor effector T cell infiltration into PDAC or mechanisms of peripheral T cell tolerance. We hypothesize that successful immunotherapy in PDAC will require strategies that reverse elements of innate immunity that regulate T cell tolerance. This hypothesis is based on our prior studies in the KrasG12D/+;Trp53R172H/+;Pdx-1-Cre (KPC) mouse model of PDAC where macrophages residing outside of the tumor microenvironment were found to regulate the efficacy of a vaccine strategy involving the combination of chemotherapy and a CD40 agonist (FGK45). Specifically, we found that depletion of peripheral phagocytes using clodronate-encapsulated liposomes (CEL) was necessary for gemcitabine chemotherapy and a CD40 agonist to induce productive anti-tumor T cell immunity against spontaneously arising PDAC tumors in the KPC model. We now investigate the mechanism by which CEL-depleted phagocytes regulate T cell tolerance in PDAC using the KPC mouse model and an orthotopic implantation model. We found that CEL depletes macrophages in the spleen and abdominal lymph nodes, thereby reversing the pathologic accumulation of macrophages in these secondary lymphoid organs that is induced by PDAC tumors. CEL targeted two macrophage subsets in the lymph node, CD11b+CD169+F4/80neg subcapsular sinus macrophages (SSM) and CD11b+CD169+F4/80+ medullary sinus macrophages (MSM). These macrophage populations may be exposed to tumor-derived antigens and apoptotic cell vesicles entering the lymph node, and have been previously identified as central orchestrators of tolerance in autoimmune models. We found that both fluorescently-labeled liposomes and OVA-FITC peptide injected into the peritoneal cavity were specifically targeted to SSM and MSM with little uptake by dendritic cells (DC). In contrast, depletion of these first-line phagocytes by CEL shifted the cellular uptake of these model antigens increasing uptake by CD11b+CD11c+ DC which are more efficient in antigen presentation and show increased expression of co-stimulatory molecules after FGK45 treatment. Using an orthotopic model of PDAC, we then determined that CEL can enhance the T cell stimulatory capacity of gemcitabine chemotherapy in combination with FGK45 as seen by a significant increase in CD38, CD44, CD69 and PD-1 expression on CD4 and CD8 T cells in secondary lymphoid organs. Together, our findings suggest that tumor-derived antigens may be sequestered by tolerogenic macrophages in peritumoral lymph nodes that act to impair optimal induction of T cell responses. Thus, strategies aimed at disrupting the tolerogenic functions of these macrophages may offer a novel approach for improving immunotherapy in PDAC. Citation Format: Fee Bengsch, Anni Liu, Kathleen Graham, Gregory L. Beatty. Macrophages in secondary lymphoid organs regulate t cell tolerance and immunosurveillance in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5609. doi:10.1158/1538-7445.AM2017-5609

414 Both sphingosine kinase 1 and 2 coordinately regulate cathelicidin antimicrobial peptide production during keratinocyte differentiation

The innate immune element, cathelicidin antimicrobial peptide (CAMP), is a vital antimicrobial peptide needed for the formation of the antimicrobial skin barrier. We recently identified a novel endoplasmic reticulum (ER) stress-mediated sphingosine-1-phosphate (S1P)-dependent mechanism of CAMP synthesis. Interestingly, in this study, we found that S1P synthesized by an isoform of sphingosine kinase (SPHK), SPHK1, serves as a signal for CAMP synthesis and conversely, another isoform (SPHK2) likely has a suppressor role in CAMP production. CAMP production is increased during epidermal differentiation and enriched in the stratum corneum. Pertinently, prior studies showed that physiological ER stress is essential for normal epidermal differentiation. We here investigated how CAMP production is increased during epidermal differentiation. We found that 1) increased ER stress is evident in differentiated cultured keratinocytes; 2) increases in both CAMP and S1P production depend upon differentiation level of keratinocyte (proliferatedwt, but not dominant negative SPHK2 suppresses CAMP production in both proliferated and differentiated KC. Our current study suggests that both an increase in SPHK1 and a decrease in SPHK2 expression coordinately stimulate CAMP production during epidermal differentiation.

Badger macrophages fail to produce nitric oxide, a key anti-mycobacterial effector molecule

The European badger is recognised as a wildlife reservoir for bovine tuberculosis (bTB); the control of which is complex, costly and controversial. Despite the importance of badgers in bTB and the well-documented role for macrophages as anti-mycobacterial effector cells, badger macrophage (bdMφ) responses remain uncharacterised. Here, we demonstrate that bdMφ fail to produce nitric oxide (NO) or upregulate inducible nitric oxide synthase (iNOS) mRNA following Toll-like receptor (TLR) agonist treatment. BdMφ also failed to make NO after stimulation with recombinant badger interferon gamma (bdIFNγ) or a combination of bdIFNγ and lipopolysaccharide. Exposure of bdMφ to TLR agonists and/or bdIFNγ resulted in upregulated cytokine (IL1β, IL6, IL12 and TNFα) mRNA levels indicating that these critical pathways were otherwise intact. Although stimulation with most TLR agonists resulted in strong cytokine mRNA responses, weaker responses were evident after exposure to TLR9 agonists, potentially due to very low expression of TLR9 in bdMφ. Both NO and TLR9 are important elements of innate immunity to mycobacteria, and these features of bdMφ biology would impair their capacity to resist bTB infection. These findings have significant implications for the development of bTB management strategies, and support the use of vaccination to reduce bTB infection in badgers.

The innate immune system in human systemic lupus erythematosus.

Although the role of adaptive immune mechanisms, e.g. autoantibody formation and abnormal T-cell activation, has been long noted in the pathogenesis of human systemic lupus erythematosus (SLE), the role of innate immunity has been less well characterized. An intricate interplay between both innate and adaptive immune elements exists in protective anti-infective immunity as well as in detrimental autoimmunity. More recently, it has become clear that the innate immune system in this regard not only starts inflammation cascades in SLE leading to disease flares, but also continues to fuel adaptive immune responses throughout the course of the disease. This is why targeting the innate immune system offers an additional means of treating SLE. First trials assessing the efficacy of anti-type I interferon (IFN) therapy or modulators of pattern recognition receptor (PRR) signalling have been attempted. In this review, we summarize the available evidence on the role of several distinct innate immune elements, especially neutrophils and dendritic cells as well as the IFN system, as well as specific innate PRRs along with their signalling pathways. Finally, we highlight recent clinical trials in SLE addressing one or more of the aforementioned components of the innate immune system.

Role of microbial biofilms in the maintenance of oral health and in the development of dental caries and periodontal diseases. Consensus report of group 1 of the Joint EFP/ORCA workshop on the boundaries between caries and periodontal disease

The scope of this working group was to review (1) ecological interactions at the dental biofilm in health and disease, (2) the role of microbial communities in the pathogenesis of periodontitis and caries, and (3) the innate host response in caries and periodontal diseases. A health-associated biofilm includes genera such as Neisseria, Streptococcus, Actinomyces, Veillonella and Granulicatella. Microorganisms associated with both caries and periodontal diseases are metabolically highly specialized and organized as multispecies microbial biofilms. Progression of these diseases involves multiple microbial interactions driven by different stressors. In caries, the exposure of dental biofilms to dietary sugars and their fermentation to organic acids results in increasing proportions of acidogenic and aciduric species. In gingivitis, plaque accumulation at the gingival margin leads to inflammation and increasing proportions of proteolytic and often obligately anaerobic species. The natural mucosal barriers and saliva are the main innate defence mechanisms against soft tissue bacterial invasion. Similarly, enamel and dentin are important hard tissue barriers to the caries process. Given that the present state of knowledge suggests that the aetiologies of caries and periodontal diseases are mutually independent, the elements of innate immunity that appear to contribute to resistance to both are somewhat coincidental.

Complement in basic processes of the cell.

The complement system is reemerging in the last few years not only as key element of innate immunity against pathogens, but also as a main regulator of local adaptive responses, affecting dendritic cells as well as T and B lymphocytes. We review data showing that leucocytes are capable of significant autocrine synthesis of complement proteins, and express a large range of complement receptors, which in turn regulate their differentiation and effector functions while cross talking with other innate receptors such as Toll-like receptors. Other unconventional roles of complement proteins are reviewed, including their impact in non-leukocytes and their intracellular cleavage by vesicular proteases, which generate critical cues required for T cell function. Thus, leucocytes are very much aware of complement-derived information, both extracellular and intracellular, to elaborate their responses, offering rich avenues for therapeutic intervention and new hypothesis for conserved major histocompatibility complex complotypes.

Unexpected Evidence That Inducible Nitric Oxide Synthase (iNOS) Is a Negative Regulator of Hematopoietic Stem/Progenitor Cell Mobilization

Background. Nitric oxide (NO) is gaseous free radical molecule involved in several biological processes related to inflammation, tissue damage, and infections. NO is synthesized by three isoforms of nitric oxide synthetase: two constitutively expressed isoforms, neuronal NOS (nNOS) and endothelial NOS (eNOS), and one isoform (iNOS) that is induced in response to inflammation. Interestingly, iNOS activity is enhanced during complement cascade (ComC) activation, which is a crucial element of innate immunity, and its cleavage fragments C3 and C5 (C3a and C5a, respectively) orchestrate the egress of HSPCs from BM into peripheral blood (PB). Mobilization studies in eNOS-/- mice revealed that the lack of constitutively expressed eNOS in endothelium reduces vascular endothelial growth factor (VEGF)-induced mobilization of endothelial progenitor cells (EPCs) and increases murine mortality after myelosuppression (Nature Med. 2003, 9:1370-6). However, no mobilization studies have been performed so far to assess the role of inducible hematopoietic cell-expressed iNOS in the mobilization of HSPCs. Because of this research void, we became interested in the potential role of iNOS in mobilization of HSPCs. This interest had two motivations. First, it was demonstrated in a recent paper that NO inhibits migration of granulocytes and monocytes, and it is known that these cells are crucial in facilitating egress of HSPCs across the bone marrow (BM)-peripheral blood (PB) barrier. Second, NO, which promotes inflammation, may have anti-inflammatory activity, and inflammation itself is one of the driving forces in HSPC mobilization. Aim of the study. To fill in this knowledge gap, we focused on the role of iNOS in the trafficking of hematopoietic cells as well as mobilization and homing of HSPCs. Materials and Methods. iNOS was upregulated or downregulated in established hematopoietic cell lines to study migration and adhesion of these cells. HSPC mobilization studies were performed in iNOS-/- mice, and, in parallel, homing and engraftment of iNOS-/- BM cells was evaluated in wild type animals. Since activation of the ComC is negatively regulated by heme oxygenase 1 (HO-1), and the ComC may downregulate HO-1, we tested the effect of HO-1 on iNOS-mediated cell trafficking. Results. Our results indicate that iNOS is a negative regulator of hematopoietic cell migration and prevents egress of HSPCs into PB during the mobilization process. At the molecular level, downregulation of iNOS resulted in downregulation of HO-1, and, vice versa, upregulation of iNOS enhanced HO-1 activity. Since, as we observed recently, HO-1 is a negative regulator of cell migration, the inhibitory effects of iNOS on the mobilization of HSPCs can be at least partially explained by its enhancing the HO-1 level in BM cells. Moreover, our studies, in which we generated hematopoietic chimeras, revealed that the iNOS effect depends on its expression in hematopoietic cells. Conclusions. We identified iNOS as a negative regulator of cell trafficking and mobilization of HSPCs. Further studies are needed to establish the mutual relationship between activation of iNOS and activation of HO-1 in hematopoietic cells, as both inducible enzymes are potent negative regulators of HSPC trafficking and together and regulate stem cell mobilization and homing. Therefore, inhibition of iNOS or HO-1 in HSPCs by employing small molecular inhibitors could find practical clinical application. DisclosuresNo relevant conflicts of interest to declare.

Fat body and hemocyte contribution to the antimicrobial peptide synthesis in Calliphora vicina R.-D. (Diptera: Calliphoridae) larvae.

Antimicrobial peptides accumulated in the hemolymph in response to infection are a key element of insect innate immunity. The involvement of the fat body and hemocytes in the antimicrobial peptide synthesis is widely acknowledged, although release of the peptides present in the hemolymph from the immune cells was not directly verified so far. Here, we studied the presence of antimicrobial peptides in the culture medium of fat body cells and hemocytes isolated from the blue blowfly Calliphora vicina using complex of liquid chromatography, mass spectrometry, and antimicrobial activity assays. Both fat body and hemocytes are shown to synthesize and release to culture medium defensin, cecropin, diptericins, and proline-rich peptides. The spectra of peptide antibiotics released by the fat body and hemocytes partially overlap. Thus, the results suggest that insect fat body and blood cells are capable of releasing mature antimicrobial peptides to the hemolymph. It is notable that the data obtained demonstrate dramatic difference in the functioning of insect antimicrobial peptides and their mammalian counterparts localized into blood cells' phagosomes where they exert their antibacterial activity.

English

The endeavor of this paper was to review cancer immunotherapy which means the modulating and using of the patient’s own immune system to target the cancer cells rather than using an extrinsic means of therapy. The best way to prevent and remove infections is through the natural 'sterilising' action of the immune response that combines elements of both innate and adaptive immunity to ward off foreign pathogens without medical intervention. The use of immunostimulants, non-specific approach, for cancer therapy is one of the earliest approaches in immunotherapy that aims to enhance the activity of the lymphocytes that are already attacking to the tumour cells but are insufficient to produce a full-powered immune response. In this review, radioimmunotherapy (coupling a radioactive atom to a monoclonal antibody (mAb)), immunotoxins (generated by coupling plant-derived or bacterial toxins to mAbs), antibody-directed enzyme prodrug therapy (an antibody is used as a vector to transfer an enzyme) and immunomodulators were among the discussed approaches to use mAbs as an anti-cancer. A new and promising immunotherapy that is especially highly effective against metastatic melanoma, adoptive cell therapy (ACT), and different cancer vaccines were also reviewed in detail. Key words: Adoptive cell therapy, cancer immunotherapy, cancer vaccines, immunostimulants, monoclonal antibodies.

Innate immunity in vertebrates: an overview.

Innate immunity is a semi-specific and widely distributed form of immunity, which represents the first line of defence against pathogens. This type of immunity is critical to maintain homeostasis and prevent microbe invasion, eliminating a great variety of pathogens and contributing with the activation of the adaptive immune response. The components of innate immunity include physical and chemical barriers, humoral and cell-mediated components, which are present in all jawed vertebrates. The understanding of innate defence mechanisms in non-mammalian vertebrates is the key to comprehend the general picture of vertebrate innate immunity and its evolutionary history. This is also essential for the identification of new molecules with applications in immunopharmacology and immunotherapy. In this review, we describe and discuss the main elements of vertebrate innate immunity, presenting core findings in this field and identifying areas that need further investigation.

ER stress stimulates production of the key antimicrobial peptide, cathelicidin, by forming a previously unidentified intracellular S1P signaling complex

We recently identified a previously unidentified sphingosine-1-phosphate (S1P) signaling mechanism that stimulates production of a key innate immune element, cathelicidin antimicrobial peptide (CAMP), in mammalian cells exposed to external perturbations, such as UVB irradiation and other oxidative stressors that provoke subapoptotic levels of endoplasmic reticulum (ER) stress, independent of the well-known vitamin D receptor-dependent mechanism. ER stress increases cellular ceramide and one of its distal metabolites, S1P, which activates NF-κB followed by C/EBPα activation, leading to CAMP production, but in a S1P receptor-independent fashion. We now show that S1P activates NF-κB through formation of a previously unidentified signaling complex, consisting of S1P, TRAF2, and RIP1 that further associates with three stress-responsive proteins; i.e., heat shock proteins (GRP94 and HSP90α) and IRE1α. S1P specifically interacts with the N-terminal domain of heat shock proteins. Because this ER stress-initiated mechanism is operative in both epithelial cells and macrophages, it appears to be a universal, highly conserved response, broadly protective against diverse external perturbations that lead to increased ER stress. Finally, these studies further illuminate how ER stress and S1P orchestrate critical stress-specific signals that regulate production of one protective response by stimulating production of the key innate immune element, CAMP.

50 Years Ago in TheJournal ofPediatrics: The Peripheral White Blood Count in Respirovirus Infection

Portnoy B, Hanes B, Salvatore, MA, Eckert HL. J Pediatr 1966;68:181-8 Portnoy et al documented the peripheral white blood cell (WBC) counts in hundreds of hospitalized children with respiratory tract viruses, comparing children who were symptomatically and asymptomatically infected. The median WBC counts were significantly different: 14 465/mm3 in the symptomatic group vs 9000 in the asymptomatic group, but with large overlap. The hypotheses driving this investigation were not clearly stated by the investigators, but in the Discussion they speculated that the higher WBC counts in the symptomatic children may have been due in part to coincident infection by bacteria. The accurate identification of bacterial superinfection in viral respiratory tract illness remains a vexing problem. Influenza has a well-documented incidence of bacterial superinfection, most commonly with Streptococcus pneumoniae, particularly in fatal cases. Indeed, the name “Haemophilus influenzae” was derived from its original isolation from the lungs of persons suffering from severe influenza in the late 19th century. The frequency of bacterial superinfection in other viral respiratory tract infection is not well established. Respiratory viruses alter upper airway defenses, upregulate bacterial adhesion factors on epithelial cells, and disrupt elements of innate immunity in the lungs, so it is remarkable that even with influenza, the marked majority of lower respiratory tract infection in children is purely viral. The dilemma, then, has been to identify the few who are truly coinfected with bacteria, especially in severe disease, allowing the clinician to intelligently use or safely withhold antibiotics. Readily assessable variables such as fever, WBC count (as suggested by the data in Portnoy et al), and the acute phase reactant C-reactive protein insufficiently discriminate viral and bacterial disease in the individual child. Procalcitonin, a sensitive and specific acute phase reactant in detecting bacterial disease, was inadequate as a stand-alone test in identifying bacterial coinfection during the H1N1 influenza pandemic, although persistently low procalcitonin measurements may allow discontinuation of antibiotics once started. In the future, viral and bacterial or mixed viral/bacterial pneumonias may prove to have unequivocally distinct and measurable cytokine signatures, but for now the perfect test to identify bacterial superinfection in viral respiratory tract disease remains elusive, and the clinician must use multiple clues in assessing the need for, and duration of, antibiotics.

Expression of the bovine neutrophil β-defensins4 (BNBD4) and 10 (BNBD10), and β-defensin 1(DEFB1) in the bovine mammary gland with chronic mastitis by Staphylococcus aureus

Bovine mastitis is the most costly infectious disease of dairy cattle worldwide and ischaracterized by inflammation of the mammary gland. The etiology of the pathogens influences the severity of the inflammation and the immune response, and specifically some elements of the innate immunity, like the antimicrobial peptides, are known to display some pathogen specificity. The antimicrobial peptides play an important role in the innate immune defense mechanisms of the mammary gland against mastitis causative microorganisms. In the present study the expression of three β -defensins was estimated across 5 localizations of the mammary gland infected with Sthapylococcus aureus , by quantitative real-time PCR. Copies of mRNA for BNBD10 and DEFB1 were detected in Lymph node, parenchyma, streak canal, cisterna, andRosette of Furstenberg, with the highest level observed in lymph node and the lowest in Rosette of Furstenberg, and the level of expression was higher for BNBD10 . The level of mRNA expression for BNBD4 was very low in all localizations, with respect to BNBD10 and DEFB1 . Therefore, BNBD10 and DEFB1 could play a key role in the mammary gland with mastitis by S. aureus .

Soluble and immobilized graphene oxide activates complement system differently dependent on surface oxidation state

Graphene oxide (GO) is believed to become applicable in biomedical products and medicine, thereby necessitating appropriate safety evaluation dependent on their applications and the route of administration. We have examined the effect of GO form (in solution versus immobilized) and oxidation state on two related elements of innate immunity: the complement system and interleukin-6 (IL-6) release in human blood. In solution, there was a decrease in GO-mediated complement activation with decreasing surface oxygen content (and altered oxygen functionality), whereas with immobilized GO complement response were reversed and increased with decreasing oxygen content. GO solutions, at concentrations below complement activating threshold, did not induce IL-6 release from human blood leukocytes, and further dampened lipopolysaccharide-induced IL-6 release in the whole blood. The latter effect became more profound with GO's having higher oxygen content. This protective role of GO solutions, however, disappeared at higher concentrations above complement-activating threshold. We discuss these results in relation to GO surface structure and properties, and implications for local administration and development of GO-based implantable devices.

Perfil de citosinas relacionadas con linfocitos Th17: rol fisiopatológico y potencial uso como biomarcadores de actividad del lupus eritematoso sistémico

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease expressed in genetically predisposed individuals. The interaction of a trigger factor together with the failure of the mechanisms for handling potential reactive autoantigens leads to the development of immune complex responsible for the damage of the target organs. Elements of both innate and adaptive immunity have been implicated in the pathophysiology of the disease, but given the heterogeneity of the SLE, we still do not have a biological marker of activity of the disease with high sensitivity, specificity and predictive value. Recently, a cell population was described as lymphocytes T helper 17 (Th17), so called because of their production of Interleukin 17 (IL-17), cytokine that mediates physiological and pathophysiological processes implicated in the development of inflammatory conditions such as SLE. It has been postulated that serum IL-17 may be a biomarker that meets these parameters; however, data on this topic is still incomplete. We present a review of the ontogenetic mechanisms of Th17 lymphocytes, an explanation of its pathophysiological role in SLE and clinical studies that support and discuss the role of Th17 lymphocytes related cytokines as biomarkers of disease activity in SLE.