Molecular and functional analysis of a lymphocyte chemoattractant factor: association of biologic function with CD4 expression

An eQTL-based Approach Reveals Candidate Regulators of LINE-1 RNA Levels in Lymphoblastoid Cells

Long interspersed element 1 (L1) are a family of autonomous, actively mobile transposons that occupy ~17% of the human genome. A number of pleiotropic effects induced by L1 (promoting genome instability, inflammation, or cellular senescence) have been observed, and L1's contributions to aging and aging diseases is an area of active research. However, because of the cell type-specific nature of transposon control, the catalogue of L1 regulators remains incomplete. Here, we employ an eQTL approach leveraging transcriptomic and genomic data from the GEUVADIS and 1000Genomes projects to computationally identify new candidate regulators of L1 RNA levels in lymphoblastoid cell lines. To cement the role of candidate genes in L1 regulation, we experimentally modulate the levels of top candidates in vitro, including IL16, STARD5, HSDB17B12, and RNF5, and assess changes in TE family expression by Gene Set Enrichment Analysis (GSEA). Remarkably, we observe subtle but widespread upregulation of TE family expression following IL16 and STARD5 overexpression. Moreover, a short-term 24-hour exposure to recombinant human IL16 was sufficient to transiently induce subtle, but widespread, upregulation of L1 subfamilies. Finally, we find that many L1 expression-associated genetic variants are co-associated with aging traits across genome-wide association study databases. Our results expand the catalogue of genes implicated in L1 RNA control and further suggest that L1-derived RNA contributes to aging processes. Given the ever-increasing availability of paired genomic and transcriptomic data, we anticipate this new approach to be a starting point for more comprehensive computational scans for transposon transcriptional regulators.

Sex differences in peripheral immune cell activation: Implications for pain and pain resolution

Decades of research into chronic pain has deepened our understanding of the cellular mechanisms behind this process. However, a failure to consider the biological variable of sex has limited the application of these breakthroughs into clinical application. In the present study, we investigate fundamental differences in chronic pain between male and female mice resulting from inflammatory activation of the innate immune system. We provide evidence that female mice are more sensitive to the effects of macrophages. Injecting small volumes of media conditioned by either unstimulated macrophages or macrophages stimulated by the inflammatory molecule TNFα lead to increased pain sensitivity only in females. Interestingly, we find that TNFα conditioned media leads to a more rapid resolution of mechanical hypersensitivity and altered immune cell recruitment to sites of injury. Furthermore, male and female macrophages exhibit differential polarization characteristics and motility after TNFα stimulation, as well as a different profile of cytokine secretions. Finally, we find that the X-linked gene Tlr7 is critical in the facilitating the adaptive resolution of pain in models of acute and chronic inflammation in both sexes. Altogether, these findings suggest that although the cellular mechanisms of pain resolution may differ between the sexes, the study of these differences may yield more targeted approaches with clinical applications.

Changes in IL-16 Expression in the Ovary during Aging and Its Potential Consequences to Ovarian Pathology

Aging in females is not only associated with the changes in hormonal status but is also responsible for dysregulation of immune functions in various organs including ovaries. The goal of this study was to determine whether the expression of interleukin 16 (IL-16), a proinflammatory and chemoattractant cytokine, changes during ovarian aging, to determine factors involved in such changes in IL-16 expression, and to examine if changes in IL-16 expression during aging predisposes the ovary to pathologies. Ovarian tissues from premenopausal women (30-50 years old), women at early menopause (55-59 years old), and late menopause (60-85 years old) were used. In addition, tumor tissues from patients with ovarian high-grade serous carcinoma at early stage (n = 5) were also used as reference tissue for comparing the expression of several selected markers in aging ovaries. The expression of IL-16, frequency of macrophages (a source of IL-16) and expression of microRNA (miR) 125a-5p (a regulator of IL-16 gene) were performed by immunohistochemistry, immunoblotting, and gene expression assays. In addition, we examined changes in nuclear expression of IL-16 expression with regards to exposure to follicle-stimulating hormone (FSH) by in vitro cell culture assays with human ovarian cancer cells. The frequencies of IL-16 expressing cells were significantly higher in ovarian stroma in women at early and late menopause as compared with premenopausal women (P < 0.0001). Similar patterns were also observed for macrophages. Expression of miR-125a-5p decreased significantly (P < 0.001) with the increase in IL-16 expression during aging. Furthermore, expression of nuclear IL-16 increased remarkably upon exposure to FSH. Consequently, ovarian aging is associated with increased expression of IL-16 including its nuclear fraction. Therefore, persistent high levels of FSH in postmenopausal women may be a factor for enhanced expression of IL-16. Effects of increased nuclear fraction of IL-16 need to be examined.

Molecular Characteristics of Regional Chromoblastomycosis in Guangdong, China: Epidemiological, Clinical, Antifungal Susceptibility, and Serum Cytokine Profiles of 45 Cases

Chromoblastomycosis (CBM) is a chronic disease caused by several species of dematiaceous fungi. In this study, a regional collection of 45 CBM cases was conducted in Guangdong, China, a hyper-endemic area of CBM. Epidemiology findings indicated that the mean age of cases was 61.38 ± 11.20 years, long duration ranged from 3 months to 30 years, and the gender ratio of male to female was 4.6:1. Thirteen cases (29%) declared underlying diseases. Verrucous form was the most common clinical manifestation (n = 19, 42%). Forty-five corresponding clinical strains were isolated, and 28 of them (62%) were identified as F. monophora; the remaining 17 (38%) were identified as F. nubica through ITS rDNA sequence analysis. Antifungal susceptibility tests in vitro showed low MICs in azoles (PCZ 0.015–0.25 μg/ml, VCZ 0.015–0.5 μg/ml, and ITZ 0.03–0.5 μg/ml) and TRB (0.015–1 μg/ml). Itraconazole combined with terbinafine was the main therapeutic strategy used for 31 of 45 cases, and 68% (n = 21) of them improved or were cured. Cytokine profile assays indicated upregulation of IL-4, IL-7, IL-15, IL-11, and IL-17, while downregulation of IL-1RA, MIP-1β, IL-8, and IL-16 compared to healthy donors (p < 0.05). The abnormal cytokine profiles indicated impaired immune response to eliminate fungus in CBM cases, which probably contributed to the chronic duration of this disease. In conclusion, we investigated the molecular epidemiological, clinical, and laboratory characteristics of CBM in Guangdong, China, which may assist further clinical therapy, as well as fundamental pathogenesis studies of CBM.

Human olfactory mesenchymal stromal cell transplantation ameliorates experimental autoimmune encephalomyelitis revealing an inhibitory role for IL16 on myelination

One of the therapeutic approaches for the treatment of the autoimmune demyelinating disease, multiple sclerosis (MS) is bone marrow mesenchymal stromal cell (hBM-MSCs) transplantation. However, given their capacity to enhance myelination in vitro, we hypothesised that human olfactory mucosa-derived MSCs (hOM-MSCs) may possess additional properties suitable for CNS repair. Herein, we have examined the efficacy of hOM-MSCs versus hBM-MSCs using the experimental autoimmune encephalomyelitis (EAE) model. Both MSC types ameliorated disease, if delivered during the initial onset of symptomatic disease. Yet, only hOM-MSCs improved disease outcome if administered during established disease when animals had severe neurological deficits. Histological analysis of spinal cord lesions revealed hOM-MSC transplantation reduced blood–brain barrier disruption and inflammatory cell recruitment and enhanced axonal survival. At early time points post-hOM-MSC treatment, animals had reduced levels of circulating IL-16, which was reflected in both the ability of immune cells to secrete IL-16 and the level of IL-16 in spinal cord inflammatory lesions. Further in vitro investigation revealed an inhibitory role for IL-16 on oligodendrocyte differentiation and myelination. Moreover, the availability of bioactive IL-16 after demyelination was reduced in the presence of hOM-MSCs. Combined, our data suggests that human hOM-MSCs may have therapeutic benefit in the treatment of MS via an IL-16-mediated pathway, especially if administered during active demyelination and inflammation.

Commensal oral microbiota induces osteoimmunomodulatory effects separate from systemic microbiome in mice

Commensal microbes critically regulate skeletal homeostasis, yet the impact of specific microbiota communities on osteoimmune response mechanisms is unknown. To discern osteoimmunomodulatory effects imparted by the commensal oral microbiota that are distinct from the systemic microbiota, osteoimmunology studies were performed in both alveolar bone and nonoral skeletal sites of specific pathogen–free (SPF) versus germ-free (GF) mice and SPF mice subjected to saline versus chlorhexidine oral rinses. SPF versus GF mice had reduced cortical/trabecular bone and an enhanced pro-osteoclastic phenotype in alveolar bone. TLR signaling and Th17 cells that have known pro-osteoclastic actions were increased in alveolar BM, but not long BM, of SPF versus GF mice. MHC II antigen presentation genes and activated DCs and CD4⁺ T cells were elevated in alveolar BM, but not long BM, of SPF versus GF mice. These findings were substantiated by in vitro allostimulation studies demonstrating increased activated DCs derived from alveolar BM, but not long BM, of SPF versus GF mice. Chlorhexidine antiseptic rinse depleted the oral, but not gut, bacteriome in SPF mice. Findings from saline- versus chlorhexidine-treated SPF mice corroborated outcomes from SPF versus GF mice, which reveals that the commensal oral microbiota imparts osteoimmunomodulatory effects separate from the systemic microbiome.

Involvement of CD4+ and CD8+ T-lymphocytes in the modulation of nociceptive processing evoked by CCL4 in mice

AIMS

To explore the mechanisms involved in the transformation of analgesia produced by low doses of CCL4 (pg/kg) to hyperalgesia when higher doses (ng/kg) are administered to mice.

MAIN METHODS

The unilateral hot plate test was used to assess thermal nociception. CD3⁺, CD4⁺ or CD8⁺ blood cells were depleted with selective antibodies. Expression of CCR5 and IL-16 in lymphocytes was studied by flow cytometry and IL-16 blood levels were measured by ELISA. IL-16 and CD8 were detected by immunofluorescence.

KEY FINDINGS

IL-16 and CCR5 expression were demonstrated in CD4⁺ and CD8⁺ T-lymphocytes by flow cytometry. Furthermore, CCL4-induced hyperalgesia was abolished by reducing circulating T-lymphocyte levels or by selectively depleting CD4⁺ lymphocytes. In contrast, when the anti-CD4 antibody was acutely administered, CCL4 induced analgesia instead of hyperalgesia. A similar response was obtained when administering A-770041, that prevents CD4-mediated CCR5 desensitization by inhibiting p56^lck kinase. As occurred with the analgesic effect evoked by low doses of CCL4, analgesia evoked by combining CCL4 and A-770041 was reverted by naloxone, naltrindole or an anti-met-enk antibody. Interestingly, flow cytometry assays showed that the number of CD8⁺, but not CD4⁺, T-cells expressing IL-16 is reduced after the acute administration of CCL4, a result compatible with the description that CD8⁺-lymphocytes can rapidly release preformed IL-16. Accordingly, the rise in IL-16 blood concentration evoked by CCL4 was prevented after CD8⁺ lymphocyte depletion.

SIGNIFICANCE

CCL4-evoked hyperalgesia is related to the desensitization of CCR5 in CD4⁺ T-cells and to the release of IL-16 from CD8⁺ lymphocytes.

Single-cell approaches to dissect adaptive immune responses involved in autoimmunity: the case of celiac disease

Single-cell analysis is a powerful technology that has found widespread use in recent years. For diseases with involvement of adaptive immunity, single-cell analysis of antigen-specific T cells and B cells is particularly informative. In autoimmune diseases, the adaptive immune system is obviously at play, yet the ability to identify the culprit T and B cells recognizing disease-relevant antigen can be difficult. Celiac disease, a widespread disorder with autoimmune components, is unique in that disease-relevant antigens for both T cells and B cells are well defined. Furthermore, the celiac disease gut lesion is readily accessible allowing for sampling of tissue-resident cells. Thus, disease-relevant T cells and B cells from the gut and blood can be studied at the level of single cells. Here we review single-cell studies providing information on such adaptive immune cells and outline some future perspectives in the area of single-cell analysis in autoimmune diseases.

Interleukin 16 Enhances the Host Susceptibility to Influenza A Virus Infection

Influenza A virus (IAV) is a major respiratory pathogen that causes seasonal and pandemic flu, being a threat to global health. Various viral and cellular factors have been characterized to support or limit IAV infection. Interleukin 16 (IL16) has been known as one of the blood signature biomarkers discriminating systemic inflammation due to viral infection vs. other etiologies. Here, we report that the level of IL16 was elevated in the serum samples, lung homogenates, and bronchoalveolar lavage fluid of IAV-infected mice. IL16 overexpression facilitated IAV replication. Conversely, loss of IL16 reduced the host susceptibility to IAV infection in vitro and in vivo. Furthermore, IL16 deficiency blocked IAV-induced body weight loss and attenuated lung injury in the infected mice. Molecular mechanism analyses further revealed that IL16 could directly inhibit IFN-β transcription and suppress the expression of IFN-β and IFN-stimulated gene. In conclusion, these findings demonstrate that IL16 is a supporting factor for IAV infection.

Serum Inflammatory Factor Profiles in the Pathogenesis of High-Altitude Polycythemia and Mechanisms of Acclimation to High Altitudes

High-altitude polycythemia (HAPC) is a common aspect of chronic mountain sickness (CMS) caused by hypoxia and is the main cause of other symptoms associated with CMS. However, its pathogenesis and the mechanisms of high-altitude acclimation have not been fully elucidated. Exposure to high altitude is associated with elevated inflammatory mediators. In this study, the subjects were recruited and placed into a plain control (PC) group, plateau control (PUC) group, early HAPC (eHAPC) group, or a confirmed HAPC (cHAPC) group. Serum samples were collected, and inflammatory factors were measured by a novel antibody array methodology. The serum levels of interleukin-2 (IL-2), interleukin-3 (IL-3), and macrophage chemoattractant protein-1 (MCP-1) in the eHAPC group and the levels of interleukin-1 beta (IL-1 beta), IL-2, IL-3, tumor necrosis factor-alpha (TNF-alpha), MCP-1, and interleukin-16 (IL-16) in the cHAPC group were higher than those in the PUC group. More interestingly, the expression of IL-1 beta, IL-2, IL-3, TNF-alpha, MCP-1, and IL-16 in the PUC group showed a remarkable lower value than that in the PC group. These results suggest that these six factors might be involved in the pathogenesis of HAPC as well as acclimation to high altitudes. Altered inflammatory factors might be new biomarkers for HAPC and for high-altitude acclimation.

Increased Levels of IL-16 in the Central Nervous System during Neuroinflammation Are Associated with Infiltrating Immune Cells and Resident Glial Cells

Simple Summary

Interleukin-16 is a protein involved in the migration of some immune cells and plays an important role in the development of multiple sclerosis, an inflammatory demyelinating disease that affects the central nervous system (i.e., brain and spinal cord). Currently, it is not fully understood which cells produce interleukin-16 during the inflammatory response in the central nervous system. This study investigates the correlation between the expression levels of interleukin-16 and the severity of neuroinflammation and determines the cells which produce interleukin-16, using a mouse model of multiple sclerosis. Our data show that the expression levels of interleukin-16 are significantly increased in the brain and spinal cord tissues of the mouse model compared to controls. Furthermore, other immune assays reveal that the significantly increased number of cells expressing interleukin-16 in the central nervous system lesions are likely to be infiltrating immune cells and resident glial cells, but not neurons. Our findings suggest that interleukin-16 is closely involved in the pathology of multiple sclerosis and other inflammatory diseases in the central nervous system via the glial and infiltrating immune cells.

Abstract

Interleukin (IL)-16, a CD4⁺ immune cell specific chemoattractant cytokine, has been shown to be involved in the development of multiple sclerosis, an inflammatory demyelinating disease of the central nervous system (CNS). While immune cells such as T cells and macrophages are reported to be the producers of IL-16, the cellular source of IL-16 in the CNS is less clear. This study investigates the correlation of IL-16 expression levels in the CNS with the severity of neuroinflammation and determines the phenotype of cells which produce IL-16 in the CNS of experimental autoimmune encephalomyelitis (EAE) mice. Our data show that IL-16 expression is significantly increased in the brain and spinal cord tissues of EAE mice compared to phosphate buffered saline (PBS) immunised controls. Dual immunofluorescence staining reveals that the significantly increased IL-16⁺ cells in the CNS lesions of EAE mice are likely to be the CD45⁺ infiltrating immune cells such as CD4⁺ or F4/80⁺ cells and the CNS resident CD11b⁺ microglia and GFAP⁺ astrocytes, but not NeuN+ neurons. Our data suggest cytokine IL-16 is closely involved in EAE pathology as evidenced by its increased expression in the glial and infiltrating immune cells, which impacts the recruitment and activation of CD4⁺ immune cells in the neuroinflammation.

A population of CD4hiCD38hi T cells correlates with disease severity in patients with acute malaria

OBJECTIVE

CD4⁺ T cells are critical mediators of immunity to Plasmodium spp. infection, but their characteristics during malarial episodes and immunopathology in naturally infected adults are poorly defined. Flow cytometric analysis of PBMCs from patients with either P. falciparum or P. knowlesi malaria revealed a pronounced population of CD4⁺ T cells co-expressing very high levels of CD4 and CD38 we have termed CD4^hiCD38^hi T cells. We set out to gain insight into the function of these novel cells.

METHODS

CD4⁺ T cells from 18 patients with P. falciparum or P. knowlesi malaria were assessed by flow cytometry and sorted into populations of CD4^hiCD38^hi or CD4^norm T cells. Gene expression in the sorted populations was assessed by qPCR and NanoString.

RESULTS

CD4^hiCD38^hi T cells expressed high levels of CD4 mRNA and canonical type 1 regulatory T-cell (TR1) genes including IL10, IFNG, LAG3 and HAVCR2 (TIM3), and other genes with relevance to cell migration and immunomodulation. These cells increased in proportion to malaria disease severity and were absent after parasite clearance with antimalarials.

CONCLUSION

In naturally infected adults with acute malaria, a prominent population of type 1 regulatory T cells arises that can be defined by high co-expression of CD4 and CD38 (CD4^hiCD38^hi) and that correlates with disease severity in patients with falciparum malaria. This study provides fundamental insights into T-cell biology, including the first evidence that CD4 expression is modulated at the mRNA level. These findings have important implications for understanding the balance between immunity and immunopathology during malaria.

IL-16 processing in sentinel node regulatory T cells is a factor in bladder cancer immunity

In the effort of developing new immunotherapies, the sentinel node (SN) has proven a promising source from which to harness an effective antitumour T cell response. However, tumour immune escape, a process in which regulatory T cells (Tregs) play a central role, remains a major limiting factor. Therefore, there is a clear need to increase the knowledge of Treg function and signalling in sentinel nodes. Here, we set out to explore whether the proteome in SN-resident T cells is altered by the tumour and to identify key proteins in SN T cell signalling, focusing on Tregs. Five patients with muscle-invasive urothelial bladder cancer were prospectively included. Mass spectrometry was performed on two patients, with validation and functional studies being performed on three additional patients and four healthy donors. At cystectomy, SN, non-SN lymph nodes and peripheral blood samples were collected from the patients and T cell subsets isolated through flow cytometry before downstream experiments. Proteomic analysis indicated that growth and immune signalling pathways are upregulated in SN-resident Tregs. Furthermore, centrality analysis identified the cytokine IL-16 to be central in the SN-Treg signalling network. We show that tumour-released factors, through activating caspase-3, increase Treg IL-16 processing into bioactive forms, reinforcing Treg suppressive capacity. In conclusion, we provide evidence that Tregs exposed to secreted factors from bladder tumours show increased immune and growth signalling and altered IL-16 processing which translates to enhanced Treg suppressive function, indicating altered IL-16 signalling as a novel tumour immune escape mechanism.

Interleukin 16 contributes to gammaherpesvirus pathogenesis by inhibiting viral reactivation

Gammaherpesviruses have evolved various strategies to take advantage of host cellular factors or signaling pathways to establish a lifelong latent infection. Like the human gammaherpesvirus Epstein-Barr virus, murine gammaherpesvirus 68 (MHV68) establishes and maintains latency in the memory B cells during infection of laboratory mice. We have previously shown that MHV68 can immortalize fetal liver-derived B cells that induce lymphomas when injected into immunodeficient mice. Here we identify interleukin 16 (IL16) as a most abundantly expressed cytokine in MHV68-immortalized B cells and show that MHV68 infection elevates IL16 expression. IL16 is not important for MHV68 lytic infection but plays a critical role in MHV68 reactivation from latency. IL16 deficiency increases MHV68 lytic gene expression in MHV68-immortalized B cells and enhances reactivation from splenic latency. Correlatively, IL16 deficiency increases the frequency of MHV68-infected plasma cells that can be attributed to enhanced MHV68 reactivation. Furthermore, similar to TPA-mediated lytic replication of Kaposi's sarcoma-associated herpesvirus, IL16 deficiency markedly induces Tyr705 STAT3 de-phosphorylation and elevates p21 expression, which can be counteracted by the tyrosine phosphatase inhibitor orthovanadate. Importantly, orthovanadate strongly blocks MHV68 lytic gene expression mediated by IL16 deficiency. These data demonstrate that virus-induced IL16 does not directly participate in MHV68 lytic replication, but rather inhibits virus reactivation to facilitate latent infection, in part through the STAT3-p21 axis.

Immune Profiling To Predict Outcome of Clostridioides difficile Infection

Clostridioides difficile infection is the most common health care-associated infection in the United States with more than 20% patients experiencing symptomatic recurrence. The complex nature of host-bacterium interactions makes it difficult to predict the course of the disease based solely on clinical parameters. In the present study, we built a robust prediction model using representative plasma biomarkers and clinical parameters for 90-day all-cause mortality. Risk prediction based on immune biomarkers and clinical variables may contribute to treatment selection for patients as well as provide insight into the role of immune system in C. difficile pathogenesis.

There is a pressing need for biomarker-based models to predict mortality from and recurrence of Clostridioides difficile infection (CDI). Risk stratification would enable targeted interventions such as fecal microbiota transplant, antitoxin antibodies, and colectomy for those at highest risk. Because severity of CDI is associated with the immune response, we immune profiled patients at the time of diagnosis. The levels of 17 cytokines in plasma were measured in 341 CDI inpatients. The primary outcome of interest was 90-day mortality. Increased tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), C-C motif chemokine ligand 5 (CCL-5), suppression of tumorigenicity 2 receptor (sST-2), IL-8, and IL-15 predicted mortality by univariate analysis. After adjusting for demographics and clinical characteristics, the mortality risk (as indicated by the hazard ratio [HR]) was higher for patients in the top 25th percentile for TNF-α (HR = 8.35, P = 0.005) and IL-8 (HR = 4.45, P = 0.01) and lower for CCL-5 (HR = 0.18, P ≤ 0.008). A logistic regression risk prediction model was developed and had an area under the receiver operating characteristic curve (AUC) of 0.91 for 90-day mortality and 0.77 for 90-day recurrence. While limited by being single site and retrospective, our work resulted in a model with a substantially greater predictive ability than white blood cell count. In conclusion, immune profiling demonstrated differences between patients in their response to CDI, offering the promise for precision medicine individualized treatment.

Evaluation of Chemokine mRNA Expression to Assess Allergic Inflammation of the Ocular Surface in Chronic Allergic Conjunctival Diseases

Purpose:

We validated the use of chemokine messenger RNA (mRNA) expression analysis for the assessment of ocular surface allergic inflammation in chronic allergic conjunctival diseases (ACDs) with proliferative lesions, including giant papillae and gelatinous infiltration of the limbus.

Methods:

This prospective sectional study included 19 patients with chronic ACDs and 10 healthy volunteers as controls. Patients with chronic ACDs were divided into 2 subgroups according to the severity of the clinical score: active stage ACD subgroup (n = 9) and stable stage ACD subgroup (n = 10). Impression cytology using a filter paper for each upper tarsal conjunctiva of the patients with chronic ACDs and control subjects was performed, and the expression levels of IL1A, CXCL8, IL16, and CCL24 mRNAs encoding interleukin (IL)-1α, CXCL8/IL-8, IL-16, and CCL24/eotaxin-2, respectively, were determined by quantitative real-time polymerase chain reaction using impression cytology specimens.

Results:

CCL24 and IL16 mRNA levels in the active ACD subgroup were significantly higher than those in the control group (P = 0.003 and 0.004, respectively). IL1A and CXCL8 expression levels in the active ACD subgroup were significantly higher than those in the stable ACD (P = 0.008 and 0.029, respectively) and control (P = 0.008 and 0.014, respectively) subgroups. Furthermore, significant correlations were detected between IL16 and CCL24 mRNA levels (r = 0.76, P = 0.0001) and between IL1A and CXCL8 (r = 0.67, P = 0.0004).

Conclusions:

At least 2 kinds of inflammatory reactions, IL-1α- and CXCL8-associated inflammation and CCL24- and IL-16-associated inflammation, may be involved in the exacerbation of chronic ACDs.

Regeneration associated transcriptional signature of retinal microglia and macrophages

Zebrafish have the remarkable capacity to regenerate retinal neurons following a variety of damage paradigms. Following initial tissue insult and a period of cell death, a proliferative phase ensues that generates neuronal progenitors, which ultimately regenerate damaged neurons. Recent work has revealed that Müller glia are the source of regenerated neurons in zebrafish. However, the roles of another important class of glia present in the retina, microglia, during this regenerative phase remain elusive. Here, we examine retinal tissue and perform QuantSeq. 3'mRNA sequencing/transcriptome analysis to reveal localization and putative functions, respectively, of mpeg1 expressing cells (microglia/macrophages) during Müller glia-mediated regeneration, corresponding to a time of progenitor proliferation and production of new neurons. Our results indicate that in this regenerative state, mpeg1-expressing cells are located in regions containing regenerative Müller glia and are likely engaged in active vesicle trafficking. Further, mpeg1+ cells congregate at and around the optic nerve head. Our transcriptome analysis reveals several novel genes not previously described in microglia. This dataset represents the first report, to our knowledge, to use RNA sequencing to probe the microglial transcriptome in such context, and therefore provides a resource towards understanding microglia/macrophage function during successful retinal (and central nervous tissue) regeneration.

IL-16/miR-125a axis controls neutrophil recruitment in pristane-induced lung inflammation

Severe lung inflammation and alveolar hemorrhage can be life-threatening in systemic lupus erythematosus (SLE) patients if not treated early and aggressively. Neutrophil influx is the driver key of this pathology, but little is known regarding the molecular events regulating this recruitment. Here, we uncover a role for IL-16/mir-125a in this pathology and show not only that IL-16 is a target for miR-125a but that reduced miR-125a expression in SLE patients associates with lung involvement. Furthermore, in the pristane model of acute "SLE-like" lung inflammation and alveolar hemorrhage, we observed reduced pulmonary miR-125a and enhanced IL-16 expression. Neutrophil infiltration was markedly reduced in the peritoneal lavage of pristane-treated IL-16-deficient mice and elevated following i.n. delivery of IL-16. Moreover, a miR-125a mimic reduced pristane-induced IL-16 expression and neutrophil recruitment and rescued lung pathology. Mechanistically, IL-16 acts directly on the pulmonary epithelium and markedly enhances neutrophil chemoattractant expression both in vitro and in vivo, while the miR-125a mimic can prevent this. Our results reveal a role for miR-125a/IL-16 in regulating lung inflammation and suggest this axis may be a therapeutic target for management of acute lung injury in SLE.

Identification and characterization of pro-interleukin-16 from mud crab Scylla paramamosain: The first evidence of proinflammatory cytokine in crab species

IL-16 is a pro-inflammatory cytokine originally designated as a lymphocyte chemoattractant factor. In mammal and avian, it has been characterized as an essential regulator of various cellular processes including cell recruitment and activation against pathogen invasion. So far, neither of the full-length of IL-16 homologue nor the response mechanism against pathogen was reported in crab species. In the present study, the pro-IL-16 homologue was firstly cloned and characterized from mud crab Scylla paramamosain. The full-length Sp-pro-IL-16 consisted of 4107 bp with an opening reading frame encoding 1369 amino acids. Multiple alignment analysis showed the putative amino acid sequence of Sp-pro-IL-16 had about 73.86% identity with Litopenaeus vannamei pro-IL-16. Additionally, two conserved PDZ domains and protein binding sites were found in Sp-pro-IL-16 and showed high similarities about 94.19% and 51.14% with their Litopenaeus vannamei and Mus musculus counterparts. RT-PCR analysis indicated that Sp-pro-IL-16 transcripts were constitutively expressed in all tissues examined with an extreme high level in hepatopancreas. Moreover, Sp-pro-IL-16 transcripts in hepatopancreas were significantly up-regulated 15-fold at 72 h after Vibrio alginolyticus challenge and 3.5-fold at 12 h after virus-analog Poly (I:C) challenge. The Western blot analysis revealed that Sp-pro-IL-16 can be cleaved to its bioactive form, an approximately 35 kDa mature IL-16, and the protein levels of both pro-IL-16 and mature IL-16 increased after Vibrio alginolyticus challenge. It is the first experimental identification of pro-inflammatory cytokine IL-16 in arthropods. This study could shed new light on further understanding of the response mechanism of pro-inflammatory cytokine IL-16 in Scylla paramamosain against pathogens. Meanwhile, it brought new insight into the origin and evolution of IL-16 in crab species.

Cytokines Are Markers of the Clostridium difficile-Induced Inflammatory Response and Predict Disease Severity

The host immune response affects pathogen virulence in Clostridium difficile infection (CDI). Thus, cytokine responses to CDI likely are associated with disease initiation and progression. Understanding the molecular drivers of inflammation and biochemical markers of disease severity is important for developing novel therapies and predicting disease prognosis. In this study, we investigated cytokine production in patients with CDI and evaluated the potential of cytokines to serve as biomarkers for CDI and predictors of disease severity. The systemic cytokine profiles of 36 CDI patients (20 with severe disease) and 8 healthy donors and the toxin-induced cytokine profiles of peripheral blood mononuclear cells (PBMC) were determined. Further, we evaluated glucosyltransferase (GT) activity in regulation of toxin-induced cytokine expression. We found upregulation of the majority of measured cytokines (11/20, 55%) in CDI patients. Interleukin-1β (IL-1β), IL-6, IL-8, IL-17A, and IL-16 were the most upregulated. High serum levels of IL-2 and IL-15 were associated with a poor prognosis in CDI patients, whereas high levels of IL-5 and gamma interferon (IFN-γ) were associated with less severe disease. Both TcdA and TcdB were potent inducers of cytokine responses, as demonstrated by stimulation of a greater number and amount of cytokines. In addition to confirming prior reports on the role of IL-8, IL-1β, and IL-6 in CDI, our data suggest that IL-16 and IL-17A, as well as the IL-1β/Th17 axis, play a key role in driving inflammatory responses in CDI. A functional GT domain of C. difficile toxins was required for the induction of a majority of cytokines investigated.

Clinical Usefulness of Simultaneous Measurement of the Tear Levels of CCL17, CCL24, and IL-16 for the Biomarkers of Allergic Conjunctival Disorders

PURPOSE

This study investigated the clinical usefulness of a multiple tear cytokine/chemokine test by simultaneously determining tear levels of CC chemokine ligand 17 (CCL17)/thymus and activation-regulated chemokine (TARC), CCL24/eotaxin-2, and interleukin-16 (IL-16) for assessing acute and chronic allergic inflammation in allergic conjunctival disorders (ACDs).

SUBJECTS AND METHODS

This study included 37 patients with ACD and 11 healthy adults (controls). Patients with ACDs were divided into the following three groups; patients with allergic conjunctivitis (AC group, n = 17), patients with atopic keratoconjunctivitis (AKC group, n = 6), and patients with vernal keratoconjunctivitis (VKC group, n = 14). Tear samples were collected using the Schirmer I method with a filter paper. Tear levels of CCL17/TARC, CCL24/eotaxin-2, and IL-16 were determined by performing a magnetic bead assay (tear cytokine/chemokine test). Tear levels of eosinophil cationic protein (ECP) were determined by performing enzyme immunoassay. In patients with AC, clinical scores of objective findings and results of the tear cytokine/chemokine test at baseline were compared with those at 7 days after treatment with the histamine H₁ receptor antagonist (epinastine) ophthalmic solution.

RESULTS

Tear positive rates of CCL17/TARC, CCL24/eotaxin-2, and IL-16 were higher in patients with AC, AKC, and VKC compared with controls. Tear levels of CCL17/TARC, CCL24/eotaxin-2, and IL-16 in patients with AKC and VKC were significantly higher than those in patients with AC. Moreover, tear levels of IL-16 in patients with AC that showed improvement of their clinical score by treatment with epinastine ophthalmic solution decreased significantly after 7 days of the treatment compared with those at baseline. In patients with AKC and VKC, a significant correlation was observed between the tear levels of CCL24/eotaxin-2 and ECP.

CONCLUSION

Simultaneous measurement of the tear levels of CCL17/TARC, CCL24/eotaxin-2, and IL-16 may be a useful test for assessing acute and chronic allergic inflammation in ACDs.

Chemical proteomic map of dimethyl fumarate-sensitive cysteines in primary human T cells

Dimethyl fumarate (DMF) is an electrophilic drug that is used to treat autoimmune conditions, including multiple sclerosis and psoriasis. The mechanism of action of DMF is unclear but may involve the covalent modification of proteins or DMF serving as a prodrug that is converted to monomethyl fumarate (MMF). We found that DMF, but not MMF, blocked the activation of primary human and mouse T cells. Using a quantitative, site-specific chemical proteomic platform, we determined the DMF sensitivity of >2400 cysteine residues in human T cells. Cysteines sensitive to DMF, but not MMF, were identified in several proteins with established biochemical or genetic links to T cell function, including protein kinase Cθ (PKCθ). DMF blocked the association of PKCθ with the costimulatory receptor CD28 by perturbing a CXXC motif in the C2 domain of this kinase. Mutation of these DMF-sensitive cysteines also impaired PKCθ-CD28 interactions and T cell activation, designating the C2 domain of PKCθ as a key functional, electrophile-sensing module important for T cell biology.

Structure of a Potential Therapeutic Antibody Bound to Interleukin-16 (IL-16): MECHANISTIC INSIGHTS AND NEW THERAPEUTIC OPPORTUNITIES

Interleukin-16 (IL-16) is reported to be a chemoattractant cytokine and modulator of T-cell activation, and has been proposed as a ligand for the co-receptor CD4. The secreted active form of IL-16 has been detected at sites of TH1-mediated inflammation, such as those seen in autoimmune diseases, ischemic reperfusion injury (IRI), and tissue transplant rejection. Neutralization of IL-16 recruitment to its receptor, using an anti-IL16 antibody, has been shown to significantly attenuate inflammation and disease pathology in IRI, as well as in some autoimmune diseases. The 14.1 antibody is a monoclonal anti-IL-16 antibody, which when incubated with CD4(+) cells is reported to cause a reduction in the TH1-type inflammatory response. Secreted IL-16 contains a characteristic PDZ domain. PDZ domains are typically characterized by a defined globular structure, along with a peptide-binding site located in a groove between the αB and βB structural elements and a highly conserved carboxylate-binding loop. In contrast to other reported PDZ domains, the solution structure previously reported for IL-16 reveals a tryptophan residue obscuring the recognition groove. We have solved the structure of the 14.1Fab fragment in complex with IL-16, revealing that binding of the antibody requires a conformational change in the IL-16 PDZ domain. This involves the rotation of the αB-helix, accompanied movement of the peptide groove obscuring tryptophan residue, and consequent opening up of the binding site for interaction. Our study reveals a surprising mechanism of action for the antibody and identifies new opportunities for the development of IL-16-targeted therapeutics, including small molecules that mimic the interaction of the antibody.

Respiratory Mucosal Proteome Quantification in Human Influenza Infections

Respiratory influenza virus infections represent a serious threat to human health. Underlying medical conditions and genetic make-up predispose some influenza patients to more severe forms of disease. To date, only a few studies have been performed in patients to correlate a selected group of cytokines and chemokines with influenza infection. Therefore, we evaluated the potential of a novel multiplex micro-proteomics technology, SOMAscan, to quantify proteins in the respiratory mucosa of influenza A and B infected individuals. The analysis included but was not limited to quantification of cytokines and chemokines detected in previous studies. SOMAscan quantified more than 1,000 secreted proteins in small nasal wash volumes from infected and healthy individuals. Our results illustrate the utility of micro-proteomic technology for analysis of proteins in small volumes of respiratory mucosal samples. Furthermore, when we compared nasal wash samples from influenza-infected patients with viral load ≥ 2⁸ and increased IL-6 and CXCL10 to healthy controls, we identified 162 differentially-expressed proteins between the two groups. This number greatly exceeds the number of DEPs identified in previous studies in human influenza patients. Most of the identified proteins were associated with the host immune response to infection, and changes in protein levels of 151 of the DEPs were significantly correlated with viral load. Most important, SOMAscan identified differentially expressed proteins heretofore not associated with respiratory influenza infection in humans. Our study is the first report for the use of SOMAscan to screen nasal secretions. It establishes a precedent for micro-proteomic quantification of proteins that reflect ongoing response to respiratory infection.

IL-14 and IL-16 are expressed in the thyroid of patients with either Graves' disease or Hashimoto's thyroiditis

OBJECTIVES

Cytokines have an important role in orchestrating the pathophysiology in autoimmune thyroid disease. The aim of the current study was to analyse the expression of interleukin (IL)-14 and IL-16 in the thyroid tissue of patients with Graves' disease (GD), Hashimoto's thyroiditis (HT) or multinodular goitre (MNG) and in that of normal individuals, in patients' intrathyroidal CD4(+) and CD8(+) T cells, and in patient and normal cultured thyroid follicular cells.

METHODS

The expression of IL-14 and IL-16 mRNA and protein was investigated using reverse transcription-polymerase chain reaction (RT-PCR) amplification, and Western blotting and ELISAs, respectively.

RESULTS

IL-14 mRNA expression was detected in thyroid tissue from 8/9 GD, 3/4 HT and 3/13 MNG patients and 1/6 normal individuals, and IL-16 mRNA expression in thyroid tissue from 9/9 GD, 4/4 HT and 9/13 MNG patients and 4/6 normal individuals. IL-14 mRNA expression was detected in intrathyroidal CD4(+) and CD8(+) T cells from 2/2 GD and 2/2 HT patients, while IL-16 mRNA was detected in samples from 1/2 HT patients but not in those from either patient with GD. IL-14 and IL-16 mRNA expression was found in thyroid follicular cells derived from 2/2 patient with GD and 1/1 normal individual. IL-14 protein was detected in thyroid tissue from 6/6 GD, 1/1 HT and 0/6 MNG patients and 0/6 normal individuals, and IL-16 protein in thyroid tissue from 6/6 GD, 1/1 HT and 1/6 MNG patients and 0/6 normal individuals. Expression of IL-14 protein was stimulated in thyroid follicular cells derived from two patients with GD and one normal individual by peripheral blood mononuclear cell (PBMC)-conditioned medium. Treatment of thyrocytes from two patients with GD and one normal individual with PBMC-conditioned medium and tumour necrosis factor (TNF)-α stimulated IL-16 protein expression. In normal thyrocytes, IL-16 protein synthesis was induced also by IL-1β, IL-17A, IL-4 and transforming growth factor (TGF)-β.

CONCLUSIONS

The data provide evidence that the intrathyroidal production of IL-14 and IL-16 is associated with the pathogenesis of autoimmune thyroid disease. Thyroid follicular cells display the ability to express IL-14 and IL-16 mRNA and can be stimulated to express IL-16 protein, by a panel of cytokines, and IL-14 protein, by as yet unidentified factors.

Interleukin-16 rs4778889 polymorphism contributes to the development of renal cell cancer in a Chinese population

We conducted a case-control study to assess the role of IL-16 rs4778889, rs11556218 and rs8034928 polymorphisms in the development of RCC. This case-control study included 181 patients with RCC and 278 control patients. The genotyping of IL-16 rs4778889, rs11556218 and rs8034928 polymorphisms were performed using polymerase chain reaction (PCR) combined with restriction fragment length polymorphism analysis. By χ(2) test, we found that patients with RCC were more likely to suffer from hypertension (χ(2) = 9.06, P = 0.003) and diabetes (χ(2) = 7.91, P = 0.005). By unconditional logistic regression analysis, the CC genotype of rs4778889 was associated with an increased risk of RCC compared to TT genotype, and the adjusted OR (95% CI) was 3.58 (1.59-8.31). In dominant model and recessive model, we found the rs4778889 polymorphisms were associated with an elevated increased risk of RCC, and the adjusted ORs (95% CI) were 1.64 (1.10-2.43) and 3.07 (1.40-6.98), respectively. We found that rs4778889 polymorphism had interaction with hypertension (OR = 2.44, 95% CI = 1.01-6.00) and diabetes (OR = 6.91, 95% CI = 1.44-37.05) in the risk of RCC. In conclusion, the results of our study suggested an association between the IL-16 rs4778889 polymorphism and an elevated risk of RCC.

Genetic polymorphisms of interleukin-16 and risk of knee osteoarthritis

BACKGROUND

Interleukin-16 (IL-16), a pleiotropic cytokine, plays a fundamental role in inflammatory diseases. This study investigates the association between IL-16 polymorphisms and the risk of knee osteoarthritis (OA) in a Chinese population.

METHODS

The IL-16 rs11556218, rs4072111, and rs4778889 polymorphisms were determined in 150 knee OA cases and 147 healthy controls through polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The results suggested that the variants in IL-16 gene rs11556218 site were associated with a decreased knee OA risk after adjusting for age, sex, BMI, and smoking and drinking status (TG vs. TT: OR, 0.69; 95% CI, 0.53-0.89; P = 0.006; GG vs. TT: OR, 0.64; 95% CI, 0.45-0.90; P = 0.042; dominant model: OR, 0.68; 95% CI, 0.29-0.87; P = 0.002; G vs. T allele: OR, 0.77; 95% CI, 0.66-0.90; P = 0.003). Similarly, subjects bearing the rs4072111 variant genotypes and alleles also had a lower susceptibility to knee OA compared with those bearing the wild-type (CT vs. CC: OR, 0.66; 95% CI, 0.53-0.83; P = 0.002; TT vs. CC: OR, 0.57; 95% CI, 0.40-0.82; P = 0.027; dominant model: OR, 0.65; 95%, CI 0.52-0.80; P <0.001; T vs. C allele: OR, 0.69; 95% CI, 0.58-0.81; P <0.001). Further, the C allele and the combined genotype (CC+CT) of rs4778889 were associated with a slightly decreased risk of knee OA. In addition, we found two high-risk haplotypes: TTT (OR, 3.70) and GCC (OR, 6.22). Finally, serum IL-16 levels of knee OA patients were significantly higher than those of controls (P = 0.001).

CONCLUSIONS

Despite the small sample size, this is the first study suggesting IL-16 gene polymorphisms to be associated with the risk of knee OA.

Interleukin-16 gene polymorphisms are considerable host genetic factors for patients' susceptibility to chronic hepatitis B infection

Host genetic background is known as an important factor in patients' susceptibility to infectious diseases such as viral hepatitis. The aim of this study was to determine the effect of genetic polymorphisms of interleukin-16 (IL-16) cytokine on susceptibility of hepatitis B virus (HBV) infected patients to develop chronic HBV infection. Genotyping was conducted using PCR followed by enzymatic digestion and RFLP (restriction fragment length polymorphism) analysis. We genotyped three single nucleotide polymorphisms (SNPs) in the Il-16 gene (rs11556218 T>G, rs4778889 T>C, and rs4072111 C>T) to test for relationship between variation at these loci and patients' susceptibility to chronic HBV infection. Allele frequency of Il-16 gene rs4072111 and rs11556218 was significantly different between chronic HBV patients and healthy blood donors. Genotype frequency of rs4778889 polymorphism of Il-16 gene was significantly different when chronic HBV patients and HBV clearance subjects were compared. Our results showed that Il-16 gene polymorphisms are considerable host genetic factors when we chase biomarkers for prognosis of HBV infected patients.

Eosinophil cytokines, chemokines, and growth factors: emerging roles in immunity

Eosinophils derive from the bone marrow and circulate at low levels in the blood in healthy individuals. These granulated cells preferentially leave the circulation and marginate to tissues, where they are implicated in the regulation of innate and adaptive immunity. In diseases such as allergic inflammation, eosinophil numbers escalate markedly in the blood and tissues where inflammatory foci are located. Eosinophils possess a range of immunomodulatory factors that are released upon cell activation, including over 35 cytokines, growth factors, and chemokines. Unlike T and B cells, eosinophils can rapidly release cytokines within minutes in response to stimulation. While some cytokines are stored as pre-formed mediators in crystalloid granules and secretory vesicles, eosinophils are also capable of undergoing de novo synthesis and secretion of these immunological factors. Some of the molecular mechanisms that coordinate the final steps of cytokine secretion are hypothesized to involve binding of membrane fusion complexes comprised of soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs). These intracellular receptors regulate the release of granules and vesicles containing a range of secreted proteins, among which are cytokines and chemokines. Emerging evidence from both human and animal model-based research has suggested an active participation of eosinophils in several physiological/pathological processes such as immunomodulation and tissue remodeling. The observed eosinophil effector functions in health and disease implicate eosinophil cytokine secretion as a fundamental immunoregulatory process. The focus of this review is to describe the cytokines, growth factors, and chemokines that are elaborated by eosinophils, and to illustrate some of the intracellular events leading to the release of eosinophil-derived cytokines.

Interleukin-16 polymorphism is associated with an increased risk of glioma

OBJECTIVE

Previous studies have shown that interleukin (IL)-16 is overexpressed in human and rat gliomas. Potential links between IL-16 polymorphisms and glioma risk are currently unclear. The aim of this study was to investigate the association between IL-16 polymorphisms and glioma risk.

METHODS

We examined IL-16 gene polymorphisms (i.e., rs 4778889, rs 11556218, and rs 4072111) in 216 patients with glioma and 275 controls in a Chinese population. Genotypes were determined using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were used to evaluate the effect of the IL-16 polymorphisms on glioma risk.

RESULTS

The rs 11556218TG genotype is associated with an increased risk of glioma compared with the TT genotype (OR=1.76; 95% CI, 1.22-2.54; p=0.002). Similarly, the rs 11556218G allele is associated with an increased risk of glioma compared with the T allele (OR=1.41; 95% CI, 1.06-1.87; p=0.017). However, no significant association was observed between the IL-16 rs 4778889 and rs 4072111 polymorphisms and the risk of glioma.

CONCLUSION

These findings suggest that the IL-16 rs 11556218 polymorphism may be used as a susceptibility marker for glioma.

Non-association of IL-16 rs4778889 T/C polymorphism with cancer risk in Asians: a meta-analysis

The IL-16 rs4778889 T/C polymorphism is associated with cancer risk. However, the results are conflicting. We performed this meta-analysis to derive a more precise estimation of the relationship. A comprehensive literature search was performed using PubMed, Embase and Web of Science databases. Odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of association. A total of 6 studies including 1,603 cases and 2,342 controls were identified. With all studies involved, results showed no statistically significant association between IL-16 rs4778889 T/C polymorphism and cancer risk (CC vs. CT+TT: OR=0.74, 95%CI: 0.55-1.02, Ph=0.15; CC+CT vs. TT: OR=0.89, 95%CI: 0.72-1.10, Ph =0.03; CC vs. TT: OR=0.73, 95%CI: 0.53- 1.00, Ph =0.08; CT vs. TT: OR=0.91, 95%CI: 0.79-1.05, Ph =0.08; C vs. T: OR=0.89, 95%CI: 0.74-1.07, Ph =0.02). In addition, the results were not changed when studies were stratified by cancer type. However, to verify our findings, it is essential to perform more well-designed studies with larger sample sizes in the future.

Regulation of cellular processes by interleukin-16 in homeostasis and cancer

Interleukin-16 (IL-16) is generated as a precursor molecule that is cleaved by caspase-3 to produce a pro-IL-16 molecule that functions as a regulator of T cell growth, and a secreted peptide that functions as a CD4 and/or CD9 ligand for induction of cell motility and activation. IL-16 has been predominantly studied as a contributing factor in the orchestration of an immune response; however, more recently IL-16 bioactivity has been closely associated with the progression of a number of different cancers. While the association between IL-16 plasma levels and tumor progression has been reported for many types of cancer, the mechanism for IL-16 involvement has been partially elucidated for three of the cancer types, cutaneous T cell lymphoma (CTCL), multiple myeloma (MM), and breast cancer. The mechanism for promoting cell growth is different in each of these cancers and involves a sequence mutation in the pro-molecule facilitating decreased p27(KIP1) levels in CTCL; over expression of the secreted IL-16 molecule to induce proliferation in CTCL T cells, and plasma cells in MM; and increased secreted IL-16 acting to recruit CD4+ pro-tumor macrophages in breast cancer. This article will review the cellular process for generating IL-16, the biological activities for both the pro- and secreted forms of the protein, and then the mechanism by which these forms contribute to cancer progression. As a soluble cytokine the ability to reduce or eliminate IL-16 synthesis through siRNA approaches or bioactivity through the use of neutralizing antibody treatment may represent a novel therapeutic approach.

Interleukin-16 polymorphism is associated with an increased risk of ischemic stroke

Clinical and experimental data have demonstrated that inflammation plays fundamental roles in the pathogenesis of ischemic stroke. Interleukin-16 (IL-16) is identified as a proinflammatory cytokine that is a key element in the ischemic cascade after cerebral ischemia. We aimed to examine the relationship between the IL-16 polymorphisms and the risk of ischemic stroke in a Chinese population. A total of 198 patients with ischemic stroke and 236 controls were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing method. We found that the rs11556218TG genotype and G allele of IL-16 were associated with significantly increased risks of ischemic stroke (TG versus TT, adjusted OR = 1.88; 95% CI, 1.15-3.07; G versus T, adjusted OR = 1.54; 95% CI, 1.05-2.27, resp.). However, there were no significant differences in the genotype and allele frequencies of IL-16 rs4778889 T/C and rs4072111 C/T polymorphisms between the two groups, even after stratification analyses by age, gender, and the presence or absence of hypertension, diabetes mellitus, hypercholesterolemia, and hypertriglyceridemia. These findings indicate that the IL-16 polymorphism may be related to the etiology of ischemic stroke in the Chinese population.

The association of interleukin-16 gene polymorphisms with IL-16 serum levels and risk of nasopharyngeal carcinoma in a Chinese population

Interleukin (IL)-16 plays a fundamental role in inflammatory diseases, as well as in the development and progression of tumors. Genetic variation in DNA sequence of IL16 gene may lead to altered cytokine production and/or activity, and this variation may modulate an individual's susceptibility to nasopharyngeal carcinoma (NPC). To test this hypothesis, we investigated the association of IL16 gene polymorphisms and serum IL-16 levels with NPC risk in a Chinese population. We analyzed IL16 gene rs11556218 T/G, rs4778889 T/C, and rs4072111 C/T polymorphisms using PCR-RFLP and DNA sequencing, and serum IL-16 levels were measured by ELISA. The IL16 rs11556218 T/G polymorphism was significantly associated with the susceptibility to NPC patients. The TG genotype was associated with a significantly higher risk of NPC as compared with the TT genotype (OR = 2.05, 95% CI 1.04-4.01; p = 0.037). Patients carrying the G allele had a significantly higher risk for developing NPC compared with individuals carrying the T allele (OR = 1.79, 95% CI 1.07-3.01; p = 0.027). The serum IL-16 levels were increased in NPC patients compared with controls (p < 0.01); the genotypes carrying the IL16 rs11556218 G variant allele were associated with increased serum IL-16 levels compared with the homozygous wild-type genotype in NPC patients (all p values <0.01). Our data suggested that IL16 rs11556218 T/G polymorphism was associated with increased susceptibility to NPC through increasing the production of serum IL-16 levels.

Correlations of serum Interleukin-16, total IgE, eosinophil cationic protein and total eosinophil counts with disease activity in children with atopic dermatitis

Several laboratory parameters have been investigated for assessing disease activity in children with atopic dermatitis (AD). Analyses of the correlation between these parameters and clinical severity can help to choose a convincing tool. This study compared the significance of serum interleukin-16 (IL-16), serum total immunoglobulin E (IgE), serum eosinophil cationic protein (ECP), and total eosinophil count (TEC) in reflecting AD severity to order to identify the most relevant objective tool for assessing AD activity and to assess the correlation between these laboratory parameters. The Severity Scoring of Atopic Dermatitis (SCORAD index) was used for the assessment of disease activity in 48 pediatric patients in the acute exacerbation phase and in the maintenance phase after improvement of clinical findings with conventional treatment for 8 weeks. Serum levels of total IgE, ECP, and IL-16 as well as TEC were measured on the same time points and compared with healthy non-atopic controls. The correlation between SCORAD and each laboratory parameter was tested for significance and compared. Serum levels of ECP and IL-16 of AD patients were significantly higher than those of controls. These serum parameters, except TEC, declined significantly after conventional treatment with clinical improvement. There was positive correlation with SCORAD for serum IgE (r=0.317, p=0.028), TEC(r=0.434, p=0.002), IL-16 (r = 0.321, p=0.026) in the acute exacerbation phase and with SCORAD for serum IgE (r=0.510, p<0.001), TEC(r=0.489, p<0.001), serum ECP (r=0.468, p=0.001) in the maintenance phase. Serum levels of total IgE, IL-16, ECP, and TEC correlated with the SCORAD index in pediatric patients with atopic dermatitis. Thus, they can serve as serum markers for monitoring disease activity in childhood atopic dermatitis.

Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases

Advancing our understanding of mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections could lead to effective and targeted therapies. Subsets of immune and inflammatory cells interact via ILs and IFNs; reciprocal regulation and counter balance among T(h) and regulatory T cells, as well as subsets of B cells, offer opportunities for immune interventions. Here, we review current knowledge about ILs 1 to 37 and IFN-γ. Our understanding of the effects of ILs has greatly increased since the discoveries of monocyte IL (called IL-1) and lymphocyte IL (called IL-2); more than 40 cytokines are now designated as ILs. Studies of transgenic or knockout mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided important information about IL and IFN functions. We discuss their signaling pathways, cellular sources, targets, roles in immune regulation and cellular networks, roles in allergy and asthma, and roles in defense against infections.

Evolutionary divergence and functions of the human interleukin (IL) gene family

Cytokines play a very important role in nearly all aspects of inflammation and immunity. The term 'interleukin' (IL) has been used to describe a group of cytokines with complex immunomodulatory functions -- including cell proliferation, maturation, migration and adhesion. These cytokines also play an important role in immune cell differentiation and activation. Determining the exact function of a particular cytokine is complicated by the influence of the producing cell type, the responding cell type and the phase of the immune response. ILs can also have pro- and anti-inflammatory effects, further complicating their characterisation. These molecules are under constant pressure to evolve due to continual competition between the host's immune system and infecting organisms; as such, ILs have undergone significant evolution. This has resulted in little amino acid conservation between orthologous proteins, which further complicates the gene family organisation. Within the literature there are a number of overlapping nomenclature and classification systems derived from biological function, receptor-binding properties and originating cell type. Determining evolutionary relationships between ILs therefore can be confusing. More recently, crystallographic data and the identification of common structural motifs have led to a more accurate classification system. To date, the known ILs can be divided into four major groups based on distinguishing structural features. These groups include the genes encoding the IL1-like cytokines, the class I helical cytokines (IL4-like, γ-chain and IL6/12-like), the class II helical cytokines (IL10-like and IL28-like) and the IL17-like cytokines. In addition, there are a number of ILs that do not fit into any of the above groups, due either to their unique structural features or lack of structural information. This suggests that the gene family organisation may be subject to further change in the near future.

Tissue expression of IL16 in prostate cancer and its association with recurrence after radical prostatectomy

BACKGROUND

Genetic polymorphism located within the IL16 gene has been reported to be associated with aggressive prostate cancer (PCa). Our aim was to establish whether the tissue expression of IL16 is a prognostic factor of survival in PCa.

METHODS

The files of patients who underwent radical prostatectomy (RP) between 1995 and 2001 were reviewed. The cases were selected and classified according to the D'Amico classification for risk of recurrence (intermediate or high). The value of IL16 and its receptor CCR5 (chemokine (C-C motif) receptor 5) expression levels were determined as witness of aggressiveness patterns and markers of biological relapse in patients with PCa treated by RP. A tissue microarray of 304 cases was constructed. IL16 and CCR5 expression levels were characterized by immunohistochemistry.

RESULTS

IL16 expression was correlated with high Gleason score (i.e., >7) (P < 0.01). It was not significant for CCR5. IL16 and CCR5 were not associated with prostate-specific antigen (PSA) or capsular extension of the disease. The accurate prediction of disease outcome, using stratification of cases, according to negative margins and D'Amico classification was significantly enhanced by status of IL16 expression (P ≤ 0.01). In univariate analyses, Gleason score, PSA level, stage and loss of IL16 expression were related to better biological-free survival (P < 0.05) but not CCR5. In a multivariate analysis, IL16 expression, Gleason score, and tumor stage were independent factors for biochemical-free survival (P = 0.001).

CONCLUSIONS

IL16 appears to be a useful prognostic factor in PCa. Its expression in PCa tissue was correlated to tumor aggressiveness and biochemical relapse of the disease.

Immunologic messenger molecules: cytokines, interferons, and chemokines

Cytokines and chemokines are secreted proteins involved in numerous aspects of cell growth, differentiation, and activation. A prominent feature of these molecules is their effect on the immune system with regard to cell trafficking and development of immune tissue and organs. The nature of an immune response determines which cytokines are produced and ultimately whether the response is cytotoxic, humoral, cell mediated, or allergic. For this chapter, cytokines are grouped according to those that are predominantly antigen-presenting cell or T lymphocyte derived; that mediate cytotoxic, humoral, cell mediated, and allergic immunity; or that are immunosuppressive. A discussion of chemokine function and their role in cell trafficking and disease follows.

Expression of CD4 on Epstein-Barr virus-immortalized B cells

Human antigen presenting cells commonly express CD4 but the significance of this phenomenon has not been clarified. We analyzed a panel of Epstein-Barr virus-immortalized B cells (so called lymphoblastoid cell lines, LCL) by using flow cytometry, DNA-microarray analysis, and reverse transcriptase-polymerase chain reaction (RT-PCR). The number of CD4(+) cells varied from cell line to cell line but expression of CD4 was detected by flow cytometry and RT-PCR in all investigated cell lines. To characterize CD4 expressing LCL in more detail, we separated CD4(+) and CD4(-) cells from single cell lines by using immunomagnetic beads. When we cultured sorted CD4(+) and CD4(-) cells, we observed that CD4 expression was stable for several passages. However, the number of CD4(+) cells decreased with time in culture. We never observed that CD4(-) cell lines returned back to a CD4(+) phenotype. DNA-microarray analysis of isolated CD4(+) and CD4(-) cells indicated that the overall gene expression profile of both cell populations was highly similar. In addition, CD4(+) and CD4(-) cells showed the same allostimulatory capacity. CD4(+) LCL showed a slightly increased interleukin-16 induced chemotaxis. Differences in the gene expression profile of CD4(+) and CD4(-) cell lines suggested that loss of CD4 expression occurred during a differentiation step involving achaete-scute complex homolog-like 1.

IL-16 can synergize with early acting cytokines to expand ex vivo CD34+ isolated from cord blood

We previously reported that interleukin (IL)-16 can induce CD34(+) hematopoietic cells to proliferate and differentiate in vitro into phenotypically and functionally mature dendritic cells. In this study, we investigated the effects of IL-16 on the expansion of CD34(+) cells from human cord blood (CB). CD34(+) CB cells were cultured for 14 days in medium containing a basal cocktail (BC) containing stem cell factor, Flt-3 ligand, thrombopoietin, IL-6, and IL-3 with and without IL-16 as a control. Interleukin-16 added to BC significantly enhanced the expansion of CD34(+) cells (66.47 +/- 1.46-fold vs. 36.23 +/- 1.67-fold), as well as CD34(+)CD38(-) early stem cells (106.67 +/- 2.34-fold vs. 63.42 +/- 1.89-fold) and progenitor cells [colony-forming unit (CFU) -mixed -(GEMM)] and multilineage-committed progenitors [burst-forming unit (BFU-E), CFU-granulocyte, macrophage (-GM), CFU-megakaryocyte (-MK)]. Interleukin-16 also significantly increased long-term culture-initiating cells (160.8 +/- 3.45-fold vs. 83 +/- 2.89-fold with BC alone). Moreover, CD34(+) cells expanded with IL-16 maintained the capacity to differentiate into the lymphoid-B and -NK lineage. The addition of IL-16 to BC increased the migratory capacity of expanded CD34(+) cells compared to BC alone, leaving the expression of CXCR4 unaffected, and decreased the percentage of CD34(+)CD4(+) cells. We showed that IL-16 released endogenously affected the ex vivo expansion of CD34(+) cells. Overall, this study suggests that IL-16 may have a new role in promoting the expansion of hematopoietic stem cells and may represent a new tool for the expansion of CD34(+) cells for clinical applications.