The biology of interleukin-2

Dynamic changes in circulating T follicular helper cell composition predict neutralising antibody responses after yellow fever vaccination

Objectives

T follicular helper (Tfh) cells are the principal T helper cell subset that provides help to B cells for potent antibody responses against various pathogens. In this study, we took advantage of the live‐attenuated yellow fever virus (YFV) vaccine strain, YF‐17D, as a model system for studying human antiviral immune responses in vivo following exposure to an acute primary virus challenge under safe and highly controlled conditions, to comprehensively analyse the dynamics of circulating Tfh (cTfh) cells.

Methods

We tracked and analysed the response of cTfh and other T and B cell subsets in peripheral blood of healthy volunteers by flow cytometry over the course of 4 weeks after YF‐17D vaccination.

Results

Using surface staining of cell activation markers to track YFV‐specific T cells, we found increasing cTfh cell frequencies starting at day 3 and peaking around 2 weeks after YF‐17D vaccination. This kinetic was confirmed in a subgroup of donors using MHC multimer staining for four known MHC class II epitopes of YF‐17D. The subset composition of cTfh cells changed dynamically during the course of the immune response and was dominated by the cTfh1‐polarised subpopulation. Importantly, frequencies of cTfh1 cells correlated with the strength of the neutralising antibody response, whereas frequencies of cTfh17 cells were inversely correlated.

Conclusion

In summary, we describe detailed cTfh kinetics during YF‐17D vaccination. Our results suggest that cTfh expansion and polarisation can serve as a prognostic marker for vaccine success. These insights may be leveraged in the future to improve current vaccine design and strategies.

CD25-Targeted IL-2 Signals Promote Improved Outcomes of Influenza Infection and Boost Memory CD4 T Cell Formation

IL-2 is a pleotropic cytokine with potent pro- and anti-inflammatory effects. These divergent impacts can be directed in vivo by forming complexes of IL-2 and anti-IL-2 mAbs (IL-2C) to target IL-2 to distinct subsets of cells based on their expression of subunits of the IL-2R. In this study, we show that treatment of mice with a prototypical anti-inflammatory IL-2C, JES6-1-IL-2C, best known to induce CD25⁺ regulatory CD4 T cell expansion, surprisingly causes robust induction of a suite of inflammatory factors. However, treating mice infected with influenza A virus with this IL-2C reduces lung immunopathology. We compare the spectrum of inflammatory proteins upregulated by pro- and anti-inflammatory IL-2C treatment and uncover a pattern of expression that reveals potentially beneficial versus detrimental aspects of the influenza-associated cytokine storm. Moreover, we show that anti-inflammatory IL-2C can deliver survival signals to CD4 T cells responding to influenza A virus that improve their memory fitness, indicating a novel application of IL-2 to boost pathogen-specific T cell memory while simultaneously reducing immunopathology.

The numbers of peripheral regulatory T cells are reduced in patients with psoriatic arthritis and are restored by low-dose interleukin-2

Background:

Although regulatory T cells (Tregs) play crucial roles in the maintenance of immune hemostasis, the numbers of peripheral Tregs in patients with psoriatic arthritis (PsA) remain unclear. We measured these numbers and the efficacy and safety of low-dose interleukin-2 (IL-2) therapy.

Methods:

We recruited 95 PsA patients, of whom 22 received subcutaneous low-dose IL-2 [0.5 million international units (MIU) per day for 5 days] combined with conventional therapies. The absolute numbers of cells in peripheral CD4⁺ T cell subsets were measured via modified flow cytometry. Clinical and laboratory indicators were compared before and after treatment.

Results:

PsA patients had lower peripheral Treg numbers than healthy controls (p < 0.01), correlating significantly and negatively with the levels of disease indicators (p < 0.05). Although low-dose IL-2 significantly increased the Th17 and Treg numbers in PsA patients compared with the baseline values, the Treg numbers rose much more rapidly than those of Th17 cells, re-balancing the Th17 and Treg proportions. Low-dose IL-2 combination therapy rapidly reduced PsA disease activities as indicated by the DAS28 instrument, thus the number of tender joints, visual analog scale pain, physician global assessment, the dermatology life quality index score, and the health assessment questionnaire score (all p < 0.05).

Conclusion:

PsA patients exhibited low Treg numbers. Low-dose IL-2 combination treatment increased these numbers and relieved disease activity without any apparent side effects. Additional studies are required to explore the long-term immunoregulatory utility of IL-2 treatment.

Direct T-cell Inhibition and Agents Targeting T-cell Migration and Chemotaxis

Lymphocyte depletion and blockade of T-cell activation and trafficking serve as therapeutic strategies for an enlarging number of immune-mediated diseases and malignancies. This review summarizes the infection risks associated to monoclonal antibodies that bind to the α chain of the interleukin-2 receptor, the cell surface glycoprotein CD52, and members of α4- and β2-integrin families acting as cell-adhesion molecules. An outline of the mechanisms of action, approved indications and off-label uses, expected impact on the host immune response, and available clinical evidence is provided for each of these agents.

Common gamma chain cytokines and CD8 T cells in cancer

Overcoming exhaustion-associated dysfunctions and generating antigen-specific CD8 T cells with the ability to persist in the host and mediate effective long-term anti-tumor immunity is the final aim of cancer immunotherapy. To achieve this goal, immuno-modulatory properties of the common gamma-chain (γ_c) family of cytokines, that includes IL-2, IL-7, IL-15 and IL-21, have been used to fine-tune and/or complement current immunotherapeutic protocols. These agents potentiate CD8 T cell expansion and functions particularly in the context of immune checkpoint (IC) blockade, shape their differentiation, improve their persistence in vivo and alternatively, influence distinct aspects of the T cell exhaustion program. Despite these properties, the intrinsic impact of cytokines on CD8 T cell exhaustion has remained largely unexplored impeding optimal therapeutic use of these agents. In this review, we will discuss current knowledge regarding the influence of relevant γ_c cytokines on CD8 T cell differentiation and function based on clinical data and preclinical studies in murine models of cancer and chronic viral infection. We will restate the place of these agents in current immunotherapeutic regimens such as IC checkpoint blockade and adoptive cell therapy. Finally, we will discuss how γ_c cytokine signaling pathways regulate T cell immunity during cancer and whether targeting these pathways may sustain an effective and durable T cell response in patients.

Interleukin-2 Deficiency Associated with Renal Impairment in Systemic Lupus Erythematosus

Impaired interleukin-2 (IL-2) production was reported in systemic lupus erythematosus (SLE). The aim of this study was to investigate the clinical relevance of serum IL-2 and therapeutic effects of recombinant IL-2 (rIL-2) in SLE, especially in lupus nephritis (LN). Decreased serum IL-2 was found in patients with active LN (P = 0.014) and correlated with 24-h urine protein excretion (r = -0.281, P = 0.026). Compared with LN patients with decreased levels of serum IL-2, patients with increased levels had better remission rate (P = 0.041). Furthermore, patients with exogenous low-dose IL-2 supplement demonstrated better improved nephritis and higher remission rate (55.56%, P = 0.058) than those with conventional therapy. In addition, the percentages of regulator T (Treg) cells expanded in LN patients with low-dose recombinant human IL-2 treatment (P = 0.007), especially in LN patients achieving remission (P = 0.010). IL-2 deficiency is associated with renal impairment that can be improved by exogenous IL-2 supplement.

Modes of Communication between T Cells and Relevance for Immune Responses

T cells are essential mediators of the adaptive immune system, which constantly patrol the body in search for invading pathogens. During an infection, T cells that recognise the pathogen are recruited, expand and differentiate into subtypes tailored to the infection. In addition, they differentiate into subsets required for short and long-term control of the pathogen, i.e., effector or memory. T cells have a remarkable degree of plasticity and heterogeneity in their response, however, their overall response to a given infection is consistent and robust. Much research has focused on how individual T cells are activated and programmed. However, in order to achieve a critical level of population-wide reproducibility and robustness, neighbouring cells and surrounding tissues have to provide or amplify relevant signals to tune the overall response accordingly. The characteristics of the immune response-stochastic on the individual cell level, robust on the global level-necessitate coordinated responses on a system-wide level, which facilitates the control of pathogens, while maintaining self-tolerance. This global coordination can only be achieved by constant cellular communication between responding cells, and faults in this intercellular crosstalk can potentially lead to immunopathology or autoimmunity. In this review, we will discuss how T cells mount a global, collective response, by describing the modes of T cell-T cell (T-T) communication they use and highlighting their physiological relevance in programming and controlling the T cell response.

Dynamic changes in the regulatory T-cell heterogeneity and function by murine IL-2 mutein

Single-cell RNA-seq analysis reveals that IL-2 mutein treatment expands multiple sub-states of regulatory T cells with superior suppressive function in mice.

The therapeutic expansion of Foxp3⁺ regulatory T cells (Tregs) shows promise for treating autoimmune and inflammatory disorders. Yet, how this treatment affects the heterogeneity and function of Tregs is not clear. Using single-cell RNA-seq analysis, we characterized 31,908 Tregs from the mice treated with a half-life extended mutant form of murine IL-2 (IL-2 mutein, IL-2M) that preferentially expanded Tregs, or mouse IgG Fc as a control. Cell clustering analysis revealed that IL-2M specifically expands multiple sub-states of Tregs with distinct expression profiles. TCR profiling with single-cell analysis uncovered Treg migration across tissues and transcriptional changes between clonally related Tregs after IL-2M treatment. Finally, we identified IL-2M–expanded Tnfrsf9⁺Il1rl1⁺ Tregs with superior suppressive function, highlighting the potential of IL-2M to expand highly suppressive Foxp3⁺ Tregs.

Immunosuppressive Activity of Artemisia argyi Extract and Isolated Compounds

The need for novel drugs for the treatment of autoimmune diseases is high, since available pharmaceuticals often have substantial side effects and limited efficacy. Natural products are a good starting point in the development of immunosuppressive leads. Since enhanced T cell proliferation is a common feature of autoimmune diseases, we investigated the T cell proliferation inhibitory potential of an extract library of plants used in traditional Chinese medicine. Using a newly established cell-based screening platform, an ethyl acetate extract of Artemisia argyi H.Lév. & Vaniot (Asteraceae, A. argyi) was found to suppress the proliferation of human primary T lymphocytes in vitro in an IL-2-dependent manner. Flow cytometry- and ELISA-based techniques further demonstrated that the A. argyi extract reduced the activation and function of T cells. Transcription factor analysis and flow cytometric calcium influx investigations indicated that the immunomodulatory effect was based on specific modification of T cell signaling in a non-cytotoxic manner which is mediated via the NFAT pathway and a non-sequestrant inhibition of the calcium influx. A series of guaianolide and seco-guaianolide sesquiterpene lactones, as well as a flavonoid, were identified in a previous study as the bioactive compounds in the A. argyi extract. The effects of these bioactive compounds were compared to those of the crude extract. The tested sesquiterpene lactones act via the transcription factor NFAT and NF-κB, thereby exhibiting their immunosuppressive potential, but have an overall effect on T cell biology on a more-downstream level than the crude A. argyi extract.

Low-dose interleukin-2 alleviates dextran sodium sulfate-induced colitis in mice by recovering intestinal integrity and inhibiting AKT-dependent pathways

Several phase 1/2 clinical trials showed that low-dose interleukin-2 (IL-2) treatment is a safe and effective strategy for the treatment of chronic graft-versus-host disease, hepatitis C virus-induced vasculitis, and type 1 diabetes. Ulcerative colitis (UC) is a chronic inflammatory condition of the colon that lacks satisfactory treatment. In this study, we aimed to determine the effects of low-dose IL-2 as a therapeutic for UC on dextran sulfate sodium (DSS)-induced colitis. Methods: Mice with DSS-induced colitis were intraperitoneally injected with low-dose IL-2. Survival, body weight, disease activity index, colon length, histopathological score, myeloperoxidase activity and inflammatory cytokine levels as well as intestinal barrier integrity were examined. Differential gene expression after low-dose IL-2 treatment was analyzed by RNA-sequencing. Results: Low-dose IL-2 significantly improved the symptoms of DSS-induced colitis in mice and attenuated pro-inflammatory cytokine production and immune cell infiltration. The most effective dose range of IL-2 was 16K-32K IU/day. Importantly, low-dose IL-2 was effective in ameliorating the disruption of epithelial barrier integrity in DSS-induced colitis tissues by restoring tight junction proteins and mucin production and suppressing apoptosis. The colon tissue of DSS-induced mice exposed to low-dose IL-2 mimic gene expression patterns in the colons of control mice. Furthermore, we identified the crucial role of the PI3K-AKT pathway in exerting the therapeutic effect of low-dose IL-2. Conclusions: The results of our study suggest that low-dose IL-2 has therapeutic effects on DSS-induced colitis and potential clinical value in treating UC.

Ubiquitin-specific peptidase 18 regulates the differentiation and function of Treg cells

Ubiquitin-specific peptidase 18 (USP18) plays an important role in the development of CD11b⁺ dendritic cells (DCs) and Th17 cells, however, its role in the differentiation of other T cell subsets, especially in regulatory T (Treg) cells, is unknown. In our study, we used Usp18 KO mice to study the loss of USP18 on the impact of Treg cell differentiation and function. We found that USP18 deficiency upregulates the differentiation of Treg cells, which may lead to disrupted homeostasis of peripheral T cells, and downregulates INF-γ, IL-2, IL-17A producing CD4⁺ T cells and INF-γ producing CD8⁺ T cells. Mechanistically, we also found that the upregulation of Tregs is due to elevated expression of CD25 in Usp18 KO mice. Finally, we found that the suppressive function of Usp18 KO Tregs is downregulated. Altogether, our study was the first to identify the role of USP18 in Tregs differentiation and its suppressive function, which may provide a new reference for the treatment of Treg function in many autoimmune diseases, and USP18 can be used as a new therapeutic target for precise medical treatment.

Chemical Synthesis of Interleukin-2 and Disulfide Stabilizing Analogues

Chemical protein synthesis allows the construction of well-defined structural variations and facilitates the development of deeper understanding of protein structure-function relationships and new protein engineering strategies. Herein, we report the chemical synthesis of interleukin-2 (IL-2) variants on a multimilligram scale and the formation of non-natural disulfide mimetics that improve stability against reduction. The synthesis was accomplished by convergent KAHA ligations; the acidic conditions of KAHA ligation proved to be valuable for the solubilization of the hydrophobic segments of IL-2. The bioactivity of the synthetic IL-2 and its analogues were shown to be equipotent to recombinant IL-2 and exhibit improved stability against reducing agents.

STAT4: an immunoregulator contributing to diverse human diseases

Signal transducer and activator of transcription 4 (STAT4) is a member of the STAT family and localizes to the cytoplasm. STAT4 is phosphorylated after a variety of cytokines bind to the membrane, and then dimerized STAT4 translocates to the nucleus to regulate gene expression. We reviewed the essential role played by STAT4 in a wide variety of cells and the pathogenesis of diverse human diseases, especially many kinds of autoimmune and inflammatory diseases, via activation by different cytokines through the Janus kinase (JAK)-STAT signaling pathway.

Pre-treatment with IL2 gene therapy alleviates Staphylococcus aureus arthritis in mice

BACKGROUND

Staphylococcus aureus (S. aureus) arthritis is one of the most detrimental joint diseases known and leads to severe joint destruction within days. We hypothesized that the provision of auxiliary immunoregulation via an expanded compartment of T regulatory cells (Tregs) could dampen detrimental aspects of the host immune response whilst preserving its protective nature. Administration of low-dose interleukin 2 (IL2) preferentially expands Tregs, and is being studied as a treatment choice in several autoimmune conditions. We aimed to evaluate the role of IL2 and Tregs in septic arthritis using a well-established mouse model of haematogenously spred S. aureus arthritis.

METHODS

C57BL/6 or NMRI mice we intravenously (iv) injected with a defined dose of S. aureus LS-1 or Newman and the role of IL2 and Tregs were assessed by the following approaches: IL2 was endogenously delivered by intraperitoneal injection of a recombinant adeno-associated virus vector (rAAV) before iv S. aureus inoculation; Tregs were depleted before and during S. aureus arthritis using antiCD25 antibodies; Tregs were adoptively transferred before induction of S. aureus arthritis and finally, recombinant IL2 was used as a treatment starting day 3 after S. aureus injection. Studied outcomes included survival, weight change, bacterial clearance, and joint damage.

RESULTS

Expansion of Tregs induced by IL2 gene therapy prior to disease onset does not compromise host resistance to S. aureus infection, as the increased proportions of Tregs reduced the arthritis severity as well as the systemic inflammatory response, while simultaneously preserving the host's ability to clear the infection.

CONCLUSIONS

Pre-treatment with IL2 gene therapy dampens detrimental immune responses but preserves appropriate host defense, which alleviates S. aureus septic arthritis in a mouse model.

Low-dose interleukin-2 therapy for the treatment of systemic lupus erythematosus

PURPOSE OF REVIEW

To provide an overview behind the concept and recent advances of low-dose interleukin-2 (IL-2) therapy in systemic lupus erythematosus (SLE).

RECENT FINDINGS

A disruption of regulatory T cell homeostasis caused by an acquired deficiency of IL-2 is a crucial event in the pathogenesis of SLE. Here, we highlight the key rationales for the clinical translation of low-dose IL-2 therapy in SLE and summarize the main findings from two independent, early phase uncontrolled clinical studies that investigated the immunological and clinical responses to low-dose IL-2 therapy in patients with active SLE. Important commonalities and differences between these studies with regard to study design and results are discussed.

SUMMARY

Low-dose IL-2 therapy is capable to promote the selective expansion of a functionally competent regulatory T cell population in a well-tolerated way and may have the potential to influence the clinical course in patients with active SLE. Although a clearer proof for the clinical efficacy of low-dose IL-2 therapy in SLE is still outstanding, these early studies provide important rationales and the scientific basis for more comprehensive and placebo-controlled trials in the future.

Novel Hemizygous IL2RG p.(Pro58Ser) Mutation Impairs IL-2 Receptor Complex Expression on Lymphocytes Causing X-Linked Combined Immunodeficiency

Hypomorphic IL2RG mutations may lead to milder phenotypes than X-SCID, named variably as atypical X-SCID or X-CID. We report an 11-year-old boy with a novel c. 172C>T;p.(Pro58Ser) mutation in IL2RG, presenting with atypical X-SCID phenotype. We also review the growing number of hypomorphic IL2RG mutations causing atypical X-SCID. We studied the patient's clinical phenotype, B, T, NK, and dendritic cell phenotypes, IL2RG and CD25 cell surface expression, and IL-2 target gene expression, STAT tyrosine phosphorylation, PBMC proliferation, and blast formation in response to IL-2 stimulation, as well as protein-protein interactions of the mutated IL2RG by BioID proximity labeling. The patient suffered from recurrent upper and lower respiratory tract infections, bronchiectasis, and reactive arthritis. His total lymphocyte counts have remained normal despite skewed T and B cells subpopulations, with very low numbers of plasmacytoid dendritic cells. Surface expression of IL2RG was reduced on his lymphocytes. This led to impaired STAT tyrosine phosphorylation in response to IL-2 and IL-21, reduced expression of IL-2 target genes in patient CD4+ T cells, and reduced cell proliferation in response to IL-2 stimulation. BioID proximity labeling showed aberrant interactions between mutated IL2RG and ER/Golgi proteins causing mislocalization of the mutated IL2RG to the ER/Golgi interface. In conclusion, IL2RG p.(Pro58Ser) causes X-CID. Failure of IL2RG plasma membrane targeting may lead to atypical X-SCID. We further identified another carrier of this mutation from newborn SCID screening, lost to closer scrutiny.

Zinc gluconate supplementation impacts the clinical improvement in patients with ulcerative colitis

Ulcerative colitis is an inflammatory bowel disease that affects the mucous membrane of the colon. The pathogenesis is not clear, but there is evidence of a complex interaction between genetic, environmental, and immunological factors. In this regard, we highlight the role of zinc in the immune system and probable control of the disease. This study evaluated the effect of zinc supplementation on the inflammatory response in patients with ulcerative colitis. A blind interventional study involving 41 patients of both sexes, who underwent either zinc gluconate supplementation (n = 23), or treatment with a placebo (corn starch) (n = 18). Patients were evaluated for dietary zinc intake, plasma and erythrocyte zinc concentrations, and serum levels of Th1/Th2/Th17 type cytokines at baseline (T0) and 30 (T1) and 60 (T2) days after intervention. Patients in the zinc supplementation group had a lower probability of having an adequate zinc intake than placebo. In this same group, there was a significant difference between plasma zinc concentrations (T1 in relation to T0, T2 in relation to T1, and T2 in relation to T0) and erythrocyte zinc (T1 in relation to T0 and T2 in relation to T1). Zinc supplementation resulted in significant changes in the concentrations of IL-2 and IL-10 without differences in the other interleukins. Zinc gluconate intervention in patients with ulcerative colitis improves the nutritional status of this mineral in these patients and positively influences their clinical outcome, reinforcing the role of zinc as an important dietary component in disease control.

Dysregulation of T Follicular Helper Cells in Lupus

Although multiple and overlapping mechanisms are ultimately responsible for the immunopathology observed in patients with systemic lupus erythematosus, autoreactive Abs secreted by autoreactive plasma cells (PCs) are considered to play a critical role in disease progression and immunopathology. Given that PCs derive from the germinal centers (GC), long-term dysregulated GC reactions are often associated with the development of spontaneous autoantibody responses and immunopathology in systemic lupus erythematosus patients. In this review, we summarize the emerging evidence concerning the roles of T follicular helper cells in regulating pathogenic GC and autoreactive PC responses in lupus.

First demonstration of giant panda's immune response to canine distemper vaccine

The Canine Distemper Virus (CDV) is a high fatal virus to the giant panda (Ailuropoda melanoleuca), where CDV vaccination is a key preventative measure in captive giant pandas. However, the immune response of giant pandas to CDV vaccination has been little studied. In this study, we investigated the blood transcriptome expression profiles of five giant panda cubs after three inoculations, 21 days apart. Blood samples were collected before vaccination (0 Day), and 24 h after each of the three inoculations; defined here as 1 Day, 21  Day, and 42  Day. Compared to 0 Day, we obtained 1262 differentially expressed genes (DEGs) during inoculations. GO and KEGG pathways enrichment analysis of these DEGs found 222 GO terms and 40 pathways. The maximum immune-related terms were enriched by DEGs from comparisons of 21  Day and 0 Day. In the PPI analysis, we identified RSAD2, IL18, ISG15 immune-related hub genes from 1 Day and 21 Day comparison. Compared to 0 Day, innate immune-related genes, TLR4 and TLR8, were up-regulated at 1 Day, and the expressions of IRF1, RSAD2, MX1, and OAS2 were highest at 21  Day. Of the adaptive immune-related genes, IL15, promoting T cell differentiation into CD8⁺T cells, was up-regulated after the first two inoculations, IL12β, promoting T cell differentiation into memory cells, and IL10, promoting B cell proliferation and differentiation, were down-regulated during three inoculations. Our results indicated that the immune response of five giant panda cubs was strongest after the second inoculation, most likely protected against CDV infection through innate immunity and T cells, but did not produce enough memory cells to maintain long-term immunity after CDV vaccination.

Differential Roles of IL-2 Signaling in Developing versus Mature Tregs

Although Foxp3⁺ regulatory T cells (Tregs) require interleukin-2 (IL-2) for their development, it has been unclear whether continuing IL-2 signals are needed to maintain lineage stability, survival, and suppressor function in mature Tregs. We generated mice in which CD25, the main ligand-binding subunit of the IL-2 receptor, can be inducibly deleted from Tregs after thymic development. In contrast to Treg development, we find that IL-2 is dispensable for maintaining lineage stability in mature Tregs. Although continuous IL-2 signaling is needed for long-term Treg survival, CD25-deleted Tregs may persist for several weeks in vivo using IL-7. We also observe defects in glycolytic metabolism and suppressor function following CD25 deletion. Thus, unlike developing Tregs in which the primary role of IL-2 is to initiate Foxp3 expression, mature Tregs require continuous IL-2 signaling to maintain survival and suppressor function, but not to maintain lineage stability.

Modeling cell-cell communication for immune systems across space and time

Communicating is crucial for cells to coordinate their behaviors. Immunological processes, involving diverse cytokines and cell types, are ideal for developing frameworks for modeling coordinated behaviors of cells. Here, we review recent studies that combine modeling and experiments to reveal how immune systems use autocrine, paracrine, and juxtacrine signals to achieve behaviors such as controlling population densities and hair regenerations. We explain that models are useful because one can computationally vary numerous parameters, in experimentally infeasible ways, to evaluate alternate immunological responses. For each model, we focus on the length-scales and time-scales involved and explain why integrating multiple length-scales and time-scales in a model remain challenging. We suggest promising modeling strategies for meeting this challenge and their practical consequences.

Distinct ocular surface soluble factor profile in human corneal dystrophies

PURPOSE

Corneal dystrophies (CD) are classified as rare eye diseases that results in visual impairment and requires corneal transplant in advanced stages. Ocular surface inflammatory status in different types of CD remains underexplored. Hence, we studied the levels of tear soluble factors in the tears of patients with various types of corneal dystrophies.

METHODS

17 healthy subjects and 30 CD subjects (including epithelial, stromal and endothelial CD) were included in the study. Schirmer's strips were used to collect the tear fluid in all subjects. 27 soluble factors including cytokines, chemokines, soluble cell adhesion molecules and growth factors were measured in the eluted tears by multiplex ELISA or single analyte sandwich ELISA.

RESULTS

Percentages of subjects with detectable levels of tear soluble factors were significantly higher in CD compared to controls. Significant higher level of IL-2 was observed in both epithelial and stromal CD. IL-4, TGFβ1 and IgE were significantly higher in stromal CD. VCAM, IL-13 and Fractalkine were significantly elevated in epithelial and macular CD. IL-1α, IL-8, IL-12, ANG, Eotaxin, MCP1, RANTES, ICAM1, L-selectin and P-selectin were significantly higher in epithelial CD. TGFBIp was significantly elevated in lattice CD and endothelial CD.

CONCLUSION

Distinct set of the tear soluble factors were dysregulated in various types of CD. Increase in tear inflammatory factors was observed in majority of the CD subjects depending on their sub-types. This suggests a plausible role of aberrant inflammation in CD pathobiology. Hence, modulating inflammation could be a potential strategy in improving the prognosis of CD.

Genomic, proteomic, and immunologic associations with a durable complete remission of measurable metastatic melanoma induced by a patient-specific dendritic cell vaccine

This report describes efforts to understand the immune mechanism of action that led to a complete response in a patient with progressive, refractory, metastatic melanoma after treatment with a therapeutic vaccine consisting of autologous dendritic cells (DC) loaded with autologous tumor antigens (ATA) derived from cells that were self-renewing in cell culture. Her histocompatibility type proved to be HLA B27 with extensive mutations in the HLA-A locus. Exomic analysis of proliferating tumor cells revealed more than 2800 non-synonymous mutations compared to her leukocytes. Histology of resected tumor lesions showed no evidence of an existing or suppressed immune response. In in vitro mixed cell cultures, DC loaded with ATA induced increased IL-22 expression, and a four-fold increase in CD8 + T lymphocytes. Cryopreserved blood samples obtained at week-0, 1 week before the first of three-weekly vaccine injections, and at week-4, 1 week after the third dose, were analyzed by protein array and compared for 110 different serum markers. At baseline, she had marked elevations of amyloid A, IL-12p40, IL21, IL-22, IL-10, IL-16, GROa, TNF-alpha, IL-3, and IL-2, and a lesser elevation of IL-15. One week after 3 weekly vaccinations she had a further 80% increase in amyloid A, a further 66% increase in IL-22, a 92% decrease in IL12p40, a 45% decrease in TGF-β and 26% decrease in IL-10. The data suggested that by 3 weeks after the first DCV injection, vaccine-induced changes in this particular patient were most consistent with enhanced innate and Th1 immune responses rather than Th2 or Th17.

Cytotoxic comparison of macrolide antibiotics and their chlorinated disinfection byproduct mixtures

Erythromycin (ERY), azithromycin (AZI) and telithromycin (TEL) are widely-used macrolide antibiotics that are frequently detected in various water environments, including resource water and drinking water. In the performed chlorination disinfection process, at least 10, 20 and 200 new disinfection byproducts of ERY, AZI and TEL, respectively, were observed (the mixtures of the disinfection byproducts of ERY, AZI and TEL were named ERY-M, AZI-M and TEL-M, respectively). There is limited information available regarding their comparative toxicities, and their potential health risks are still unknown. In this study, the Jurkat cell line was used to compare the toxicities of the disinfection byproduct mixtures and their precursor compounds. The cell viability results indicated that the toxicity of ERY-M may not be enhanced after disinfection by chlorination. In contrast, at the same concentrations, AZI-M and TEL-M induced more significant inhibitory effects on cell viability than their parent compounds. Additionally, the total antioxidant capacity (T-AOC) and cell cytokine release (including interleukin-2, interleukin-8 and tumor necrosis factor-α) analyses of AZI-M and TEL-M further verified these results. Our findings demonstrate that the cytotoxicity of AZI and TEL was enhanced during the chlorination disinfection process. This investigation will provide substantial new details related to the toxicity of the mixed disinfection byproducts (DBPs) of ERY, AZI and TEL generated in the chlorination disinfection process.

Antimicrobial peptide, cLF36, affects performance and intestinal morphology, microflora, junctional proteins, and immune cells in broilers challenged with E. coli

This study investigated the effects of an antimicrobial peptide (AMP), cLF36, on growth performance and the histophysiological changes of the intestine in E. coli-challenged broiler chickens. A total number of 360 day old male chicks were randomly assigned to 4 groups of 6 replicates as follows: T1) negative control diet based on corn-soybean meal without E. coli challenge and additives; T2) positive control diet based on corn-soybean meal and challenged with E. coli without any additives; T3) positive control diet challenged with E. coli and supplemented with 20 mg AMP (cLF36)/kg diet; T4) positive control diet challenged with E. coli and supplemented with 45 mg antibiotic (bacitracin methylene disalicylate)/kg diet. Results showed that T3 improved growth performance and the jejunal morphology of E. coli-challenged chickens similar to those of T4. While antibiotic non-selectively decreased the population of ileal bacteria, AMP increased the population of Lactobacillus spp. and decreased harmful bacteria in the ileum of E. coli-challenged chickens. Supplementing E. coli-challenged chickens with AMP improved the gene expression of immune cells and upregulated the expression of tight junction proteins compared to other challenged groups. In conclusion, although cLF36 beneficially affected growth performance and the intestinal morphology of E. coli-challenged chickens similar to those of the antibiotic group, this AMP drastically improved the intestinal microbiome, immune cells, and junctional proteins compared to other E. coli-challenged birds, and can be nominated as an alternative for growth promoter antibiotics.

Interleukin-2 (IL-2) in flounder (Paralichthys olivaceus): Molecular cloning, characterization and bioactivity analysis

Interleukin-2 (IL-2) is mainly produced by CD4⁺ T helper lymphocytes, which is an important immunomodulatory cytokine that primarily promotes activation, proliferation and differentiation of T cells. In the present study, flounder (Paralichthys olivaceus) interleukin 2 homologue (poIL-2) was identified for the first time, and its expression patterns were characterized in healthy, virus- or bacteria-infected flounder. The full-length cDNA sequences of poIL-2 was 989 bp with an open reading frame of 423 bp coding a polypeptide of 140 amino acids (aa). The deduced aa sequences shared low similarities (<53%) with other known fish IL-2s. Multiple alignment of aa sequences revealed that poIL-2 own the classical IL-2 family signature of "C-X(3)-EL-X(2)-(T/V)-(V/M/L)-(K/T/R)-X-EC" and "DS-X-(F/L)Y(A/T/S)P". In healthy flounder, IL-2 mRNA was highly expressed in PBLs, spleen and hindgut, and moderately expressed in gill, trunk kidney and stomach. PHA, LPS and Con-A could effectively induce poIL-2 expression in primary cultured peripheral blood leukocytes in vitro. poIL-2 transcripts were significantly up-regulated in spleen, kidney, gill and hindgut post infections with Edwardsiella tarda and Hirame novirhabdovirus (HIRRV). The eukaryotic expression vector encoding poIL-2 (pcIL-2) was constructed and intramuscularly injected, which could be successfully expressed in flounders and induced significantly higher expressions of six immune related genes including poIL-2, β-defensin, CD4-1, CD8α, IFN-γ and TNF-α compared with the injection with control plasmid. Moreover, pretreatment with pcIL-2 could markedly increase the survival rate of flounder challenged with HIRRV. Our results demonstrated that poIL-2 plays an important role in the induction of immune responses and immune defense against bacterial and virus infection, which indicated its potential use as an immunopotentiator to prevent diseases in flounder.

Immunological characteristics of Interleukin-2 receptor subunit beta (IL-2Rβ) in flounder (Paralichtlys olivaceus): Implication for IL-2R function

Interleukin-2 receptor subunit beta of flounder (Paralichthys olivace, fIL-2Rβ) was annotated on the NCBI, its gene was cloned and characterized functionally in this study. And then the amino acids sequences and tertiary structure of fIL-2Rβ were analyzed, respectively. RT-PCR and ImageJ analyzed showed that fIL-2Rβ mRNA were expressed in the gill, spleen, kidney, intestines, liver, blood, muscle and skin, which showed high signals in spleen and blood. And then the recombinant protein of fIL-2Rβ extracellular region and its polyclonal antibodies were produced, native fIL-2Rβ molecules in flounder peripheral blood leukocytes (PBLs) were identified at 60.7 kDa by Mass spectrometry, which were in accordance with the molecular mass of full fIL-2Rβ protein calculated on the predicted protein sequence. Then the IL-2Rβ+ cell in T/B lymphocytes were characterized by Flow cytometry and indirect immunofluorescence assay, respectively. The results showed that the percentages of IL-2Rβ+ leukocytes, IL-2Rβ+/CD4+, IL-2Rβ+/IgM+ lymphocytes were 18.4 ± 2.7%, 4.5 ± 0.8%, 4.3% ± 0.5 in PBLs, and were 13.6 ± 0.9%, 4.6 ± 1.1%, 6.1% ± 0.4 in spleen, similarly, the percentages of IL-2Rβ+ leukocytes, IL-2Rβ+/CD4+, IL-2Rβ+/IgM+ lymphocytes were 9.4 ± 0.3%, 4.0 ± 0.5%, 5.7 ± 0.1% in head kidney, respectively. After KLH injection, compared with control group, the gene expression of IL-2, IL-2Rβ, CD3, TCR, CD79b and IgM in spleen of flounder were up-regulated, respectively (p < 0.05). And the FCM results showed that the percentages of IL-2Rβ+ leukocytes in PBLs were significantly increased post Keyhole limpet hemocyanin (KLH) injection, which peaked 23.9 ± 0.9% at 9^th day (p < 0.05). To our knowledge, those results first reported that the characteristics of IL-2R and IL-2R + molecules were expressed on both B and T lymphocytes in fish. At the same time, this study lays a foundation for further exploring the interaction between IL-2 and IL-2R to promote cell proliferation and carrying out biological functions.

Anti-human CD63 monoclonal antibody COS3A upregulates monocyte-induced IL-10 excretion leading to diminution of CD3-mediated T cell response

Human CD63 has been reported to play a role either as an inhibitor or as a co-stimulator of T- cell responses, although the mechanism of this is unclear. In this study, an anti-human CD63 monoclonal antibody (mAb) COS3A was used to monitor the role of CD63 in T-cell activation. MAb COS3A could inhibit CD3-mediated T-cell proliferation and CD25 expression in peripheral blood mononuclear cells (PBMCs), used as a study model, but the suppressive effect was not observed when purified T-cells were used instead of PBMCs. The inhibitory phenomenon was associated with downregulation of IL-2 and IFN-γ by T-cells, but upregulation of IL-10 by monocytes. Neutralizing IL-10 with anti-IL-10 mAb improved the T-cell response, indicating the role of IL-10 in T-cell suppression. In this study, monocytes were demonstrated to play a role in impeding T-cell activation by the anti-CD63 mAb COS3A. This is the first evidence that anti-CD63 mAb induces IL-10 secretion by monocytes, which later play a role in T-cell hypo-responsiveness.

NK Cell Hyporesponsiveness: More Is Not Always Better

Natural Killer (NK) cells are a type of cytotoxic lymphocytes that play an important role in the innate immune system. They are of particular interest for their role in elimination of intracellular pathogens, viral infection and tumor cells. As such, numerous strategies are being investigated in order to potentiate their functions. One of these techniques aims at promoting the function of their activating receptors. However, different observations have revealed that providing activation signals could actually be counterproductive and lead to NK cells’ hyporesponsiveness. This phenomenon can occur during the NK cell education process, under pathological conditions, but also after treatment with different agents, including cytokines, that are promising tools to boost NK cell function. In this review, we aim to highlight the different circumstances where NK cells become hyporesponsive and the methods that could be used to restore their functionality.

JunB plays a crucial role in development of regulatory T cells by promoting IL-2 signaling

The AP-1 transcription factor JunB plays crucial roles in multiple biological processes, including placental formation and bone homeostasis. We recently reported that JunB is essential for development of Th17 cells, and thus Junb-deficient mice are resistant to experimental autoimmune encephalomyelitis. However, the role of JunB in CD4⁺ T cells under other inflammatory disease conditions is unknown. Here we show that mice lacking JunB in CD4⁺ T cells (Junb^fl/flCd4-Cre mice) were more susceptible to dextran sulfate sodium (DSS)-induced colitis because of impaired development of regulatory T (Treg) cells. Production of interleukin (IL)-2 and expression of CD25, a high affinity IL-2 receptor component, were decreased in Junb-deficient CD4⁺ T cells in vitro and in vivo. Naive CD4⁺ T cells from Junb^fl/flCd4-Cre mice failed to differentiate into Treg cells in the absence of exogenously added IL-2 in vitro. A mixed bone marrow transfer experiment revealed that defective Treg development of Junb-deficient CD4⁺ T cells was not rescued by co-transferred wild-type cells, indicating a significance of the cell-intrinsic defect. Injection of IL-2-anti-IL-2 antibody complexes induced expansion of Treg cells and alleviated DSS-induced colitis in Junb^fl/flCd4-Cre mice. Thus JunB plays a crucial role in the development of Treg cells by facilitating IL-2 signaling.

CD4+ T cell activation and associated susceptibility to HIV-1 infection in vitro increased following acute resistance exercise in human subjects

Early studies in exercise immunology suggested acute bouts of exercise had an immunosuppressive effect in human subjects. However, recent data, show acute bouts of combined aerobic and resistance training increase both lymphocyte activation and proliferation. We quantified resistance exercise-induced changes in the activation state of CD4+ T lymphocytes via surface protein expression and using a medically relevant model of infection (HIV-1). Using a randomized cross-over design, 10 untrained subjects completed a control and exercise session. The control session consisted of 30-min seated rest while the exercise session entailed 3 sets × 10 repetitions of back squat, leg press, and leg extensions at 70% 1-RM with 2-min rest between each set. Venous blood samples were obtained pre/post each session. CD4+ T lymphocytes were isolated from whole blood by negative selection. Expression of activation markers (CD69 & CD25) in both nonstimulated and stimulated (costimulation through CD3+ CD28) cells were assessed by flow cytometry. Resistance exercised-induced effects on intracellular activation was further evaluated via in vitro infection with HIV-1. Nonstimulated CD4+ T lymphocytes obtained postexercise exhibited elevated CD25 expression following 24 h in culture. Enhanced HIV-1 replication was observed in cells obtained postexercise. Our results demonstrate that an acute bout of resistance exercise increases the activation state of CD4+ T lymphocytes and results in a greater susceptibility to HIV-1 infection in vitro. These findings offer further evidence that exercise induces activation of T lymphocytes and provides a foundation for the use of medically relevant pathogens as indirect measures of intracellular activation.

Memory CD4 T cell-derived IL-2 synergizes with viral infection to exacerbate lung inflammation

Defining the most penetrating correlates of protective memory T cells is key for designing improved vaccines and T cell therapies. Here, we evaluate how interleukin (IL-2) production by memory CD4 T cells, a widely held indicator of their protective potential, impacts immune responses against murine influenza A virus (IAV). Unexpectedly, we show that IL-2-deficient memory CD4 T cells are more effective on a per cell basis at combating IAV than wild-type memory cells that produce IL-2. Improved outcomes orchestrated by IL-2-deficient cells include reduced weight loss and improved respiratory function that correlate with reduced levels of a broad array of inflammatory factors in the infected lung. Blocking CD70-CD27 signals to reduce CD4 T cell IL-2 production tempers the inflammation induced by wild-type memory CD4 T cells and improves the outcome of IAV infection in vaccinated mice. Finally, we show that IL-2 administration drives rapid and extremely potent lung inflammation involving NK cells, which can synergize with sublethal IAV infection to promote acute death. These results suggest that IL-2 production is not necessarily an indicator of protective CD4 T cells, and that the lung environment is particularly sensitive to IL-2-induced inflammation during viral infection.

Gelatinase B/matrix metalloproteinase-9 and other neutrophil proteases switch off interleukin-2 activity

Interleukin 2 (IL-2) is critical for T cell development and homeostasis, being a key regulator of adaptive immune responses in autoimmunity, hypersensitivity reactions and cancer. Therefore, its abundance in serum and peripheral tissues needs tight control. Here, we described a new mechanism contributing to the immunobiology of IL-2. We demonstrated, both in biochemical and cell-based assays, that IL-2 is subject to proteolytic processing by neutrophil matrix metalloproteinase-9 (MMP-9). IL-2 fragments produced after cleavage by MMP-9 remained linked by a disulfide bond and displayed a reduced affinity for all IL-2 receptor subunits and a distinct pattern and timing of signal transduction. Stimulation of IL-2-dependent cells, including murine CTLL-2 and primary human regulatory T cells, with cleaved IL-2 resulted in significantly decreased proliferation. The concerted action of neutrophil proteases destroyed IL-2. Our data suggest that in neutrophil-rich inflammatory conditions in vivo, neutrophil MMP-9 may reduce the abundance of signaling-competent IL-2 and generate a fragment that competes with IL-2 for receptor binding, whereas the combined activity of granulocyte proteases has the potential to degrade and thus eliminate bioavailable IL-2.

Signaling and Function of Interleukin-2 in T Lymphocytes

The discovery of interleukin-2 (IL-2) changed the molecular understanding of how the immune system is controlled. IL-2 is a pleiotropic cytokine, and dissecting the signaling pathways that allow IL-2 to control the differentiation and homeostasis of both pro- and anti-inflammatory T cells is fundamental to determining the molecular details of immune regulation. The IL-2 receptor couples to JAK tyrosine kinases and activates the STAT5 transcription factors. However, IL-2 does much more than control transcriptional programs; it is a key regulator of T cell metabolic programs. The development of global phosphoproteomic approaches has expanded the understanding of IL-2 signaling further, revealing the diversity of phosphoproteins that may be influenced by IL-2 in T cells. However, it is increasingly clear that within each T cell subset, IL-2 will signal within a framework of other signal transduction networks that together will shape the transcriptional and metabolic programs that determine T cell fate.

A strategy for the selection of monovalent antibodies that span protein dimer interfaces

Ligand-induced dimerization is the predominant mechanism through which secreted proteins activate cell surface receptors to transmit essential biological signals. Cytokines are a large class of soluble proteins that dimerize transmembrane receptors into precise signaling topologies, but there is a need for alternative, engineerable ligand scaffolds that specifically recognize and stabilize these protein interactions. Recombinant antibodies can potentially serve as robust and versatile platforms for cytokine complex stabilization, and their specificity allows for tunable modulation of dimerization equilibrium. Here, we devised an evolutionary strategy to isolate monovalent antibody fragments that bridge together two different receptor subunits in a cytokine-receptor complex, precisely as the receptors are disposed in their natural signaling orientations. To do this, we screened a naive antibody library against a stabilized ligand-receptor ternary complex that acted as a "molecular cast" of the natural receptor dimer conformation. Our selections elicited "stapler" single-chain variable fragments (scFvs) of antibodies that specifically engage the interleukin-4 receptor heterodimer. The 3.1 Å resolution crystal structure of one such stapler revealed that, as intended, this scFv recognizes a composite epitope between the two receptors as they are positioned in the complex. Extending our approach, we evolved a stapler scFv that specifically binds to and stabilizes the interface between the interleukin-2 cytokine and one of its receptor subunits, leading to a 15-fold enhancement in interaction affinity. This demonstration that scFvs can be selected to recognize epitopes that span protein interfaces presents new opportunities to engineer structurally defined antibodies for a broad range of research and therapeutic applications.

Check-control of inflammation displayed by bone marrow mesenchymal stem cells in rheumatoid arthritis patients

Background: Mesenchymal stem cells (MSCs) are a promising treatment of different musculoskeletal diseases including osteoarthritis and rheumatoid arthritis (RA). Results from different approaches in this treatment have been not conclusive. Aim: To analyze factors related to interactions between peripheral blood mononuclear cells (PBMCs) and MSCs and the influence of cellular activation. Materials & methods: PBMCs from RA patients and healthy controls (HC) were obtained. MSCs from bone marrow (BM-MSCs) were obtained from six donors. CD4, CD25, CD69 and CD127 expression was measured by flow cytometry. Repeated measures analysis of variance (ANOVA) models were performed using activation, co-culture with BM-MSCs and time of culture (24 h, 72 h, 6 days) as within-subject variables. Results: PBMCs activated and co-cultured with BM-MSCs showed a lower proportion of CD25-positive and CD25high/CD127low-negative cells in both RA and HC. Additionally, a maintained expression of CD69 was also observed in RA and HC when PBMCs were activated and co-cultured with BM-MSCs. Conclusion: Both PBMC activation grade and RA disease activity influence the immunomodulatory effect of BM-MSCs on T-cell activation.

Cancer-driven changes link T cell frequency to muscle strength in people with cancer: a pilot study

BACKGROUND

Tumour growth can promote the loss of muscle mass and function. This is particularly disturbing because overall survival is significantly reduced in people with weaker and smaller skeletal muscle. The risk of cancer is also greater in people who are immune deficient. Muscle wasting in mice with cancer can be inhibited by infusion of CD4⁺ precursor T cells that restore balanced ratios of naïve, memory, and regulatory T cells. These data are consistent with the hypothesis that stronger anti-cancer T cell immunity leads to improved muscle mass and function. As a first step to testing this hypothesis, we determined whether levels of circulating T cell subsets correlate with levels of muscle strength in people with cancer.

METHODS

The frequency of circulating CD4⁺ and CD8⁺ naïve, memory, and regulatory T cell subsets was quantified in 11 men with gastrointestinal cancer (aged 59.3 ± 10.1 years) and nine men without cancer (aged 60 ± 13 years), using flow cytometry. T cell marker expression was determined using real-time PCR and western blot analyses in whole blood and peripheral blood mononuclear cells. Handgrip strength, one-repetition maximum chest press, and knee extension tests were used to determine muscle strength. Performance was determined using a stair climb test. Body composition was determined using dual-energy X-ray absorptiometry scan. The Karnofsky and ECOG scales were used to assess functional impairment. Correlations between frequencies of cell subsets with strength, performance, and body composition were determined using regression analyses.

RESULTS

Our data show significant correlations between (i) higher frequencies of CD8⁺ naïve (P = 0.02) and effector memory (P = 0.003) T cells and lower frequencies of CD8⁺ central memory T cells (P = 0.002) with stronger handgrip strength, (ii) lower frequency of regulatory cells with greater lean mass index (P = 0.04), (iii) lower frequency of CD8⁺ T cells that express CD95 with greater stair climb power (P = 0.003), (iv) higher frequency of T cells that co-express CD197 and CD45RA and greater one-repetition maximum knee extension strength (P = 0.008), and (iv) higher expression of CD4 in whole blood with greater functional impairment (P = 0.004) in people with cancer.

CONCLUSIONS

We have identified significant correlations between levels of T cell populations and muscle strength, performance, and body composition in people with cancer. These data justify a follow-up study with a larger cohort to test the validity of the findings.

Differential Interleukin-2 Transcription Kinetics Render Mouse but Not Human T Cells Vulnerable to Splicing Inhibition Early after Activation

T cells are nodal players in the adaptive immune response against pathogens and malignant cells. Alternative splicing plays a crucial role in T cell activation, which is analyzed mainly at later time points upon stimulation. Here we have discovered a 2-h time window early after stimulation where optimal splicing efficiency or, more generally, gene expression efficiency is crucial for successful T cell activation. Reducing the splicing efficiency at 4 to 6 h poststimulation significantly impaired murine T cell activation, which was dependent on the expression dynamics of the Egr1-Nab2-interleukin-2 (IL-2) pathway. This time window overlaps the time of peak IL-2 de novo transcription, which, we suggest, represents a permissive time window in which decreased splicing (or transcription) efficiency reduces mature IL-2 production, thereby hampering murine T cell activation. Notably, the distinct expression kinetics of the Egr1-Nab2-IL-2 pathway between mouse and human render human T cells refractory to this vulnerability. We propose that the rational temporal modulation of splicing or transcription during peak de novo expression of key effectors can be used to fine-tune stimulation-dependent biological outcomes. Our data also show that critical consideration is required when extrapolating mouse data to the human system in basic and translational research.

Effect of IL2RA and IL2RB gene polymorphisms on lung cancer risk

BACKGROUND

Inflammation is crucial for lung cancer development. Variants of multiple genes in inflammation pathways may lead to susceptibility to lung cancer. In the present study, we aimed to assess the influence of polymorphisms in inflammation-related genes (IL2RA and IL2RB) on lung cancer risk.

METHODS

A total of 507 patients with lung cancer and 503 healthy controls were genotyped for seven polymorphisms of IL2RA and IL2RB using the Agena MassARRAY platform. We evaluated the relationship of the genotypes with lung cancer susceptibility using odds ratio (OR), 95% confidence interval (95% CI) and chi square test.

RESULTS

We found that IL2RA rs12722498 was significantly associated with a decreased risk of lung cancer in dominant (p = 0.040, OR = 0.71, 95% CI = 0.51-0.98), additive (p = 0.016, OR = 0.68, 95% CI = 0.50-0.93) and allele (p = 0.019, OR = 0.69, 95% CI = 0.51-0.94) models. After stratification analysis, the results showed that IL2RA rs12569923 (non-smokers), IL2RA rs791588 (≤60 years old, non-drinkers, BMI < 24 kg/m²), IL2RA rs12722498 (≤60 years old, non-drinkers, BMI < 24 kg/m², female) and IL2RB rs2281089 (female, stage) significantly decreased the risk of lung cancer. Additionally, the haplotypes of rs12569923 and rs791588 in IL2RA had strong relationships with lung cancer in the subgroups of BMI < 24 kg/m², age ≤ 60 years old, non-smokers and non-drinkers.

CONCLUSION

Our results showed that the IL2RA and IL2RB polymorphisms were associated with lung cancer risk in the Chinese Han population, which suggests roles for IL2RA and IL2RB polymorphisms in lung cancer.

The promise of CD4+FoxP3+ regulatory T-cell manipulation in vivo: applications for allogeneic hematopoietic stem cell transplantation

CD4⁺FoxP3⁺ regulatory T cells (Tregs) are a non-redundant population critical for the maintenance of self-tolerance. Over the past decade, the use of these cells for therapeutic purposes in transplantation and autoimmune disease has emerged based on their capacity to inhibit immune activation. Basic science discoveries have led to identifying key receptors on Tregs that can regulate their proliferation and function. Notably, the understanding that IL-2 signaling is crucial for Treg homeostasis promoted the hypothesis that in vivo IL-2 treatment could provide a strategy to control the compartment. The use of low-dose IL-2 in vivo was shown to selectively expand Tregs versus other immune cells. Interestingly, a number of other Treg cell surface proteins, including CD28, CD45, IL-33R and TNFRSF members, have been identified which can also induce activation and proliferation of this population. Pre-clinical studies have exploited these observations to prevent and treat mice developing autoimmune diseases and graft-versus-host disease post-allogeneic hematopoietic stem cell transplantation. These findings support the development of translational strategies to expand Tregs in patients. Excitingly, the use of low-dose IL-2 for patients suffering from graft-versus-host disease and autoimmune disease has demonstrated increased Treg levels together with beneficial outcomes. To date, promising pre-clinical and clinical studies have directly targeted Tregs and clearly established the ability to increase their levels and augment their function in vivo. Here we review the evolving field of in vivo Treg manipulation and its application to allogeneic hematopoietic stem cell transplantation.

CD137 (4-1BB) Engagement Fine-Tunes Synergistic IL-15- and IL-21-Driven NK Cell Proliferation

To understand and dissect the mechanisms driving human NK cell proliferation, we exploited the methodology used in cell therapy to numerically expand NK cells in the presence of K562-derived artificial APC (aAPCs) and cytokines. For four consecutive weeks, high expression of CD137L by a K562-derived aAPC cell line could sustain NK cell expansion by 3 × 10⁵-fold, whereas low expression of CD137L by the parental K562 cell line only supported the expansion by 2 × 10³-fold. The level of expression of CD137L, however, did not modulate the sensitivity of K562 cells to the intrinsic cytotoxicity of NK cells. Similarly, the low NK cell proliferation in the presence of the parental K562 cell line and cytokines was increased by adding agonistic anti-CD137 Abs to levels similar to CD137L-expressing K562-derived aAPCs. Finally, synergy between IL-15 and IL-21 was observed only upon CD137 engagement and the presence of aAPCs. Therefore, we conclude that NK cell proliferation requires cell-to-cell contact, activation of the CD137 axis, and presence of IL-15 (or its membranous form) and IL-21. By analogy with the three-signal model required to activate T cells, we speculate that the cell-to-cell contact represents "signal 1," CD137 represents "signal 2," and cytokines represent "signal 3." The precise nature of signal 1 remains to be defined.

Regulatory T cells as therapeutic targets and mediators

With the advent of the concept of dominant tolerance and the subsequent discovery of CD4⁺ regulatory T cells expressing the transcription factor FOXP3 (Tregs), almost all productive as well as nonproductive immune responses can be compartmentalized to a binary of immune effector T cells and immune regulatory Treg populations. A beneficial immune response warrants the timely regulation by Tregs, whereas a nonproductive immune response indicates insufficient effector functions or an outright failure of tolerance. There are ample reports supporting role of Tregs in suppressing spontaneous auto-immune diseases as well as promoting immune evasion by cancers. To top up their importance, several non-immune functions like tissue homeostasis and regeneration are also being attributed to Tregs. Hence, after being in the center stage of basic and translational immunological research, Tregs are making the next jump towards clinical studies. Therefore, newer small molecules, biologics as well as adoptive cell therapy (ACT) approaches are being tested to augment or undermine Treg responses in the context of autoimmunity and cancer. In this brief review, we present the strategies to modulate Tregs towards a favorable clinical outcome.

Network pharmacology-based identifcation of potential targets of the flower of Trollius chinensis Bunge acting on anti-inflammatory effectss

The flower of Trollius chinensis Bunge was widely used for the treatment of inflammation-related diseases in traditional Chinese medicine (TCM). In order to clarify the anti-inflammatory mechanism of this Chinese herbs, a comprehensive network pharmacology strategy that consists of three sequential modules (pharmacophore matching, enrichment analysis and molecular docking.) was carried out. As a result, Apoptosis signal-regulating kinase 1 (ASK1), Janus kinase 1 (JAK1), c-Jun N-terminal kinases (JNKs), transforming protein p21 (HRas) and mitogen-activated protein kinase 14 (p38α) that related to the anti-inflammatory effect were filtered out. In further molecular dynamics (MD) simulation, the conformation of CID21578038 and CID20055288 were found stable in the protein ASK1 and JNKs respectively. The current investigation revealed that two effective compounds in the flower of Trollius chinensis Bunge played a crucial role in the process of inflammation by targeting ASK1 and JNKs, the comprehensive strategy can serve as a universal method to guide in illuminating the mechanism of the prescription of traditional Chinese medicine by identifying the pathways or targets.

Lectin isolated from Bothrops jararacussu venom induces IL-10 release by TCD4+ cells and TNF-α release by monocytes and natural killer cells

BjcuL is a C-type lectin isolated from Bothrops jararacussu snake venom with specificity for binding β-d-galactose units. BjcuL is not toxic to human peripheral blood mononuclear cells (PBMCs), but it inhibits PBMC proliferation and stimulates these cells to produce superoxide anions and hydrogen peroxide primarily via lymphocyte stimulation; it does not stimulate the production of nitric oxide and PGE₂ . The purpose of this study was to investigate the effect of BjcuL on PBMC activation with a focus on cytokine release modulating PBMC proliferation. The results showed for the first time that BjcuL coupled to FITC interacted with monocytes, B cells, natural killer (NK) cells, and with subpopulations of T cells. These cell-cell interactions can lead to cell activation and inflammatory cytokines release, such as IL-6 and TNF-α, as well as the anti-inflammatory cytokine IL-10. In addition, TNF-α release was attributed to NK cells and monocytes, whereas IL-10 was attributed to TCD4⁺ and Treg cells when stimulated by BjcuL. The temporal cytokines profile produced by cells when stimulated with this lectin allows us to assert that BjcuL has immunomodulatory activity in this context.

CD25 and Protein Phosphatase 2A Cooperate to Enhance IL-2R Signaling in Human Regulatory T Cells

Low-dose IL-2 therapy is a direct approach to boost regulatory T cells (Tregs) and promote immune tolerance in autoimmune patients. However, the mechanisms responsible for selective response of Tregs to low-dose IL-2 is not fully understood. In this study we directly assessed the contribution of CD25 and protein phosphatase 2A (PP2A) in promoting IL-2R signaling in Tregs. IL-2-induced tyrosine phosphorylation of STAT5 (pSTAT5) was proportional to CD25 levels on human CD4⁺ T cells and YT human NK cell line, directly demonstrating that CD25 promotes IL-2R signaling. Overexpression of the PP2A catalytic subunit (PP2Ac) by lentiviral transduction in human Tregs increased the level of IL-2R subunits and promoted tyrosine phosphorylation of Jak3 and STAT5. Interestingly, increased expression of CD25 only partially accounted for this enhanced activation of pSTAT5, indicating that PP2A promotes IL-2R signaling through multiple mechanisms. Consistent with these findings, knockdown of PP2Ac in human Tregs and impaired PP2Ac activity in mouse Tregs significantly reduced IL-2-dependent STAT5 activation. In contrast, overexpression or knockdown of PP2Ac in human T effector cells did not affect IL-2-dependent pSTAT5 activation. Overexpression of PP2Ac in human Tregs also increased the expressions of proteins related to survival, activation, and immunosuppressive function, and upregulated several IL-2-regulated genes. Collectively, these findings suggest that CD25 and PP2A cooperatively enhance the responsiveness of Tregs to IL-2, which provide potential therapeutic targets for low-dose IL-2 therapy.

Influence of traditionally used Nepalese plants on wound healing and immunological properties using primary human cells in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

The improvement of wound healing has always been an important issue for both ethnopharmacological and modern medical research. In this study, we used state-of-the-art methods to investigate extracts of plants used traditionally in Nepal for more than 1000 years to treat inflammatory injuries.

AIM OF THE STUDY

We focused on the potential of the plant extracts to ameliorate wound healing and to influence immune modulatory properties.

MATERIALS AND METHODS

Nine Nepalese plant extracts in three different solvents (methanol, ethyl acetate, petroleum ether) were immunologically characterised. Water-soluble tetrazolium (WST-1) assays and scratch assays were performed to determine their impact on viability and wound healing capacity of human keratinocytes and fibroblasts. Effects on proliferation, viability and function of physiologically relevant anti-CD3 and anti-CD28 stimulated primary human T lymphocytes were assessed using carboxyfluorescein succinimidyl ester (CFSE), annexin V/propidium iodide staining assays and flow cytometry-based surface receptor characterisation. The secretion level of interleukin-2 (IL-2) was analysed with the ELISA technique. Dendritic cells were generated out of peripheral blood mononuclear cells (PBMC) by CD14⁺ magnetic bead selection. Flow cytometry-based surface receptor characterisation and ELISA-based technique were used to evaluate the DC activation state and the interleukin-8 (IL-8) secretion level.

RESULTS

We demonstrate that an ethyl acetate extract of Bassia longifolia and of Gmelina arborea have anti-inflammatory capacities, indicated by reduced proliferation, inhibition of IL-2 secretion and degranulation capacity of activated human T cells, when compared with adequate concentrations of synthetic positive drug controls. Furthermore, Gmelina arborea improved the wound healing of keratinocytes and fibroblasts and has tendency to increase the secretion of IL-8 by human primary dendritic cells.

CONCLUSION

With this preliminary screening, we offer a scientific basis for the immunomodulatory properties of the two Nepalese medicinal plants Bassia longifolia and Gmelina arborea. However, further detailed studies regarding the responsible compounds are necessary.

New therapeutic strategies based on IL-2 to modulate Treg cells for autoimmune diseases

Interleukin-2 (IL-2) is a multifunctional cytokine in immune regulation. It is essential for the differentiation, expansion and stability of CD25⁺Foxp3⁺ regulatory T (Treg) cells, which is an important factor in immune suppression and self-tolerance. Meanwhile, IL-2 also stimulate effector T (Teff) cells to promote immune responses. The opposite and diverse function of IL-2 impedes its application to boost Treg cell populations in autoimmune disease treatment. Thus, it became focus of the research to modulate IL-2 activities to enhance Treg cell functions selectively. Based on the characteristic properties of Treg cells such as constitutively expression of high affinity IL-2 receptors (IL-2Rs), multiple approaches, including IL-2/mAb complexes, IL-2 muteins and low-dose of IL-2 have emerged in recent years to selectively target Treg cells and treat autoimmunity. These therapeutic approaches have achieved favorable results in both clinical trials and experimental animal models, and provided engineering blueprints to develop novel strategies of IL-2 treatments for autoimmune diseases.

Treg cells in autoimmunity: from identification to Treg-based therapies

Regulatory (Treg) cells are key regulators of inflammation and important for immune tolerance and homeostasis. A major progress has been made in the identification and classification of Treg cells. Due to technological advances, we have gained deep insights in the epigenetic regulation of Treg cells. The use of fate reporter mice allowed addressing the functional consequences of loss of Foxp3 expression. Depending on the environment Treg cells gain effector functions upon loss of Foxp3 expression. However, the traditional view that Treg cells become necessarily pathogenic by gaining effector functions was challenged by recent findings and supports the notion of Treg cell lineage plasticity. Treg cell stability is also a major issue for Treg cell therapies. Clinical trials are designed to use polyclonal Treg cells as therapeutic tools. Here, we summarize the role of Treg cells in selected autoimmune diseases and recent advances in the field of Treg targeted therapies.