Severe influenza remains unusual in its virulence for humans. Complications or ultimately death arising from these infections are often associated with hyperinduction of proinflammatory cytokine production, which is also known as ＇cytokine storm＇. For this disease, it has been proposed that immunomodulatory therapy may improve the outcome, with or without the combination of antiviral agents. Here, we review the current literature on how various effectors of the immune system initiate the cytokine storm and exacerbate pathological damage in hosts. We also review some of the current immunomodulatory strategies for the treatment of cytokine storms in severe influenza, including corticosteroids, peroxisome proliferator-activated receptor agonists, sphingosine-l-phosphate receptor 1 agonists, cyclooxygenase-2 inhibitors, antioxidants, anti-tumour-necrosis factor therapy, intravenous immunoglobulin therapy, statins, arbidol, herbs, and other potential therapeutic strategies.
Allergen-specific immunotherapy has been proposed as an attractive strategy to actively treat food allergy using the following three different immunotherapy routes: oral (OIT), sublingual (SLIT) and epicutaneous (EPIT) immunotherapy. Regulatory T cells (Tregs) have been shown to have a pivotal role in the mechanisms of immunotherapy. The aim of this study was to compare the phenotype and function of Tregs induced in peanut-sensitized BALB/c mice using these three routes of treatment. We show that although EPIT, OIT and SLIT were all able to effectively desensitize peanutsensitized mice, they induced different subsets of Tregs. Foxp3+ Tregs were induced by the three treatment routes but with greater numbers induced by EPIT. EPIT and OIT also increased the level of LAP+ Tregs, whereas SLIT induced IL-10+ cells. The suppressive activity of EPIT-induced Tregs did not depend on IL-10 but required CTLA-4, whereas OIT acted through both mechanisms and SLIT was strictly dependent on IL-10. Moreover, the three routes influenced the homing properties of induced Tregs differently, with a larger repertoire of chemokine receptors expressed by EPIT-induced Tregs compared with OIT- and SLIT-induced cells, resulting in different protective consequences against allergen exposure. Furthermore, whereas OIT-or SLIT-induced Tregs lost their suppressive activities after treatment was discontinued, the suppressive activities of EPIT-induced Tregs were still effective 8 weeks after the end of treatment, suggesting the induction of a more long-lasting tolerance. In summary, EPIT, OIT and SLIT mediated desensitization through the induction of different subsets of Tregs, leading to important differences in the subsequent protection against allergen exposure and the possible induction of tolerance.
MicroRNAs （miRNAs） are a series of conserved, short, non-coding RNAs that modulate gene expression in a posttranscriptional manner, miRNAs are involved in almost every physiological and pathological process. Type 1 diabetes （TID） is an autoimmune disease that is the result of selective destruction of pancreatic p-cells driven by the immune system, miRNAs are also important participants in TID pathogenesis. Herein, we review the most recent data on the potential involvement of miRNAs in TID. Specifically, we focus on two aspects： the roles of miRNAs in maintaining immune homeostasis and regulating β-cell survival and/or functions in TID. We also discuss circulating miRNAs as potent biomarkers for the diagnosis and prediction of TID and investigate potential therapeutic approaches for this disease.
Currently, display-based methods are well established and widely used in antibody engineering for affinity maturation and structural stability improvement. We obtained a novel anti-human programmed death 1 (PD-1) antibody using computer-aided design and a mammalian cell display technology platform. We used computer-aided modeling and distance geometry methods to predict and assign the key residues that contributed to the binding of human PD-L1 to PD-1. Then, we analyzed the sequence of nivolumab (an anti-human PD-1 antibody, referred to as MIL75 in the article) to determine the template for antibody design and library construction. We identified a series of potential substitutions on the obtained template and constructed a virtual epitope-targeted antibody library based on the physicochemical properties and each possible location of the assigned key residues. The virtual antibody libraries were displayed on the surface of mammalian cells as the antigen-binding fragments of full-length immunoglobulin G. Then, we used flow cytometry and sequencing approaches to sort and screen the candidates. Finally, we obtained a novel anti-human PD-1 antibody named FV78. FV78 competitively recognized the PD-1 epitopes that interacted with MIL75 and possessed an affinity comparable to MIL75. Our results implied that FV78 possessed equivalent bioactivity in vitro and in vivo compared with MIL75, which highlighted the probability and prospect of FV78 becoming a new potential antibody therapy.
We investigated the effects of bone marrow-derived mesenchymal stem cells （MSCs） transplantation on the recovery of neurological functions in rat＇s MCAO （middle cerebral artery occlusion） model and its mechanism. MSCs were isolated from bone marrow of male Sprague Dawley （SD） rats. Female adult SD rats were randomly assigned into 4 groups： sham-operated group, MCAO group, vehicle group and MCAO ＋ MSCs-treated group. MSCs were injected into the lateral ventricle of rats in the MSCs-treated group and the same volume of PBS was given to the vehicle group. The expressions of IL-10 and TNF-α were assayed by RT-PCR and ELISA detections at day 1 and 4 after MCAO. The infarction volume was measured by TTC-staining. All rats underwent behavioral tests before, as well as 1, 4, and 14 days after MCAO. MSCs significantly improved functional recovery compared with the control at day 14 after transplantation. Compared with the MCAO group and the vehicle group, the expression of IL-10 mRNA and its protein level in the MSCs group significantly upregulated. However, the expression of TNF-α at day 4 after MCAO in the MSCs group significantly decreased compared with that of the MCAO group and the vehicle group. As a result, transplantation with MSCs significantly decreased infarct volume at day 1 and 4. This study strongly suggested transplantation with MSCs could reduce neuronal injury post focal cerebral ischemia in rats partly by regulating the expressions of IL-10 and TNF-α in the brain.
Epigallocatechin-3-gallate (EGCG), a bioactive component of green tea, has been reported to exert anti-inflammatory effects on immune cells. EGCG is also shown to activate the metabolic regulator, adenosine 5'-monophosphate-activated protein kinase (AMPK). Reports have also indicated that EGCG inhibits the immune-stimulated phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway. The PI3K/Akt/mTOR pathway has been implicated in mesangial cell activation in lupus. Mesangial cells from MRL/lpr lupus-like mice are hyper-responsive to immune stimulation and overproduce nitric oxide (NO) and other inflammatory mediators when stimulated. In our current studies, we sought to determine the mechanism by which EGCG attenuates immune-induced expression of pro-inflammatory mediators. Cultured mesangial cells from MRL/lpr mice were pre-treated with various concentrations of EGCG and stimulated with lipopolysaccharide (LPS)/interferon (IFN)-gamma. EGCG activated AMPK and blocked LPS/IFN-gamma-induced inflammatory mediator production (iNOS expression, supernatant NO and interleukin-6). Interestingly, EGCG attenuated inflammation during AMPK inhibition indicating that the anti-inflammatory effect of EGCG may be partially independent of AMPK activation. Furthermore, we found that EGCG effectively inhibited the immune-stimulated PI3K/Akt/mTOR pathway independently of AMPK, by decreasing phosphorylation of Akt, suggesting an alternate mechanism for EGCG-mediated anti-inflammatory action in mesangial cells. Taken together, these studies show that EGCG attenuated inflammation in MRL/lpr mouse mesangial cells via the PI3K/Akt/mTOR pathway. Our findings suggest a potential therapeutic role for the use of EGCG to regulate inflammation and control autoimmune disease. Cellular & Molecular Immunology(2010) 7, 123-132; doi:10.1038/cmi.2010.1; published online 8 February 2010
Follicular helper T cells （Tfh） have been referred as a lineage that provides a help for B cells to proliferate and undergo antibody affinity maturation in the germinal center. Evidence has supported that Tfh subset development, like other lineages, is dependent on microenvironment where a particular transcriptional program is initiated. It has been shown that Bcl-6 and IL-21 act as master regulators for the development and function of Tfh cells. Tfh dysregulation is involved in the development of autoimmune pathologies, such as systemic lupus erythematosus, rheumatoid arthritis and other autoimmune diseases. The present review highlights the recent advances in the field of Tfh cells and focus on their development and function.
The initial inflammatory phase of bone fracture healing represents a critical step for the outcome of the healing process. However, both the mechanisms initiating this inflammatory phase and the function of immune cells present at the fracture site are poorly understood. In order to study the early events within a fracture hematoma, we established an in vitro fracture hematoma model： we cultured hematomas forming during an osteotomy （artificial bone fracture） of the femur during total hip arthroplasty （THA） in vitro under bioenergetically controlled conditions. This model allowed us to monitor immune cell populations, cell survival and cytokine expression during the early phase following a fracture. Moreover, this model enabled us to change the bioenergetical conditions in order to mimic the in vivo situation, which is assumed to be characterized by hypoxia and restricted amounts of nutrients. Using this model, we found that immune cells adapt to hypoxia via the expression of angiogenic factors, chemoattractants and pro-inflammatory molecules. In addition, combined restriction of oxygen and nutrient supply enhanced the selective survival of lymphocytes in comparison with that of myeloid derived cells （i.e., neutrophils）. Of note, non-restricted bioenergetical conditions did not show any similar effects regarding cytokine expression and/or different survival rates of immune cell subsets. In conclusion, we found that the bioenergetical conditions are among the crucial factors inducing the initial inflammatory phase of fracture healing and are thus a critical step for influencing survival and function of immune cells in the early fracture hematoma.
Deletion of HAX1 in mice causes a severe reduction in the numbers of lymphocytes in the bone marrow and in the spleen. Additionally, B220＋ B progenitor cells in the bone marrow are reduced, suggesting an important function of HAX1 in B cell development. HAX1 is thought to play a protective role in apoptotic processes; therefore, we investigated the role of HAX1 in bone marrow B progenitor cells and splenic B cells. We did not observe an effect on the survival of Hax1-/- bone marrow cells but detected enhanced survival of splenic Hax1-/- B cells upon in vitro starvation/ growth-factor withdrawal. To explain this apparent inconsistency with previous reports of HAX1 function, we also studied the B cell receptor （BCR）-induced apoptosis of IgM-stimulated splenic naive B cells and found that apoptosis decreased in these cells. We further found impaired internalization of the BCR from Hax1-/- splenic B cells after IgM crosslinking; this impaired internalization may result in decreased BCR signaling and, consequently, decreased BCR-mediated apoptosis. We measured HAX1 binding to the cytoplasmic domains of different Ig subtypes and identified KVKWI（V）F as the putative binding motif for HAX1 within the cytoplasmic domains. Because this motif can be found in almost all Ig subtypes, it is likely that HAX1 plays a general role in BCR-mediated internalization events and BCR-mediated apoptosis.
microRNAs are a novel group of small, conserved, non-coding RNA molecules that are present in all species. These molecules post-transcriptionally regulate gene expression by targeting mRNAs for degradation or by repressing the translation of the mRNAs. A good understanding of miRNA-mediated gene regulation is critical to gain a comprehensive view of many physiological processes and disease states. Emerging evidence demonstrates that miRNAs play an important role in the differentiation and function of the adaptive immune system. This review provides an overview of the diverse functions of miRNAs in modulating immune responses and in immune cell development, particularly the development of Th17 cells, and explores the involvement of miRNAs in several autoimmune diseases including multiple sclerosis ( MS), rheumatoid arthritis ( RA), inflammatory bowel disease (IBD) and diabetes. Cellular & Molecular Immunology (2010) 7, 175-181; doi:10.1038/cmi.2010.19; published online 5 April 2010
Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease for which an autoimmune pathogenesis is supported by clinical and experimental data, including the presence of autoantibodies and autoreactive T cells. The etiology remains to be determined, yet data suggest that both a susceptible genetic background and unknown environmental factors determine disease onset. Multiple infectious and chemical candidates have been proposed to trigger the disease in a genetically susceptible host, mostly by molecular mimicry. Most recently, several murine models have been reported, including genetically determined models as well as models induced by immunization with xenobiotics and bacteria. Cellular & Molecular Immunology (2010) 7, 1-10; doi:10.1038/cmi.2009.104; published online 23 December 2009
Hepatitis B immunoglobulin （HBIG） is important in the management of hepatitis B virus （HBV） infection. Aiming to develop recombinant monoclona# antibodies as an alternative to HBIG, we report the successful identification of HBV surface antigen （HBsAg）-specific antibodies from a full-length human antibody library displayed on mammalian cell surface. Using total RNA of peripheral blood mononuclear cells of a natively immunized donor as template, the antibody repertoire was amplified. Combining four-way ligation and the FIp recombinase-mediated integration （FIp-ln） system, we constructed a mammalian cell-based, fully human, full-length antibody display library in which each cell displayed only one kind of antibody molecule. By screening the cell library using fluorescence-activated cell sorting （FACS）, eight cell clones that displayed HBsAg-specific antibodies on cell surfaces were identified. DNA sequence analysis of the antibody genes revealed three unique antibodies. FACS data indicated that fluorescent strength of expression （FSE）, fluorescent strength of binding （FSB） and relative binding ability （RBA） were all different among them. These results demonstrated that by using our antibody mammalian display and screening platform, we can successfully identify antigen-specific antibodies from an immunized full-length antibody library. Therefore, this platform is very useful for the development of therapeutic antibodies.
Immunoglobulins （Igs） are known to be synthesized and secreted only by B lymphocytes. Class switch recombination （CSR） is a key event that enables B cells to express Igs, and one of the crucial steps for CSR initiation is the germline transcription of Iggenes. Surprisingly, recent studies have demonstrated that the Iggenes are also expressed in some epithelial cancer cells; however, the mechanisms underlying how cancer cells initiate CSR and express Igs are still unknown. In this study, we confirmed that the Ig la I promoter in cancer cell lines was activated by the Ets- 1 transcription factor, and the activity of the Ig la I promoter and ig lal-C~l germiine transcription were attenuated after knockdown of Ets-1 by specific small interfering RNAs （siRNA）. Furthermore, the expression of Ets-1 and Iga heavy chain in cancer cells was dose dependently upregulated by TGF-I~I. These results indicate that activation of the Ig lal promoter by the transcriotion factor Ets-1 is a critical Dathwav and orovides a novel mechanism for le exoression in non-B cell cancers.
SOCS1 is a key regulator of cytokine signaling and is important for maintaining balance in the immune system. It is thought to participate in negative feedback loops in cytokine signaling and may be an important signal for the regulation of dendritic cell (DC) maturation. However, it remains unclear whether DCs transduced with SOCS1 exhibit characteristics of regulatory DCs and induce allogeneic T-cell hyporesponsiveness. In this study, we constructed adenoviral vector coding SOCS1 (Ad-SOCS1) that can efficiently increase SOCS1 gene expression in bone marrow-derived dendritic cells. DCs transduced with Ad-SOCS1 (DC-SOCS1) expressed low levels of costimulatory and MHC molecules, were resistant to maturation and activation stimulation, induced allogeneic T-cell hyporesponsiveness, and promoted the generation of regulatory-like T cells in vitro. DC-SOCS1 pretreatment significantly prolonged the survival of allografts and led to a substantial increase in the generation of regulatory T cells. Our data suggest that SOCS1 inhibits DC maturation and induces regulatory DC generation, therefore possessing therapeutic potential to prevent rejection in organ transplantation. Cellular & Molecular Immunology. 2009;6(2):87-95.
Anterior gradient-2 （AGR2） promotes tumor growth, cell migration and cellular transformation and its enhanced expression is almost completely restricted to malignant tissues, thus making AGR2 an interesting target for the development of immunotherapeutic strategies. We investigated whether the AGR2 molecule comprises human leukocyte antigen （HLA）-A 0201-binding epitopes recognized by human cytotoxic T lymphocytes （CTLs）, which could be targeted in dendritic cell （DC）-based cancer immunotherapy against colorectal cancer （CRC）. We reviewed the sequence of AGR2 for peptides that could potentially bind to HLA-A 0201 with the aid of a computer-based program. Five candidate peptides with different binding scores were synthesized and tested. These peptides were then assessed for their immunogenicity to elicit specific immune responses mediated by CTLs in vitro by means of enzyme-linked immunospot assays and CTL assays. AGR2 was highly expressed in several CRC cell lines, including DK01, DLD1, KM 12C, HCT-8 and HT-29. DCs pulsed with AGR2-P2 （aa 11-19; LLVALSYTL） or AGR2-P4 （aa 127-135; RIMFVDPSL） generated potent CTLs that could lyse T2 cells pulsed with AGR2-P2 or AGR2-P4 and HLA-A0201＋ AGR2-positive CRC cell lines in a strong dose-dependent and HLA-A 0201-restricted manner. In conclusion, these novel epitopes derived from AGR2 protein may be attractive candidates for DC-based immunotherapy for CRC.
MiR-122 is one of the non-coding RNAs which showed its effects on the lipo-metablism, virus infection and HCC forming through regulation of liver gene expression. Its eukaryotic expression vector was constructed by using pSuper which was widely applied in the siRNA expression. The precursor of human miR-122 gene was amplified by polymerase chain reaction （PCR） from the human genomic DNA. The positive clones were screened by PCR and restriction enzyme digestion. The new expression vector of miR-122 was named pHsa-m122. PHsa-m122 and its controls were transfected to HepG2 cells. The miR-122 expression activity was evaluated by GFP122i sensor reporter plasmid through fluorescence detection and Western blot. It was shown that the fluorescence intensity of GFP122si and pHsa-m122 co-transfection group was weaker than that of the controls, so the functional activity of expressed miR-122 was detected. When HepG2 cells were co-transfected with HBV1.3 and pHsa-m122 plasmids, the results showed miR-122 may down-regulate the gene expression of HBV. The human liver specific microRNA eukaryotic expression vector of miR-122 was constructed successfully, which may facilitate further study of its function in the development of liver virus infection diseases and HCC. Cellular ＆ Molecular Immunology.