CpG DNA: a pathogenic factor in systemic lupus erythematosus?

Locus-Specific Bisulfate NGS Sequencing of GSTP1, RNF219, and KIAA1539 Genes in the Total Pool of Cell-Free and Cell-Surface-Bound DNA in Prostate Cancer: A Novel Approach for Prostate Cancer Diagnostics

The locus-specific methylation of three genes (GSTP1, RNF219, and KIAA1539, also known as FAM214B) in the total pool of blood cell-free DNA, including cell-free DNA from plasma and cell-surface-bound DNA, of patients with prostate cancer and healthy donors was studied on the MiSeq platform. Our study found a higher methylation index of loci for total cell-free DNA compared with cell-free DNA. For total cell-free DNA, the methylation of GSTP1 in each of the 11 positions provided a complete separation of cancer patients from healthy donors, whereas for cell-free DNA, there were no positions in the three genes allowing for such separation. Among the prostate cancer patients, the minimum proportion of GSTP1 genes methylated in any of the 17 positions was 12.1% of the total circulated DNA fragments, and the minimum proportion of GSTP1 genes methylated in any of the 11 diagnostically specific positions was 8.4%. Total cell-free DNA was shown to be more convenient and informative as a source of methylated DNA molecules circulating in the blood than cell-free DNA.

The Immunomodulatory Functions of Various CpG Oligodeoxynucleotideson CEF Cells and H9N2 Subtype Avian Influenza Virus Vaccination

CpG oligodeoxynucleotides (CpG ODN) present adjuvant activities for antigen proteins, which can induce humoral and cellular immune responses to antigens. However, the immunomodulatory functions of CpG ODNs with different sequences are very different. In this paper, six CpG ODNs with different sequences were designed based on CpG2007 as a template. Through the screening of CEF cells in vitro, the stimulating activity of CpG ODNs was determined. Then, two selected CpG ODN sequence backbones were modified by substituting the oxygen with sulfur (S-CpG) and verifying the immune activity. Next, to prove the feasibility of S-CpG as an immune potentiator, two immune models with or without white oil adjuvant were prepared in 20-day-old chicken vaccinations. The screening experiment in vitro showed that the inducing roles of CpG ODN 4 and 5 could strongly stimulate various immune-related molecular expressions. Additionally, CpG ODN 4 and 5 with sulfation modification significantly induced various cytokines’ expressions. Furthermore, CpG ODN 4 and 5 induced the strongly humoral and cellular immune responses during vaccination, in which white oil, as an adjuvant, could significantly improve the immune effect of CpG ODN. These results provide an important experimental basis for exploring the structural characteristics and vaccine immunity of CpG ODN.

Approaches of the Innate Immune System to Ameliorate Adaptive Immunotherapy for B-Cell Non-Hodgkin Lymphoma in Their Microenvironment

A dominant paradigm being developed in immunotherapy for hematologic malignancies is of adaptive immunotherapy that involves chimeric antigen receptor (CAR) T cells and bispecific T-cell engagers. CAR T-cell therapy has yielded results that surpass those of the existing salvage immunochemotherapy for patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) after first-line immunochemotherapy, while offering a therapeutic option for patients with follicular lymphoma (FL) and mantle cell lymphoma (MCL). However, the role of the innate immune system has been shown to prolong CAR T-cell persistence. Cluster of differentiation (CD) 47-blocking antibodies, which are a promising therapeutic armamentarium for DLBCL, are novel innate immune checkpoint inhibitors that allow macrophages to phagocytose tumor cells. Intratumoral Toll-like receptor 9 agonist CpG oligodeoxynucleotide plays a pivotal role in FL, and vaccination may be required in MCL. Additionally, local stimulator of interferon gene agonists, which induce a systemic anti-lymphoma CD8⁺ T-cell response, and the costimulatory molecule 4-1BB/CD137 or OX40/CD134 agonistic antibodies represent attractive agents for dendritic cell activations, which subsequently, facilitates initiation of productive T-cell priming and NK cells. This review describes the exploitation of approaches that trigger innate immune activation for adaptive immune cells to operate maximally in the tumor microenvironment of these lymphomas.

Morbid Sequences Suggest Molecular Mimicry between Microbial Peptides and Self-Antigens: A Possibility of Inciting Autoimmunity

Understanding etiology of autoimmune diseases has been a great challenge for designing drugs and vaccines. The pathophysiology of many autoimmune diseases may be attributed to molecular mimicry provoked by microbes. Molecular mimicry hypothesizes that a sequence homology between foreign and self-peptides leads to cross-activation of autoreactive T cells. Different microbial proteins are implicated in various autoimmune diseases, including multiple sclerosis, human type 1 diabetes, primary biliary cirrhosis and rheumatoid arthritis. It may be imperative to identify the microbial epitopes that initiate the activation of autoreactive T cells. Consequently, in the present study, we employed immunoinformatics tools to delineate homologous antigenic regions between microbes and human proteins at not only the sequence level but at the structural level too. Interestingly, many cross-reactive MHC class II binding epitopes were detected from an array of microbes. Further, these peptides possess a potential to skew immune response toward Th1-like patterns. The present study divulges many microbial target proteins, their putative MHC-binding epitopes, and predicted structures to establish the fact that both sequence and structure are two important aspects for understanding the relationship between molecular mimicry and autoimmune diseases. Such findings may enable us in designing potential immunotherapies to tolerize autoreactive T cells.

Associations between PTPN22 and TLR9 polymorphisms and systemic lupus erythematosus: a comprehensive meta-analysis

Previous studies have explored the relationship of PTPN22 and TLR9 polymorphisms with systemic lupus erythematosus (SLE). In consideration of the population stratification, conflicting results and updating data, we conducted a comprehensive meta-analysis, which consists of a total of 17 research articles (9120 cases and 11,724 controls) for PTPN22 and 20 articles (including up to 2808 cases and 3386 controls) for TLR9. Significant association was verified between PTPN22 rs2476601 and SLE in the overall population (OR = 1.511 per T allele, 95% CI 1.338-1.706, P = 2.931 × 10^-11) and under dominant model of T allele (TT+CT vs. CC: OR = 1.531, 95% CI 1.346-1.742, P = 9.17 × 10^-11). Analysis after stratification by ethnicity indicated that PTPN22 rs2476601 was related to SLE in Americans (OR = 2.566, 95% CI 1.796-3.665, P = 2.219 × 10^-7), Europeans (OR = 1.399, 95% CI 1.261-1.552, P = 2.153 × 10^-10), and Africans (OR = 4.14, 95% CI 1.753-9.775, P = 1.0 × 10^-3). We did not observe any association between TLR9 polymorphisms (rs187084, rs352140, rs5743836 and rs352139) and SLE under any model, after excluding the data that were inconsistent with Hardy-Weinberg equilibrium (HWE). In summary, PTPN22 rs2476601 was significantly interrelated with SLE and contributed to susceptibility and development of SLE in Americans, Europeans and Africans in this analysis, while their relationship needs to be validated in Africans by future research.

Epigenomics of autoimmune diseases

Autoimmune diseases are complex disorders of largely unknown etiology. Genetic studies have identified a limited number of causal genes from a marginal number of individuals, and demonstrated a high degree of discordance in monozygotic twins. Studies have begun to reveal epigenetic contributions to these diseases, primarily through the study of DNA methylation, but chromatin and non-coding RNA changes are also emerging. Moving forward an integrative analysis of genomic, transcriptomic and epigenomic data, with the latter two coming from specific cell types, will provide an understanding that has been missed from genetics alone. We provide an overview of the current state of the field and vision for deriving the epigenomics of autoimmunity.

Epigenetics and autoimmune diseases: the X chromosome-nucleolus nexus

Autoimmune diseases occur more often in females, suggesting a key role for the X chromosome. X chromosome inactivation, a major epigenetic feature in female cells that provides dosage compensation of X-linked genes to avoid overexpression, presents special vulnerabilities that can contribute to the disease process. Disruption of X inactivation can result in loss of dosage compensation with expression from previously sequestered genes, imbalance of gene products, and altered endogenous material out of normal epigenetic context. In addition, the human X has significant differences compared to other species and these differences can contribute to the frequency and intensity of the autoimmune disease in humans as well as the types of autoantigens encountered. Here a link is demonstrated between autoimmune diseases, such as systemic lupus erythematosus, and the X chromosome by discussing cases in which typically non-autoimmune disorders complicated with X chromosome abnormalities also present lupus-like symptoms. The discussion is then extended to the reported spatial and temporal associations of the inactive X chromosome with the nucleolus. When frequent episodes of cellular stress occur, the inactive X chromosome may be disrupted and inadvertently become involved in the nucleolar stress response. Development of autoantigens, many of which are at least transiently components of the nucleolus, is then described. Polyamines, which aid in nucleoprotein complex assembly in the nucleolus, increase further during cell stress, and appear to have an important role in the autoimmune disease process. Autoantigenic endogenous material can potentially be stabilized by polyamines. This presents a new paradigm for autoimmune diseases: that many are antigen-driven and the autoantigens originate from altered endogenous material due to episodes of cellular stress that disrupt epigenetic control. This suggests that epigenetics and the X chromosome are important aspects of autoimmune diseases.

The innate immune system in Alzheimer's disease

Alzheimer's disease (AD) is the leading cause for dementia in the world. It is characterized by two biochemically distinct types of protein aggregates: amyloid β (A β ) peptide in the forms of parenchymal amyloid plaques and congophilic amyloid angiopathy (CAA) and aggregated tau protein in the form of intraneuronal neurofibrillary tangles (NFT). Several risk factors have been discovered that are associated with AD. The most well-known genetic risk factor for late-onset AD is apolipoprotein E4 (ApoE4) (Potter and Wisniewski (2012), and Verghese et al. (2011)). Recently, it has been reported by two groups independently that a rare functional variant (R47H) of TREM2 is associated with the late-onset risk of AD. TREM2 is expressed on myeloid cells including microglia, macrophages, and dendritic cells, as well as osteoclasts. Microglia are a major part of the innate immune system in the CNS and are also involved in stimulating adaptive immunity. Microglia express several Toll-like receptors (TLRs) and are the resident macrophages of the central nervous system (CNS). In this review, we will focus on the recent advances regarding the role of TREM2, as well as the effects of TLRs 4 and 9 on AD.

Increased polyamines alter chromatin and stabilize autoantigens in autoimmune diseases

Polyamines are small cations with unique combinations of charge and length that give them many putative interactions in cells. Polyamines are essential since they are involved in replication, transcription, translation, and stabilization of macro-molecular complexes. However, polyamine synthesis competes with cellular methylation for S-adenosylmethionine, the methyl donor. Also, polyamine degradation can generate reactive molecules like acrolein. Therefore, polyamine levels are tightly controlled. This control may be compromised in autoimmune diseases since elevated polyamine levels are seen in autoimmune diseases. Here a hypothesis is presented explaining how polyamines can stabilize autoantigens. In addition, the hypothesis explains how polyamines can inappropriately activate enzymes involved in NETosis, a process in which chromatin is modified and extruded from cells as extracellular traps that bind pathogens during an immune response. This polyamine-induced enzymatic activity can lead to an increase in NETosis resulting in release of autoantigenic material and tissue damage.

Down-regulation of ATP-binding cassette transporter G1 expression by unmethylated CpG oligodeoxynucleotides in RAW 264.7 macrophages

We have investigated the effect of various forms of phosphodiester cytidine-phosphate-guanosine oligodeoxynucleotides (CpG ODNs) on the production of pro-inflammatory cytokines and related genes in RAW 264.7 macrophages. Treatment with the CpG ODNs increased the expression of tumor necrosis factor α (TNF-α), IL-6, and inducible nitric oxide synthase but not interleukin-1β (IL-1β). We also investigated the effect of CpG ODNs on the expression of ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) genes which are known to facilitate cholesterol efflux from macrophages for anti-atherosclerosis. CpG 2006 significantly reduced the levels of ABCG1 mRNA as determined by real-time polymerase chain reaction, whereas ABCA1 mRNA level was not changed. Western blot analysis further confirmed the reduction of ABCG1 protein expression by CpG 2006. In addition, we also determined the protein level of peroxisome proliferator activated receptor γ (PPARγ), which is recognized as a transcriptional activator of ABC transporters, was also reduced by CpG 2006. Thus, these results suggest that ABCG1 is specifically down-regulated by CpG 2006 in a PPARγ-dependent manner in macrophages.

Control of poultry coccidiosis: changing trends

Coccidiosis is the most important protozoan disease affecting the poultry industry worldwide. Control of poultry coccidiosis is presently based on managerial skills and the use of prophylactic coccidiostatic drugs. With the emergence of drug resistant Eimeria strains, emphasis has been laid on development and use of safer vaccines; some of them have been commercialized successfully. The present review deals with the various factors responsible for the development of clinical coccidiosis in poultry as well as an overview of the currently available inducers and boosters of immunity against coccidiosis. There are three groups of vaccines currently available against coccidiosis which can be distinguished on the basis of characteristics of the Eimeria species included in the respective products, viz. vaccines based on live virulent strains, vaccines based on live attenuated strains, and vaccines based on live strains that are relatively tolerant to the ionophore compounds. The latter vaccine combines the early chemotherapeutic effect of ionophores with the late prophylactic effect of vaccination. Although in the near future more varieties of oocyst based live vaccines are expected, identification of selective coccidian-specific immunoprotective molecules is likely to get more attention to facilitate the sustainable control of poultry coccidiosis.

CpG DNA as a vaccine adjuvant

Synthetic oligodeoxynucleotides (ODNs) containing unmethylated CpG motifs trigger cells that express Toll-like receptor 9 (including human plasmacytoid dendritic cells and B cells) to mount an innate immune response characterized by the production of Th1 and proinflammatory cytokines. When used as vaccine adjuvants, CpG ODNs improve the function of professional antigen-presenting cells and boost the generation of humoral and cellular vaccine-specific immune responses. These effects are optimized by maintaining ODNs and vaccine in close proximity. The adjuvant properties of CpG ODNs are observed when administered either systemically or mucosally, and persist in immunocompromised hosts. Preclinical studies indicate that CpG ODNs improve the activity of vaccines targeting infectious diseases and cancer. Clinical trials demonstrate that CpG ODNs have a good safety profile and increase the immunogenicity of coadministered vaccines.

5'-Phosphate oligodeoxynucleotides enhance the phosphodiester-CpG DNA-induced inflammatory response in macrophages

Dying cells release genomic DNA into the surroundings where the DNA is first degraded to oligodeoxynucleotides, then to nucleotides, nucleosides and so on. Given that the unmethylated CpG dinucleotide (CpG motif), which is characteristic of bacterial DNA, is also contained in mammalian DNA and has been reported to be involved in the exacerbation of DNA-associated autoimmune diseases, we investigated whether nucleotides and nucleosides affect immune responses to phosphodiester (PO)-CpG DNA. Addition of non-CpG DNA to RAW264.7, murine macrophage-like cells, induced no significant TNF-α production irrespective of treatment with DNase I; however, DNase I-treated, but not untreated, non-CpG DNA increased the PO-CpG DNA-mediated TNF-α production. This increase was not observed with phosphorothioate-CpG DNA or ligands for TLR3, TLR4 or TLR7. Deoxynucleotides with a 5'-phosphate showed similar effects to those of DNase I-treated non-CpG DNA, but DNase II-treated DNA or deoxynucleosides did not. Subcutaneous injection of PO-CpG DNA into the mouse footpad induced little swelling of the paw; however, significant swelling was observed when DNase I-treated DNA was co-injected with PO-CpG DNA. These results imply that PO-CpG DNA-dependent inflammatory responses are increased by DNA molecules with a 5'-phosphate; such molecules could therefore be considered as exacerbating factors for CpG motif-related inflammation.

Plasmacytoid dendritic cells regulate autoreactive B cell activation via soluble factors and in a cell-to-cell contact manner

Plasmacytoid dendritic cells (pDCs) are specialized type I IFN producers, which play an important role in pathogenesis of autoimmune disorders. Dysregulated autoreactive B cell activation is a hallmark in most autoimmune diseases. This study was undertaken to investigate interactions between pDCs and autoreactive B cells. After coculture of autoreactive B cells that recognize self-Ag small nuclear ribonucleoprotein particles with activated pDCs, we found that pDCs significantly enhance autoreactive B cell proliferation, autoantibody production, and survival in response to TLR and BCR stimulation. Neutralization of IFN-alpha/beta and IL-6 abrogated partially pDC-mediated enhancement of autoreactive B cell activation. Transwell studies demonstrated that pDCs could provide activation signals to autoreactive B cells via a cell-to-cell contact manner. The involvement of the ICAM-1-LFA-1 pathway was revealed as contributing to this effect. This in vitro enhancement effect was further demonstrated by an in vivo B cell adoptive transfer experiment, which showed that autoreactive B cell proliferation and activation were significantly decreased in MyD88-deficient mice compared with wild-type mice. These data suggest the dynamic interplay between pDCs and B cells is required for full activation of autoreactive B cells upon TLR or BCR stimulation.

Avoidance of radiotherapy-related, gastrointestinal complications in a patient with systemic lupus erythematosus: a case report and review of literature

Systemic lupus erythematosus (SLE) is associated with major gastrointestinal complications due to radiotherapy. A patient with active SLE and grade 4 nephropathy presented with inoperable advanced cancer of the cervix which proved to be contraindicated for chemotherapy. The patient was treated with intensity-modulated radiotherapy technique (IMRT). The patient, however, did not experience severe radiotherapy-related complications as expected with conventional techniques of radiotherapy. The tolerance of SLE patients to radiotherapy can thus be achieved by proper delivery of radiation and the sparing of normal tissues by IMRT although further confirmatory studies are required.

Immunostimulatory sequence oligdeoxynucleotide/cholera toxin B conjugate: a novel allergen-independent intranasal vaccine for allergic rhinitis

BACKGROUND

Recent studies have shown that by acting as strong TH1 response-inducing adjuvants, DNA immunostimulatory sequence oligdeoxynucleotides (ISS-ODNs) can be used in the treatment of allergic diseases, and efforts are being made to enhance these TH1 adjuvant actions.

OBJECTIVE

To determine whether intranasally delivered ISS-ODN/cholera toxin B (CTB) conjugate has enhanced antiallergic effects in an allergic rhinitis mouse model.

METHODS

BALB-c mice were sensitized with ovalbumin. Chemical conjugation of ISS-ODN and CTB was performed. After a single local intranasal administration of 50 microg of ISS-ODN or high- and low-dose (50- and 5-microg) ISS-ODN/CTB conjugate, we measured the allergic response in terms of sneezing events, eosinophil infiltration in the nasal mucosa, serum ovalbumin specific IgE and IgG2a levels, and TH1 and TH2 cytokine levels in nasal lavage fluid and spleen cell cultures.

RESULTS

A single local administration of 50 microg of ISS-ODN did not suppress the allergic phenotype. However, 50 and 5 microg of ISS-ODN/CTB conjugate significantly attenuated allergic symptoms, eosinophil infiltration in the nasal mucosa, and interleukin 4 production from nasal lavage fluid and cultured splenocyte supernatant compared with the allergic control. Serum specific IgG2a and interleukin 12 production in nasal lavage fluid and spleen cell cultures was significantly increased.

CONCLUSIONS

In a mouse model of allergic rhinitis, a single intranasal delivery of low-dose ISS-ODN/CTB conjugate effectively protects previously sensitized mice from allergic hypersensitivity responses. With further research, ISS-ODN/CTB conjugate may serve as a new allergen-independent intranasal vaccine for the treatment of allergic rhinitis.

CpG oligonucleotides as adjuvants for vaccines targeting infectious diseases

Synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG motifs act as immune adjuvants, accelerating and boosting antigen-specific immune responses. CpG motifs promote the induction of Th1 and pro-inflammatory cytokines and support the maturation/activation of professional antigen presenting cells (particularly plasmacytoid dendritic cells). These effects are optimized by maintaining close physical contact between the CpG ODN and the immunogen. Co-administering CpG ODN with a variety of vaccines has improved the resultant humoral and/or cellular immune responses, culminating in enhanced protective immunity in rodent and primate challenge models. Ongoing clinical studies indicate that CpG ODN are safe and well-tolerated when administered as adjuvants to humans, and that they can support increased vaccine-specific immune responses.

DNA vaccines against influenza viruses

As an attractive alternative to conventional vaccines, DNA vaccines play a critical role in inducing protection against several infectious diseases. In this review, we discuss the advantages that DNA vaccines offer in comparison to conventional protein-based vaccines. We discuss strategies to improve the potency and efficacy of DNA vaccines. Specifically, we focus on the potential use of DNA-based vaccines to elicit broad-spectrum humoral and cellular immunity against influenza virus. Finally, we discuss the advances made in the use of DNA vaccines to prevent avian H5N1 influenza.

Synthetic oligonucleotides as modulators of inflammation

Synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG motifs mimic the immunostimulatory activity of bacterial DNA. CpG ODN directly stimulate human B cells and plasmacytoid dendritic cells, promote the production of Th1 and proinflammatory cytokines, and trigger the maturation/activation of professional APC. CpG ODN are finding use in the treatment of cancer, allergy, and infection. In contrast, ODN containing multiple TTAGGG motifs mimic the immunosuppressive activity of self-DNA, down-regulating the production of proinflammatory and Th1 cytokines. Preclinical studies suggest that "suppressive" ODN may slow or prevent diseases characterized by pathologic immune stimulation, including autoimmunity and septic shock. Extensive studies in animal models suggest that the therapeutic value of CpG and TTAGGG ODN may be optimized by early administration.

Attenuated cytokine responses in porcine lymph node cells stimulated with CpG DNA are associated with low frequency of IFNalpha-producing cells and TLR9 mRNA expression

The immune stimulatory effects of synthetic CpG DNA, on porcine peripheral blood mononuclear cells (PBMC) have been reported, but little is known about CpG-induced responses in other lymphoid tissues of pigs. We investigated innate immune responses induced by CpG DNA in cells from blood, lymph nodes (LN) and spleens of pigs. Porcine PBMC and lymph node cells (LNC) were stimulated in vitro with three classes (A-, B- and C-class) of CpG oligodeoxynucleotides (ODNs), and a non-CpG control ODN. All three classes of CpG ODNs induced significant production of IFNalpha, TNFalpha, IL-1, IL-6 and IL-12 in PBMC. In contrast, in LNC, only IL-12 was stimulated by all three classes of CpG ODNs, while IFNalpha, and IL-6 were induced by A- and C-class ODNs. No TNFalpha was induced in LNC by any of the ODNs. Significant lymphocyte proliferation was induced in PBMC by all three classes of CpG ODNs and non-CpG control. However, in LNC, B- and C-class ODNs induced significant proliferation, while no proliferation was seen with A-class and non-CpG control ODN. All three classes of ODNs induced NK-like cytotoxicity in PBMC and spleen cells, but were less effective in inducing NK cytotoxicity in LNC. We then investigated the reasons for the relatively poor CpG-induced responses in LNC. Our investigations revealed that LNC had a lower frequency of IFNalpha-secreting cells and expressed low levels of TLR9 mRNA compared to PBMC. We conclude that the lower number of IFNalpha-secreting cells and receptor expression may contribute to the attenuated responses in LNC following stimulation with CpG ODN.

Immunostimulatory oligodeoxynucleotide containing TTTCGTTT motif from Lactobacillus rhamnosus GG DNA potentially suppresses OVA-specific IgE production in mice

In a previous study of the immunoregulatory properties of commensal bacterial DNA, we identified the strong immunostimulatory oligodeoxynucleotide (ISS-ODN) ID35 in the genomic DNA of Lactobacillus rhamnosus GG (LGG). The observed effects of ID35 are because of the unique TTTCGTTT motif located at the 5' end of the ODN, which is different from the previously identified ISS motifs in humans and mice. In the present study, we used an ovalbumin (OVA)-sensitized mouse model to show that ID35 is a potent suppressor of antigen-specific immunoglobulin E (IgE) production in vivo. This effect was toll-like receptor 9-dependent, as GpC negID35 failed to suppress antigen-specific IgE production. ID35 activated the specific subset of CD11c+CD8a+ dendritic cells, which are associated with T-helper 1 (Th1)-type systemic responses, and effectively induced interferon-gamma (IFN-gamma) production by CD4+ T cells in OVA-challenged mice. These immunoregulatory effects of ID35 were comparable with those induced by the murine prototype ODN 1826. Thus, ID35 is the first ISS-ODN with such a strong immunostimulatory and IgE suppressor activity to be found in immunobiotic bacterial DNA.

IRF3-dependent type I interferon response in B cells regulates CpG-mediated antibody production

Hypomethylated CpG oligonucleotides (CpG) are not only potent adjuvants for enhancing adaptive immune responses but may also play a critical role in the development of autoimmune diseases such as Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE). Here we provide evidence that, in addition to dendritic cells, murine B lymphocytes also exhibit a type I IFN response to CpG-B. Unlike dendritic cells, B cell-mediated type I IFN induction depended on the transcription factor IRF3, but similar to dendritic cells this pathway was independent of the IRF3 kinase TBK1. Utilizing type I IFN receptor-deficient mice, we were able to demonstrate that this IFN pathway enhanced Syndecan-1 expression and IgM production and was required for IgG2a production following CpG-B stimulation. Overall, our findings identify a unique IFN pathway in B cells that may play a central role in mediating B cell biology in response to CpG, potentially implicating this pathway in autoantibody production and the pathogenesis of certain autoimmune diseases.

Lymphoma immunotherapy with CpG oligodeoxynucleotides requires TLR9 either in the host or in the tumor itself

Established widely metastatic tumor was cured in a transplanted mouse B cell lymphoma model, by the combination of chemotherapy plus intratumoral injection of oligodeoxynucleotides containing unmethylated C-G motifs (CpG). This therapeutic effect required that the CpG be injected directly into the tumor and was dependent on CD8 T cells. Although the efficacy of CpG oligodeoxynucleotides has been thought to depend on the expression of TLR9, we unexpectedly found that tumor rejection did not require host expression of TLR9. By using a TLR9-deficient tumor and a TLR9KO host, we demonstrate that TLR9 expression either by the host or the tumor is required. These results indicate that activation of Ag presentation by cells within the tumor via TLR9 stimulation can be an effective form of immunotherapy. This study forms the basis of an ongoing clinical trial in patients with lymphoma.

Synthetic CpG oligodeoxynucleotides augment BAFF- and APRIL-mediated immunoglobulin secretion

The B lymphocyte-activating factor belonging to TNF superfamily (BAFF) acts on B lymphocytes through BAFF receptor (BAFF-R), the transmembrane activator, calcium modulator, and cyclophilin ligand interactor (TACI), and the B cell maturation antigen (BCMA). Another cytokine, a proliferation-inducing ligand (APRIL), only binds to TACI and BCMA. In this study, we sought to determine the effect of Toll-like receptor agonists (TLR-A) on the expression of BAFF/APRIL receptors by murine splenic B lymphocytes. CpG oligodeoxynucleotides (ODN) and LPS strongly up-regulated TACI expression, while BAFF-R was only up-regulated by CpG ODN. CpG ODN pretreatment up-regulated TACI expression on follicular and marginal zone B lymphocytes and increased their responses to BAFF- and APRIL-mediated Ig secretion. TACI seemed to be playing a pivotal role in BAFF- or APRIL-induced Ig secretion because B lymphocytes from TACI-knockout mouse or the blocking of TACI with a neutralizing antibody resulted in total inhibition of IgA and IgG secretion in CpG ODN-pretreated and BAFF- or APRIL-stimulated B cells. Thus, CpG ODN-induced increase in TACI expression is likely to play an important role in Ig secretion following activation of B lymphocytes through TLR9.

Prevalence of ZAP-70, LAT, SLP-76, and DNA methyltransferase 1 expression in CD4+ T cells of patients with systemic lupus erythematosus

T cells from systemic lupus erythematosus (SLE) patients exhibit defective function of CD4(+) T cells that can be responsible for improper activation of B cells and antibody biosynthesis against host antigens. We compared the level of ZAP-70, LAT, and SLP-76, transcripts and proteins in CD4(+) T cells from SLE patients (n = 22) and healthy individuals (n = 15). We also determined DNA methyltransferase 1 (DNMT1) protein content in CD4(+) T cells of SLE patients. The CD4(+) T cells were isolated by positive biomagnetic separation technique. The quantitative analysis of messenger RNA (mRNA) was performed by reverse transcription and real-time quantitative polymerase chain reaction (RQ-PCR) SYBR Green I system. The protein level in the CD4(+) T cells was determined by Western blotting analysis. We found that the LAT protein level was significantly higher in SLE CD4(+) T cells than in controls (P = 0.006). Western blot analysis revealed that ZAP-70 protein content in SLE CD4(+) T cells may be reciprocally correlated with disease activity expressed in SLEDAI scale (R = -0.623, P = 0.002) or number of affected organ systems (R = -0.549, P = 0.008). We also observed reciprocal correlation between DNMT1 protein content in CD4(+) T cells and disease activity scored with SLEDAI scale (R = -0.779, P = 0.001) or number of affected organ systems (R = -0.617, P = 0.019), respectively. Our findings might indicate that LAT, ZAP-70, and DNMT1 protein levels in CD4(+) T cells can be associated with SLE disease.

Vaccination as a control strategy against the coccidial parasitesEimeria,ToxoplasmaandNeospora

The protozoan parasitesEimeriaspp.Toxoplasma gondiiandNeospora caninumare significant causes of disease in livestock worldwide andT. gondiiis also an important human pathogen. Drugs have been used with varying success to help control aspects of these diseases and commercial vaccines are available for all three groups of parasites. However, there are issues with increasing development of resistance to many of the anti-coccidial drugs used to help control avian eimeriosis and public concerns about the use of drugs in food animals. In addition there are no drugs available that can act against the tissue cyst stage of eitherT. gondiiorN. caninumand thus cure animals or people of infection. All three groups of parasites multiply within the cells of their host species and therefore cell mediated immune mechanisms are thought to be an important component of host protective immunity. Successful vaccination strategies for bothEimeriaandToxoplasmahave relied on using a live vaccination approach using attenuated parasites which allows correct processing and presentation of antigen to the host immune system to stimulate appropriate cell mediated immune responses. However, live vaccines can have problems with safety, short shelf-life and large-scale production; therefore there is continued interest in devising new vaccines using defined recombinant antigens. The major challenges in devising novel vaccines are to select relevant antigens and then present them to the immune system in an appropriate manner to enable the induction of protective immune responses. With all three groups of parasites, vaccine preparations comprising antigens from the different life cycle stages may also be advantageous. In the case ofEimeriaparasites there are also problems with strain-specific immunity therefore a cocktail of antigens from different parasite strains may be required. Improving our knowledge of the different parasite transmission routes, host-parasite relationships, disease pathogenesis and determining the various roles of the host immune response being at times host-protective, parasite protective and in causing immunopathology will help to tailor a vaccination strategy against a particular disease target. This paper discusses current vaccination strategies to help combat infections withEimeria,ToxoplasmaandNeosporaand recent research looking towards developing new vaccine targets and approaches.

Cancer immunosuppression and autoimmune disease: beyond immunosuppressive networks for tumour immunity

Cancer immunosuppression evolves by constitution of an immunosuppressive network extending from a primary tumour site to secondary lymphoid organs and peripheral vessels and is mediated by several tumour-derived soluble factors (TDSFs) such as interleukin-10 (IL-10), transforming growth factor-beta (TGF-beta) and vascular endothelial growth factor (VEGF). TDSFs induce immature myeloid cells and regulatory T cells in accordance with tumour progression, resulting in the inhibition of dendritic cell maturation and T-cell activation in a tumour-specific immune response. Tumour cells grow by exploiting a pro-inflammatory situation in the tumour microenvironment, whereas immune cells are regulated by TDSFs during anti-inflammatory situations--mediated by impaired clearance of apoptotic cells--that cause the release of IL-10, TGF-beta, and prostaglandin E2 (PGE2) by macrophages. Accumulation of impaired apoptotic cells induces anti-DNA antibodies directed against self antigens, which resembles a pseudo-autoimmune status. Systemic lupus erythematosus is a prototype of autoimmune disease that is characterized by defective tolerance of self antigens, the presence of anti-DNA antibodies and a pro-inflammatory response. The anti-DNA antibodies can be produced by impaired clearance of apoptotic cells, which is the result of a hereditary deficiency of complements C1q, C3 and C4, which are involved in the recognition of phagocytosis by macrophages. Thus, it is likely that impaired clearance of apoptotic cells is able to provoke different types of immune dysfunction in cancer and autoimmune disease in which some are similar and others are critically different. This review discusses a comparison of immunological dysfunctions in cancer and autoimmune disease with the aim of exploring new insights beyond cancer immunosuppression in tumour immunity.

Stimulatory effect of fragments from transcribed region of ribosomal repeat on human peripheral blood lymphocytes

Fragments from the transcribed region of the ribosomal repeat include considerable amounts of unmethylated CpG DNA motifs. These motifs activate immune cells via the interaction with Toll receptors. In vitro experiments confirmed the stimulatory effect of transcribed region of ribosomal repeat on human lymphocytes. Culturing of lymphocytes in a medium containing 2-20,000 ng/ml fragments from transcribed region of ribosomal repeat was accompanied by structural changes in the nucleus in a considerable number of cells. These changes manifested in translocation of pericentromeric heterochromatin from the membrane to the center of the nucleus and activation of the nucleolus and were accompanied by a significant increase in interleukin-6 production and slight stimulation of tumor necrosis factor-a synthesis. The transcribed region of the ribosomal repeat and E. coli DNA had various effects on quantitative parameters of lymphocytes. Our results suggest the existence of mechanisms of stimulation not mediated by the interaction of CpG DNA motifs with Toll receptors.

Toll-like receptor engagement stimulates anti-snRNP autoreactive B cells for activation

Autoreactive B cells are the source of pathogenic autoantibodies (autoAb) in systemic lupus erythematosus (SLE). Previous studies have demonstrated that anti-small nuclear ribonucleoprotein particles (snRNP) B cells from normal background mice tolerize T cells in the periphery and do not secrete autoAb. In this study, we examined whether these anti-snRNP B cells can be activated for autoAb production by the engagement of Toll-like receptors (TLR). Anti-snRNP B cells proliferated vigorously and secreted abundant anti-snRNP autoAb upon exposure to CpG or polyriboinosinic polyribocytidylic acid [poly (I:C)] in vitro. In addition, the costimulatory molecules CD80 and CD86 were up-regulated. While both anti-snRNP B cells and wild-type B cells produced similar levels of IL-6 and IL-10, anti-snRNP B cells secreted predominately IFN-gamma in response to CpG or poly (I:C) stimulation. Furthermore, we showed that in vivo engagement of TLR stimulated immature anti-snRNP B cells to further differentiate and produce autoAb and form germinal centers. The activated anti-snRNP B cells became expanded and migrated into the T-B cell interface. Moreover, TLR engagement directly or indirectly activated autoreactive B cells via a CD4 T cell-independent manner. These results provide in vitro and in vivo evidence that BCR/TLR co-engagement promotes the activation of anti-snRNP B cells for autoAb production.

Higher-order CpG-DNA stimulation reveals distinct activation requirements for marginal zone and follicular B cells in lupus mice

Mouse follicular B cells express TLR9 and respond vigorously to stimulation with single-stranded CpG-oligodeoxynucleotides (ODN). Surprisingly, follicular B cells do not respond to direct stimulation with other TLR9 ligands, such as bacterial DNA or class A(D) CpG-ODN capable of forming higher-order structures, unless other cell types are present. Here, we show that priming with interferons or with B cell-activating factor, or simultaneous co-engagement of the B cell receptor for antigen (BCR), can overcome this unresponsiveness. The effect of interferons occurs at the transcriptional level and is mediated through an autocrine/paracrine loop, which is dependent on IRF-1, IL-6 and IL-12 p40. We hypothesize that the lack of bystander activation of follicular B cells with more complex CpG ligands may be an important safety mechanism for avoiding autoimmunity. This will prevent resting B cells from responding to foreign or self-derived hypomethylated double-stranded CpG ligands unless these ligands are either delivered through the B cell receptor or under conditions where B cells are simultaneously co-engaged by activated plasmacytoid dendritic cells or TH1 cells. A corollary is that the heightened responsiveness of lupus B cells to TLR9-induced stimulation cannot be ascribed to unprimed follicular B cells, but is rather mediated by hypersensitive marginal zone B cells.

Adjuvant activity of CpG oligodeoxynucleotides

Synthetic oligodeoxynucleotides (ODNs) containing unmethylated CpG motifs directly stimulate human B cells and plasmacytoid dendritic cells (pDCs), thereby promoting the production of Th1 and proinflammatory cytokines and the maturation/activation of professional antigen-presenting cells. These activities enable CpG ODNs to act as immune adjuvants, accelerating and boosting antigen-specific immune responses by 5- to 500-fold. The CpG motifs present in bacterial DNA plasmids may contribute to the immunogenicity of DNA vaccines. Ongoing clinical studies indicate that CpG ODNs are safe and well tolerated when administered as adjuvants to humans and can improve vaccine-induced immune responses.

Therapeutic potential of Toll-like receptor 9 activation

In the decade since the discovery that mouse B cells respond to certain unmethylated CpG dinucleotides in bacterial DNA, a specific receptor for these 'CpG motifs' has been identified, Toll-like receptor 9 (TLR9), and a new approach to immunotherapy has moved into the clinic based on the use of synthetic oligodeoxynucleotides (ODN) as TLR9 agonists. This review highlights the current understanding of the mechanism of action of these CpG ODN, and provides an overview of the preclinical data and early human clinical trial results using these drugs to improve vaccines and treat cancer, infectious disease and allergy/asthma.

Postulated vasoactive neuropeptide autoimmunity in fatigue-related conditions: a brief review and hypothesis

Disorders such as chronic fatigue syndrome (CFS) and gulf war syndrome (GWS) are characterised by prolonged fatigue and a range of debilitating symptoms of pain, intellectual and emotional impairment, chemical sensitivities and immunological dysfunction. Sudden infant death syndrome (SIDS) surprisingly may have certain features in common with these conditions. Post-infection sequelae may be possible contributing factors although ongoing infection is unproven. Immunological aberration may prove to be associated with certain vasoactive neuropeptides (VN) in the context of molecular mimicry, inappropriate immunological memory and autoimmunity. Adenylate cyclase-activating VNs including pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP) act as hormones, neurotransmitters, neuroregulators, immune modulators and neurotrophic substances. They and their receptors are potentially immunogenic. VNs are widely distributed in the body particularly in the central and peripheral nervous systems and have been identified in the gut, adrenal gland, blood cells, reproductive system, lung, heart and other tissues. They have a vital role in maintaining cardio-respiratory function, thermoregulation, memory, concentration and executive functions such as emotional responses including social cues and appropriate behaviour. They are co-transmitters for a number of neurotransmitters including acetylcholine and gaseous transmitters, are potent immune regulators with primarily anti-inflammatory activity, and have a significant role in protection of the nervous system against toxic assault as well as being important in the maintenance of homeostasis. This paper describes a biologically plausible mechanism for the development of certain fatigue-related syndromes based on loss of immunological tolerance to these VNs or their receptors following infection, other events or de novo resulting in significant pathophysiology possibly mediated via CpG fragments and heat shock (stress) proteins. These conditions extend the public health context of autoimmunity and VN dysregulation and have implications for military medicine where radiological, biological and chemical agents may have a role in pathogenesis. Possible treatment and prevention options are considered.

Exacerbation of viral and autoimmune animal models for multiple sclerosis by bacterial DNA

Theiler's murine encephalomyelitis virus (TMEV) infection and relapsing-remitting experimental allergic encephalomyelitis (R-EAE) have been used to investigate the viral and autoimmune etiology of multiple sclerosis (MS), a possible Th1-type mediated disease. DNA immunization is a novel vaccination strategy in which few harmful effects have been reported. Bacterial DNA and oligodeoxynucleotides, which contain CpG motifs, have been reported to enhance immunostimulation. Our objectives were two-fold: first, to ascertain whether plasmid DNA, pCMV, which is widely used as a vector in DNA immunization studies, could exert immunostimulation in vitro; and second, to test if pCMV injection could modulate animal models for MS in vivo. We demonstrated that this bacterially derived DNA could induce interleukin (IL)-12, interferon (IFN)gamma, (Th1-promoting cytokines), and IL-6 production as well as activate NK cells. Following pCMV injections, SJL/J mice were infected with TMEV or challenged with encephalitogenic myelin proteolipid protein (PLP) peptides. pCMV injection exacerbated TMEV-induced demyelinating disease in a dose-dependent manner. Exacerbation of the disease did not correlate with the number of TMEV-antigen positive cells but did with an increase in anti-TMEV antibody. pCMV injection also enhanced R-EAE with increased IFNgamma and IL-6 responses. These results caution the use of DNA vaccination in MS patients and other possible Th1-mediated diseases.

Targeting Toll-like receptor signaling in plasmacytoid dendritic cells and autoreactive B cells as a therapy for lupus

This review focuses on the role of Toll-like receptors (TLRs) in lupus and on possibilities to treat lupus using TLR modulating inhibitory oligodeoxynucleotides (INH-ODNs). TLRs bridge innate and adaptive immune responses and may play an important role in the pathogenesis of systemic lupus erythematosus. Of particular interest are TLR3, -7, -8, and -9, which are localized intracellularly. These TLRs recognize single-stranded or double-stranded RNA or hypomethylated CpG-DNA. Exposure to higher order CpG-DNA ligands or to immune complexed self-RNA triggers activation of autoreactive B cells and plasmacytoid dendritic cells. INH-ODNs were recently developed that block all downstream signaling events in TLR9-responsive cells. Some of these INH-ODNs can also target TLR7 signaling pathways. Based on their preferential cell reactivity, we classify INH-ODNs into class B and class R. Class B ('broadly reactive') INH-ODNs target a broad range of TLR-expressing cells. Class R ('restricted') INH-ODNs easily form DNA duplexes or higher order structures, and are preferentially recognized by autoreactive B cells and plasmacytoid dendritic cells, rather than by non-DNA specific follicular B cells. Both classes of INH-ODNs can block animal lupus. Hence, therapeutic application of these novel INH-ODNs in human lupus, particularly class R INH-ODNs, may result in more selective and disease-specific immunosuppression.

Inhibitory oligodeoxynucleotides - therapeutic promise for systemic autoimmune diseases?

Recent studies have shed new light on a possible link between the innate activation of plasmocytoid dendritic cells and marginal zone B cells and the pathogenesis of systemic lupus erythematosus. Animal studies have identified that this response requires the Toll-like receptor 9 (TLR9). Engagement of the TLR9 by various ligands, including non-canonical CpG-motifs, can cause or aggravate pathogenic autoantibody production and cytokine secretion in lupus. Attempts to neutralize this activity either by blocking the acidification of the endosomal compartment with chloroquine and related compounds, or by preventing the interaction between the CpG-DNA sequences and TLR9 using inhibitory oligonucleotides could be a promising therapeutic option for lupus.

Suppressive oligodeoxynucleotides delay the onset of glomerulonephritis and prolong survival in lupus-prone NZB x NZW mice

OBJECTIVE

Synthetic oligodeoxynucleotides (ODN) expressing TTAGGG motifs suppress the production of proinflammatory cytokines and have been proven effective at blocking the development of certain organ-specific autoimmune diseases. We undertook this study to determine whether suppressive ODN alter the development of systemic autoimmunity, by evaluating their effect on the progression of lupus-like disease in NZB x NZW (NZB/NZW) mice.

METHODS

We repeatedly treated mice with suppressive ODN before or after the onset of proteinuria. We monitored the effect of treatment on the onset, severity, and immunologic correlates of disease.

RESULTS

Treatment with suppressive ODN significantly prolonged lifespan while delaying the onset and progression of glomerulonephritis in NZB/NZW mice. Clinical improvement was accompanied by a significant reduction in anti-double-stranded DNA autoantibody production and by significantly reduced secretion of interferon-gamma and interleukin-12 in vivo.

CONCLUSION

Suppressive ODN may be of benefit in the treatment of chronic systemic autoimmune diseases such as systemic lupus erythematosus.

Human innate B cells: a link between host defense and autoimmunity?

B cells play a variety of immunoregulatory roles through their antigen-presentation ability and through cytokine and chemokine production. Innate immune activation of B cells may play a beneficial role through the generation of natural cross-reactive antibodies, by maintaining B cell memory and by exercising immunomodulatory functions that may provide protection against autoimmunity. In this article, we review human B cell populations and their functional properties, with a particular focus on a population of inherently autoreactive B cells, which seem to play an important physiological role in innate immunity, but which, if selected into adaptive immune responses, appear to become pathogenic agents in systemic lupus erythematosus.

Activation of Marginal Zone B Cells from Lupus Mice with Type A(D) CpG-Oligodeoxynucleotides

Several types of CpG-oligodeoxynucleotides (ODN) have been recently characterized. In mice, type A(D) CpG-ODNs primarily stimulate macrophages and dendritic cells, but fail to stimulate B cells. On the contrary, type B(K) CpG-ODNs are excellent B cell activators. Type C CpG-ODNs combine features of both types A(D) and B(K) CpG-ODNs. Despite cell type preferences, all CpG-ODNs require the presence of TLR9 for activation. In this study, we show that a subset of B cells from lupus mice responds to type A(D) CpG-ODN stimulation vigorously and directly with increased CD25 and CD86 expression and IL-10 secretion. Furthermore, these CpG-ODNs induce high surface IgM expression and promote 50- to 100-fold higher IgM and IgG3 secretion in lupus B cells than in controls. This response is similar to that seen with bacterial DNA stimulation of B cells. Type A(D)-responsive cells are enriched within lupus B cells with the marginal zone (MZ) phenotype. These cells are at least twice more numerous in lupus mice than in controls. The ability of lupus B cells to respond to type A(D) CpG-ODN stimulation is not due to differential TLR9 expression. Therefore, type A(D) CpG-ODNs may contribute to the lupus pathogenesis by inducing MZ-B cell activation, costimulatory molecule expression, and polyclonal Ig secretion. Through increased IL-10 secretion, MZ-B cells may also modify the activity of other cell types, particularly dendritic cells and macrophages.

TLR-9 Activation of Marginal Zone B Cells in Lupus Mice Regulates Immunity Through Increased IL-10 Production

Bacterial DNA triggers B-cell proliferation and induces immunoglobulin secretion. Chromatin-IgG complexes activate autoreactive B cells by co-engaging B-cell receptor (BCR) and TLR-9, thus suggesting a role for innate signaling in systemic autoimmunity. Spleen cells from lupus prone Palmerston North (PN) mice produce several fold less IL-12p40 than controls in response to CpG-oligodeoxynucleotides (ODNs). Here we show that B cells are primarily responsible for this abnormality. The removal of B cells from PN cultures markedly increased IL-12p40. Moreover, the addition of purified B cells back to PN splenocyte cultures resulted in a B-cell number dependent/ IL-10-mediated suppression of IL-12p40. The B cells were the major source of IL-10. In response to CpG, B cells from several lupus strains produced twice as a much IL-10 as controls, but failed to produce IL-10 when stimulated through BCR or CD40. PN and control mice expressed IL-10R similarly, and the difference in IL-10 secretion remained when anti-IL-10R blocking antibodies were used. IFN-gamma and IL-4 regulated CpG-induced IL-10 secretion in opposite directions. The abnormal IL-10 response in lupus mice was derived from B cells with the marginal zone phenotype, and could be downregulated with inhibitory ODNs. We hypothesize that TLR-9 activated lupus B cells can modulate T-cell mediated inflammatory responses through IL-10 production. Therefore, B cells may contribute to the lupus pathogenesis in many different ways: as antigen-presenting cells for self antigens, as effector cells for autoantibody production, and as IL-10 secreting regulatory cells.

Do cytosine guanine dinucleotide (CpG) fragments induce vasoactive neuropeptide mediated fatigue-related autoimmune disorders?

Autoimmune dysfunction of certain vasoactive neuropeptides (e.g., vasoactive intestinal peptide, pituitary adenylate cyclase activating polypeptide) may be implicated in a range of disorders associated with fatigue-like states (chronic fatigue syndrome, Gulf War syndrome) and even sudden infant death syndrome (SIDS). The important roles of these vasoactive neuropeptides make them a vulnerable target for autoimmune dysfunction. They are known to be associated with heat shock proteins for intracellular functioning with which they may form immunostimulating complexes. Cytosine guanine dinucleotide (CpG) fragments are potently immunogenic DNA fragments which serve as friend or foe recognition systems between bacterial (hypomethylated) and mammalian (methylated) DNA and are being assessed for suitability for use in human vaccines as adjuvants. Interactions between CpG fragments, heat shock proteins and vasoactive neuropeptides may be associated with fatigue-related autoimmune conditions.