CpG Oligodeoxynucleotides Treatment Research Articles

Abstract 08: Soluble agonists in the in vivo macroenvironment generate phenotypic de novo resistance to BTK/Bcl-2 targeted therapies in diverse B-cell malignancies

Abstract The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib (IBR) is FDA approved for chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). However, IBR responses are incomplete in majority of cases, and not durable in MCL and high-risk CLL. We hypothesize that de novo resistance, incomplete responses, and rapid recurrence can be due to adaptive signaling that should be cotargeted with BTK to achieve deeper and durable responses. We previously showed that venetoclax (VEN), an inhibitor of Bcl-2, generates synergistic cytotoxicity with IBR in MCL lines (Axelrod et al. Leukemia 2014;28:407-10). Recently, we extended these findings to circulating leukemic B cells in CLL, MCL (Jayappa et al. ASH 2016), and follicular lymphoma (FL) patient PBMCs treated ex vivo. Based on these results we initiated a phase I/Ib trial for IBR+VEN combination in MCL. Our ex vivo cytotoxicity studies showed a surprisingly high frequency of de novo resistance to IBR+VEN. Resistance did not correlate with previous therapy or clinical characteristics of patients. However, FACS analysis of primary CLL cells showed that cells displaying an “activation” phenotype (CD5+/CD19+/CD69+) were less sensitive to cytotoxicity of IBR+VEN, suggesting that cellular activation by extrinsic factors could generate drug resistance. To test this, we cocultured or preincubated CLL patient PBMCs with various stromal cells, cytokines, and other agonists and found that soluble CD40L, IL10, and CpG oligodeoxynucleotides (ODN) generated variable resistance to IBR+VEN in CLL samples, with CpG ODN, a specific TLR9 agonist, being the most effective. The combination of CpG ODN, sCD40L, and IL10 (“agonist mix”) generated near-complete resistance to IBR+VEN in most CLL(N=22)/MCL(N=7)/FL(N=4) patient PBMCs. The agonist mix treatment significantly upregulated nuclear localization of RelA and RelB proteins in CLL/MCL/FL cells analyzed by ImageStream, suggesting activation of NF-kB signaling. Agonist mix treatment also induced the NF-kB dependent overexpression of anti-apoptotic proteins Mcl-1, Bcl-xL, and survivin, and inhibitors of NF-kB or of upregulated anti-apoptotic proteins overcame this drug resistance (Jayappa et al. ASH 2016). To further explore the role of TLR9 and other innate immune receptors in resistance, we performed IBR+VEN cytotoxicity analysis in CLL/MCL patient PBMCs cocultured with agonists of various TLRs and NOD1/2 receptors. Preliminary results showed that TLR9 agonist CpG ODN generated significant resistance to IBR+VEN in most CLL/MCL samples, and agonists of TLR1/2, TLR7, and NOD1/2 induced a moderate level of resistance in a MCL sample. The CpG ODN treatment induced a significant increase in NF-kB signaling measured by increased nuclear localization of RelB in CLL patient samples. To determine if soluble agonists in the extranodal macroenvironment of patients could generate NF-kB dependent resistance to IBR+VEN, we analyzed drug cytotoxicity in CLL(N=6) and MCL(N=1) patient PBMCs cultured with autologous plasma. We found that preincubation with autologous plasma induced variable levels of resistance to IBR+VEN in CLL/MCL samples, but did not induce resistance to a NF-kB inhibitor BMS-345541. In conclusion, soluble factors in the patient nodal/extranodal macroenvironment, particularly a TLR9 agonist, generate resistance to IBR+VEN by activating NF-kB signaling and overexpression of multiple anti-apoptotic proteins. The same resistance mechanism, based on innate immune signaling, occurs in three mature B-cell malignancies, CLL, MCL and FL, that differ in etiology and clinical course. The signaling pathway responsible for resistance contains new targets for therapeutic intervention with potential to prevent or reverse resistance to IBR and VEN in these and perhaps other cancers as well. Citation Format: Kallesh D. Jayappa, Craig A. Portell, Vicki L. Gordon, Timothy P. Bender, Michael E. Williams, Michael J. Weber. Soluble agonists in the in vivo macroenvironment generate phenotypic de novo resistance to BTK/Bcl-2 targeted therapies in diverse B-cell malignancies [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr 08.

CEREBRAL AMYLOID ANGIOPATHY TREATMENT VIA INNATE IMMUNITY STIMULATION IN AGED NON-HUMAN PRIMATES

Immunotherapeutic approaches for Alzheimer's disease (AD) are hampered by complications related to ineffectual clearance of cerebral amyloid angiopathy (CAA). Given the independent correlation of the degree of CAA pathology with the severity of cognitive impairment, as well as the key role of CAA in the pathophysiology leading to development of amyloid-related imaging abnormalities, our studies were designed to determine whether stimulation of innate immunity with TLR9 agonist CpG oligodeoxynucleotides (ODNs) could have beneficial effects in a non-human primate model of sporadic CAA, squirrel monkey (Saimiri Boliviensis). Our prior work has shown that treatment with CpG ODN is effective at improving cognitive deficits in aged monkeys without inducing adverse events. Elderly female monkeys with expected CAA deposits were subcutaneously injected with either predetermined non-toxic dosages of the class B CpG ODN or saline for a 25 month period. Animals were continuously examined for signs of toxicity. Plasma taken at specific times in the course of treatment was analyzed to identify immune responses and AD biomarkers. Histological and biochemical brain analyses commenced upon completion of the behavioral protocols. Long term treatment with CpG ODN significantly reduced total amyloid burden (6E10/4G8 immunohistochemistry), which in this model corresponds primarily to CAA. Histological evaluation of CpG ODN effect on pyroglutamate levels (AβpE3 immunohistochemistry) revealed region specific reduction in AβpE3 burden in monkeys treated with CpG ODN. These favorable histological data will be corroborated by measurements of Aβ levels in the brain homogenates. Our initial biomarker analyses exhibited a noticeable increase in AβpE3 plasma levels in CpG ODN-treated animals. Subsequent evaluation showed no increase in the extent of Iba1 microgliosis and GFAP astrogliosis in CpG ODN group at the end of the treatment. Additionally, there was no evidence of increased microhemorrhages or T cell infiltration in association with CpG ODN treatment, further supporting the viability of our approach. Concluding assessment of microglia/macrophage activation is currently in progress. Overall, the present findings together with our earlier experimental evidence validate this novel concept of immunomodulation as a safe method to successfully ameliorate AD related pathology, suggesting CpG ODN would have a significant potential of achieving clinical efficacy.

Effects of systemic pretreatment with CpG oligodeoxynucleotides on skin wound healing in mice

Unmethylated CpG oligodeoxynucleotides (ODN) bind to the Toll-like receptor 9, thus stimulating the immune system. To study the effects of systemic pretreatment with CpG ODN on dermal regeneration, C57BL6/J Tyr mice were treated with CpG or control ODN 6 days prior to implantation of a dorsal skinfold chamber and skin wounding. Wound epithelialization was analyzed by planimetric microscopy. On day 18, wound tissues were taken for (immuno)histochemical staining. CpG ODN increased epithelialization compared with control ODN treatment. Histological analysis revealed reduced capillary density, reduced wound cellularity, and reduced numbers of infiltrating leukocytes, as well as reduced F4/80-positive macrophages, but increased numbers of RELM-α-positive M2 macrophages after CpG ODN treatment, reflecting a better quality of wound healing on day 18 compared with control ODN treatment. Reverse transcription-polymerase chain reaction analysis of Toll-like receptor 9 showed the receptor expression on both fibroblasts and keratinocytes. Fibroblasts showed an increase of migration upon increasing dosages of CpG and not control ODN, reaching ∼50% of the response of basic fibroblast growth factor-exposed cells. Keratinocytes dose-dependently responded to both CpG and control ODN up to values found in keratinocyte growth factor-exposed cells. In summary, CpG ODN support late tissue-remodeling processes that contribute to resolution of inflammation and solid wounds during skin regeneration.

Toll‐like receptor‐9 agonists increase cyclin D1 expression partly through activation of activator protein‐1 in human oral squamous cell carcinoma cells

Increasing evidence suggests that malignant transformation can result from chronic infection, and Toll-like receptors (TLRs) may play an important role in this process. We have previously reported that the increased expression of TLR-9 is associated with tumor cell proliferation in oral cancer. However, the mechanisms involved have not been elucidated. The aim of this study was to investigate whether CpG-oligodeoxynucleotides (CpG-ODN), a special TLR-9 agonist, is able to exert the proliferation-promoting effect in human oral squamous cell carcinoma (OSCC), and to explore the possible underlying molecular mechanism. Flow cytometry, MTT, and colony formation assay were used to evaluate cell proliferation and cell cycle distribution. The mRNA and protein levels were analyzed by quantitative RT-PCR and Western blot assay. Luciferase reporter gene, EMSA, and ChIP assays were used to detect the activity of activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) in HB cells. Results showed that CpG-ODN could stimulate proliferation of HB cells in a dose- and time-dependent manner with a promoted G(1) /S cell cycle progression. Increased cyclin D1 expression was detected in the nuclear region after CpG-ODN treatment. Moreover, CpG-ODN promoted nuclear translocation and activation of AP-1, which appeared to be required for TLR-9-mediated cyclin D1 expression and subsequently cell proliferation, but seemed to have little impact on NF-κB activity. Our results indicate that CpG-ODN stimulates tumor cell proliferation through TLR-9-mediated AP-1-activated cyclin D1 expression in OSCC HB cells. Pharmacologic inhibition of the TLR-9/AP-1/cyclin D1 pathway may be a new therapeutic approach for prevention as well as treatment of OSCC.

Treatment of newly hatched chicken with CpG oligodeoxynucleotides decreases liver/spleen colonization of Salmonella enteritidis in broiler chickens

Induction of the innate immune response in newly hatched chickens is important to reduce the risk infection with bacteria, such as Salmonella enteritidis. CpG oligodeoxynucleotides (CpG-ODNs) can stimulate the innate immune response of young chickens. In this study, 2-day-old chickens were treated with CpG-ODN (treatment) or phosphate buffered saline (PBS) solutions (control). Chickens in each group were orally challenged with S. enteritidis at 3 h and 4, 7, and 14 days after the administration of CpG-ODN and PBS solutions. A significant reduction (P < 0.05) in colonization of S. enteritidis was observed in chickens 3 h after treatment with CpG-ODN. Regardless of the time of inoculation, fewer liver and spleen infected with S. enteritidis were observed in the treatment group than those in the control groups (P < 0.05). This study demonstrated that CpG-ODN is able to enhance the immune response and resistance to S. enteritidis in neonatal chickens.

CpG ODN treatment in radiation-combined injury (172.31)

Abstract In the scenario of a nuclear event, radiation injury will be accompanied by additional trauma, especially burns. We developed a mouse model to allow us to study the changes in the immune system induced by these injuries. In this study, we tested the potential of using CpG oligodeoxynucleotides (ODN) as treatments in radiation combined injury (RCI). Mice were exposed to 1, 4 and 6 Gy whole body radiation and underwent near simultaneous burn injury. One day after injury, mice were injected with either CpG ODNs or saline. Seven days later, sepsis was induced by cecal ligation and puncture (CLP) and survival was recorded. Spleen immune cell subsets were assessed by FACS and inflammatory cytokine production by splenocytes was determined at 7 days after CLP. To investigate the role of regulatory T cells (Tregs) in this model, mice were Treg depleted after class A CpG treatment. Treatment with class A CpG increased survival after RCI with 1 Gy followed by CLP significantly whereas treatment with class B or C did not. Class A treatment also conferred a survival benefit following RCI with 4 and 6 Gy. Inflammatory cytokine production was decreased with class A treatment but not with class B or C. The effects of class A treatment were not seen in Treg depleted mice. Class A CpG tracking showed increased uptake in Tregs when compared to class B or C. In summary, CpG treatment is effective in enhancing host defense mechanisms following RCI.

Interleukin-4 and CpG oligonucleotide therapy suppresses the outgrowth of tumors by activating tumor-specific Th1-type immune responses

Because IL-4 and CpG oligodeoxynucleotides (CpG-ODNs) are immune stimulants, we evaluated the antitumor effects of IL-4 gene therapy and CpG-ODN treatment in a poorly immunogenic murine cancer model. We used a murine colorectal cancer MC38 cell line overexpressing the IL-4 gene (MC38-IL4). Incubation with MC38-IL4 and CpG-ODN enhanced bone marrow-derived dendritic cell (DC) maturation in vitro. In addition, interferon (IFN)-γ production was significantly increased in naïve splenocytes after they were coincubated with MC38-IL4 and CpG-ODN. When mice bearing MC38 wild-type tumors were inoculated subcutaneously with MC38-IL4 cells and CpG-ODN, the outgrowth of established parental tumors was significantly suppressed compared to those in the MC38-IL4-treated group (IL-4 vs. IL-4 + CpG-ODN, p=0.015). A marked infiltration of CD8+ cells in the established parental tumors of mice treated with MC38-IL4 and CpG-ODN was confirmed by immunohistochemical analyses (MC38-IL4, 2.8 ± 1.9 cells/field vs. MC38-IL4 + CpG-ODN, 20.7 ± 15.3 cells/field, p=0.027). Significant tumor-specific cytolysis was detected when splenocytes of MC38-IL4 + CpG-ODN-treated mice were stimulated by γ-irradiated MC38-IL4 cells and CpG-ODN twice weekly in vitro and used as effector cells in a chromium-release assay (32.2 ± 3.5% for MC38 cells vs. 3.2 ± 1.1% for YAC-1 cells; at an effector to target ratio of 40). These results suggest that IL-4 and CpG-ODN treatment promotes potent Th1-type antitumor immune responses. Therefore, the combination of IL-4 gene therapy and CpG-ODN treatment for cancer should be evaluated in clinical trials.

Changes in Murine Hyalocytes Are Valuable Early Indicators of Ocular Disease

The distribution, density, and phenotype of hyalocytes or vitreous macrophages in mouse eyes was examined during normal aging and in models of background diabetic retinopathy, retinal vascular proliferation, and exposure to TLR4 and TLR9 ligands. The phenotype and density of hyalocytes were investigated in retinal and ciliary body wholemounts of normal wild-type (WT; C57BL/6) mice at 7, 17, and 120 weeks of age, Ins2(Akita) mice, transgenic Kimba mice (VEGF-induced retinal neovascularization), and WT mice 24 hours after single intraperitoneal injection with lipopolysaccharide (LPS) or 1 week after three identical doses administered 2 weeks apart. Another group of mice each received a single topical drop of 20 μg CpG-oligodeoxynucleotides (CpG-ODN) to the abraded corneal surface and were euthanized 1 week later. The data revealed an approximately fivefold increase in the density of preretinal hyalocytes in 120-week-old mice. Some hyalocytes in older eyes contained phagocytosed melanin. Hyalocyte density was doubled in Ins2(Akita) mice after only 3 to 4 weeks of hyperglycemia. Kimba mice had an eightfold increase in the density of hyalocytes, and many displayed signs of activation. WT mice exposed to single or multiple systemic doses of LPS showed a twofold to threefold increase in hyalocytes. Topical CpG-ODN treatment led to a very marked (sevenfold) increase in preretinal hyalocyte density. The present study demonstrated that murine hyalocytes were responsive to aging, hyperglycemia, locally produced VEGF, and both systemic and ocular-derived TLR ligands. Thus hyalocytes or vitreous macrophages may be a valuable and previously unrecognized sensitive indicator of pathologic changes in the eye.

Molecular chaperoning by glucose‐regulated protein 170 in the extracellular milieu promotes macrophage‐mediated pathogen sensing and innate immunity

Recognition of pathogen-associated molecular patterns by innate immune receptors is essential for host defense responses. Although extracellular stress proteins are considered as indicators of the stressful conditions (e.g., infection or cell injury), the exact roles of these molecules in the extracellular milieu remain less defined. We found that glucose-regulated protein 170 (Grp170), the largest stress protein and molecular chaperone, is highly efficient in binding CpG oligodeoxynucleotides (CpG-ODN), the microbial DNA mimetic sensed by toll-like receptor 9 (TLR9). Extracellular Grp170 markedly potentiates the endocytosis and internalization of CpG-ODN by mouse bone marrow-derived macrophages and directly interacts with endosomal TLR9 on cell entry. These molecular collaborations result in the synergistic activation of the MyD88-dependent signaling and enhanced production of proinflammatory cytokines and nitric oxide in mouse primary macrophages as well as human THP-1 monocyte-derived macrophages, suggesting that Grp170 released from injured cells facilitates the sensing of pathogen-associated "danger" signals by intracellular receptors. This CpG-ODN chaperone complex-promoted innate immunity confers increased resistance in mice to infection of Listeria monocytogenes compared with CpG-ODN treatment alone. Our studies reveal a previously unrecognized attribute of Grp170 as a superior DNA-binding chaperone capable of amplifying TLR9 activation on pathogen recognition, which provides a conceptual advance in understanding the dynamics of ancient chaperoning functions inside and outside the cell.

Plasmacytoid Dendritic Cells Alter the Antitumor Activity of CpG-Oligodeoxynucleotides in a Mouse Model of Lung Carcinoma

The effect of CpG-oligodeoxynucleotides (CpG) has been studied on a number of tumors. Although CpG may facilitate tumor regression in mouse models of melanoma, its activity in lung cancer is unclear. The aim of our study was to elucidate the effect of CpG (0.5-50 μg/mouse) in a mouse model of Lewis lung carcinoma cell-induced lung cancer. Lung tumor growth increased at 3 and 7 d after a single administration of CpG. This was associated with a greater influx of plasmacytoid dendritic cells (pDCs), immature myeloid dendritic cells, and greater recruitment of regulatory T cells. Depletion of pDCs using a specific Ab (m927) reversed the immune-suppressive environment and resulted in a decreased lung tumor burden, accompanied by a greater influx of active myeloid dendritic cells and CD8(+) T cells, and a higher production of Th1- and Th17-like cytokines. Furthermore, the rate of apoptosis in the lungs of mice treated with CpG increased following the depletion of pDCs. CpG treatment alone does not lead to tumor regression in the lung. However, ablation of pDCs renders CpG a good adjuvant for lung cancer chemotherapy in this experimental model.

CpG Stimulates Protective Immunity In Balb/cJ Mice Infected with Larval Taenia crassiceps

Balb/cJ mice infected in the peritoneal cavity with larval Taenia crassiceps fail to mount a protective immune response. In mice, inflammatory immune responses are believed to control larval reproduction, whereas antibody-mediated responses are believed to be permissive. In the present study, mice were treated with CpG-oligodeoxynucleotides (CpG) to determine whether stimulation of the innate inflammatory response would confer increased resistance to larval growth. Female mice treated with CpG displayed a decrease in mean parasite burden by 54%, while male mice displayed a 73% reduction. Moreover, 5 of 12 CpG-treated male mice completely eliminated all larvae by 9 wk post-infection. In contrast, no female animals were found to be infection free. CpG treatment induced an increase in the transcript levels of tumor necrosis factor-α and inducible nitric oxide synthase (iNOS) from splenocytes and resulted in elevated levels of the proinflammatory molecules monocyte chemotactic protein (MCP)-1, MCP-3, and interleukin-6 at the site of infection. Additionally, CpG administration induced the enhanced recruitment of neutrophils and macrophages to the site of infection. The finding that both neutrophils and macrophages were recruited in significantly higher numbers in the male host as compared to the female host may explain the increased level of protection realized in male animals in response to CpG treatment.

Accelerated wound healing in mice by local administration of sustained-release CpG oligodeoxynucleotide (136.4)

Abstract Recent reports show that wounds in mice lacking MyD88 heal at a delayed rate, suggesting that the innate immune pathway can affect the healing process. Preliminary studies revealed that the kinetics of wound healing in TLR9 KO mice were also delayed when compared to congenic controls, suggesting that this activation pathway may contribute physiologically to wound healing. Synthetic oligodeoxynucleotides (ODN) expressing unmethylated CpG motifs mimic the ability of bacterial DNA to stimulate an innate immune response via TLR9. We incorporated CpG ODN into a vehicle (basement membrane extract) that slowly released bioactive ODN to wound sites. The effect of the ODN was then examined using a murine excisional skin biopsy model. Results show that CpG ODN treatment significantly accelerates wound repair in normal adult and aged mice (p &amp;lt; 0.0001 and p &amp;lt; 0.01, respectively). Consistent with these effects being mediated by CpG signaling via TLR9, no effect was observed in TLR9 KO mice. Histologic studies indicate that CpG treatment promotes local accumulation of macrophages, increases production of VEGF, and accelerates neovascularization, resulting in accelerated granulation and wound closure in wildtype (but not TLR9 KO mice, p &amp;lt; 0.01). Current findings suggest that immunostimulatory oligonucleotides may represent a novel, inexpensive, safe and effective means of improving wound repair.

CpG oligodeoxynucleotide incorporated basement membrane extract facilitate wound repair in mice (135.5)

Abstract Wound healing involves complex processes including re epithelialization and wound contraction. Recent reports showed that the innate immune pathway of TLR4-mediated MyD88 signaling can affect the healing process by modulating epithelial cell migration and the production of angiogenesis factors. However, it has not been elucidated whether the TLR9 pathway could promote wound healing. Synthetic oligodeoxynucleotides (ODN) expressing unmethylated CpG motifs mimic the ability of bacterial DNA to stimulate an innate immune response via TLR9. We incorporated CpG ODN into a vehicle (basement membrane extract, BME) that slowly released bioactive ODN to wound sites. In vivo studies using an excisional skin biopsy model showed that CpG ODN treatment significantly accelerated wound repair in normal mice (p &amp;lt; 0.0001). The same effect was observed in aged mice (whose wound healing was otherwise delayed). Consistent with these effects being mediated by CpG signaling via TLR9, CpG ODN did not accelerate wound healing in TLR9 knock out mice. Histologic studies indicate that CpG treatment promoted the local accumulation of macrophages, increased the production of VEGF, and promoted neovascularization, resulting in accelerated granulation and wound closure (p &amp;lt; 0.01). These findings suggest that CpG ODN may represent a promising novel therapy for wound repair.

Comparative Proteomics Study Reveals That Bacterial CpG Motifs Induce Tumor Cell Autophagy in Vitro and in Vivo

Unmethylated CpG dinucleotides, present in bacterial DNA, are recognized in vertebrates via the Toll-like receptor 9 (TLR9) and are known to act as an anticancer agent by stimulating immune cells to induce a proinflammatory response. Although the effects of CpG-oligodeoxynucleotides (CpG-ODNs) in immune cells have been widely studied, little is known regarding their molecular effects in TLR9-positive tumor cells. To better understand the role of these bacterial motifs in cancer cells, we analyzed proteome modifications induced in TLR9-positive tumor cells in vitro and in vivo after CpG-ODN treatment in a rat colon carcinoma model. Proteomics analysis of tumor cells by two-dimensional gel electrophoresis followed by mass spectrometry identified several proteins modulated by bacterial CpG motifs. Among them, several are related to autophagy including potential autophagic substrates. In addition, we observed an increased glyceraldehyde-3-phosphate dehydrogenase expression, which has been shown to be sufficient to trigger an autophagic process. Autophagy is a self-digestion pathway whereby cytoplasmic material is sequestered by a structure termed the autophagosome for subsequent degradation and recycling. As bacteria are known to trigger autophagy, we assessed whether bacterial CpG motifs might induce autophagy in TLR9-positive tumor cells. We showed that CpG-ODN can induce autophagy in rodent and human tumor cell lines and was TLR9-dependent. In addition, an increase in the number of autophagosomes can also be observed in vivo after CpG motif intratumoral injection. Our findings bring new insights on the effect of bacterial CpG motifs in tumor cells and may be relevant for cancer treatment and more generally for gene therapy approaches in TLR9-positive tissues.

In ovo treatment with CpG oligodeoxynucleotides decreases colonization of Salmonella enteriditis in broiler chickens

Induction of the innate immune response in newly hatched chickens is important for limiting infections with bacteria, such as Salmonella enterica serovar Enteriditis (SE). CpG oligodeoxynucleotides (CpG-ODN) can stimulate the innate immune response of young chickens. Therefore, we examined the effectiveness of CpG-ODN administered in ovo on intestinal colonization by SE and the ability to modulate the function of heterophils in young chickens. Heterophils were isolated from 2-day-old chickens and were stimulated with heat-killed SE (HK-SE) or PMA for oxidative burst and HK-SE or live SE for degranulation assays. CpG-ODN treatment had no effect on heterophil oxidative burst when stimulated with HK-SE or PMA. However, HK-SE and live SE increased degranulation ( P < 0.01) in heterophils from CpG-ODN-treated birds compared to PBS-treated controls. In a second experiment, chickens were orally infected with SE on day 10 post-hatch and cecal contents were collected 6 days later for assessment of SE intestinal colonization. CpG-ODN treatment reduced SE colonization by greater than 10-fold ( P < 0.001) compared to PBS-injected control birds. Overall, we show for the first time that CpG-ODN given in ovo stimulates innate immune responsiveness of chicken heterophils and increases resistance of young chickens to SE colonization.

CpG oligodeoxynucleotides induce cyclooxygenase-2 in human B lymphocytes: Implications for adjuvant activity and antibody production

Synthetic CpG oligodeoxynucleotides (ODN), similar to DNA sequences found in certain microorganisms, have shown promise as adjuvants for humans by enhancing immune responses. Since antibodies are often indicators of successful vaccination, it is important to understand how CpG ODNs affect human B cells and influence antibody production. Treatment of human B cells with synthetic CpG ODN sequences increased both steady-state Cox-2 mRNA levels and protein expression. B cell receptor stimulation in concert with CpG ODN treatment induced Cox-2 expression and production of prostaglandin E 2, well above that seen with CpG ODN alone. Importantly, CpG-induced human B cell IgM and IgG production was attenuated by dual Cox-1/Cox-2 inhibitors and Cox-2-selective inhibitors. Our findings support a key role for CpG ODN-induced human B cell Cox-2 in the production of IgM and IgG antibodies, revealing that drugs that attenuate Cox-2 activity have the potential to reduce optimal antibody response to adjuvants/vaccination.

Improved systemic pharmacokinetics, biodistribution, and antitumor activity of CpG oligodeoxynucleotides complexed to endogenous antibodies in vivo

CpG oligodeoxynucleotides (CpG-ODNs) fail to elicit antitumor immunity after intravenous administration presumably due to their rapid renal clearance and low tumor accumulation. To address this issue, we tested the hypothesis that endogenous IgG can be used as systemic drug carriers to improve the pharmacokinetics, tumor accumulation, and antitumor activity of intravenously administered CpG-ODNs. To this end, tritium-labeled CpG-ODNs conjugated with one or two dinitrophenyl (DNP) haptens (DNP- and DNP 2-[ 3H]-CpG-ODN) were intravenously dosed into DNP-immunized Balb/c mice bearing subcutaneous CT26 colorectal tumors. Serum and tissue samples for pharmacokinetic and biodistribution profiling were collected at predetermined timepoints and analyzed by liquid scintillation. In antitumor efficacy studies, DNP-immunized, CT26 tumor-bearing mice were intravenously dosed with PBS, CpG-ODN, or DNP-CpG-ODN every five days. Tumor volumes and macroscopic and histological examination of resected solid tumors were used to quantitatively and qualitatively assess tumor growth inhibition. Relative to [ 3H]-CpG-ODN, dinitrophenylated [ 3H]-CpG-ODNs displayed substantial increases in systemic exposure (900–1650 fold) and half-life (100–300 fold), marked decreases in systemic clearance (750–1500 fold) and volume of tissue distribution (13–37 fold), as well as substantial and sustained tumor accumulation (∼ 30% vs. < 2% injected dose/g). Antitumor efficacy studies demonstrated that DNP-CpG-ODN inhibited tumor growth by up to 60% relative to PBS control whereas CpG-ODN treatment had no apparent effect. Macroscopic and histological examination of harvested tumors at various timepoints revealed the presence of regions of necrotic tissue only in tumors from mice treated with DNP-CpG-ODN. Collectively, these results show the potential of endogenous IgG to mediate the systemic delivery of CpG-ODN to solid tumors and to enhance their antitumor activity following intravenous administration.

Inhibition of the hepatitis B virus replication in vitro by an oligodeoxynucleotide containing cytidine-guanosine motifs

Oligodeoxynucleotides (ODNs) containing unmethylated CpG dinucleotides within specific sequence contexts (CpG motifs) are known as potent activators of the immune system and inducers of several Th1-associated immunomodulatory cytokines. CpG ODNs show promise as vaccine adjuvants and immunoprotective agents in animals. Here, we investigated the inhibitory effects of D type CpG ODN on hepatitis B virus (HBV) replication in vitro. The experiments were performed in HepG2 2.2.15 cells, which contain an integrated tandem dimer of the HBV genome and are routinely used for anti-HBV study. HepG2 2.2.15 cells co-cultured with peripheral blood mononuclear cells (PBMCs) plus CpG ODN for 3 days, remarkably reduced the secretion of HBsAg and HBeAg, when compared to cells treated with PBMCs plus non-CpG ODN. The levels of intracellular HBV DNA and HBV mRNA were also decreased. Treatment of HepG2 2.2.15 cells with the culture supernatants of PBMCs activated by CpG ODN can remarkably suppress the secretion of HBsAg and HBeAg as compared with that of PBMCs without CpG ODN activation under the same conditions. There were no inhibitory effects on the replication of HBV to be found for CpG ODN treatment alone. These results suggest that CpG ODN can inhibit indirectly HBV replication in vitro via activating the immune cells, and could contribute to the development of an immunoregulator against HBV infection.

CpG Oligodeoxynucleotides Prevent the Development of Scleroderma-Like Syndrome in Tight-Skin Mice by Stimulating a Th1 Immune Response

Tight-skin (Tsk/+) mice develop a disease similar to human scleroderma, characterized by the spontaneous appearance of cutaneous hyperplasia, anti-nuclear antibodies, and emphysema. T helper (Th) 2 cells secreting interleukin (IL)-4 are known to play a critical role in the etiopathogenesis of this disease. Th2-mediated responses can be blocked by treatment with synthetic oligodeoxynucleotides (ODN) containing immunomodulatory CpG motifs. Thus, we examined whether CpG ODN might be of therapeutic benefit in Tsk/+ mice. Administering CpG ODN to Tsk/+ mice every 3 wk starting at 1 wk of age abrogated skin fibrosis. This reduction in skin thickness persisted even after the cessation of therapy, and was accompanied by increased serum levels of IL-12 and an increased ratio of T cells available to secrete interferon-gamma rather than IL-4. CpG ODN therapy also reduced autoantibody production, but did not inhibit the incidence of lung emphysema. Delaying the initiation of CpG ODN treatment until 6 wk of age failed to prevent skin disease. These results indicate that by preferentially promoting the development of a Th1-biased immune milieu in young Tsk/+ mice, CpG ODN can ameliorate Th2-driven scleroderma-like syndrome.

CpG ODNs Treatments of HIV-1 Infected Patients May Cause the Decline of Transmission in High Risk Populations – A Review, Hypothesis and Implications

The Joint United Nations Program on HIV-1/AIDS (UNAIDS) announced its goal to stop HIV-1 transmission by antiviral (HAART) treatment of patients since at the end of 2003 the number of people living with HIV-1 was 38 million, 25 million in the sub-Saharan region of Africa. The present review deals with a new approach to simultaneously treat HIV-1/AIDS patients in HIV-1 endemic regions with CpG oligodeoxynucleotides (ODNs) and people at high risk of infection with a vaccine containing CpG ODNs combined with synthetic HIV-1 peptides by intranasal and intradermal applications.