The effect of dexamethasone on the generation of plasma DNA from dead and dying cells.

To determine the effects of glucocorticoids on the clearance of apoptotic and necrotic cells, the influence of dexamethasone on plasma levels of DNA was assessed in BALB/c mice receiving Jurkat cells treated with etoposide or ethanol. In untreated mice, administration of 10(8) apoptotic or necrotic Jurkat cells led to the appearance of DNA in the plasma. In mice treated 24 hours previously with dexamethasone, levels of DNA were reduced in a dose-dependent manner, with mice receiving 1 and 2.

Induction of immune activation by a novel immunomodulatory oligonucleotide without thymocyte apoptosis.

Bacterial DNA and synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG motifs (CpG DNA) can potently stimulate innate immunity. While the actions of CpG DNA resemble those of LPS, these molecules stimulate distinct Toll-like receptors as well as cell types. In a previous study, we showed that a CpG ODN could induce cytokine production but, unlike LPS, did not induce thymocyte apoptosis.

Specificity and immunochemical properties of anti-DNA antibodies induced in normal mice by immunization with mammalian DNA with a CpG oligonucleotide as adjuvant.

To elucidate the role of DNA antigen drive in the anti-DNA response, the specificity and immunochemical properties of anti-DNA antibodies induced in normal mice by immunization with double stranded (ds) mammalian DNA with a CpG oligonucleotide (ODN) adjuvant were characterized. Like spontaneous anti-DNA from MRL/lpr mice, the induced anti-DNA bound cross-reactively to DNA from five different species by ELISA. The induced antibodies displayed a predominance of IgG2a and had much lower amount of IgG3 than spontaneous antibodies.

B lymphocytes and systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by B cell hyperactivity in association with autoantibodies, most prominently those directed to components of the cell nucleus. The source of the antigens that drive B cell responses in SLE is unknown, although recent studies suggest mechanisms by which the self-antigens become immunogenic and stimulate responses. Among these mechanisms, abnormalities in the generation of apoptotic cells or their clearance may increase the availability of nuclear antigens to drive responses.

Informed consent in a clinical trial of a novel treatment for rheumatoid arthritis.

Objective: To evaluate the informed consent process for a clinical trial of intravenous doxycycline for rheumatoid arthritis.

Methods: Participants completed a self-administered questionnaire about the consent process at baseline and 16 weeks following enrollment in a clinical trial.

Results: Respondents (n = 30) affirmed voluntary participation in the parent trial.

The use of fluorometric assays to assess the immune response to DNA in murine systemic lupus erythematosus.

Antibodies to DNA (anti-DNA) play an important role in the pathogenesis of systemic lupus erythematosus (SLE). In blood, these antibodies may exist in a free, unbound state or as part of complexes with DNA. Furthermore, circulating DNA may be either complexed or free.

Role of macrophages in the generation of circulating blood nucleosomes from dead and dying cells.

After apoptosis or necrosis, macrophages clear dead cells by phagocytosis. Although this process is efficient, circulating nucleosomes can occur in certain diseases, presumably reflecting either increased production or impaired clearance. To investigate the generation of blood nucleosomes, graded numbers of apoptotic and necrotic cells were administered to healthy mice, and levels of blood nucleosomes and DNA were determined.

Enhancing immunogenicity by CpG DNA.

Bacterial DNA and oligonucleotides containing unmethylated CpG dinucleotides (CpG DNA) can stimulate immune responses and have potential for use as novel agents to enhance immunogenicity. CpG DNA can interact with toll-like receptor 9 and cause activation through a myeloid differentiation primary response gene (MyD88)-dependent signaling pathway. Due to its pattern of immune cell activation, CpG DNA can induce a cytokine milieu to promote T-helper cell responses and serve as an adjuvant.

Effect of cytofectins on the immune response of murine macrophages to mammalian DNA.

DNA, depending on base sequence, can induce a wide range of immune responses. While bacterial DNA is stimulatory, mammalian DNA is inactive alone and can, moreover, inhibit the response to bacterial DNA. To determine whether the mode of cell entry affects the immune properties of mammalian DNA, we have investigated the effects of the cytofectin agents Fugene 6 (Roche Diagnostics Corp.

Screening the genome for rheumatoid arthritis susceptibility genes: a replication study and combined analysis of 512 multicase families.

Objective: A number of non-HLA loci that have shown evidence (P < 0.05) for linkage with rheumatoid arthritis (RA) have been previously identified. The present study attempts to confirm these findings.

The expression of plasma nucleosomes in mice undergoing in vivo apoptosis.

Nucleosomes occur in the blood of patients with systemic lupus erythematosus and are thought to result from in vivo cell death. To determine the conditions for the release of nucleosomes into the blood, normal mice were treated with four agents that have the potential to induce apoptosis or immune cell activation in vivo: LPS, CpG DNA, anti-Fas antibody, and dexamethasone. Blood nucleosomes were measured by a capture ELISA immunoassay, with the DNA component assessed by fluorimetry with the dye PicoGreen.

Regulation of matrix turnover in meniscal explants: role of mechanical stress, interleukin-1, and nitric oxide.

The meniscus is an intra-articular fibrocartilaginous structure that serves essential biomechanical roles in the knee. With injury or arthritis, the meniscus may be exposed to significant changes in its biochemical and biomechanical environments that likely contribute to the progression of joint disease. The goal of this study was to examine the influence of mechanical stress on matrix turnover in the meniscus in the presence of interleukin-1 (IL-1) and to determine the role of nitric oxide (NO) in these processes.

Inhibition of murine dendritic cell activation by synthetic phosphorothioate oligodeoxynucleotides.

Depending on sequence and backbone structure, DNA can inhibit as well as stimulate immune responses. As previously shown, single-base phosphorothioate (Ps) oligodeoxynucleotides (ODN) can inhibit murine macrophage activation. To determine whether these compounds can also affect dendritic cells (DC), the effects of 30-mer Ps ODN (SdA, SdT, SdG, and SdC) on DC activation were assessed in an in vitro system.

Induction of cyclooxygenase-2 by mechanical stress through a nitric oxide-regulated pathway.

Objective: Biomechanical signals play important roles in regulating the homeostasis of articular cartilage, but under abnormal conditions may be a critical factor in the onset and progression of arthritis. Prostaglandin E(2) (PGE(2)) and nitric oxide (NO), derived from the enzymes cyclo-oxygenase 2 (COX2) and NO synthase 2 (NOS2), are inflammatory mediators that modulate numerous physiological and pathophysiological processes and are potentially important pharmacological targets in osteoarthritis. The goal of this study was to determine the effect of mechanical compression on PGE(2) production in the presence of selective NOS2 and COX2 inhibitors.

Influence of hypoxia and reoxygenation on cytokine-induced production of proinflammatory mediators in articular cartilage.

Objective: Articular cartilage is an avascular tissue that functions at a lower oxygen tension than do most tissues. With mobilization, arthritic joints may undergo cycles of hypoxia and reoxygenation. The goal of this study was to determine the effects of hypoxia and reoxygenation on cytokine-induced nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production in articular cartilage.

Inhibition of murine macrophage nitric oxide production by synthetic oligonucleotides.

Synthetic 30-mer phosphorothioate (Ps) oligonucleotides (ODN) comprised of single bases (SdA30, SdC30, SdG30, and SdT30) were assessed for their effects on nitric oxide (NO) production by murine bone marrow macrophages (BMMC) and macrophage cell lines J774 and RAW264.7. Pretreatment of these cells with any of the four Ps ODN inhibited NO production induced by CpG ODN, E.

The role of surface ig binding in the activation of human B cells by phosphorothioate oligodeoxynucleotides.

Phosphorothioate oligodeoxynucleotides (sODNs) can induce T-cell-independent polyclonal activation of human B cells by a mechanism that depends on both sequence and back-bone structure. Because matrix-bound as well as soluble sODNs are mitogenic, this stimulation may result from the engagement of surface receptor(s). In order to investigate whether surface immunoglobin (Ig) could be a receptor for sODNs, the interaction of sODNs-fluorescein isothiocyanate (FITC) with Ig-coated beads was examined.

Immune response to DNA in systemic lupus erythematosus.

Antibodies to DNA occur prominently in systemic lupus erythematosus and have been extensively studied as probes for underlying immune disturbances. These antibodies have features of DNA antigen drive. While previous models for this response posited DNA as simple and inert, recent studies have indicated that DNA is immunologically diverse and, depending upon sequence and backbone structure, can stimulate or suppress immune responses.

Host response to infection: the role of CpG DNA in induction of cyclooxygenase 2 and nitric oxide synthase 2 in murine macrophages.

Depending on sequence, bacterial and synthetic DNAs can activate the host immune system and influence the host response to infection. The purpose of this study was to determine the abilities of various phosphorothioate oligonucleotides with cytosine-guanosine-containing motifs (CpG DNA) to activate macrophages to produce nitric oxide (NO) and prostaglandin E(2) (PGE(2)) and to induce expression of NO synthase 2 (NOS2) and cyclooxygenase 2 (COX2). As little as 0.