How Do You See CG?

Abstract

uptake into the cell by receptor-mediated endocytosis * Institute for Systems Biology and endosome acidification, suggesting that the recog-Seattle, Washington nition structure is either endosome-associated or cyto- † Institute for Molecular Bioscience plasmic (Krieg and Wagner, 2000). Therapeutic applica-University of Queensland Q4072 tions of the response to foreign DNA have been Australia expedited by the observation that short, CG-containing oligonucleotides (CpG-ODN) retain activity, even when stabilized with noncleavable phosphorothioate bonds The mammalian immune response to microbial patho-(Krieg and Wagner, 2000). The remarkable specificity of gens relies on both innate and adaptive components the response is seen in the observation that reversal of (Hoffmann et al., 1999). The immediate, innate response the CG motif to GC in active CpG-ODN is sufficient is mediated largely by white blood cells such as neutroto abolish activity. Aside from the core dinucleotide, phils and macrophages, cells that phagocytose and kill variation in flanking bases alters the dose response the pathogens, and that concurrently coordinate addicurve for activation, for example a 5Ј C residue (a CCG tional host responses by synthesizing a wide range of core) reduces the efficacy (Sester, et al., 1999, Krieg inflammatory mediators and cytokines (Aderem and Unand Wagner, 2000). Such structure-function studies imderhill, 1999). In macrophages, the infectious agent is ply the existence of a recognition protein that can bind killed and degraded within the maturing phagosome, to either single-stranded or double-stranded DNA and and components of the pathogen are presented to T that it has exquisite specificity for the CG core in an cells, resulting in the activation of the adaptive immune optimal context. The nature of that recognition molecule response and the establishment of protective immunity has thus far eluded identification. Two recent papers (Aderem and Underhill, 1999). A major challenge to the (Chu et al., 2000; Hemmi et al., 2000) promise a rapid innate immune system is the discrimination of a large resolution of this issue, but the connection between their number of potential pathogens from self. This challenge conclusions is not immediately apparent. has been met by the evolution of a variety of receptors Toll-like Receptor 9 and Components that recognize conserved motifs on pathogens that are of Its Signaling Pathway Are Required not found in higher eukaryotes; these so called patternfor the Response to CpG-DNA recognition receptors recognize pathogen-associated The study of Akira and colleagues (Hemmi et al., 2000) molecular patterns (Janeway and Medzhitov, 1998). builds on parallels between the recognition of foreign Every organism, even bacteria, have mechanisms of DNA and other microbial products. The Toll-like recepinnate host defense to protect against invasion by potors, first identified in Drosophila, have been implicated tential pathogens. The major defense mechanism emas the receptors that enable the innate imm...

Influence of stimulatory and suppressive DNA motifs on host susceptibility to inflammatory arthritis

“…Unmethylated CpG motifs in bacterial DNA trigger an immune response characterized by the production of proinflammatory and Th1 cytokines (6)(7)(8)(9). This evolutionarily conserved response can protect the host from infectious pathogens (18)(19)(20), but it also increases the risk of developing autoimmune and inflammatory diseases (4,(21)(22)(23)(24).…”

“…Blinded histologic evaluation of joints 4 days after injection of CpG ODNs or bacterial DNA provides rigorous evidence of pathology, which correlates with joint swelling (Pearson's correlation coefficient r ϭ 0.59, P Ͻ 0.0001) (5). Although systemically administered CpG DNA stimulates B cells, natural killer cells, and dendritic cells to proliferate, mature, and/or secrete in vivo (6)(7)(8)(9), no direct effect on the joints has ever been reported (Table 1) (4). The findings of the present study demonstrate that the generalized immune activation triggered by systemic CpG ODN treatment increases host susceptibility to a subsequent arthritogenic stimulus.…”

“…Numerous studies have shown that CpG DNA has immunostimulatory properties, triggering immune cells to proliferate, mature, and secrete a variety of proinflammatory chemokines and cytokines (6)(7)(8)(9). This immune activation can be inhibited by "suppressive" ODNs, which block the production of Th1 and proinflammatory cytokines (10)(11)(12)(13).…”

A genomic-scale view of the cAMP response element-enhancer decoy: A tumor target-based genetic tool

“…A focused set of 1,152 genes were PCR-amplified and printed in duplicate at high density onto nylon membranes. 33 P-labeled cDNAs prepared from total RNA isolated (RNeasy MidiKit, Qiagen, Chatsworth, CA) from experimental and control samples were used to probe Signal Transduction arrays, washed, and exposed to phosphorimager screens for 1-3 days. IMAGEQUANT software (Molecular Dynamics) was used to convert the hybridization signals into raw intensity values, and the data were transferred into Microsoft EXCEL spreadsheets predesigned to associate the IMAGEQUANT data format to the correct gene identities.…”

Serpin 2a Is Induced in Activated Macrophages and Conjugates to a Ubiquitin Homolog

“…Macrophages are strongly activated by bacterial DNA, and transient transfection using bacterial vectors results in the enhanced expression of many proteins associated with the activated state (25). We therefore examined the conjugation of spi2a and ISG15 in stably transfected macrophages, where the transient activation induced by the bacterial plasmid DNA has subsided.…”