Role of endogenous 4-1BB in the development of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by the production of autoantibodies directed against nuclear antigens including nucleosomes and DNA. To determine the role of T-cell costimulatory molecule 4-1BB in the regulation of SLE, MRL-Fas(lpr) (lpr) mice deficient in 4-1BB (lpr/4-1BB(-/-)) were generated and their disease phenotype was compared to that of control lpr mice. The main finding of this study is that the lpr/4-1BB(-/-) mice had more pronounced skin lesions which appeared earlier, increased lymphadenopathy, increased renal damage, and higher mortality than 4-1BB-intact control lpr mice. The increased severity of lesions in lpr/4-1BB(-/-) mice was closely associated with increases in CD4(+) T, CD3(+) B220(+) double-negative T cells, serum immunoglobulin, anti-dsDNA autoantibodies, and tissue immunoglobulin deposits. These data suggest that the 4-1BB-4-1BB ligand signalling pathway plays an important role in SLE and that deletion of 4-1BB confers susceptibility to lpr mice, leading to accelerated induction of disease and early mortality.

4-1BB stimulation induces pregnancy failure that is mediated by CD8+ T cells (52.16)

4-1BB (CD137) regarded as a powerful T-cell costimulatory molecule. However, recent studies indicate that in vivo 4-1BB stimulation is able to actively suppress the antigen-specific immune response by inducing indoleamine 2,3-dioxygenase (IDO) in antigen-presenting cells. Since we found that both 4-1BB and IDO were induced in the placenta during pregnancy, we questioned whether 4-1BB signaling would be negative or positive on the pregnancy. By treating agonistic anti-4-1BB mAb or blocking anti-4-1BBL mAb to the pregnant mice, we tested the role of 4-1BB. Treatment of agonistic anti-4-1BB mAb markedly increased the abortion of allogeneic fetus, which was primarily dependent on the CD8+ T cells. Since anti-4-1BB treatment induced the accumulation of C3 component in the placenta, which was reversed by treating depleting anti-CD8 mAb, C3 complement seemed to be functioned as an effector molecule in the placenta. However, blockade of 4-1BB / 4-1BBL interaction or 4-1BB stimulation to the syngeneic fetus showed a marginal effect on the pregnancy. These results indicate that 4-1BB signal may be involved in the regulation of immune responses between maternal T cells and fetal tissues.

This study was supported by the Science Research Center Fund from KOSEF and the Korean Ministry of Science and Technology.

4-1BB triggers IL-13 production from T cells to limit the polarized, Th1-mediated inflammation

4-1BB (CD137) triggering typically induces Th1 response by increasing IFN-gamma from T cells upon TCR ligation. We found recently that 4-1BB costimulation increased the expression of IL-13 from CD4(+) T cells, as well as CD8(+) T cells. The enhanced IL-13 expression by agonistic anti-4-1BB treatment was mediated via MAPK1/2, PI-3K, JNK, mammalian target of rapamycin, NF-AT, and NF-kappaB signaling pathways. The signaling for IL-13 induction was similar to that of IFN-gamma production by anti-4-1BB treatment in T cells. When the anti-4-1BB-mediated IL-13 expression was tested in an in vivo viral infection model such as HSV-1 and vesicular stomatitis virus, 4-1BB stimulation enhanced IL-13 expression of CD4(+) T, rather than CD8(+) T cells. Although IL-13 was enhanced by anti-4-1BB treatment, the increased IL-13 did not significantly alter the anti-4-1BB-induced Th1 polarization of T cells--increase of T-bet and decrease of GATA-3. Nevertheless, anti-4-1BB treatment polarized T cells excessively in the absence of IL-13 and even became detrimental to the mice by causing liver inflammation. Therefore, we concluded that IL-13 was coinduced following 4-1BB triggering to maintain the Th1/2 balance of immune response.

Blockade of the 4-1BB (CD137)/4-1BBL and/or CD28/CD80/CD86 costimulatory pathways promotes corneal allograft survival in mice

To explore the roles of 4-1BB (CD137) and CD28 in corneal transplantation, we examined the effect of 4-1BB/4-1BB ligand (4-1BBL) and/or CD28/CD80/CD86 blockade on corneal allograft survival in mice. Allogeneic corneal transplantation was performed between two strains of wild-type (WT) mice, BALB/c and C57BL/6 (B6), and between BALB/c and B6 WT donors and various gene knockout (KO) recipients. Some of the WT graft recipients were treated intraperitoneally with agonistic anti-4-1BB or blocking anti-4-1BBL monoclonal antibody (mAb) on days 0, 2, 4 and 6 after transplantation. Transplanted eyes were observed over a 13-week period. Allogeneic grafts in control WT B6 and BALB/c mice treated with rat immunoglobulin G showed median survival times (MST) of 12 and 14 days, respectively. Allogeneic grafts in B6 WT recipients treated with anti-4-1BB mAb showed accelerated rejection, with an MST of 8 days. In contrast, allogeneic grafts in BALB/c 4-1BB/CD28 KO and B6 CD80/CD86 KO recipients had significantly prolonged graft survival times (MST, 52.5 days and 36 days, respectively). Treatment of WT recipients with anti-4-1BB mAb resulted in enhanced cellular proliferation in the mixed lymphocyte reaction and increased the numbers of CD4(+) CD8(+) T cells, and macrophages in the grafts, which correlated with decreased graft survival time, whereas transplant recipients with costimulatory receptor deletion showed longer graft survival times. These results suggest that the absence of receptors for the 4-1BB/4-1BBL and/or CD28/CD80/CD86 costimulatory pathways promotes corneal allograft survival, whereas triggering 4-1BB with an agonistic mAb enhances the rejection of corneal allografts.

Glucocorticoid-induced tumour necrosis factor receptor family-related receptor signalling exacerbates hapten-induced colitis by CD4+ T cells

The glucocorticoid-induced tumour necrosis factor receptor family related gene (GITR) has been reported to be expressed on the activated T and CD4(+)CD25(+) regulatory T cells (Treg). Signalling triggered by GITR not only neutralizes the suppressive effect of Treg cells, but also augments activation, proliferation and cytokine production of effector T cells. To test the role of GITR in 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis - a murine model of mucosal inflammation - TNBS-injected Balb/c mice were treated with agonistic anti-GITR monoclonal antibody (mAb). Anti-GITR treatment increased the death rate compared to rat IgG-treated mice. Typically, death occurred within 4 days after the TNBS injection when the mice were treated with anti-GITR. The mice that survived anti-GITR treatment suffered from severe inflammation in their entire intestines. CD4(+) T-depletion protected the mice from colitis; even an anti-GITR effect was not apparent. In contrast, CD8(+) T depletion showed less protective than did CD4(+) T depletion. Stimulation of GITR enhanced the production of proinflammatory cytokines including interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-12. It also enhanced the humoral response such as serum levels of IgG(2b) and IgA, which was completely dependent on CD4(+) T cells. Taken together, this study demonstrated that GITR signalling on CD4(+) T cells is involved in the development and progress of colitis by enhancing both T helper type 1 (Th1) and Th2 type responses.

4-1BB-mediated amelioration of experimental autoimmune uveoretinitis is caused by indoleamine 2,3-dioxygenase-dependent mechanisms

Interphotoreceptor retinoid binding protein (IRBP)-induced experimental autoimmune uveoretinitis (EAU) is a CD4+ T cell-mediated autoimmune disease. Development of EAU is inhibited by treatment with an agonistic anti-4-1BB mAb. Even established EAU was alleviated by anti-4-1BB mAb. However, inhibition of 4-1BB/4-1BB ligand (4-1BBL) interaction does not suppress the development of EAU. It appears that cross-linking of 4-1BB evokes an active antigen-specific suppression mechanism rather than merely blocking 4-1BB/4-1BBL interaction. We found that administration of anti-4-1BB mAb induced massive clonal expansion of CD11c+CD8+ T cells that produced IFN-gamma, resulting in accumulation of a high level of indoleamine 2,3-dioxygenase (IDO) in CD11c+ dendritic cells. 4-1BB-mediated suppression of EAU was reversed by the pharmacological IDO inhibitor, 1-methyl-tryptophan (1-MT). These studies demonstrate that suppression of EAU results from antigen-driven, 4-1BB-mediated expansion of novel CD11c+CD8+ T cells that suppress antigen-specific CD4+ T cells via an IDO-dependent mechanism.

Rerupture following endovascular treatment for dissecting aneurysm of distal anterior inferior cerebellar artery with parent artery preservation: retreatment by parent artery occlusion with Guglielmi detachable coils

Distal anterior inferior cerebellar artery (AICA) aneurysms are rare and most cases have been treated surgically by clipping, wrapping or trapping. We recently treated this 20-year-old male patient by an endovascular technique. At first, he was treated by intra-aneurysmal embolisation with parent artery preservation. But he presented with rerupture 1 month after embolisation. Follow-up angiography revealed the regrowth of the aneurysm, which was considered as a dissecting aneurysm. We performed occlusion of the AICA just proximal to the aneurysm to prevent fatal rebleeding. He gradually improved and his level of consciousness fully recovered. At 2 year follow up, he had no neurological deficits. We suggest that embolisation of distal AICA aneurysm with parent artery occlusion may be safe and a simple method in the treatment of distal AICA aneurysms.

4-1BB costimulation enhances HSV-1-specific CD8+ T cell responses by the induction of CD11c+CD8+ T cells

Since 4-1BB plays a predominant role in CD8+ T cell responses, we investigated the effects of 4-1BB triggering on the primary and memory CD8+ T responses to HSV-1 infection. 4-1BB was detected on 10-15% of CD4+ and CD8+ T cells following the infection. 4-1BB-positive T cells were in the proliferative mode and showed the enhanced expression of anti-apoptotic proteins. Agonistic anti-4-1BB treatment exerted preferential expansion of CD8+ T cells and gB/H-2Kb-positive CD8+ T cells, and enhanced cytotoxicity against HSV-1 that was mainly mediated by CD11c+CD8+ T cells. CD11c+CD8+ T cells were re-expanded following re-challenge with HSV-1 at post-infection day 50, indicating that CD11c+CD8+ phenotype was maintained in memory CD8+ T cell pool. Our studies demonstrated that 4-1BB stimulation enhanced both primary and memory anti-HSV-1 CD8+ T cell responses, which was mediated by a massive expansion of antigen-specific CD11c+CD8+ T cells.

Emergence of Rsv-resistance breaking Soybean mosaic virus isolates from Korean soybean cultivars

Twelve Rsv resistance-breaking (RB) isolates of Soybean mosaic virus (SMV) were obtained from field-grown soybean plants showing mosaic symptoms and subsequently examined biologically and molecularly. All of these RB isolates were identified as SMV based on serological and infectivity assays, and the amplification of P1 gene products by reverse transcription-polymerase chain reaction (RT-PCR). Differential soybean cultivars, lines or accessions Lee 68 (rsv), PI 96983, York, Marshall, Ogden, Kwanggyo, Suweon 97 (Rsv1 alleles), L29 (Rsv3), and V94-5152 (Rsv4), following inoculation with each RB isolate, showed similar systemic symptoms suggesting that these RB isolates can overcome Rsv resistance at three loci. To differentiate the 12 RB isolates molecularly, the P1 coding region for each isolate was amplified, cloned, sequenced and compared to known SMV strains. The P1 region from the RB isolates shared 86-90% and 90-99% similarities in amino acid (aa) and nucleotide sequence, respectively, with known SMV strains. Comparison of aa sequences indicated that these RB isolates are newly emerging isolates capable of breaking Rsv resistance. Phylogenetic analysis further suggested that the RB isolates can be classified as three major types. However, recombination was not observed within the coding region of P1 protein among the types. This is the first report on the emergence of SMV isolates capable of overcoming all of the known resistance alleles at the Rsv1 locus, as well as distinct resistance genes at Rsv3 and Rsv4.

Inhibitory effects of Cnidium officinale Makino and Tabanus fulvus Meigan on the high glucose-induced proliferation of glomerular mesangial cells

This study describes a potent activity of Cnidium officinale Makino (Cnidii rhizoma) and Tabanus fulvus Meigan (Tabanus) as an inhibitor of high glucose-induced proliferation of glomerular mesangial cells (GMCs). Raising the ambient glucose concentration from 5.6 to 25 mM for 24 h caused a dramatic increase in [3H]thymidine incorporation, and these increases were attenuated by treatment of GMCs with the extracts of Cnidii rhizoma and Tabanus (2.5-20 microg/ml) in a dose-dependent manner. In contrast, extracts of Cnidii rhizoma or Tabanus (20 microg/ml) did not change the growth of GMCs cultured under normal glucose condition. To clarify the mechanism involved in anti-proliferative activity of these medicines, this study examined the effects of Cnidii rhizoma and Tabanus on high glucose-stimulated extracellular matrix (ECM) protein accumulation and transforming growth factor-beta1 (TGF-beta1) production. Exposure of GMCs to high glucose significantly stimulated the ECM protein, collagen and fibronectin, accumulation and TGF-beta1 secretion, and these changes were dramatically diminished by treatment of GMCs with extracts of Cnidii rhizoma or Tabanus (10 microg/ml). Taken together, these results indicate that Cnidii rhizoma and Tabanus inhibit the high glucose-induced GMC proliferation partially through suppressing the ECM accumulation and TGF-beta1 production, suggesting that these medicines may be a promising agent for treating the development and progression of diabetic glomerulopathy.

Herpesvirus infection of ICAM-1-deficient mice

PURPOSE

To determine the effect of ICAM-1 deficiency on viral infection of the cornea.

MATERIALS AND METHODS

Wild-type and intercellular adhesion molecule 1 (ICAM-1)-deficient mice were infected with the RE strain of herpes simplex virus type 1 (HSV-1). Corneal swabs and trigeminal ganglia were obtained and analyzed for infectious virus. Corneas and trigeminal ganglia were evaluated for signs of inflammation by immunohistochemical staining and for interferon-gamma (IFN-gamma)-producing cells by enzyme-linked immunospot assay (ELISPOT). Serum anti-HSV-1 antibody titers were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Viral titers in corneal swabs from the wild-type and ICAM-1-deficient mice were not significantly different during the 21-day study. Infectious virus was present in the trigeminal ganglia of wild-type and ICAM-1-deficient mice through day 6 after infection. Serum anti-HSV-1 antibody titers were significantly higher in wild-type mice 6 days after infection, compared with ICAM-1-deficient mice; by day 8 and thereafter, however, antibody titers were not significantly different. Production of interferon gamma was greater in trigeminal ganglion cells from wild-type mice stimulated with interleukin 12 and interleukin 18 on days 4, 6, and 8 after infection compared with cells from ICAM-1-deficient mice. Histopathologic analysis of corneal and ganglion sections from wild-type and ICAM-1-deficient mice showed no significant differences in the time-course of appearance or the intensity of the inflammatory infiltrate. Immunohistochemical staining for CD3(+) T-lymphocytes and CD11b(+) neutrophils and macrophages demonstrated equivalent numbers of these cells in the corneas and trigeminal ganglia of wild-type and ICAM-1-deficient mice.

CONCLUSIONS

The results of these experiments indicate that ICAM-1 deficiency has only a modest effect on viral infection of the cornea and the development of an acquired immune response.

4-1BB-mediated immunotherapy of rheumatoid arthritis

Collagen type II-induced arthritis is a CD4(+) T-cell-dependent chronic inflammation in susceptible DBA/1 mice and represents an animal model of human rheumatoid arthritis. We found that development of this condition, and even established disease, are inhibited by an agonistic anti-4-1BB monoclonal antibody. Anti-4-1BB suppressed serum antibodies to collagen type II and CD4(+) T-cell recall responses to collagen type II. Crosslinking of 4-1BB evoked an antigen-specific, active suppression mechanism that differed from the results of blocking the interaction between 4-1BB and its ligand, 4-1BBL. Anti-4-1BB monoclonal antibodies induced massive, antigen-dependent clonal expansion of CD11c(+)CD8(+) T cells and accumulation of indoleamine 2,3-dioxygenase in CD11b(+) monocytes and CD11c(+) dendritic cells. Both anti-interferon-gamma and 1-methyltryptophan, a pharmacological inhibitor of indoleamine 2,3-dioxygenase, reversed the anti-4-1BB effect. We conclude that the suppression of collagen-induced arthritis was caused by an expansion of new CD11c(+)CD8(+) T cells, and that interferon-gamma produced by these cells suppresses antigen-specific CD4(+) T cells through an indoleamine 2,3-dioxygenase-dependent mechanism.

CD137-Deficient Mice Have Reduced NK/NKT Cell Numbers and Function, Are Resistant to Lipopolysaccharide-Induced Shock Syndromes, and Have Lower IL-4 Responses

CD137, a member of the TNF superfamily, is involved in T cell and NK cell activation and cytokine production. To establish its in vivo role in systems dependent on NK and NKT cells, we studied the response of CD137-/- mice to LPS-induced shock, tumor killing, and their IL-4-controlled Th2 responses. In both high and low dose shock models, all the CD137-deficient mice, but none of the wild-type BALB/c mice, survived. After injection of LPS/2-amino-2-deoxy-D-galactose (D-gal), CD137-/- mice had reduced serum cytokine levels and substantially impaired liver IFN-gamma and TNF-alpha mRNA levels. Phenotypic analysis of mononuclear cells revealed fewer NK and NKT cells in the CD137-/- mice. The knockout mice did not generate a rapid IL-4 response after systemic T cell activation, or effective Ag-specific Th2 responses. In addition, both in vitro and in vivo NK-specific cytolytic activities were reduced. These findings suggest that CD137-directed NK/NKT cells play an important role in the inflammatory response leading to the production of proinflammatory cytokines, LPS-induced septic shock, and tumor killing, as well as IL-4-dependent Th2 responses.

Cloning and characterization of GITR ligand

The gene encoding the natural ligand of murine glucocorticoid-induced tumor necrosis factor receptor (GITR) was cloned and characterized. The putative GITR ligand (GITRL) is composed of 173 amino acids with features resembling those of type II membrane proteins and is 51% identical to the human activation-inducible TNF receptor (AITR) ligand, TL6. Expression of the GITRL is restricted to immature and mature splenic dendritic cells. GITRL binds GITR expressed on HEK 293 cells and triggers NF-kappaB activation. Functional studies reveal that soluble CD8-GITRL prevents CD4+CD25+ regulatory T-cell-mediated suppressive activities.

Seungnoidan increases cerebrocortical ATP and acetylcholine contents in ovariectomized rats

This study investigated the effects of Seungnoidan (SND), which has been widely used as a remedy for cerebroneuronal diseases in Korean folk medicine, on the cerebrocortical adenosine triphosphate (ATP) and acetylcholine (ACh) contents in ovariectomized (OVX) rats. Female Sprague-Dawley rats were ovariectomized and maintained for 12 weeks to deplete ovarian steroid hormones, followed by oral administration of SND at 500 mg/kg/day for 14 weeks. SND markedly attenuated the high rate of body weight increase in OVX rats, and also reduced the decline of cerebral weight caused by ovariectomy (p < 0.05). Superfusion of SND at 50 mg/kg significantly increased the rate of cerebral blood fl ow, but did not change the mean arterial blood pressure. Deprivation of ovarian steroid hormones significantly decreased the cerebral ATP, choline and ACh contents, and these reductions were reduced by treatment of OVX rats with SND (p < 0.01). Additionally, SND also significantly elevated the cerebral choline acetyltransferase activities reduced by OVX (p < 0.01). Taken together, these results suggest that the pharmacological properties of SND may be implicated in the improvement of metabolic pathways of cerebral energy and cholinergic neurotransmitter function induced by deprivation of ovarian steroid hormones, and SND may be a promising herbal remedy for treatment of cerebral dysfunctions including dementia.

4-1BB-dependent inhibition of immunosuppression by activated CD4+CD25+ T cells

4-1BB (CD137) is a costimulatory molecule involved in the activation and survival of CD4, CD8, and natural killer cells. Although a great deal has been learned as to how 4-1BB-mediated signaling governs the immunity of conventional T cells, the functional role of 4-1BB in the context of CD4(+)CD25(+) regulatory T cell (Tr) activation is largely unknown. Using 4-1BB-intact and -deficient mice, we investigated the effect of the 4-1BB/4-1BB ligand pathway on the suppressive function of Tr cells. Our data indicate that although 4-1BB is expressed on Tr cells, its contribution to their proliferation is minimal. We also showed that signaling through the 4-1BB receptor inhibited the suppressive function of Tr cells in vitro and in vivo. It is interesting that anti-4-1BB-mediated but not anti-GITR-directed inhibition was more potent when Tr cells were preactivated. Collectively, these data indicate that 4-1BB signaling is critical in Tr cell immunity.

Immunity in the absence of CD28 and CD137 (4-1BB) molecules

We report the generation and immune regulation of mice that are deficient in CD28 and 4-1BB (CD137) genes. These mice were viable, fertile and did not display any overt abnormalities and had a normal T cell phenotype in thymus and spleen. Proliferative responses to anti-CD3 and ConA were enhanced in 4-1BB-/- but not in either CD28-/- or double mutant mice, while levels of interleukin-2 were decreased in all mutant mice. Although the 4-1BB-/- mice displayed increased basal levels of most immunoglobulin isotypes tested, the plateau levels of immunoglobulin G2a, immunoglobulin G2b and immunoglobulin A were particularly high compared to wild type controls. The immunoglobulin class switch to T-dependent antigen was normal in 4-1BB-/- mice but was greatly affected in both CD28-/- and 4-1BB-/- CD28-/- mice. Vesicular stomatitis virus-specific cytotoxic T lymphocyte responses and plaque reduction neutralizing ability was differentially reduced in all mutant mice. Contact sensitivity to allergens showed marginal but not significant change in ear thickness in 4-1BB-/- mice, but an ability to mount contact hypersensitivity to the same antigens was greatly curtailed in CD28-/- and double mutant mice.

4-1BB promotes the survival of CD8+ T lymphocytes by increasing expression of Bcl-xL and Bfl-1

4-1BB, a T cell costimulatory receptor, prolongs CD8(+) T cell survival. In these studies, 4-1BB stimulation was shown to increase expression of the antiapoptotic genes bcl-x(L) and bfl-1 via 4-1BB-mediated NF-kappaB activation. This signaling pathway was specifically inhibited by PDTC and was different from the pathways that enhanced CD8(+) T cell proliferation. The results suggest a role for the antiapoptotic activities of Bcl-x(L) and Bfl-1 proteins in 4-1BB-mediated CD8(+) T cell survival in vivo.

Immune responses in 4-1BB (CD137)-deficient mice

The 4-1BB (a TNFR superfamily member) is an inducible costimulatory molecule that can exert regulatory effects on T cells independently of CD28 stimulation. The in vitro expression of 4-1BB (CD137) is induced following activation of T cells with various stimuli, including anti-TCR mAbs, lectins, and a combination of PMA and ionomycin. To delineate further the physiological role of 4-1BB in immunity, mice deficient in this receptor were generated. These mutant mice developed normally, and were viable and fertile. Humoral responses to vesicular stomatitis virus were comparable with those seen in wild-type mice, whereas the IgG2a and IgG3 isotype responses to keyhole limpet hemocyanin were somewhat reduced in the mutant mice. The 4-1BB-deficient mice demonstrated enhanced T cell proliferation in response to mitogens or anti-CD3 even in the environment of reduced ability to secrete growth-supporting cytokines (IL-2 and IL-4). Although T cells from 4-1BB-deficient mice showed enhanced proliferation, the T cell immune responses of these animals, such as cytokine production and CTL activity, were diminished. In addition, 4-1BB deletion appears to play a role in the regulation of myeloid progenitor cell growth, leading to an increase in these precursor cells in peripheral blood, bone marrow, and spleen.

In vitro antimicrobial activity of a chitooligosaccharide mixture against Actinobacillus actinomycetemcomitans and Streptococcus mutans

The purpose of this study was to evaluate the in vitro antibacterial activity of a chitooligosaccharide mixture (MW 2000-30000 Da) with a deacetylation degree of 91.5% against two representative oral pathogens, Actinobacillus actinomycetemcomitans and Streptococcus mutans. A 0.1% concentration of the chitooligosaccharides (derived from the exoskeletons of marine crustaceans) was used to estimate antibacterial activity. Approximately 2 logcolony forming units (CFU)/ml of A. actinomycetemcomitans were inactivated by 0.1% chitosan after 30 min, while 120 min exposure inactivated about 4.5 logCFU/ml of this organism. In contrast, the level of inactivation against S. mutans was less than 0.5 logCFU/ml after an exposure of up to 120 min. Electron microscopy showed that the exposure of A. actinomycetemcomitans to the chitooligosaccharides resulted in the disruption of cell membranes and that it could be considered for the treatment of periodontal diseases associated with A. actinomycetemcomitans.

Activation of matrix metalloproteinase-2 by a novel oral spirochetal species Treponema lecithinolyticum

BACKGROUND

Periodontal tissue destruction is a characteristic of periodontitis. This can be caused by either bacterial enzymes or host cell-derived matrix metalloproteinases (MMPs). In order to elucidate the etiologic role of oral spirochetes, we investigated the effects of Treponema lecithinolyticum, a novel saccharolytic species, on MMP-2 activation.

METHODS

Gingival fibroblasts (GFs) and periodontal ligament (PDL) cells obtained from healthy human subjects were cultured to confluence in alpha-minimal essential medium (alpha-MEM) supplemented with 10% fetal bovine serum. After serum starvation for a day, the cultures were treated with whole cell sonicates, heat-denatured whole cell sonicates, outer membrane fraction (OMF) or formaldehyde-fixed cells of T. lecithinolyticum. Culture supernatants were collected after incubation for 24 to 48 hours and analyzed for MMP-2 activation by gelatin zymography. Collagenolytic activity was quantitatively measured using human [3H] type IV collagen as a substrate.

RESULTS

Treatment of GFs and PDL cells with whole cell sonicates, formaldehyde-fixed whole cells, or the OMF of T. lecithinolyticum resulted in the production of MMP-2 partly in the fully active form with a molecular mass of 62 kDa, whereas non-treated control cultures and cultures treated with a heat-denatured fraction did not show the active form. Cultures exposed to T. lecithinolyticum had higher collagenolytic activity than non-treated cultures.

CONCLUSIONS

Our results demonstrate that T. lecithinolyticum, possibly mediated by proteinaceous cell surface-associated components, may participate in extracellular matrix degradation by activation of MMP-2 during periodontal inflammation.

Characterization of FasG segments required for 987P fimbria-mediated binding to piglet glycoprotein receptors

The 987P fimbriae of enterotoxigenic strains of Escherichia coli bind to both glycoprotein and glycolipid receptors on the brush borders of piglet enterocytes. A mutation in lysine residue 117 of the adhesive subunit FasG [fasG(K117A)] previously shown to abrogate 987P binding to the lipid receptor sulfatide did not affect the interaction with the glycoprotein receptors. Both the fimbriae and the FasG subunits of the wild type and the fasG(K117A) mutant bound to the glycoprotein receptors, confirming that lysine 117 was not required for binding to the glycoprotein receptors. Truncated FasG molecules were used to identify domains required for glycoprotein receptor recognition. At least two segments which did not include lysine117, namely, residues 211 (glutamine) to 220 (serine) and 20 (aspartic acid) to 41 (serine), were shown to be involved in the FasG-glycoprotein receptor interactions by ligand-blotting assays. Changing isoleucine 217 or leucine 215 of FasG to alanine abolished the property of a truncated FasG fusion protein to inhibit 987P recognition of its glycoprotein receptors. Thus, the K117 residue of FasG is required only for binding to the glycolipid receptor, whereas the newly identified hydrophobic residues of the FasG subunit are required specifically for the recognition of the glycoprotein receptor. Taken together, our data indicate that different residues of the FasG adhesin are important in 987P fimbrial binding to sulfatide and glycoprotein receptors, suggesting different mechanisms of interaction.

Effects of whole cell sonicates of Treponema lecithinolyticum on osteoclast differentiation

BACKGROUND

Alveolar bone destruction is a characteristic feature of periodontal diseases and multinucleated osteoclast cells derived from hemopoietic cells are responsible for bone resorption. Treponema lecithinolyticum is a novel oral spirochete isolated from the periodontal lesions.

METHODS

The effect of whole cell sonicates on the osteoclast differentiation was examined in a co-culture system of hemopoietic mouse bone marrow cells and calvaria derived-osteoblastic cells to clarify the role of T. lecithinolyticum in the alveolar bone destruction associated with periodontal diseases. The differentiated osteoclasts were confirmed by tartrate-resistant acid phosphatase (TRAP) staining.

RESULTS

Sonicates of this bacterium stimulated the osteoclast formation in the co-culture system in a dose-dependent manner. The sonicates-induced osteoclast formation was partially inhibited by the heat treatment of sonicates. Indomethacin, which is a prostaglandin inhibitor, decreased the osteoclast formation induced by the bacterial sonicates.

CONCLUSIONS

These findings suggest that T. lecithinolyticum induces osteoclast differentiation by a prostaglandin E2-dependent mechanism and that heat-labile components may be involved in this process.

Outer sheath associated proteins of the oral spirochete Treponema maltophilum

We recently cloned the major outer membrane protein of Treponema maltophilum [Heuner, K., Choi, B.K., Schade, R., Moter, A., Otto, A., Göbel, U.B., J. Bacteriol. 181, 1025-1029]. Here we report the localization of the major sheath protein (Msp)A protein in T. maltophilum by immunogold electron microscopy and its expression. Northern blot analysis revealed that mspA is expressed constitutively as a monocistronic unit. The transcription initiation site of the mspA gene was identified by primer extension analysis. A further screening of a genomic library of T. maltophilum with an anti-outer membrane fraction antibody was done. We were able to clone DNA regions of T. maltophilum encoding putative sugar transport operons and putative outer membrane proteins of this oral treponeme which has a high prevalence in periodontal lesions.

Expression and purification of glycosylated bovine beta-casein (L70S/P71S) in Pichia pastoris

Post-translational glycosylation of bovine beta-casein (L70S/P71S) that results in Asn(68)-linked glycan on the protein was obtained in up to 30% of total beta-casein expressed in the methylotrophic yeast Pichia pastoris. Among the growth/induction media used, buffered minimal glycerol (BMG)/buffered minimal methanol (BMM) media were best for the production of glycosylated bovine beta-casein, indicating pH-dependent glycosylation. Glycosylated bovine beta-casein (L70S/P71S) expressed in P. pastoris was purified to homogeneity by the combination of ammonium sulfate fractionation, Concanavalin A--Sepharose affinity column, and Mono Q anion-exchange FPLC. The purified glycosylated bovine beta-casein was specific only to Concanavalin A, and the oligosaccharide structure of glycosylated beta-casein was of high-mannose type. Unlike the hyperglycosylation that occurred in yeast, the majority of bovine beta-casein was not hyperglycosylated in P. pastoris, and its molecular weight was estimated to be 33.6 kDa. Glycosylated bovine beta-casein was normally phosphorylated to the same degree as native bovine beta-casein.

LC-MS/MS signal suppression effects in the analysis of pesticides in complex environmental matrices

The application of LC separation and mobile phase additives in addressing LC-MS/MS matrix signal suppression effects for the analysis of pesticides in a complex environmental matrix was investigated. It was shown that signal suppression is most significant for analytes eluting early in the LC-MS analysis. Introduction of different buffers (e.g. ammonium formate, ammonium hydroxide, formic acid) into the LC mobile phase was effective in improving signal correlation between the matrix and standard samples. The signal improvement is dependent on buffer concentration as well as LC separation of the matrix components. The application of LC separation alone was not effective in addressing suppression effects when characterizing complex matrix samples. Overloading of the LC column by matrix components was found to significantly contribute to analyte-matrix co-elution and suppression of signal. This signal suppression effect can be efficiently compensated by 2D LC (LC-LC) separation techniques. The effectiveness of buffers and LC separation in improving signal correlation between standard and matrix samples is discussed.

Effect of liquid chromatography separation of complex matrices on liquid chromatography-tandem mass spectrometry signal suppression

The effect of liquid chromatography separation on liquid chromatography-tandem mass spectrometry (LC-MS-MS) signal response for the characterization of low-molecular-mass compounds in a complex matrix was investigated. Matrix induced signal suppression appears throughout the entire LC-MS-MS analysis of wheat forage extract, with greatest suppression occurring at early retention times. Experimental results show that co-elution of matrix components and analytes from the LC column may be most strongly attributed to column overloading rather than similar analyte and matrix retention behavior. As a result, two-dimensional (LC-LC) separation can be a highly effective approach to address signal suppression effects for the quantitative LC-MS-MS analysis of complex matrix samples.

Cation-exchange purification of mutagenized bovine beta-casein expressed in transgenic mouse milk: its putative Asn68-linked glycan is heterogeneous

Bovine beta-casein (A2 genetic variant) was mutagenized to (L70S/P71S) and expressed in transgenic mouse milk. This protein now carries the signal (N68S69S70S71) that mimics a consensus eukaryotic glycosylation signal (N-X-S/T) (3). Hypothetically this protein should be glycosylated at N68 by any eukaryotic organism producing it. This novel protein was purified from transgenic mouse milk by Mono-S cation-exchange fast protein liquid chromatography (FPLC). The novel beta-casein was separated without cross contamination from mouse caseins by using acetate buffer (pH 5.0) in the presence of 6 M urea, octyl-glucopyranoside and 2-beta-mercaptoethanol. The purified (L70S/P71S) beta-casein showed an N-linked oligosaccharide attached to Asn68 and different lectin binding profiles compared with the same protein expressed in yeast. The mouse-expressed beta-casein (L70S/P71S) was specific to Concanavalin A, wheat germ agglutinin, Erythrina cristagalli agglutinin, and Ulex europaeus, indicating its oligosaccharide structure is different in the mammary gland of mouse than the reported glycosylated beta-casein expressed in Pichia pastoris (4). In addition, the five serine residues located at amino terminus of wild type bovine beta-casein were shown to be normally phosphorylated as in native bovine beta-casein.

Molecular epidemiology and association of putative pathogens in root canal infection

The purpose of this study was to investigate the epidemiology of putative pathogens in root canals with apical periodontitis and to determine the associations among the putative pathogens. Eighteen symptomatic and 20 asymptomatic teeth from 36 subjects were studied. This research was performed with polymerase chain reaction and hybridization using rRNA-based oligonucleotide probes. The most frequently found species was Fusobacterium sp. (68.4%), followed by Peptostreptococcus micros (44.7%) and Porphyromonas gingivalis (26.3%). Sixteen teeth (42.1%) contained one or more species of the selected black-pigmented bacteria. Bacteroides forsythus and Treponema sp. were detected in 8 teeth and 6 teeth, respectively. Among the analyzed bacteria, significant relationships were shown in the combination of B. forsythus/P. gingivalis and Treponema sp./P. gingivalis. There was no significant association between any bacteria and any symptoms.

Detection of major putative periodontopathogens in Korean advanced adult periodontitis patients using a nucleic acid-based approach

BACKGROUND

Although extensive microbial analyses have been performed from subgingival plaque samples of periodontitis patients, systematic analysis of subgingival microbiota has not been carried out in a Korean population so far. The purpose of this study was to describe the prevalence of major putative periodontopathogens in Korean patients by culture-independent methods.

METHODS

A total of 244 subgingival plaque samples (5 sites in each participant) were taken from 29 advanced adult periodontitis (AP) patients and 20 periodontally healthy subjects. AP samples were obtained from the 4 deepest periodontal pockets (> or =6 mm probing depth [PD]) and 1 healthy site (< or =3 mm PD) in each patient. Polymerase chain reaction (PCR) of 16S ribosomal DNA (rDNA) of subgingival plaque bacteria was performed with eubacterial primers. Aliquots of PCR products were then applied on nylon membranes and hybridized with specific oligonucleotide probes labeled with digoxigenin.

RESULTS

All diseased sites harbored Fusobacterium sp., while Porphyromonas gingivalis, Treponema sp., and Bacteroides forsythus were detected in more than 96% of 116 diseased sites. Peptostreptococcus micros, Actinobacillus actinomycetemcomitans, and Prevotella intermedia were present in 82%, 74%, and 71% of diseased sites, respectively. In sites of periodontally healthy subjects, Fusobacterium sp. was present in the highest proportion (58%). Treponema sp., P. gingivalis, and B. forsythus were detected in 22%, 18%, and 18% of healthy sites, respectively. P. micros, P. intermedia, and A. actinomycetemcomitans were found in 8%, 2%, and 1% of healthy sites, respectively. The prevalence of the periodontopathogens, with the exceptions of Fusobacterium sp. and B. forsythus, was significantly higher in the healthy sites of periodontitis subjects than in the healthy sites of periodontally healthy subjects (P <0.05).

CONCLUSIONS

Using highly sensitive methods relying on 16S ribosomal RNA-based oligonucleotide probes, we confirmed the strong association of 7 putative periodontopathogens with AP patients in a Korean population. With the exceptions of Fusobacterium sp. and B. forsythus, all the periodontopathogens were significantly more associated with the healthy sites of periodontitis subjects than in the healthy sites of periodontally healthy subjects.

Prevention of encephalomyocarditis virus-induced diabetes by live recombinant Mycobacterium bovis bacillus Calmette-Guérin in susceptible mice

The D variant of encephalomyocarditis (EMC-D) virus causes diabetes in susceptible mice by direct cytolysis of pancreatic beta-cells. cDNA covering the major outer capsid protein (VP1) of the EMC-D virus was cloned into Mycobacterium bovis bacillus Calmette-Guerin (BCG). None of the SJL/J mice immunized with live recombinant BCG-VP1 (rBCG-VP1) became diabetic when challenged with the highly diabetogenic EMC-D virus, but the control mice inoculated with normal BCG developed diabetes during the same challenge. VP1-specific antibodies (including neutralizing antibodies) were markedly increased over time and reached the maximum titer at week 10 after a single immunization. The plateau of the titer lasted longer than 4 weeks. Mice and guinea pigs immunized with live rBCG-VP1 showed strong delayed-type hypersensitivity to the VP1 of the EMC-D virus. The preventive immunity still worked effectively 10 months after the primary immunization. At that time, the VP1-specific antibody was almost undetectable in the bloodstream, but a large number of VP1-specific lymphocytes was found in the spleen of the immunized mice. Our results show that live rBCG-VP1 elicits effective humoral and long-lasting cellular immune responses against EMC-D virus infection that results in the prevention of virus-induced diabetes in susceptible mice.

Shibimijihwang-tang elevates intracellular ATP and choline content in the cerebral cortex of ovariectomized rats

Shibimijihwang-tang (SJT) has been used traditionally to improve systemic blood circulation and biological energy production in patients with circulatory and neuronal diseases. The object of this study is to determine the effect of SJT extract on the intracellular adenosine triphosphate (ATP) and choline content in the cerebral cortex of ovariectomized (OVX) rats. Bilateral ovaries of 8-week-old rats were removed. Rats were maintained for 12 weeks to deplete ovarian steroid hormones, followed by treatment with SJT at 500 mg/kg body weight per day for 12 weeks. High rate of body weight increase in the OVX rats was markedly reduced by treatment with SJT, but the change in body weight of normal rats was not affected by it. SJT also significantly reduced the decline of cerebral weight in the OVX rats (P<0.05). Tissue glucose content in the cerebral cortex of OVX rats was significantly increased by SJT treatment (P<0.05). A decline in cerebral ATP content in OVX rats was dramatically restored by SJT administration (P<0.01), but SJT did not change the cerebral ATP content in normal rats. Cerebral choline content also declined following ovariectomy. This reduction was significantly elevated by SJT treatment (P<0.05), but SJT did not affect the change in cerebral choline in normal rats. Taken together, these results demonstrate that SJT can reduce the decrease in brain weight, cerebral ATP and choline content caused by deprivation of ovarian steroid hormones. This suggests that pharmacological properties of SJT may play a role in improvement of reduced cerebral energy production and cholinergic neurotransmitter synthesis caused by deficiency of ovarian steroid hormones in the cerebroneuronal cells of postmenopausal women.

Radish extract stimulates motility of the intestine via the muscarinic receptors

The effects of radish (Brassica oleraceae, Cruciferae) on gastrointestinal motility were examined using rat intestinal segments with myenteric plexus in-vitro and measuring the intestinal transit of charcoal in-vivo. Radish extract (10 microg mL(-1) to 2 mg mL(-1)) caused a dose-dependent increase in contractions of the duodenum, jejunum and ileum, and 1 mg mL(-1) was the maximum effective dose. The largest contraction by the extract was found in ileal segments. The extract-induced (0.5 mg mL(-1)) ileal contraction was remarkably inhibited by pretreatment of segments with atropine (10(-7) M) for 10 min, but not by hexamethonium (0.5 mM). Moreover, antagonists of the muscarinic receptor reduced the radish-induced ileal contraction by a different ratio. The rank order of inhibitory effects was 4-diphenylacetoxy-N-methyl-(2-chloroethyl)-piperidine methiodide (90.5% of control) > tropicamide (67.4%) > pirenzepine (42.8%) > methoctramine (16.7%). Oral administration of radish extract (300-500 mg kg(-1) body weight) to mice remarkably improved the intestinal transit of charcoal, and this was significantly attenuated by co-administration of atropine (50 mg kg(-1)). Taken together, these results suggest that radish extract stimulates gastrointestinal motility through activation of muscarinic pathways.

Lysine residue 117 of the FasG adhesin of enterotoxigenic Escherichia coli is essential for binding of 987P fimbriae to sulfatide

The FasG subunit of the 987P fimbriae of enterotoxigenic strains of Escherichia coli was previously shown to mediate fimbrial binding to a glycoprotein and a sulfatide receptor on intestinal brush borders of piglets. Moreover, the 987P adhesin FasG is required for fimbrial expression, since fasG null mutants are nonfimbriated. In this study, fasG was modified by site-directed mutagenesis to study its sulfatide binding properties. Twenty single mutants were generated by replacing positively charged lysine (K) or arginine (R) residues with small, nonpolar alanine (A) residues. Reduced levels of binding to sulfatide-containing liposomes correlated with reduced fimbriation and FasG surface display in four fasG mutants (R27A, R286A, R226A, and R368). Among the 16 remaining normally fimbriated mutants with wild-type levels of surface-exposed FasG, only one mutant (K117A) did not interact at all with sulfatide-containing liposomes. Four mutants (K117A, R116A, K118A, and R200A) demonstrated reduced binding to such liposomes. Since complete phenotypic dissociation between the structure and specific function of 987P was observed only with mutant K117A, this residue is proposed to play an essential role in the FasG-sulfatide interaction, possibly communicating with the sulfate group of sulfatide by hydrogen bonding and/or salt bridge formation. Residues K17, R116, K118, and R200 may stabilize this interaction.

Age-related alteration of intracellular ATP maintenance in the cell suspensions of mice cerebral cortex

Neurological alteration in the aging brain has been suggested to be due to, in part, a declined cellular energy metabolism. In order to understand age-related alteration of intracellular ATP maintenance, the present in vitro study measured change of intracellular adenosine triphosphate (ATP) content in cell suspensions of cerebral cortex isolated from male ICR mice aged 2 days (infant), 8 weeks (young adult) and 12 months (aged) under several different conditions, using the chemiluminescence technique. Among the three different ages, significant decrease of intracellular ATP content by oxygen deprivation for 15 min was observed in the cell suspensions of cerebral cortex from 12-month-old mice (P < 0.05). When cell suspensions of 8-week cerebral cortex were incubated with or without glucose (0-60 min), intracellular ATP content decreased in a time-dependent manner under both conditions, but depletion rate was significantly high in the glucose-free condition. This decrease was maximally restored by adding 1 mM glucose as tested. In addition, the ability for intracellular ATP maintenance in the presence or absence of glucose was age-dependently different. The rank order of difference of intracellular ATP content between with and without glucose was 3 months > 12 months > 2 days. The highest decrease of intracellular ATP content by incubation without glucose was observed in the 12-month samples. Sodium cyanide (100 microM) produced a gradual ATP depletion in cerebral cortex suspended from 2-day-old mice, but rapid change in both 8-week and 12-month samples. Combination of cyanide and iodoacetate (3.5 mM) rapidly depleted the intracellular ATP content in all age groups tested. These results suggest that the aging process in the cerebral cortex of mice is accompanied by alteration of maintenance of intracellular ATP homeostasis under a given condition, and this may be associated with pathological change of overall mechanisms involved in the development of neuronal disease in the senescent brain.

Treponema lecithinolyticum sp. nov., a small saccharolytic spirochaete with phospholipase A and C activities associated with periodontal diseases

Strong phospholipase A (PLA) and phospholipase C (PLC) activities as potential virulence factors are the outstanding characteristics of eight strains of small oral spirochaetes isolated from deep periodontal lesions. By qualitative dot-blot DNA-DNA hybridization and 16S rDNA sequence comparison, these spirochaetes form a distinct phylogenetic group, with Treponema maltophilum as its closest cultivable relative. Growth of these treponemes, cells of which contain two endoflagella, one at each pole, was autoinhibited by the PLA-mediated production of lysolecithin unless medium OMIZ-Pat was prepared without lecithin. N-Acetylglucosamine was essential and D-ribose was stimulatory for growth. All isolates were growth-inhibited when 1% foetal calf serum was added to the medium. Growth on agar plates supplemented with human erythrocytes produced haemolysis. In addition to PLA and PLC, the new isolates displayed strong activities of alkaline and acid phosphatases, beta-galactosidase, beta-glucuronidase, N-acetyl-beta-glucosaminidase and sialidase, intermediate activities of C4- and C8-esterases, naphthol phosphohydrolase and alpha-fucosidase and a distinctive 30 kDa antigen detectable on Western blots. This phenotypically and genotypically homogeneous group is proposed as a novel species, Treponema lecithinolyticum sp. nov., with isolate OMZ 684T designated as the type strain. A molecular epidemiological analysis using a T. lecithinolyticum-specific probe showed this organism to be associated with affected sites when compared with unaffected sites of periodontitis patients. This association was more pronounced in patients with rapidly progressive periodontitis than in those with adult periodontitis.

Spinal involvement of hematopoietic malignancies and metastasis: differentiation using MR imaging

The purpose of this study was to determine the usefulness of magnetic resonance imaging (MRI) for distinguishing spinal involvement of hematopoietic malignancies (lymphoma, leukemia, and multiple myeloma) from metastasis. 62 spinal MRIs were obtained in 60 patients with hematopoietic malignancies (n = 24) and metastasis (n = 36) in clinically and pathologically proven cases. MRI findings were evaluated in each group of patients for the pattern of involvement, signal change of vertebral body, location of paraspinal mass formation, location of epidural mass formation, cortical destruction, contour change, and compression fracture. Diffuse involvements were more commonly seen in hematopoietic malignancies than in metastasis (p < 0.05). Signal change confined to anterior element was seen in 9 metastasis but was not seen in hematopoietic malignancies. Cortical destructions were more commonly seen in metastasis than in hematopoietic malignancies (p < 0.05). Other findings did not show any statistical significance in both groups. MRI findings such as diffuse involvement, posterior epidural mass formation, and cortical destruction were useful to distinguish spinal involvement of hematopoietic malignancies and metastasis.

Cloning and characterization of a gene (mspA) encoding the major sheath protein of Treponema maltophilum ATCC 51939(T)

The major sheath protein-encoding gene (mspA) of the oral spirochete Treponema maltophilum ATCC 51939(T) was cloned by screening a genomic library with an anti-outer membrane fraction antibody. The mspA gene encodes a precursor protein of 575 amino acids with a predicted molecular mass of 62.3 kDa, including a signal peptide of 19 amino acids. The native MspA formed a heat-modifiable, detergent- and trypsin-stable complex which is associated with the outer membrane. Hybridization with an mspA-specific probe showed no cross-reactivity with the msp gene from Treponema denticola.

Treponema brennaborense sp. nov., a novel spirochaete isolated from a dairy cow suffering from digital dermatitis

A novel Treponema species was isolated from an ulcerative lesion of a cow suffering from digital dermatitis (DD), a disease which causes painful ulcerations along the coronary band. Among other anaerobic bacteria, high numbers of spirochaetes have been regularly found in DD lesions. Here data are presented of a spirochaete isolated from a DD ulcer. By chemotaxonomy, protein analysis and comparative 16S rDNA sequence analysis this isolate was classified as a treponeme that differed from all Treponema species described previously. The only isolate, DD5/3T, for which the name Treponema brennaborense is proposed, is designated the type strain of the novel species. The strain is a small, highly motile spirochaete that has two periplasmic flagella, one flagellum being attached at each cell pole. Strain DD5/3T exhibits alpha-glucosidase and N-acetyl-beta-glucosaminidase activity and growth is inhibited by rabbit serum. T. brennaborense was phylogenetically most closely related (89.5% 16S rRNA similarity) to Treponema maltophilum, an oral spirochaete isolated from a periodontitis patient.

Molecular epidemiology of oral treponemes associated with periodontal disease

Periodontitis, a disease responsible for tooth loss worldwide, is characterized by chronic inflammation of the periodontium, eventually leading to destruction of periodontal ligaments and supporting alveolar bone. Spirochetes, identified by dark-field microscopy as being the most predominant bacteria in advanced lesions, are thought to play a causative role. Various spirochetal morphotypes were observed, but most of these morphotypes are as yet uncultivable. To assess the role of these organisms we designed oligonucleotide probes for the identification of both cultivable and so far uncultivable spirochetes in periodontitis patients. Subgingival plaque specimens taken from diseased sites (n = 200) and healthy control sites (n = 44) from 53 patients with rapidly progressive periodontitis (RPP) were submitted to direct in situ hybridization or dot blot hybridization after prior amplification with eubacterial primers. Spirochetes were found in all patients, but their distributions varied considerably. Parallel use of oligonucleotide probes specific for cultivable or so far uncultivable treponemes suggested the presence of novel yet unknown organisms at a high frequency. These uncultivable treponemes were visualized by fluorescence in situ hybridization, and their morphologies, sizes, and numbers could be estimated. All RPP patients included in this study harbored oral treponemes that represent either novel species, e.g., Treponema maltophilum, or uncultivable phylotypes. Therefore, it is necessary to include these organisms in etiologic considerations and to strengthen efforts to cultivate these as yet uncultivable treponemes.

Treponema amylovorum sp. nov., a saccharolytic spirochete of medium size isolated from an advanced human periodontal lesion

A highly motile, medium-size, saccharolytic spirochete was isolated from an advanced human periodontal lesion in medium OMIZ-Pat supplemented with 1% human serum. The growth of this organism is dependent on either glucose, maltose, starch, or glycogen. The cells contain six endoflagella, three per pole, which overlap in the central region of the cell body. On the basis of its cell morphology and enzyme activities, as well as its sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein and antigen profiles, this organism is clearly distinct from all previously cultured spirochetes. The presence of a novel species is supported by the 16S rRNA sequence of this organism, which places it in phylotype 19 of Choi et al. (B. K. Choi, B. J. Paster, F. E. Dewhirst, and U. B. Göbel, Infect. Immun. 62:1889-1895, 1994). The only isolate, strain HA2P, is designated the type strain of a novel species, for which we propose the name Treponema amylovorum.

Spirochetes from digital dermatitis lesions in cattle are closely related to treponemes associated with human periodontitis

Digital dermatitis (DD), first described in 1974 by Cheli and Mortellaro (R. Cheli and C. Mortellaro, p. 208-213, in Proceedings of the 8th International Conference on Diseases of Cattle, 1974), is a major problem in diary cows and beef cattle causing significant economic losses worldwide. Lesions are typically found at the volar skin proximal to the heel bulbs. Microscopic examination of biopsies or touch preparations of these lesions revealed a variety of different bacterial morphotypes including significant numbers of spirochetes which often represent the predominant morphotype. We used comparative 16S rRNA sequence analysis to determine the diversity and phylogeny of these hitherto unclassified DD spirochetes. Results indicate that those lesions looked at so far contained at least five spirochetal phylotypes, all clustering within the genus Treponema. Phylotype DDKL-4 was nearly identical (99.4% similarity) to that of a nonpathogenic human treponeme, T. phagedenis. Two phylotypes DDKL-3 and DDKL-13 were closely related to those from treponemes commonly found in human periodontitis lesions, i.e., T. denticola and T. vincetii, exhibiting 95 and 98% similarity, respectively. The other two phylotypes, DDKL-12 and DDKL-20, had no close relatives to any cultivable treponemal species but clustered to previously described group IV oral treponemes. Preliminary analysis using in situ hybridization with fluorescently labeled oligonucleotide probes against smears from DD biopsies revealed that from all lesions analyzed so far, T. denticola-like spirochetes were detected in the highest proportion of all spirochetal morphotypes.

Cloning and characterization of cDNAs coding for heavy and light chains of a monoclonal antibody (MabA34) specific for human plasma apolipoprotein A-I

We have determined the nucleotide (nt) sequences encoding the heavy (H)- and light (L)-chains of the Fab fragment of a murine monoclonal antibody, MabA34 (gamma1, kappa), which is specific for human plasma apolipoprotein A-I of high-density lipoproteins. The variable (V) regions of the H- and L-chains were revealed to be members of mouse H-chain subgroup II(A) and kappa L-chain subgroup II, respectively. A few unusual amino acids in the V region of the H-chain, and nt residues probably introduced by somatic mutations from germline genes were also identified.

Phylogenetic analysis of pathogen-related oral spirochetes

Recently, Riviere et al. reported as yet uncultivable invasive oral spirochetes that cross-reacted with monoclonal antibodies (MAbs) specific for Treponema pallidum (G. R. Riviere, K. S. Elliot, D. F. Adams, L. G. Simonson, L. B. Forgas, A. M. Nilius, and S. A. Lukehart, J. Periodontol. 63:131-136, 1992; G. R. Riviere, M. A. Wagoner, S. A. Baker-Zander, K. S. Weisz, D. F. Adams, L. Simonson, and S. A. Lukehart, N. Engl. J. Med. 325:539-543, 1991; G. R. Riviere, K. S. Weisz, D. F. Adams, and D. D. Thomas, Infect. Immun. 59:3377-3380, 1991; G. R. Riviere, K. S. Weisz, L. G. Simonson, and S. A. Lukehart, Infect. Immun. 59:2653-2657, 1991). In an attempt to phylogenetically analyze these pathogen-related oral spirochetes, we used immunomagnetic separation, combined with comparative sequence analysis of 16S rRNA genes amplified in vitro by the PCR. The bacteria were immunomagnetically enriched from subgingival plaque samples of patients with rapidly progressive periodontitis by using MAb H9-2 specific for the 37-kDa endoflagellum sheath protein of T. pallidum. After PCR amplification with universal eubacterial primers 16S rRNA gene fragments were cloned into Escherichia coli. A total of 20 randomly selected recombinants were analyzed by sequencing about 200 to 300 bases of the 500-bp inserts. All the spirochetal 16S rRNA sequences clustered to previously described, as yet uncultivable cluster 7 treponemes of group I (B. K. Choi, B. J. Paster, F. E. Dewhirst, and U. B. Göbel, Infect. Immun. 62:1889-1895, 1994). With a sequence similarity of 96.4% the most closely related cultivable treponeme was Treponema vincentii, which also belongs to the group I treponemes. Subsequent immunological analysis of cultured treponemes with MAb H9-2 revealed that only T. vincentii strains showed specific immunofluorescence or a characteristic 37-kDa band in immunoblots. We therefore conclude that pathogen-related oral spirochetes constitute a heterogeneous population of treponemes comprising T. vincentii and T. vincentii-related organisms that have common epitopes cross-reacting with MAb H9-2.

Treponema maltophilum sp. nov., a small oral spirochete isolated from human periodontal lesions

A novel culture medium for cultivation of fastidious oral anaerobes is described. This medium, OMIZ-Pat, consists of a rich chemically defined basal medium supplemented with asialofetuin, as well as yeast extract and Neopeptone fractions. Addition of 1 mg of rifampin per liter and 100 mg of fosfomycin per liter allowed routine isolation of spirochetes by a limit dilution method in 96-well plates containing liquid OMIZ-Pat. In addition to members of the four previously recognized species of oral treponemes (Treponema denticola, Treponema pectinovorum, Treponema socranskii, and Treponema vincentii), 26 previously undescribed spirochete strains belonging to one group were isolated. We propose the name Treponema maltophilum sp. nov. for these small spirochetes, which have two endoflagella; one endoflagellum is attached at each cell pole, and the endoflagella overlap in the middle of the cell. Growth of these organisms was dependent on a carbohydrate like D-arabinose, L-fucose, D-maltose, L-rhamnose, D-ribose, D-sucrose, or D-trehalose and was inhibited by fetal bovine serum. T. Maltophilum is distinguished from other oral Treponema species by its 16S rRNA sequence, its protein and antigen patterns as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting, and its characteristic alpha-glucosidase activity. The strains included in the new species on the basis of their 16S rRNA sequences are heterogeneous with respect to their alpha-fucosidase, and beta-glucuronidase activities, their dependence on N-acetylglucosamine, and their antigens as detected with patient antibodies. Strain BR is designated the type strain, and strains HO2A and PNA1 are reference strains of the new species.

Cloning and characterization of cDNAs coding for heavy and light chains of a monoclonal antibody (MabB23) specific for human plasma apolipoprotein B-100

We have determined the nucleotide sequences encoding the heavy and light chains of the Fab fragment of murine monoclonal antibody MabB23(gamma2b,lambda), which is specific for human plasma apolipoprotein B-100 of low-density lipoproteins. The sequence analyses revealed that the variable regions of the heavy and light chains are members of mouse heavy-chain subgroup I(B) and lambda light-chain, respectively. A few unusual amino acids in the framework and constant regions of the heavy-chain were also noticed.

Characterization of an upstream regulatory sequence and its binding protein in the mouse apolipoprotein E gene

The mouse apolipoprotein (apo) E gene from strain C57BL/6 was isolated from a genomic DNA library and its complete nucleotide sequence, together with 1.3 kilobase of 5' flanking DNA and 300 base pairs of the 3' flanking DNA, was determined. Regulatory sequences in the proximal 5' flanking region of the gene were identified. Using a chloramphenicol acetyltransferase transient assay system, positive and negative cis-acting sequences were mapped within 380 base pairs of the 5' flanking region of the mouse apoE gene. Two nuclear protein binding sites were identified within this region by DNase I footprinting. We have characterized one of these regions, termed mouse apoE regulatory sequence (MARS-2), which spans nucleotides -151 to -133. Gel mobility shift assays using oligonucleotides of the MARS-2 sequence having specific deletions or substitutions as probes or competitors showed that the essential sequence of MARS-2 required for nuclear protein binding consists of 16 nucleotides encompassing -151 to -136. When nuclear extracts from different cells were examined, L cells and mouse liver nuclear protein contained the highest levels of binding protein for the MARS-2 probe. This protein, termed MARS-2 binding protein, was purified from mouse liver nuclear extracts to homogeneity using gel filtration and MARS-2 oligonucleotide-specific column chromatographic procedures. The Mr = 66,000 binding protein showed a gel mobility shift band that was identical to that of crude nuclear extracts.

Diversity of cultivable and uncultivable oral spirochetes from a patient with severe destructive periodontitis

To determine the genetic diversity of cultivable and uncultivable spirochetes in the gingival crevice of a patient with severe periodontitis, partial 16S rRNA genes were cloned from PCR-amplified products of DNA and RNA extracted from a subgingival plaque sample. Approximately 500 bp were amplified in PCRs by using universally conserved primers with polylinker tails. Purified PCR products were cloned into Escherichia coli by using the plasmid vector pUC19. The resultant clone library was screened by colony hybridization with a radiolabeled, treponeme-specific oligonucleotide probe. The 16S rRNA inserts of 81 spirochetal clones were then sequenced by standard procedures. Sequences were compared with 16S rRNA sequences of 35 spirochetes, including the four known cultivable oral treponeme species. The analysis revealed an unexpected diversity of oral treponemes from a single patient. When 98% or greater sequence similarity was used as the definition of a species-level cluster, the clone sequences were found to represent 23 species. When 92% similarity was used as the definition, the clones fell into eight major groups, only two of which contained named species, Treponema vincentii and Treponema denticola, while Treponema pectinovorum and Treponema socranskii were not represented in any cluster. Seven of the 81 spirochetal clones were found to contain chimeric 16S rRNA sequences. In situ fluorescence hybridization with a fluorescein isothiocyanate-labeled oligonucleotide probe specific for one of the new species representing cluster 19 was used to identify cells of the target species directly in clinical samples.

Muscarine receptors regulating electrically evoked release of acetylcholine in hippocampus are linked to pertussis toxin-sensitive G proteins but not to adenylate cyclase

[3H]Acetylcholine release elicited with 360 pulses/3 Hz from slices of rabbit hippocampus is facilitated in the presence of the muscarine (M) receptor antagonist atropine (indicating the existence of autoinhibition) and diminished by the M receptor agonists carbachol and oxotremorine. N-Ethylmaleimide (30 microM) and pertussis toxin (8 micrograms/ml) counteracted antagonist-induced facilitation and agonist-induced inhibition of release, suggesting that a pertussis toxin-sensitive GTP-binding protein is involved in the chain of events mediating activation of M receptors to inhibition of release. Neither 8-bromo-cyclic AMP (300 microM), a membrane analogue of cyclic AMP, nor rolipram (10 microM), a phosphodiesterase inhibitor, affected electrically evoked release of [3H]acetylcholine. They also did not influence the oxotremorine-induced inhibition of transmitter release. In conclusion, no evidence was found for the assumption that activation of M autoreceptors is linked to inhibition of adenylate cyclase.