Failure to identify alveolar echinococcosis in trappers from South Dakota in spite of high prevalence of Echinococcus multilocularis in wild canids

Echinococcus multilocularis causes a rare but potentially lethal zoonotic disease in humans. This tapeworm has been known to be endemic in foxes (Vulpes vulpes) and coyotes (Canis latrans) within the northern United States since the 1960s. One purpose of this study was to provide recent data on the prevalence of E. multilocularis in foxes and coyotes from eastern South Dakota. In a survey conducted from 1987 to 1991 and involving 137 foxes and 9 coyotes from this area, 74.5% of the foxes and 4 of the coyotes were infected. To assess the possible prevalence of alveolar echinococcosis in a group at presumptive high risk, we also conducted a serological survey of members of the South Dakota Trappers Association in 1990 and 1991. Serum samples from 115 trappers were evaluated for the presence of E. multilocularis antibodies using enzyme-linked immunosorbent assay tests involving a purified antigen called Em2, a crude E. multilocularis antigen, and a recombinant E. multilocularis antigen called II/3-10. None of the trappers showed antibody evidence for the presence of E. multilocularis. Roughly half of the surveyed individuals had trapped more than 50 foxes during their life, and almost one-fourth had trapped more than 1,000 foxes.

Induction of interleukin-12/p40 by superantigens in macrophages is mediated by activation of nuclear factor-kappaB

Multimerization of the MHC class II molecule by superantigens results in activation of cellular signal transduction pathways in macrophage and B cells. Here we show that superantigen staphylococcal enterotoxin B (SEB) induces IL-12/p40 secretion in macrophages. SEB-induced expression of the IL-12/p40 gene involves activation and nuclear translocation of nuclear factor kappaB (NF-kappaB). The NF-kappaB heterodimer bound to the NF-kappaB consensus sequence of the IL-12/p40 gene promoter is p50/C-Rel. Inhibition of PKC and PKA activation results in suppression of activation and translocation of NF-kappaB. We conclude that signals for IL-12/p40 gene transcription from MHC class II molecules follow activation of PKC and PKA, which in turn leads to the activation and translocation of NF-kappaB to the nucleus. Our study suggests that superantigens are capable of influencing the nature of the immune response by regulating cytokine production. Induction of IL-12 production by superantigens may therefore play a role in the regulation of Th 1-mediated immune response and autoimmune disease.

Does Chlamydia pneumoniae play a role in the pathogenesis of multiple sclerosis?

It is proposed that the genome of human cytomegalovirus (HCMV) consists of two unique sequences, L and S, bounded by two sets of redundant sequences (P. Sheldrick et al. unpublished data). In this arrangement the terminal sequences (TR1 and TR8) are repeated in an intenal inverted form (IR1 and IR8) and delimit L and S. After restriction endonuclease cleavage of the DNA, four o.5 M and four 0.25 M fragments are found, indicating that HCMV DNA preparations consist of four equimolar populations differing only in the relative orientation of the L and S components. Cleavage of the CMV DNA with the restriction endonucleases BglII, HindIII and XbaI results in 32, 27 and 21 fragments, respectively. The arrangement of these fragments has been determined using molecular hybridization techniques, identification of terminal fragments and the identification of linkage groups by double-digestion. In this report the physical maps for the restriction endonucleases BglII, HindIII and XbaI are presented.

mCRY1 and mCRY2 are essential components of the negative limb of the circadian clock feedback loop

We determined that two mouse cryptochrome genes, mCry1 and mCry2, act in the negative limb of the clock feedback loop. In cell lines, mPER proteins (alone or in combination) have modest effects on their cellular location and ability to inhibit CLOCK:BMAL1 -mediated transcription. This suggested cryptochrome involvement in the negative limb of the feedback loop. Indeed, mCry1 and mCry2 RNA levels are reduced in the central and peripheral clocks of Clock/Clock mutant mice. mCRY1 and mCRY2 are nuclear proteins that interact with each of the mPER proteins, translocate each mPER protein from cytoplasm to nucleus, and are rhythmically expressed in the suprachiasmatic circadian clock. Luciferase reporter gene assays show that mCRY1 or mCRY2 alone abrogates CLOCK:BMAL1-E box-mediated transcription. The mPER and mCRY proteins appear to inhibit the transcriptional complex differentially.

Mucosal immunity in extrinsic allergic alveolitis: salivary immunoglobulins and antibody against inhaled avian antigens among pigeon breeders

BACKGROUND

Inhaled antigens from pigeons can cause extrinsic allergic alveolitis (EAA); a model disease of pulmonary inflammation. Among pigeon breeders, serum antibody and sensitized lymphocytes specific for these antigens have been described primarily, but not always, with disease. Antibody activity within the lung may have a closer association with disease, however, sampling by alveolar lavage at bronchoscopy is impractical for screening, therefore we used saliva to quantify the mucosal antibody response.

OBJECTIVE

To establish: (a) if antibody activity against inhaled avian antigens was detectable in the saliva of pigeon breeders, (b) if the distribution of saliva antibody and total immunoglobulin levels were quantitatively or qualitatively different from serum, and (c) whether the hypersensitivity symptoms of EAA were associated more with the mucosal or the systemic humoral immune response.

MEASURES

Saliva and serum total and avian antigen-specific IgG, IgA (IgA1 and IgA2) antibody activity in 87 pigeon breeders and 24 control subjects with no avian exposure. Albumin levels were used as a protein reference and cotinine levels confirmed smoking status. Specific hypersensitivity symptoms and various exposure indices to pigeons were established by interview.

RESULTS

Absolute levels and relative proportions (vs albumin) of IgG, IgA and IgA1 in saliva, and IgG in serum, were significantly higher in pigeon breeders compared with controls, suggesting mucosal inflammation. Avian antigen-specific antibody of all isotypes was readily demonstrable in saliva (predominantly IgA) and serum (predominantly IgG) from pigeon breeders, and there were no significant titres in controls. The levels of IgG antibody in saliva and in serum correlated significantly (r = 0.52, P < 0.001), and both correlated with the raised immunoglobulin levels. In both saliva and serum the IgG rather than the IgA antibody activity was associated with symptoms of EAA.

CONCLUSIONS

Antibody activity in saliva and serum, representing the mucosal and systemic responses, respectively, were both strongly stimulated by inhaled antigens. The IgG antibody titres of saliva and serum correlated significantly and were a useful index of inflammation, as measured by the raised total immunoglobulin levels, and symptoms. This suggests that IgG antibody in serum may reflect clinical and immunological sensitization of the lung mucosa. Collecting saliva is noninvasive, and saliva antibody measurement is a convenient method for monitoring EAA, especially in children, and will facilitate sampling for example in epidemiological studies of antibody prevalence.

Chlamydia pneumoniae infection of the central nervous system in multiple sclerosis

Our identification of Chlamydia pneumoniae in the cerebrospinal fluid (CSF) of a patient with multiple sclerosis (MS) led us to examine the incidence of this organism in the CSF from 17 patients with relapsing-remitting MS, 20 patients with progressive MS, and 27 patients with other neurological diseases (OND). CSF samples were examined for C pneumoniae by culture, polymerase chain reaction assays, and CSF immunoglobulin (Ig) reactivity with C pneumoniae elementary body antigens. C pneumoniae was isolated from CSF in 64% of MS patients versus 11% of OND controls. Polymerase chain reaction assays demonstrated the presence of C pneumoniae MOMP gene in the CSF of 97% of MS patients versus 18% of OND controls. Finally, 86% of MS patients had increased CSF antibodies to C pneumoniae elementary body antigens as shown by enzyme-linked immunosorbent assay absorbance values that were 3 SD greater than those seen in OND controls. The specificity of this antibody response was confirmed by western blot assays of the CSF, using elementary body antigens. Moreover, CSF isoelectric focusing followed by western blot assays revealed cationic antibodies against C pneumoniae. Infection of the central nervous system with C pneumoniae is a frequent occurrence in MS patients. Although the organism could represent the pathogenetic agent of MS, it may simply represent a secondary infection of damaged central nervous system tissue. A therapeutic trial directed at eliminating C pneumoniae from the central nervous system may provide additional information on its role in MS.

Sputum endothelin-1 is increased in cystic fibrosis and chronic obstructive pulmonary disease

Many patients with cystic fibrosis (CF) have airflow obstruction, with peribronchial and peribronchiolar fibrosis. Endothelin (ET)-1 is a potent bronchoconstrictor with mitogenic activity for airway smooth muscle. Do the levels of ET-1 in sputum support the putative role of ET-1 in contributing to airway remodelling with airflow obstruction in CF? The levels of ET-1 in plasma, saliva and sputum from 12 adult patients with CF not in exacerbation (spontaneous sputum), 17 normal control subjects (induced sputum) and as an additional control population, nine patients with stable chronic obstructive pulmonary disease (COPD) (seven spontaneous sputum) were measured. Total and differential sputum cell counts were performed. Median (interquartile range) sputum ET-1 level was elevated in CF (77.6 (29.0-122.8) pg x mL(-1)) compared to normal subjects (6.00 (2.8-14.8) pg x mL(-1)) and COPD (16.4 (6.8-38.2) pg x mL(-1)), and in COPD compared to normal subjects. There was a slight elevation of plasma ET-1 level in CF (5.3 (3.2-6.0) pg x mL(-1)) compared to normal subjects (3.1 (1.7-4.4) pg x mL(-1)) and COPD (3.3 (2.7-4.2) pg x mL(-1)). Sputum and saliva ET-1 levels were significantly higher than plasma levels in all groups, suggesting local production or release in the respiratory tract. Sputum differential cell counts revealed pronounced neutrophilia in CF and COPD compared to normal subjects. Sputum endothelin-1 concentrations are elevated in cystic fibrosis sputum compared to chronic obstructive pulmonary disease, and in cystic fibrosis and chronic obstructive pulmonary disease compared to normal subjects. The role of endothelin-1 in contributing to airflow obstruction through bronchoconstriction and mitogenesis in cystic fibrosis needs now to be explored.

Tyrphostin B42 inhibits IL-12-induced tyrosine phosphorylation and activation of Janus kinase-2 and prevents experimental allergic encephalomyelitis

IL-12 is a macrophage-derived cytokine that induces proliferation, cytokine production, and cytotoxic activity of T and NK cells. Signaling through its receptor, IL-12 induces these cellular responses by tyrosine phosphorylation and activation of Janus kinase-2 (Jak-2), Tyk-2, Stat3, and Stat4. We have used tyrphostin B42 (AG490), a Jak-2 inhibitor, to determine the role of Jak-2 kinase in IL-12 signaling and IL-12-induced T cell functions. Treatment of activated T cells with tyrphostin B42 inhibited the IL-12-induced tyrosine phosphorylation and activation of Jak-2 without affecting Tyk-2 kinase. In contrast, treatment with tyrphostin A1 inhibited the tyrosine phosphorylation of Tyk-2 but not that of Jak-2 kinase. Inhibition of either Jak-2 or Tyk-2 leads to a decrease in the IL-12-induced tyrosine phosphorylation of Stat3, but not of Stat4, protein. While inhibition of Jak-2 lead to programmed cell death, the inhibition of Jak-2 or Tyk-2 resulted a decrease in IFN-gamma production. We have further tested the in vivo effects of tyrphostin B42 in experimental allergic encephalomyelitis, a Th1 cell-mediated autoimmune disease. In vivo treatment with tyrphostin B42 decreased the proliferation and IFN-gamma production of neural Ag-specific T cells. Treatment of mice with tyrphostin B42 also reduced the incidence and severity of active and passive EAE. These results suggest that tyrphostin B42 prevents EAE by inhibiting IL-12 signaling and IL-12-mediated Th1 differentiation in vivo.

Superantigens augment antigen-specific Th1 responses by inducing IL-12 production in macrophages

Superantigens (SAg) are microbial proteins that mediate antigen-presenting cell (APC)-T cell interaction by cross-linking MHC class II molecules with subsets of TcRVbeta. SAgs are implicated in the pathogenesis of several infectious, inflammatory, and autoimmune diseases. In this study, we examined the influence of SEB on interleukin-12 (IL-12) production and the activation of antigen-specific Th1 responses. Addition of SEB augmented the antigen-induced proliferation of HS-17, a murine MBPp91-103 peptide-specific TcRVbeta6+ CD4+ Th1 clone. SEB augments HS-17 T cell proliferation through its interaction with IA(S) molecules on macrophages, but not with the TcRVbeta6 on HS-17 cells. On binding to IA(S), SEB induces IL-12 production in macrophages, which in turn augments antigen-induced proliferation of HS-17 T cells. Treatment with anti-IA(S) nmAb 10-3.6 inhibited the antigen- and SEB-induced IL-12 production and T cell proliferation. These results suggest that SAgs augment antigen-specific T cell responses by inducing IL-12 production in macrophages.

Differential influence of interleukin-12 in the pathogenesis of autoimmune and virus-induced central nervous system demyelination

Experimental allergic encephalomyelitis (EAE) and Theiler's murine encephalomyelitis virus (TMEV) disease are two demyelinating diseases of the central nervous system (CNS) that serve as animal models for multiple sclerosis. Th1 cells are thought to play a role in the pathogenesis of CNS demyelination in both these diseases. We show here the differential influence of interleukin 12, a critical cytokine for the development of Th1 cells in EAE and TMEV disease.

Prevention of experimental allergic encephalomyelitis via inhibition of IL-12 signaling and IL-12-mediated Th1 differentiation: an effect of the novel anti-inflammatory drug lisofylline

Experimental allergic encephalomyelitis (EAE) is an inflammatory, CD4+ Th1-mediated autoimmune disease, which serves as a model for multiple sclerosis. We examined the effect of a novel anti-inflammatory drug, lisofylline (LSF), on EAE induced either by injection of mouse spinal cord homogenate or following transfer of myelin basic protein-reactive T cells. Orally administered LSF significantly inhibited EAE in both cases, decreasing peak clinical scores by >70% and >80%, respectively. In addition, analysis of representative spinal cord sections from LSF-treated mice showed complete lack of demyelination and lymphocyte infiltration. The reduction in EAE correlated with the inhibition of Th1 differentiation by LSF in vivo, as indicated by a reduction in T cell IFN-gamma production ex vivo after Ag restimulation. The inhibition of Th1 differentiation in vivo is consistent with a block in IL-12 receptor signaling, because LSF blocked IL-12-driven Th1 differentiation and T cell proliferation in vitro, yet had no effect on IL-12 secretion from APCs ex vivo or in vitro.

The potential role of a late gene expression factor, lef2, from Bombyx mori nuclear polyhedrosis virus in very late gene transcription and DNA replication

Several late gene expression factors (Lefs) have been implicated in fostering high levels of transcription from the very late gene promoters of polyhedrin and p10 from baculoviruses. We cloned and characterized from Bombyx mori nuclear polyhedrosis virus a late gene expression factor (Bmlef2) that encodes a 209-amino-acid protein harboring a Cys-rich C-terminal domain. The temporal transcription profiles of lef2 revealed a 1.2-kb transcript in both delayed early and late periods after virus infection. Transcription start site mapping identified the presence of an aphidicolin-sensitive late transcript arising from a TAAG motif located at -352 nucleotides and an aphidicolin-insensitive early transcript originating from a TTGT motif located 35 nucleotides downstream to a TATA box at -312 nucleotides, with respect to the +1 ATG of lef2. BmLef2 trans-activated very late gene expression from both polyhedrin and p10 promoters in transient expression assays. Internal deletion of the Cys-rich domain from the C-terminal region abolished the transcriptional activation. Inactivation of Lef2 synthesis by antisense lef2 transcripts drastically reduced the very late gene transcription but showed little effect on the expression from immediate early promoter. Decrease in viral DNA synthesis and a reduction in virus titer were observed only when antisense lef2 was expressed under the immediate early (ie-1) promoter. Furthermore, the antisense experiments suggested that lef2 plays a direct role in very late gene transcription.

Relationship of cesarean delivery to lower birth weight-specific neonatal mortality in singleton breech infants in the United States

OBJECTIVE

The preferred route of delivery for breech presentation has been controversial. We compared the birth weight-specific neonatal mortality of vaginal births to cesarean births in singleton births with breech presentation.

METHODS

A total of 371,692 singleton live births with breech presentation were selected for the study from the United States birth cohorts for the years 1989-1991. Differences in birth weight specific mortality were compared using a z-statistic for differences in proportions and by logistic regression.

RESULTS

Compared to primary vaginal births, primary cesarean births had significantly lower neonatal mortality for all birth weight groups, despite increased prevalence of fetal malformations in the cesarean as compared with vaginally delivered group. This mortality difference was greatest in the first hour of life. Difference in overall neonatal (less than 28 days) mortality rate ranged from a low of 1.6-fold in the 500-749 g group (726.6 per 1000 vaginal births compared with 456.3 per 1000 cesarean births, P < .001) to as high as about three-fold in the 1250-1499 g group (232.9 per 1000 vaginal births compared to 72.5 per 1000 cesarean births, P < .001). In the group with birth weights over 2500 g, neonatal mortality in the primary vaginal births was 5.3 per 1000 and in the primary cesarean births, 3.2 per 1000 (P < .001). Similarly, repeat cesarean births had significantly lower birth weight-specific neonatal mortality, compared with vaginal births after previous cesarean.

CONCLUSION

Singleton live births with breech presentation delivered by cesarean had lower birth weight-specific neonatal mortality as compared with vaginal births.

TGF-beta inhibits IL-12-induced activation of Jak-STAT pathway in T lymphocytes

IL-12 is a macrophage-derived heterodimeric cytokine, capable of inducing proliferation, cytokine production, and cytotoxic activity of NK cells and T cells, and is critical for the development of Th1 responses. TGF-beta is an immunosuppressive cytokine that inhibits IL-12-mediated responses in NK and T cells. To determine the mechanism of action of TGF-beta, we examined its inhibitory effect on IL-12 signal-transduction pathway in T cells. Stimulation of activated T cells with IL-12 leads to tyrosine phosphorylation and activation of Jak-2 and Tyk-2 kinases and STAT3 and STAT4 transcription factors. Treatment of activated T cells with TGF-beta blocked IL-12-induced tyrosine phosphorylation and activation of both Jak-2 and Tyk-2 kinases. Furthermore, inhibition of Jak kinases by TGF-beta was associated with a decrease in tyrosine phosphorylation of STAT3 and STAT4 proteins. Abrogation of IL-12-induced Jak-Stat pathway by TGF-beta resulted in decreased T cell proliferation and IFN-gamma production, and increased apoptotic cell death. These findings highlight that TGF-beta inhibits IL-12-mediated responses by blocking IL-12 signal transduction in T cells.

Vasoactive intestinal peptide inhibits IL-12 and nitric oxide production in murine macrophages

Vasoactive intestinal peptide (VIP) is a naturally occurring neuropeptide widely distributed in the nervous system. In this study, we investigated the effect of VIP on IL-12, TNF alpha and nitric oxide (NO) production in macrophages following activation with lipopolysaccharide (LPS) or superantigens. In vitro studies show that at physiologic concentrations, VIP inhibited IL-12 and NO but not TNF alpha production in macrophages which were stimulated with LPS or superantigens. The inhibitory effect of VIP on IL-12 production appeared to be cAMP mediated since other cAMP inducing agents were also potent in inhibiting IL-12 production. Since IL-12 plays a critical role in T cell function, we suggest that naturally occurring neural hormones can regulate the type and direction of the immune response.

Mechanism of inhibition of LPS-induced IL-12p40 production by IL-10 and TGF-beta in ANA-1 cells

IL-12, a macrophage-derived proinflammatory cytokine, consists of two polypeptide subunits (p40 and p35) encoded by two separate genes. The p35 subunit is constitutively expressed, whereas the p40 subunit is induced after activation. The bioactive interleukin-12 (IL-12; p70) influences the development of Th1 responses and is a potent activator of natural killer (NK) and T cells. In contrast to IL-12, transforming growth factor beta (TGF-beta) and IL-10 inhibit production of proinflammatory cytokines, including IL-12, and attenuate Th1-mediated immune response. We have examined the molecular mechanisms by which TGF-beta and IL-10 inhibit production of the IL-12p40 subunit in LPS-stimulated murine macrophage cell line. We show that both IL-10 and TGF-beta suppress IL-12p40 production by inhibiting the transcription of IL-12p40 gene. At equal concentrations, IL-10 was more potent than TGF-beta in inhibiting IL-12p40 gene transcription. TGF-beta also reduces the stability of IL-12p40 mRNA, accounting thereby to an additional mechanism of inhibition of IL-12 production.

Expression of individual members of a tRNA(Gly)1 multigene family in vivo follows the same pattern as in vitro

Individual members of a tRNA(Gly)1 multigene family from Bombyx mori are transcribed to different levels in vitro in homologous nuclear extracts but their transcription status in vivo is not known. Two sets of tRNA(Gly)1 belonging to the extreme groups of highly transcribed and barely transcribed copies have been examined for their expression patterns in vivo in B. mori-derived cell lines following transfection. We have developed a sensitive and reliable method for directly quantifying the transcription levels of transfecting tRNA genes without relying on the biological activity of the transcript. The strategy involved the insertion of synthetic oligodeoxyribonucleotide sequences into the coding region of the transfecting gene and monitoring the transcripts in an RNase protection assay using an antisense probe that clearly distinguished them from the endogenous tRNAs. The oligonucleotide insertion did not significantly affect the transcriptional status of the genes, even though the distance between the A and B boxes was enhanced by 10-15 nt. In vivo also the transcription of tRNA(Gly)1 reached very high levels, whereas the transcripts arising from tRNA(Gly)1-6:7 accounted for only 2-5% of the former, closely resembling the transcription patterns in vitro. These individual gene copies having identical coding sequences and consequently the same internal conserved regions, differed only in their flanking sequences which modulate their transcription levels.

TGF-beta inhibits IL-2-induced tyrosine phosphorylation and activation of Jak-1 and Stat 5 in T lymphocytes

Signaling through IL-2R, IL-2 induces tyrosine phosphorylation and activation of Jak-1 and Jak-3 kinases and Stat 3 and Stat 5 transcription factors leading to cell cycle progression of activated T cells from G1 to S phase. TGF-beta is an immunosuppressive cytokine, which inhibits T cell proliferation at G1 to S phase transition. We examined the effect of TGF-beta on IL-2R signal transduction pathway in activated T cells. We show here that treatment of activated T cells with TGF-beta inhibited IL-2-induced tyrosine phosphorylation and activation of Jak-1 and Stat 5 but not Jak-3 and Stat 3. TGF-beta also inhibited IL-2-induced expression of alpha- and beta-chains of IL-2R and induced apoptotic cell death in T cells. These results suggest that TGF-beta-induced growth arrest and apoptosis are associated with the modulation of IL-2-induced activation of Jak-Stat pathway in T cells.

TGF-beta inhibits IL-2-induced tyrosine phosphorylation and activation of Jak-1 and Stat 5 in T lymphocytes

Signaling through IL-2R, IL-2 induces tyrosine phosphorylation and activation of Jak-1 and Jak-3 kinases and Stat 3 and Stat 5 transcription factors leading to cell cycle progression of activated T cells from G1 to S phase. TGF-beta is an immunosuppressive cytokine, which inhibits T cell proliferation at G1 to S phase transition. We examined the effect of TGF-beta on IL-2R signal transduction pathway in activated T cells. We show here that treatment of activated T cells with TGF-beta inhibited IL-2-induced tyrosine phosphorylation and activation of Jak-1 and Stat 5 but not Jak-3 and Stat 3. TGF-beta also inhibited IL-2-induced expression of alpha- and beta-chains of IL-2R and induced apoptotic cell death in T cells. These results suggest that TGF-beta-induced growth arrest and apoptosis are associated with the modulation of IL-2-induced activation of Jak-Stat pathway in T cells.