Soluble thrombomodulin activity and soluble thrombomodulin antigen in plasma

Endothelial cell membrane-bound thrombomodulin (TM) plays a critical role as a cofactor in the protein C pathway, important in regulating coagulation as well as inflammation. Heterogeneous soluble TM fragments circulate in the plasma and are found at increased levels in various diseases such as cardiovascular disease and diabetes, and in ischemic and/or inflammatory endothelial injuries. The anticoagulant function of these soluble fragments has not been measured in healthy individuals or in patients. Using an immobilized monoclonal antibody against TM and a microtiter plate format, an assay was designed to capture the soluble TM fragments in plasma and measure their cofactor activity in the thrombin-mediated activation of protein C. In addition, soluble TM antigen levels were measured by enzyme-linked immunosorbent assay. Both assays were used to investigate a group of healthy blood donors. TM fragments released into plasma were shown to retain significant cofactor activity, and reference intervals for healthy men and women were established. Furthermore, a statistically significant correlation was observed between soluble TM antigen levels and soluble TM cofactor activity. This notwithstanding, soluble TM activity only accounted for a minor part of all variation in soluble TM antigen levels (R2 = 22% in men and R2 = 16% in women).

Sorbent-assisted liquid-liquid extraction (Chem-Elut) of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in the lipid fraction of human blood plasma

This work compares two lipid extraction methods for determining 24 polychlorinated biphenyls (PCBs), seven dibenzo-p-dioxins (PCDDs) and ten dibenzofurans (PCDFs) in human blood plasma. The first method was based on conventional liquid-liquid partitioning with chloroform-methanol and the other made use of a sorbent (Chem-Elut) to facilitate the partitioning of lipids into a mixture of hexane and 2-propanol. A multi-layer-silica column including acid- and base-impregnated silica gel was used to reduce the amounts of lipid present in the samples before a basic alumina clean-up step and activated carbon fractionation of planar analytes (PCDD/Fs and non-ortho-PCBs) and non-planar analytes (including ortho-chlorinated PCBs). Gas chromatography coupled to high resolution mass spectrometry was used to identify and quantify the analytes in the two fractions. The wet weight based concentrations obtained by the two methods were in agreement but both methods suffer from large organic solvent consumption. The toxic equivalencies derived for PCBs and PCDD/Fs using the two methods were also in agreement. However, the chloroform-methanol method gave slightly higher lipid recoveries, although with greater variation, than the sorbent-assisted method. Nevertheless, despite giving lower lipid recoveries, the sorbent-assisted method has advantages in ease of use and applicability to whole blood samples. The formation of emulsions was avoided with the Chem-Elut method, which probably explains the lower variability in the lipid determinations.

EM single particle analysis of the ATP-dependent BchI complex of magnesium chelatase: an AAA+ hexamer

BchI, belonging to the AAA+ -protein family, forms the enzyme magnesium chelatase together with BchD and BchH. This enzyme catalyses the insertion of Mg2+ into protoporphyrin IX upon ATP hydrolysis. Previous studies have indicated that BchI forms ATP-dependent complexes and it is a member of the AAA+ -protein family (ATPases associated with various cellular activities) and it was suggested based on structural homology that the BchI formed hexameric complexes. AAA+ -proteins are Mg2+ -dependent ATPases that normally form oligomeric ring complexes in the presence of ATP. Single particle analysis of fully formed ring complexes of BchI observed by negative staining EM indicate that the BchI has strong 6- and 2-fold rotational symmetries and a weaker 4-fold rotational symmetry which are reminiscent of DNA helicase. A 2D average of the fully formed BchI-ATP ring complex is presented here from images of the complex obtained from negative staining EM. Other complexes are also observed in the EM micrographs and the class averages of these are indicative of the fragility and dynamic nature of the BchI complex which has been reported and they are suggestive of partially circular complexes with six or less protomers per particle. The resolution of the average circular complex is estimated at approximately 30A and it is similar in shape and size to an atomic resolution hexameric model of BchI rendered at 30A.

Biosynthesis and sorting of myeloperoxidase in hematopoietic cells

The neutrophil granulocytes have a critical role in innate immunity through killing of phagocytized microorganisms, in which myeloperoxidase (MPO) participates. MPO is stored in cytoplasmic azurophil lysosome-like granules together with other antibiotic proteins and digestive enzymes. During passage in the secretory pathway pro-MPO is folded, subjected to oligosaccharide modification, and retrieval from constitutive secretion to become targeted to azurophil granules for final processing and storage. Propeptide-deleted MPO precursor was found not to be processed to mature MPO and not to be targeted for storage but instead degraded or secreted. This indicated that the propeptide of the MPO precursor was a prerequisite for the final processing and granule targeting of proMPO. When the MPO propeptide was expressed as a chimera with a normally secretory protein, the ER retention of the chimera was prolonged compared with that of the native protein. Thus, the propeptide of MPO precursor may also mediate the normally long ER-residence of proMPO. Both mature MPO and secreted proMPO contained complex oligosaccharide side chains indicating that proMPO and, thus, mature MPO has passed the medial Golgi stack where complex oligosaccharides are formed, and exited at TGN like other proteins targeted for azurophil granules.

High-resolution record of Northern Hemisphere climate extending into the last interglacial period

Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period. The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5 degrees C warmer than today. We find unexpectedly large temperature differences between our new record from northern Greenland and the undisturbed sections of the cores from central Greenland, suggesting that the extent of ice in the Northern Hemisphere modulated the latitudinal temperature gradients in Greenland. This record shows a slow decline in temperatures that marked the initiation of the last glacial period. Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time.

Activation of cytotoxic lymphocytes by interferon-alpha: role of oxygen radical-producing mononuclear phagocytes

A significant part of the therapeutic benefit of interferon-alpha (IFN-alpha) therapy in malignant diseases and in chronic viral infections is assumed to result from activation of lymphocytes with natural killer (NK) and T cell phenotype. In tumor tissue and in chronically infected tissue, the function and viability of these lymphocytes are frequently impaired. Mononuclear phagocyte (MP)-derived reactive oxygen species (ROS) have been proposed to contribute to the lymphocyte suppression in these tissues. Here, we report that three types of human cytotoxic lymphocytes of relevance to immunoactivation by IFN-alpha, CD3epsilon+/8+/56- T cells, CD3epsilon-/56+ NK cells, and CD3epsilon+/56+ NK/T cells became anergic to IFN-alpha induction of the cell-surface activation marker CD69 after exposure to autologous MPs in vitro. In addition to their incapacity to express CD69, cytotoxic lymphocytes acquired features characteristic of apoptosis after incubation with MPs. The lymphocyte apoptosis and nonresponsiveness to IFN-alpha were prevented by two inhibitors of reduced nicotinamide adenine dinucleotide phosphate oxidase-dependent formation of ROS in MPs, histamine dihydrochloride and diphenylene ionodonium, as well as by catalase, a scavenger of ROS. We conclude that MP-derived ROS may negatively affect IFN-alpha-induced immunostimulation and propose that ROS inhibitors or scavengers may be useful to improve lymphocyte activation during treatment with IFN-alpha.

Sorting soluble tumor necrosis factor (TNF) receptor for storage and regulated secretion in hematopoietic cells

Hematopoietic cells contain secretory lysosomes that degranulate at sites of inflammation. We envisage that secretory granules can act as vehicles for targeting inflammatory sites, including malignancies, and thereafter, locally release therapeutically active agents to these sites. Exogenous proteins, such as the soluble tumor necrosis factor receptor 1 (sTNFR1), have been shown previously to be targeted to secretory lysosomes [1]. In this work, we asked whether exogenous, secretory lysosome-targeted proteins were subject to regulated secretion. sTNFR1-transmembrane (tm)-cytosol-sorting signal (Y) and sTNFR1-tm-Y-enhanced green fluorescent protein (egfp) were expressed in rat basophilic leukemia cell clones having different secretory capacities. sTNFR1-tm-Y was targeted directly from the Golgi to secretory lysosomes, followed by generation of membrane-free sTNFR1, whose secretion could be triggered by a Ca2+ ionophore or immunoglobulin E receptor activation. In contrast, sTNFR1-tm-Y-egfp was targeted to the plasma membrane and then subjected to endocytosis and presumably, secretory lysosome targeting, as judged by results from antibody ligation and cell-surface biotinylation. Activation of protein kinase C with phorbol ester promoted ectodomain shedding at the cell surface, resulting in sTNFR1 release from sTNFR1-tm-Y-egfp. These results support a concept for using the storage organelles of hematopoietic cells as vehicles for targeting sites of inflammation with therapeutically active agents.

Hematopoietic secretory granules as vehicles for the local delivery of cytokines and soluble cytokine receptors at sites of inflammation

Cytokines play an important role in the regulation of homeostasis and inflammation. A de-regulated cytokine function can subsequently promote chronic inflammation. This is supported by clinical evidence showing the beneficial effect of inhibiting TNF-alpha through injection of antibodies and soluble receptor in disorders such as rheumatoid arthritis and Crohn's disease. Systemic anti-TNF-alpha therapy however is associated with infectious complications. We therefore suggest a concept for the local deposition of therapeutically active agents into areas of inflammation or malignancy, based on the use of hematopoietic storage and secretory granules as delivery vehicles. Hematopoietic cells are induced to express the therapeutically active protein and to store it in the secretory lysosomes. The cells migrate into a tumour or site of inflammation, where the cells become activated and release the contents of their secretory lysosomes resulting in the local delivery of the therapeutically active protein. In support of this concept, gene transfer and granule loading can be achieved using the soluble TNF-alpha receptor (sTNFR1) after cDNA expression in hematopoietic cell lines. Endoplasmic reticulum (ER)-export can be facilitated by the addition of a transmembrane domain, and constitutive secretion can be prevented by incorporating a cytosol-sorting signal resulting in secretory lysosome targeting. The sTNFR1 is released from the transmembrane domain by proteolytic cleavage and finally, regulated sTNFR1-secretion can be triggered by a calcium signal. In vivo investigations are currently determining the feasibility of local protein delivery at sites of inflammation.

Mercuric chloride induces a strong immune activation, but does not accelerate the development of dermal fibrosis in tight skin 1 mice

In susceptible mice, mercuric chloride induces a systemic autoimmune disease characterized by increased serum levels of immunoglobulin (Ig) G1 and IgE, production of anti-nucleolar autoantibodies (ANolA) and formation of renal IgG deposits. We have previously hypothesized that mercury confers more adverse immunological effects on those mouse strains, which are genetically prone to develop spontaneous autoimmune diseases than on normal strains. In this study, we tested our hypothesis in tight skin 1 (Tsk1/+) mice, a murine model for human scleroderma. As a support for our hypothesis, we observed that in Tsk1/+ mice, B cells were spontaneously hyperactive and that treatment with mercury induced a strong immune/autoimmune response in these mice, but not in their non-Tsk (+/+) littermates. This response was characterized by the formation of high numbers of splenic IgG1, IgG2b and IgG3 antibody-secreting cells, increased serum levels of IgE, production of IgG1 antibodies against single-stranded DNA (ssDNA), trinitrophenol (TNP) as well as thyroglobulin and the development of renal IgG1 deposits. Neither Tsk1/+ mice nor F1 hybrid crosses between this strain, and mercury susceptible B10.S (H-2(s)) were able to produce IgG1-ANolA in response to mercury. Moreover, mercury-induced immune activation in Tsk1/+ was not able to potentiate the progression of skin fibrosis in this strain. Thus, exposure to mercury accelerates the immune dysregulation, but not the development of skin fibrosis in Tsk1/+ mice.

Development of a technology platform for large-scale clinical grade production of DC

BACKGROUND

Clinical studies require protocols where a sufficient number of well-characterized highly immunogenic DC are produced according to good manufacturing practice (GMP) guidelines.

METHODS

In the present study, using leukapheresis products from 10 cancer patients, we validated an elutriation technology for large-scale clinical grade production of monocyte-derived DC.

RESULTS

The elutriation method gave a very high purity (mean+/-SD) (86+/-5.3%) and recovery (66+/-10.4%) of monocytes. Specifically for the two monocyte-rich fractions (3 and 4,) the recovery was 42+/-13% of viable cells that could be further differentiated into immature DC in hydrophobic culture bags using GM-CSF and IL-4. The immature DC exhibited<1% CD83+ expression and >98% phagocytic activity. Maturation with TNF-alpha or poly I:C resulted in DC with expression of CD80+, CD86+ and HLA-DR+ (>99%) and CD83+ (80+/-11.9%), as well as producing IL-12p70 and lacking phagocytic activity (<5%). This cell product can be cryopreserved with cell viability >85% and cell recovery >80% after thawing.

DISCUSSION

The elutriation procedure, when optimized and if the monocyte content of the starting material exceeds 5%, does not require further selection or depletion using affinity approaches.

Nicotinamide inhibits endotoxin-induced monocyte tissue factor expression

BACKGROUND

Tissue factor (TF) is the main initiator of blood coagulation in vivo. Its increased expression on activated monocytes is associated with thrombotic complications and mortality in conditions such as sepsis, disseminated intravascular coagulation and coronary artery disease.

OBJECTIVE

The effect of the vitamin B derivative nicotinamide on endotoxin-induced monocyte TF and CD11b expression, soluble interleukin(IL)-6, and clotting onset time (COT) was studied.

METHODS

Experiments were conducted in human peripheral blood leukocyte suspensions and in whole blood from eight healthy volunteers. Free oscillating rheometry (measuring COT) and flow cytometry were applied to evaluate the effect of endotoxin on TF, CD11b, IL-6 and the overall coagulation response of plasma supplemented with activated autologous leukocytes.

RESULTS

In response to endotoxin, there was an increase in IL-6, TF and CD11b expression and a procoagulant shift of COT. At 4 mmol L-1 nicotinamide, inhibition of TF expression and IL-6 and a normalization of COT were seen. At 16 mmol L-1 nicotinamide, CD11b decreased also. The level of monocyte TF expression correlated with the COT readings, and the endotoxin-induced procoagulant shift of COT could be totally inhibited by blocking TF with an inhibitory antibody.

CONCLUSIONS

These results demonstrate the ability of nicotinamide to inhibit the activation of coagulation associated with endotoxemia. We have previously shown that nicotinamide exerts strong anti-inflammatory effects. Evidence is accumulating for nicotinamide to have a therapeutic potential in modulating disease states in which there is a profound activation of coagulation and inflammation, such as in sepsis and disseminated intravascular coagulation.

Targeting proteins to secretory lysosomes of natural killer cells as a principle for immunoregulation

Secretory lysosomes of natural killer (NK) cells combine storage, regulated secretion and lysosomal activity. We asked whether one could target exogenous proteins to the secretory lysosomes of NK-cells for final delivery into a tumor site upon degranulation. cDNAs for both soluble and transmembrane (tm) proteins were expressed in the human YT-Indy NK-cell line. Targeting of a soluble TNF receptor (sTNFR1) was achieved by expressing a cDNA construct with a transmembrane sequence to facilitate ER-export and by incorporating a cytosolic sorting signal (Y) from CD63 to overcome constitutive secretion. The resulting sTNFR1-tm-Y was targeted to secretory lysosomes as confirmed by results from biosynthetic radiolabeling in combination with subcellular fractionation, immunoelectron microscopy, and immunofluorescence microscopy. A soluble sTNFR1 form was generated in the secretory lysosome by endogenous proteolytic activity. Expression of exogenous normally secretory non-membrane proteins, such as alpha1-microglobulin (alpha1-m) and alpha1-antitrypsin (alpha1-at) resulted mostly in constitutive secretion although a small amount of alpha1-microglobulin was targeted to secretory lysosomes. Our results suggest a potential for delivery of pharmacologically active agents into tumor sites by use of the NK-cell secretory lysosome as a carrier.

Xenobiotic metal-induced autoimmunity: mercury and silver differentially induce antinucleolar autoantibody production in susceptible H-2s, H-2q and H-2f mice

Xenobiotic-metals such as mercury (Hg) and silver (Ag) induce an H-2 linked antinucleolar autoantibody (ANolA) production in susceptible mice. The mechanism for induction of ANolA synthesis is not well understood. However, it has been suggested that both metals interact with nucleolar proteins and reveal cryptic self-peptides to nontolerant autoreactive T cells, which in turn stimulate specific autoreactive B cells. In this study, we considered this suggestion and asked if mercury and silver display, if not identical, similar cryptic self-peptides, they would induce comparable ANolA responses in H-2 susceptible mice. We analysed the development of ANolA production in mercury- and/or silver-treated mice of H-2s, H-2q and H-2f genotypes. We found that while mercury stimulated ANolA synthesis in all strains tested, silver induced ANolA responses of lower magnitudes in only H-2s and H-2q mice, but not in H-2f mice. Resistance to silver in H-2f mice was independent of the dosage/time-period of silver-treatment and non-H-2 genes. Further studies showed that F1 hybrid crosses between silver-susceptible A.SW (H-2s) and -resistant A.CA (H-2f) mice were resistant to silver, but not mercury with regard to ANolA production. Additionally, the magnitudes of mercury-induced ANolA responses in the F1 hybrids were lower than those of their parental strains. The above differential ANolA responses to mercury and silver can be explained by various factors, including the different display of nucleolar cryptic peptides by these xenobiotics, determinant capture and coexistence of different MHC molecules. Our findings also suggest that the ability of a xenobiotic metal merely to create cryptic self-peptides may not be sufficient for the induction of an ANolA response.

On-line NIR monitoring during anaerobic treatment of municipal solid waste

An anaerobic digester (81) was fed with the organic fraction of municipal solid waste and monitored intermittently for two years with on-line near-infrared (NIR) spectroscopy and traditional chemical parameters analysed off-line. The dynamics that occurred due to changes in substrate composition (changed C:N ratio) and changes in operating conditions (overloading) could be followed using principal component analysis of the obtained NIR-spectra. In addition, process disturbances such as failed stirring and increased foaming were readily detected by the NIR-spectra. Using PLS regression the propionate concentration could be predicted in the range 0.1-3.6 g/l, RMSEP 0.53 g/l with slope 0.74 and correlation coefficient 0.85. The response on changes in the digester fluid was reproducible and could be detected within 2.5 minutes, which can be considered as real-time monitoring.

Three semidominant barley mutants with single amino acid substitutions in the smallest magnesium chelatase subunit form defective AAA+ hexamers

Many enzymes of the bacteriochlorophyll and chlorophyll biosynthesis pathways have been conserved throughout evolution, but the molecular mechanisms of the key steps remain unclear. The magnesium chelatase reaction is one of these steps, and it requires the proteins BchI, BchD, and BchH to catalyze the insertion of Mg(2+) into protoporphyrin IX upon ATP hydrolysis. Structural analyses have shown that BchI forms hexamers and belongs to the ATPases associated with various cellular activities (AAA(+)) family of proteins. AAA(+) proteins are Mg(2+)-dependent ATPases that normally form oligomeric ring structures in the presence of ATP. By using ATPase-deficient BchI subunits, we demonstrate that binding of ATP is sufficient to form BchI oligomers. Further, ATPase-deficient BchI proteins can form mixed oligomers with WT BchI. The formation of BchI oligomers is not sufficient for magnesium chelatase activity when combined with BchD and BchH. Combining WT BchI with ATPase-deficient BchI in an assay disrupts the chelatase reaction, but the presence of deficient BchI does not inhibit ATPase activity of the WT BchI. Thus, the ATPase of every WT segment of the hexamer is autonomous, but all segments of the hexamer must be capable of ATP hydrolysis for magnesium chelatase activity. We suggest that ATP hydrolysis of each BchI within the hexamer causes a conformational change of the hexamer as a whole. However, hexamers containing ATPase-deficient BchI are unable to perform this ATP-dependent conformational change, and the magnesium chelatase reaction is stalled in an early stage.

Early warning of disturbances in a laboratory-scale MSW biogas process

The use of near-infrared spectroscopy (NIR) to monitorthe dynamics of a biogas process was evaluated using multivariate data analysis. The digester was a completely stirred 8 I tank reactor fed with the organic fraction of source-sorted MSW. Intermittently the digester was overloaded with feed. Before and after overload on-line monitoring of NIR spectra and off-line analysis in the liquid and the gas phase of traditional chemical variables and microbial biomass, determined as total concentration of phospholipid fatty acids (PLFA and PLEL), were done. The dynamics that occurred due to overloading could be followed using principal component analysis of the obtained NIR-spectra. In addition, the response to changes in the digester fluid was reproducible and could be detected within five minutes, which can be considered as real-time monitoring. Selected wavelengths in the region 800-2,000 nm were used to make a PLS1 -regression with propionate. The regression resulted in a good correlation for propionate (R= 0.94 and RMSEP of 0.21 g/l in the range of 0.3-3 g/l). The results indicate the possibility to develop an early warning biogas control system based on near-infrared spectroscopy monitoring of propionate.

Living with spine-related pain in a changing society--a qualitative study

PURPOSE

To elucidate life lived with recurrent, spine-related pain and to explore the development from work to disability pension.

METHOD

A qualitative design at individual level was chosen. Nineteen people--five on disability pension, four physicians and ten rehabilitation officials--were interviewed. Data were analysed using grounded theory.

RESULTS

A process of 'coming to terms with pain' with four phases was identified. During the phases pain had a deteriorating course and was combined with other medical problems. Together with changes on the labour market these factors caused the persons to leave their employment and also hindered reorientation on the labour market. Committed as they were to social norms, the persons found adjustment to a place outside the labour market difficult.

CONCLUSIONS

Our findings suggest how recurrent back and neck pain can develop, interact with medical, individual, work-related and structural factors and result in incapacity to work. To avoid this incapacity pain has to be followed and the other factors considered in the design and timing of rehabilitation.

Interplay between an AAA module and an integrin I domain may regulate the function of magnesium chelatase

In chlorophyll biosynthesis, insertion of Mg(2+) into protoporphyrin IX is catalysed in an ATP-dependent reaction by a three-subunit (BchI, BchD and BchH) enzyme magnesium chelatase. In this work we present the three-dimensional structure of the ATP-binding subunit BchI. The structure has been solved by the multiple wavelength anomalous dispersion method and refined at 2.1 A resolution to the crystallographic R-factor of 22.2 % (R(free)=24.5 %). It belongs to the chaperone-like "ATPase associated with a variety of cellular activities" (AAA) family of ATPases, with a novel arrangement of domains: the C-terminal helical domain is located behind the nucleotide-binding site, while in other known AAA module structures it is located on the top. Examination by electron microscopy of BchI solutions in the presence of ATP demonstrated that BchI, like other AAA proteins, forms oligomeric ring structures. Analysis of the amino acid sequence of subunit BchD revealed an AAA module at the N-terminal portion of the sequence and an integrin I domain at the C terminus. An acidic, proline-rich region linking these two domains is suggested to contribute to the association of BchI and BchD by binding to a positively charged cleft at the surface of the nucleotide-binding domain of BchI. Analysis of the amino acid sequences of BchI and BchH revealed integrin I domain-binding sequence motifs. These are proposed to bind the integrin I domain of BchD during the functional cycle of magnesium chelatase, linking porphyrin metallation by BchH to ATP hydrolysis by BchI. An integrin I domain and an acidic and proline-rich region have been identified in subunit CobT of cobalt chelatase, clearly demonstrating its homology to BchD. These findings, for the first time, provide an insight into the subunit organisation of magnesium chelatase and the homologous colbalt chelatase.

Mammalian cell production of a respiratory syncytial virus (RSV) candidate vaccine recovered using a product-specific affinity column

The recombinant production of a respiratory syncytial virus (RSV) candidate vaccine BBG2Na in baby hamster kidney cells (BHK-21 cells) was investigated. BBG2Na consists of a serum-albumin-binding region (BB) fused to a 101-amino-acid fragment of the RSV G-protein. Semliki Forest virus-based expression vectors encoding both intracellular and secreted forms of BBG2Na were constructed and found to be functional. Affinity recovery of BBG2Na employing human serum albumin columns was found to be inefficient due to the abundance of BSA in the applied samples. Instead, a strategy using a tailor-made affinity ligand based on a combinatorially engineered Staphylococcus aureus protein A domain, showing specific binding to the G-protein part of the product, was evaluated. In conclusion, a strategy for production and successful recovery of BBG2Na in mammalian cells was created, through the development of a product-specific affinity column.

Genetic control of resistance to mercury-induced immune/autoimmune activation

Previous studies have shown that genetic factors control the susceptibility to mercury-induced immunoglobulin (Ig)G1 antibody formation, IgE synthesis, renal IgG deposits and antinucleolar autoantibodies (ANolA) production in the susceptible mice. In this study, we examined the genetic control of resistance to these characteristics after HgCl2 injection in F1 hybrid crosses between the highly mercury resistant DBA/2 and mercury susceptible NZB (H-2d), SJL (H-2 s), A.CA (H-2f) and DBA/1 (H-2q) mice and also in backcross hybrids between (DBA/2 x SJL)F1 and SJL mice. We observed that mercury-induced immune/autoimmune manifestations were profoundly downregulated in most (if not all) of the F1 hybrids, indicating that the resistance to mercury was a dominant trait. Analysis of mercury-induced immune/autoimmune responses in the (DBA/2 x SJL) x SJL backcross hybrids suggested that only one gene or a cluster of genes determined the resistance to the ANolA production, whereas the resistance to other characteristics was controlled by two and/or three gene loci. By H-2 genotyping the backcross mice, it was found that H-2d haplotype per se could confer resistance to ANolA production. However, we did not find any significant association between the H-2d haplotype and the resistance to increase of IgG1 and IgE synthesis and the development of renal IgG1 deposits. Thus, while in DBA/2 mice, gene(s) in the H-2 loci strictly contribute to the inheritance of resistance to ANolA production; non-H-2 genes mainly govern the inheritance of unresponsiveness regarding other characteristics.

Surface display on gram positive bacteria

Heterologous surface display on Gram-positive bacteria was first described almost a decade ago and has since then developed into an active research area. Gram-positive bacterial surface display has today found a range of applications, in immunology, microbiology and biotechnology. Live bacterial vaccine delivery vehicles are being developed through the surface display of selected foreign antigens on the bacterial surfaces. In this field, "second generation" vaccine delivery vehicles are at present being generated by the addition of mucosal targeting signals through co-display of adhesins, in order to achieve targeting of the live bacteria to immunoreactive sites to thereby increase immune responses. Engineered Gram-positive bacteria are further being evaluated as novel microbial biocatalysts with heterologous enzymes immobilized as surface exposed on the bacterial cell surface. A discussion has started whether bacteria can find use as new types of whole-cell diagnostic devices since single-chain antibodies and other variants of tailor-made binding proteins can be displayed on bacteria. Bacteria with increased binding capacity for certain metal ions can be created and potential environmental or biosensor applications for such recombinant bacteria as biosorbents are being discussed. This article explains the basis of Gram-positive bacterial surface display, and discusses current uses and possible future trends of this emerging technology.