CRISPR/Cas9-mediated mutation of OsSWEET14 in rice cv. Zhonghua11 confers resistance to Xanthomonas oryzae pv. oryzae without yield penalty.

BACKGROUND: Bacterial blight of rice, caused by Xanthomonas oryzae pv. oryzae (Xoo), is a devastating rice disease in Southeast Asia and West Africa. OsSWEET14, encoding a sugar transporter, is known to be a major susceptible gene of bacterial blight targeted by four different transcription activator-like (TAL) effectors from either Asian or African Xoo strains. However, the OsSWEET14 single knockout or promoter mutants in the Kitaake background are moderately resistant or even susceptible to African Xoo strains. Therefore, in this study, we knocked out OsSWEET14 in rice cv. Zhonghua 11 background for disease assessment. RESULTS: In this study, CRISPR/Cas9 was utilized to disrupt the function of OsSWEET14 by modifying its corresponding coding region in the genome of rice cv. Zhonghua 11 (CR-S14). In total, we obtained nine different OsSWEET14-mutant alleles. Besides conferring broad-spectrum resistance to Asian Xoo strains, tested mutant alleles also showed strong resistance to African Xoo strain AXO1947. Moreover, the expression of OsSWEET14 was detected in vascular tissues, including the stem, leaf sheath, leaf blade and root. The disruption of OsSWEET14 led to increased plant height without a reduction in yield. CONCLUSIONS: Disruption of OsSWEET14 in the Zhonghua 11 background is able to confer strong resistance to African Xoo strain AXO1947 and Asian Xoo strain PXO86. CR-S14 has normal reproductive growth and enhanced plant height under normal growth conditions. These results imply that CR-S14 may serve as a better tester line than sweet14 single-knockout mutant in the Kitaake background for the diagnostic kit for rice blight resistance. The genetic background and increased plant height need to be taken into consideration when utilizing OsSWEET14 for resistant rice breeding.

The Role of Autoimmunity-Related Gene CLEC16A in the B Cell Receptor-Mediated HLA Class II Pathway.

C-type lectin CLEC16A is located next to CIITA, the master transcription factor of HLA class II (HLA-II), at a susceptibility locus for several autoimmune diseases, including multiple sclerosis (MS). We previously found that CLEC16A promotes the biogenesis of HLA-II peptide-loading compartments (MIICs) in myeloid cells. Given the emerging role of B cells as APCs in these diseases, in this study, we addressed whether and how CLEC16A is involved in the BCR-dependent HLA-II pathway. CLEC16A was coexpressed with surface class II-associated invariant chain peptides (CLIP) in human EBV-positive and not EBV-negative B cell lines. Stable knockdown of CLEC16A in EBV-positive Raji B cells resulted in an upregulation of surface HLA-DR and CD74 (invariant chain), whereas CLIP was slightly but significantly reduced. In addition, IgM-mediated Salmonella uptake was decreased, and MIICs were less clustered in CLEC16A-silenced Raji cells, implying that CLEC16A controls both HLA-DR/CD74 and BCR/Ag processing in MIICs. In primary B cells, CLEC16A was only induced under CLIP-stimulating conditions in vitro and was predominantly expressed in CLIPhigh naive populations. Finally, CLIP-loaded HLA-DR molecules were abnormally enriched, and coregulation with CLEC16A was abolished in blood B cells of patients who rapidly develop MS. These findings demonstrate that CLEC16A participates in the BCR-dependent HLA-II pathway in human B cells and that this regulation is impaired during MS disease onset. The abundance of CLIP already on naive B cells of MS patients may point to a chronically induced stage and a new mechanism underlying B cell-mediated autoimmune diseases such as MS.

Glucose transporter type 1 deficiency syndrome associated with autoantibodies to glutamate receptors.

BACKGROUND: The clinical spectrum of glucose transporter type 1 deficiency syndrome (GLUT1DS) has broadened, with increasing recognition of a milder phenotype. Antibodies targeting the subunits of glutamate receptors (GluRs), including GluN1, GluN2B, and GluD2, have been detected in various neurological disorders. Anti-GluD2 antibodies in particular may be associated with cerebellar symptoms. CASE REPORT: A 3-year-5-month-old boy with normal development exhibited myoclonus refractory to antiepileptic drugs from one year ago. He developed tremor and ataxia. Cerebrospinal fluid (CSF) revealed fasting-state glucose 50 mg/dl (CSF/blood glucose ratio of 0.50). Single photon emission computed tomography with 123I-iodoamphetamine revealed hypoperfusion in the cerebellum. At age 4 years and 5 months, treatment with intravenous methylprednisolone (IVMP) relieved his symptoms and improved the cerebellar hypoperfusion. However, his symptoms reappeared at age 5 years and 1 month. Treatment with IVMP was repeated, resulting in transient disappearance of symptoms. At age 6 years and 9 months, he was diagnosed with GLUT1DS by genetic analysis, and treatment with modified Atkins diet was started with efficacy. Levels of anti-GluN1, -GluN2B, and -GluD2 antibodies in the serum and CSF were measured 4 times. All antibodies in the CSF were elevated over 2 standard deviations above controls, and the levels fluctuated along with the severity of his symptoms. The level of anti-GluD2 antibodies in CSF declined to the normal range only after starting the modified Atkins diet. CONCLUSION: Treatment with IVMP transiently improved this patient's symptoms. Levels of anti-GluR antibodies may be associated with symptom severity.

Diversity in kinetics correlated with structure in nano body-stabilized LacY.

The structure of lactose permease, stabilized in a periplasmic open conformation by two Gly to Trp replacements (LacYww) and complexed with a nanobody directed against this conformation, provides the highest resolution structure of the symporter. The nanobody binds in a different manner than two other nanobodies made against the same mutant, which also bind to the same general region on the periplasmic side. This region of the protein may represent an immune hotspot. The CDR3 loop of the nanobody is held by hydrogen bonds in a conformation that partially blocks access to the substrate-binding site. As a result, kon and koff for galactoside binding to either LacY or the double mutant complexed with the nanobody are lower than for the other two LacY/nanobody complexes though the Kd values are similar, reflecting the fact that the nanobodies rigidify structures along the pathway. While the wild-type LacY/nanobody complex clearly stabilizes a similar 'extracellular open' conformation in solution, judged by binding kinetics, the complex with wild-type LacY did not yet crystallize, suggesting the nanobody does not bind strongly enough to shift the equilibrium to stabilize a periplasmic side-open conformation suitable for crystallization. However, the similarity of the galactoside binding kinetics for the nanobody-bound complexes with wild type LacY and with LacYWW indicates that they have similar structures, showing that the reported co-structures reliably show nanobody interactions with LacY.

Cryptococcus neoformans Evades Pulmonary Immunity by Modulating Xylose Precursor Transport.

Cryptococcus neoformans is a fungal pathogen that kills almost 200,000 people each year and is distinguished by abundant and unique surface glycan structures that are rich in xylose. A mutant strain of C. neoformans that cannot transport xylose precursors into the secretory compartment is severely attenuated in virulence in mice yet surprisingly is not cleared. We found that this strain failed to induce the nonprotective T helper cell type 2 (Th2) responses characteristic of wild-type infection, instead promoting sustained interleukin 12p40 (IL-12p40) induction and increased IL-17A (IL-17) production. It also stimulated dendritic cells to release high levels of proinflammatory cytokines, a behavior we linked to xylose expression. We further discovered that inducible bronchus-associated lymphoid tissue (iBALT) forms in response to infection with either wild-type cryptococci or the mutant strain with reduced surface xylose; although iBALT formation is slowed in the latter case, the tissue is better organized. Finally, our temporal studies suggest that lymphoid structures in the lung restrict the spread of mutant fungi for at least 18 weeks after infection, which is in contrast to ineffective control of the pathogen after infection with wild-type cells. These studies demonstrate the role of xylose in modulation of host response to a fungal pathogen and show that cryptococcal infection triggers iBALT formation.

The Autoimmune Disorder Susceptibility Gene CLEC16A Restrains NK Cell Function in YTS NK Cell Line and Clec16a Knockout Mice.

CLEC16A locus polymorphisms have been associated with several autoimmune diseases. We overexpressed CLEC16A in YTS natural killer (NK) cells and observed reduced NK cell cytotoxicity and IFN-γ release, delayed dendritic cell (DC) maturation, decreased conjugate formation, cell-surface receptor downregulation and increased autophagy. In contrast, siRNA mediated knockdown resulted in increased NK cell cytotoxicity, reversal of receptor expression and disrupted mitophagy. Subcellular localization studies demonstrated that CLEC16A is a cytosolic protein that associates with Vps16A, a subunit of class C Vps-HOPS complex, and modulates receptor expression via autophagy. Clec16a knockout (KO) in mice resulted in altered immune cell populations, increased splenic NK cell cytotoxicity, imbalance of dendritic cell subsets, altered receptor expression, upregulated cytokine and chemokine secretion. Taken together, our findings indicate that CLEC16A restrains secretory functions including cytokine release and cytotoxicity and that a delicate balance of CLEC16A is needed for NK cell function and homeostasis.

Long noncoding RNA Malat1 regulates differential activation of macrophages and response to lung injury.

Macrophage activation, i.e., classical M1 and the alternative M2, plays a critical role in many pathophysiological processes, such as inflammation and tissue injury and repair. Although the regulation of macrophage activation has been under extensive investigation, there is little knowledge about the role of long noncoding RNAs (lncRNAs) in this event. In this study, we found that lncRNA Malat1 expression is distinctly regulated in differentially activated macrophages in that it is upregulated in LPS-treated and downregulated in IL-4-treated cells. Malat1 knockdown attenuates LPS-induced M1 macrophage activation. In contrast, Malat1 knockdown enhanced IL-4-activated M2 differentiation as well as a macrophage profibrotic phenotype. Mechanistically, Malat1 knockdown led to decreased expression of Clec16a, silencing of which phenocopied the regulatory effect of Malat1 on M1 activation. Interestingly, Malat1 knockdown promoted IL-4 induction of mitochondrial pyruvate carriers (MPCs) and their mediation of glucose-derived oxidative phosphorylation (OxPhos), which was crucial to the Malat1 regulation of M2 differentiation and profibrotic phenotype. Furthermore, mice with either global or conditional myeloid knockout of Malat1 demonstrated diminished LPS-induced systemic and pulmonary inflammation and injury. In contrast, these mice developed more severe bleomycin-induced lung fibrosis, accompanied by alveolar macrophages displaying augmented M2 and profibrotic phenotypes. In summary, we have identified what we believe is a previously unrecognized role of Malat1 in the regulation of macrophage polarization. Our data demonstrate that Malat1 is involved in pulmonary pathogeneses in association with aberrant macrophage activation.

Synthesis of a model trisaccharide for studying the interplay between the anti α-Gal antibody and the trans-sialidase reactions in Trypanosoma cruzi.

Trypanosoma cruzi, the etiologic agent of Chagas disease, is covered by a dense glycocalix mainly composed by glycoproteins called mucins which are also the acceptors of sialic acid in a reaction catalyzed by a trans-sialidase (TcTS). Sialylation of trypomastigote mucins protects the parasite from lysis by the anti α-Galp antibodies from serum. The TcTS is essential for the infection process since T. cruzi is unable to biosynthesize sialic acid. The enzyme specifically transfers it from a terminal ß-d-Galp unit in the host glycoconjugate to terminal ß-d-Galp units in the parasite mucins to construct the d-NeuNAc(α2→3)ß-d-Galp motif. On the other hand, although galactose is the most abundant sugar in mucins of both, the infective trypomastigotes and the insect stage epimastigotes, α-d-Galp is only present in the infective stage whereas ß-d-Galf is characteristic of the epimastigote stage of the less virulent strains. Neither α-d-Galp nor d-Galf is acceptor of sialic acid. In the mucins, some of the oligosaccharides are branched with terminal ß-d-Galp units to be able to accept sialic acid in the TcTS reaction. Based on previous reports showing that anti α-Galp antibodies only partially colocalize with sialic acid, we have undertaken the synthesis of the trisaccharide α-d-Galp(1→3)-[ß-d-Galp(1→6)]-d-Galp, the smallest structure containing both, the antigenic d-Galp(α1→3)-d-Galp unit and the sialic acid-acceptor ß-d-Galp unit. The trisaccharide was obtained as the 6-aminohexyl glycoside to facilitate further conjugation for biochemical studies. The synthetic approach involved the α-galactosylation at O-4 of a suitable precursor of the reducing end, followed by ß-galactosylation at O-6 of the same precursor and introduction of the 6-aminohexyl aglycone. The fully deprotected trisaccharide was successfully sialylated by TcTS using either 3'-sialyllactose or fetuin as donors. The product, 6-aminohexyl α-d-NeuNAc(2→3)-ß-d-Galp(1→6)-[α-d-Galp(1→3)]-ß-d-Galp, was purified and characterized.

Cryptococcus neoformans UGT1 encodes a UDP-Galactose/UDP-GalNAc transporter.

Cryptococcus neoformans, an opportunistic fungal pathogen, produces a glycan capsule to evade the immune system during infection. This definitive virulence factor is composed mainly of complex polysaccharides, which are made in the secretory pathway by reactions that utilize activated nucleotide sugar precursors. Although the pathways that synthesize these precursors are known, the identity and the regulation of the nucleotide sugar transporters (NSTs) responsible for importing them into luminal organelles remain elusive. The UDP-galactose transporter, Ugt1, was initially identified by homology to known UGTs and glycan composition analysis of ugt1Δ mutants. However, sequence is an unreliable predictor of NST substrate specificity, cells may express multiple NSTs with overlapping specificities, and NSTs may transport multiple substrates. Determining NST activity thus requires biochemical demonstration of function. We showed that Ugt1 transports both UDP-galactose and UDP-N-acetylgalactosamine in vitro. Deletion of UGT1 resulted in growth and mating defects along with altered capsule and cellular morphology. The mutant was also phagocytosed more readily by macrophages than wild-type cells and cleared more quickly in vivo and in vitro, suggesting a mechanism for the lack of virulence observed in mouse models of infection.

Crystal structure of a LacY-nanobody complex in a periplasmic-open conformation.

The lactose permease of Escherichia coli (LacY), a dynamic polytopic membrane protein, catalyzes galactoside-H+ symport and operates by an alternating access mechanism that exhibits multiple conformations, the distribution of which is altered by sugar binding. We have developed single-domain camelid nanobodies (Nbs) against a mutant in an outward (periplasmic)-open conformation to stabilize this state of the protein. Here we describe an X-ray crystal structure of a complex between a double-Trp mutant (Gly46→Trp/Gly262→Trp) and an Nb in which free access to the sugar-binding site from the periplasmic cavity is observed. The structure confirms biochemical data indicating that the Nb binds stoichiometrically with nanomolar affinity to the periplasmic face of LacY primarily to the C-terminal six-helix bundle. The structure is novel because the pathway to the sugar-binding site is constricted and the central cavity containing the galactoside-binding site is empty. Although Phe27 narrows the periplasmic cavity, sugar is freely accessible to the binding site. Remarkably, the side chains directly involved in binding galactosides remain in the same position in the absence or presence of bound sugar.

Short-term effects of ketogenic diet on anthropometric parameters, body fat distribution, and inflammatory cytokine production in GLUT1 deficiency syndrome.

OBJECTIVE: The aim of this study was to evaluate the effects of a 12-wk ketogenic diet (KD) on inflammatory status, adipose tissue activity biomarkers, and abdominal visceral (VAT) and subcutaneous fat (SAT) in children affected by glucose transporter 1 deficiency syndrome GLUT1 DS. METHODS: We carried out a short-term longitudinal study on 10 children (mean age: 8.4 y, range 3.3-12 y, 5 girls, 5 boys) to determine fasting serum proinflammatory cytokines (high sensitivity C-reactive protein, tumor necrosis factor-α interleukin-6), adipocyte-derived chemokines (leptin and adiponectin), lipid profile, homeostatic model assessment-insulin resistance (HOMA-IR), quantitative insulin sensitivity index (QUICKI), anthropometric measurements, and VAT and SAT (by ultrasonography). RESULTS: Children showed no significant changes in inflammatory and adipose tissue activity biomarkers, blood glucose, lipid profile, anthropometric measurements, VAT, and SAT. Fasting insulin decreased (6 ± 3.2 µU/mL versus 3 ± 2 µU/mL; P = 0.001), and both HOMA-IR and QUICKI indexes were significantly modified (1.2 ± 0.6 versus 0.6 ± 0.4; P = 0.002; 0.38 ± 0.03 versus 0.44 ± 0.05; P = 0.002, respectively). CONCLUSIONS: Only HOMA-IR and QUICKI indexes changed after 12 wk on a KD, suggesting that over a short period of time KD does not affect inflammatory cytokines production and abdominal fat distribution despite being a high-fat diet. Long-term studies are needed to provide answers concerning adaptive metabolic changes during KD.

Association of the C-type lectin-like domain family-16A (CLEC16A) gene polymorphisms with acute coronary syndrome in Mexican patients.

The CLEC16A gene has an important role in the immune activation and regulation inflammatory. This gene encodes to C-type lectin domain that is involved in the recognition of DAMPS. The aim of this study was assess the CLEC16A gene polymorphisms in the risk of developing ACS in a group of patients. Four rs12708716, rs12917716, rs6498142 and rs9925481 (positions 146529 A>G, 155804 G>C, 47905 C>G and 64135 C>T, respectively) single nucleotide polymorphisms of CLEC16A gene were analyzed by TaqMan assays in a group of 452 patients with ACS and 456 healthy controls. The analysis was performed on the total group of individuals and then in groups of men and women separately. Under co-dominant model adjusted by cardiovascular risk factors the rs12708716 (146529 A>G) and rs12917716 (155804 G>C) polymorphisms were significantly associated with decrease risk of ACS in men (OR=0.16, PCo-dom=0.027 and OR=0.37, PCo-dom=0.016, respectively). In summary, our data suggests that two polymorphisms of the CLEC16A gene play an important role in the developing of ACS in men.

Semi-continuous, label-free immunosensing approach for Ca2+-based conformation change of a calcium-binding protein.

A label-free immunosensing method based on the conformational change of calcium-binding protein (CBP) depending on analyte concentration was explored for semi-continuous analysis of free Ca(2+). Glucose-galactose-binding protein as a CBP and produced as a recombinant protein by Escherichia coli was used as the immunogen to produce monoclonal antibodies by hybridoma technology. We finally screened the 3-6F cell clone, which produced the desired antibody specific to a particular structural conformation of the protein that occurred only upon CBP-calcium complex formation. To construct an immunosensor, the antibody was immobilized via a secondary antibody on an Octet Red optical fiber-based label-free sensor. Calcium analysis was conducted on the sensor in combination with CBP previously added to the aqueous sample, which distinguished the sensor signal according to the analyte concentration. The immunosensor produced a signal in real time with a response time of approximately 15 min and could be reused for analyses of different samples in a semi-continuous manner. The minimum detection limit of the analyte under optimal conditions was 0.09 mM and the upper limit was about 5 mM (log-logit transformed standard curve linearity: R(2) > 98%). In sample tests with milk, the analytical performance of the sensor was highly correlated (R(2) > 99%) with that of the reference system based on the KMnO4 titration method (ISO 12081). Although the sensor showed cross-reactivity at high concentrations (>1 mM) of cations including zinc, iron, manganese, and copper, these ionic components were not traceable (<0.01 mM) in milk.

Protein expressions and their immunogenicity from Riemerella anatipestifer cultured in iron restriction medium.

Riemerella anatipestifer was cultured in both iron restriction media and normal media. Two-dimensional gel electrophoresis identified 23 proteins that significantly increased in the iron restriction media. Of them 12 proteins were analyzed with mass spectrography. Nine of 12 proteins belong to 6 different protein families: fibronectin type iii domain protein, secreted subtilase family protein, phosphoglycerate kinase, translation elongation factor, leucine-rich repeat-containing protein, and Galactose-binding domain-like protein. Other 3 proteins were novel with unknown function. Two novel proteins (Riean_1750 and Riean_1752) were expressed in prokaryotic expression systems. The specificities of these 2 novel proteins to R. anatipestifer were confirmed by western-blotting analysis. The ducks immunized with either protein had low mortality challenged by R. anatipestifer, 33.3% and 16.7%, respectively. The ducks developed 100% immunity when immunized with combined Riean_1750 and Riean_1752 proteins. The data suggested 2 novel proteins play important roles in the bacterial survival in the iron restricted environment. They could be used as subunit vaccines of R. anatipestifer.

RelAp43, a member of the NF-κB family involved in innate immune response against Lyssavirus infection.

NF-κB transcription factors are crucial for many cellular processes. NF-κB is activated by viral infections to induce expression of antiviral cytokines. Here, we identified a novel member of the human NF-κB family, denoted RelAp43, the nucleotide sequence of which contains several exons as well as an intron of the RelA gene. RelAp43 is expressed in all cell lines and tissues tested and exhibits all the properties of a NF-κB protein. Although its sequence does not include a transactivation domain, identifying it as a class I member of the NF-κB family, it is able to potentiate RelA-mediated transactivation and stabilize dimers comprising p50. Furthermore, RelAp43 stimulates the expression of HIAP1, IRF1, and IFN-ß - three genes involved in cell immunity against viral infection. It is also targeted by the matrix protein of lyssaviruses, the agents of rabies, resulting in an inhibition of the NF-κB pathway. Taken together, our data provide the description of a novel functional member of the NF-κB family, which plays a key role in the induction of anti-viral innate immune response.

No influence on disease progression of non-HLA susceptibility genes in MS.

Recently, several non-HLA loci have been shown to be convincingly associated with Multiple Sclerosis (MS) susceptibility, assumingly indicating important pathways in the pathogenesis. A genotype influence on disease outcome measures by these genes would support a role of these pathways in ongoing tissue damage. Here, however, we report a consistent dissociation between causation and progression for five non-HLA genotypes (IL7R, IL2RA, CLEC16A, CD226 and SH2B3) in 1776 Scandinavian MS patients.

Natural self-assembly of allergen-S-layer fusion proteins is no prerequisite for reduced allergenicity and T cell stimulatory capacity.

BACKGROUND: Recombinant allergen-S-layer fusion proteins display a strongly reduced IgE-binding activity and promote the induction of allergen-specific Th0/1 cells and regulatory T cells. Such fusion proteins show a natural capacity to self-assemble into mono- or double-layer sheets reaching particle-like dimensions of 0.5-2 microm. We were interested in finding out whether self-assembly was crucial for the immunological characteristics of allergen-S-layer fusion proteins. METHODS: The IgE-binding and mediator-releasing capacities of nonassembled and self-assembled rSbpA-Bet v 1, consisting of the major birch pollen allergen Bet v 1 and the S-layer protein SbpA, were compared in inhibition ELISA and basophil activation assays using sera from patients allergic to birch pollen. T cell stimulation was evaluated using Bet v 1-specific T cell clones reactive to distinct epitopes of Bet v 1. Autologous B lymphocytes, monocytes and monocyte-derived dendritic cells were employed to evaluate potential differences in uptake and processing by different antigen-presenting cells. RESULTS: Both rSbpA-Bet v 1 variants showed significantly less IgE-binding and mediator-releasing activity than Bet v 1. However, self-assembly further minimized the reduced allergenicity of nonassembled rSbpA-Bet v 1. Both rSbpA-Bet v 1 variants induced comparable proliferation in Bet v 1-specific T cell clones. B cells inappropriately presented either variant of rSbpA-Bet v 1. Self-assembly amplified the T cell stimulatory capacity of monocytes and dendritic cells. CONCLUSIONS: The promising characteristics of allergen-S-layer fusion proteins regarding their potential use for allergy treatment do not depend on the formation of particle-like structures.

Immunodetection of the expression of microsomal proteins encoded by the glucose 6-phosphate transporter gene.

Glucose 6-phosphate transport has been well characterized in liver microsomes. The transport is required for the functioning of the glucose-6-phosphatase enzyme that is situated in the lumen of the hepatic endoplasmic reticulum. The genetic deficiency of the glucose 6-phosphate transport activity causes a severe metabolic disease termed type 1b glycogen storage disease. The cDNA encoding a liver transporter for glucose 6-phosphate was cloned and was found to be mutated in patients suffering from glycogen storage disease 1b. While related mRNAs have been described in liver and other tissues, the encoded protein(s) has not been immunologically characterized yet. In the present study, we report (using antibodies against three different peptides of the predicted amino acid sequence) that a major protein encoded by the glucose 6-phosphate transporter gene is expressed in the endoplasmic reticulum membranes of rat and human liver. The protein has an apparent molecular mass of approx. 33 kDa using SDS/PAGE, but several lines of evidence indicate that its real molecular mass is 46 kDa, as expected. The glucose 6-phosphate transporter protein was also immunodetected in kidney microsomes, but not in microsomes derived from human fibrocytes, rat spleen and lung, and a variety of cell lines. Moreover, little or no expression of the glucose 6-phosphate transporter protein was found in liver microsomes obtained from three glycogen storage disease 1b patients, even bearing mutations that do not directly interfere with protein translation, which can be explained by a (proteasome-mediated) degradation of the mutated transporter.

Immunological characteristics of patients infected with common intestinal helminths: results of a study based on reverse-transcriptase PCR.

To determine whether common helminth infections could modify the intestinal immunopathological status of the host, the expression in the human duodenal mucosa of cytokines, eosinophil- and mast-cell-specific molecules and monosaccharide transporters of the glucose-transporter (GLUT) family was explored. The 31 subjects were all patients at the gastro-intestinal disease unit of Nongkhai Hospital, Thailand. Four of the 10 patients who presented with eosinophilia (> or = 6.0% of their leucocytes were eosinophils), and five of the other 21 patients, had intestinal infections with helminths when they presented or within the previous 3 months. Studies based on semi-quantitative, reverse-transcriptase PCR revealed that the interleukin-5/interferon-gamma ratio was significantly higher in the noneosinophilic, helminth-infected patients than in the non-eosinophilic, uninfected patients, whereas the IgE receptor type I (Fc epsilon RI)/mast-cell tryptase ratio was significantly higher in the eosinophilic, helminth-infected patients than in the eosinophilic, uninfected patients. Expression of Charcot-Leyden-crystal protein, GLUT-1 and GLUT-5, however, showed no significant inter-group differences. Principal-components analysis of the data on eosinophils, interleukin-5, interferon-gamma, Fc epsilon RI and mast-cell tryptase revealed that one principal component could discriminate the patients who had helminth infection from the non-eosinophilic, uninfected patients, but not from the eosinophilic, uninfected patients. These results indicate that, whatever the intestinal pathology, patients infected with common intestinal helminths tend to develop a mucosal immunological response of the Th2 type.

Effects of anti-GLUT antibodies on glucose transport into human erythrocyte ghosts.

We have studied the effects of anti-GLUT1 antibodies on the uptake of glucose into erythrocytes. Glucose transport into human erythrocyte ghosts was measured directly using 3H-2-deoxy-glucose, or indirectly by monitoring associated volume changes using light scattering. The uptake of glucose was significantly inhibited in ghosts resealed in solutions containing specific antibodies against GLUT1. Such an effect was not observed when an antibody against the oestrogen receptor, lacking specificity towards GLUT1, was employed instead. The antibodies were also without effect on the efflux of preloaded glucose from erythrocyte ghosts. The demonstration that anti-GLUT antibodies can inhibit glucose uptake is support for the hypothesis that they exaggerate the cytoplasmic barrier to glucose uptake created by endofacial segments of GLUT1.