bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Evidence for SAA Deposition in Tissues During Murine Amyloidogenesis
Authors: YAKAR S. , KAPLAN B. , LIVNEH A. , MARTIN B. , MIURA K. , ALI‐KHAN Z. , SHTRASBURG S. , PRAS M. 
Published: July 2006

To study the mechanism of amyloid deposition, the nature of amyloid proteins formed in experimental murine amyloidosis, was examined. Spleen specimens, 15–60mg, were homogenized and extracted using aqueous acidic acetonitrile, in a recently developed procedure, making it possible to obtain amyloid proteins from minute amounts of tissue. The extracted material, 1.5–4mg, was analysed by Western blotting and ELISA using antibodies recognizing differentially proteins AA and SAA. Two immunoreactive proteins of 8 and 12 KDa were isolated and subjected to amino acid analysis and N‐terminal sequence determination. The results of immunochemical and chemical examination showed that the 8 and 12 KDa proteins represented proteins AA and SAA, respectively.The data obtained provide new direct evidence for SAA deposition in tissues during murine amyloidogenesis.
Effects of Human Calprotectin (L1) on In Vitro Immunoglobulin Synthesis
Authors: BRUN J. G. , ULVESTAD E. , FAGERHOL M. K. , JONSSON R. 
Published: July 2006

Calprotectin (LI) is a major cytoplasmic protein of neutrophilic granulocytes and monocytes/macrophages which is released from leucocytes during activation or cell death. Apart from in vitro antimicrobial and antiproliferative activity little is known about the biological function of the protein. Since previous investigations have shown that Calprotectin plasma levels are elevated in various inflammatory rheumatic diseases, we wanted to investigate if Calprotectin has an effect on immune cell functions. Peripheral blood mononuclear cells, either unstimulated or polyclonally stimulated with mitogen, were incubated with Calprotectin and effects were assessed by enumeration of immunoglobulin secreting cells (ELISPOT).The results indicate that incubation with high concentrations of Calprotectin (> 64 μ/ml) inhibit the production of the three classes of immunoglobulins investigated (IgG, IgM and IgA), both for mitogen stimulated and unstimulated lymphocytes. Except for the highest concentration of Calprotectin (500 μ/ml), it seems plausible that the observed inhibitory effect of Calprotectin on Ig production is not a result of a direct toxic effect of Calprotectin on B lymphocytes. Altogether, these effects of high Calprotectin levels might be of importance in the immunoregulation of inflammatory conditions
Freshly Isolated Tumour‐Infiltrating T‐Lymphocytes have a High Cytotoxic Potential, as Measured by their Ability to Induce Apoptosis in the Target Cell
Authors: ØSTENSTAD B. , SIOUD M. , SCHLICHTING E. , LEA T. , HARBOE M. 
Published: July 2006

To test if freshly isolated tumour‐infiltrating lymphocytes (TIL) can induce apoptosis in a target cell, we have combined two previously described methods. Because TIL predominantly are T‐lymphocytes. we have applied a redirected approach. When the target cells that express anti‐human‐CD3 monoclonal antibodies in their membranes bind to the T cell receptor‐associated CD3‐complex, signals are generated, which activate T cell effector mechanisms. This approach circumvents problems with MHC‐restriction and allows for functional testing of all T cells, irrespective of their clonal specificity.In order to assay for induction of DNA fragmentation, we have labelled the target cell nuclei with [3H]thymidine. Upon harvesting fragmented DNA are washed away. Electrophoretic analysis of the fragmented DNA demonstrated the characteristic ‘ladder’ pattern, consistent with apoptosis.This rapid and simple assay monitors the capacity of different T cells to induce apoptosis in the target cell. It depends on intercellular interactions and clearly discriminates between different T cell subsets. With this assay we demonstrate the functional integrity of the cytotoxic effector arm of freshly isolated TIL.
Clustering of B and T Epitopes Within Short Sequence Regions of the Nieotinic Acetylcholine Receptor
Authors: BELLONE M. , KARACHUNSKI P. I. , OSTLIE N. , LEI S. , CONTI‐FINE B. M. 
Published: July 2006

The epitope repertoire of B cells, due to their selective ability to process their specific antigen and the potential bias imposed on the resulting peptides by the surface immunoglobulins bound to the antigen, may influence the T‐helper repertoire.Immunization of C57B1/6 mice with Torpedo acetylcholine receptor (TAChR) causes experimental autoimmune myasthenia gravis (EAMG). Anti‐TAChR CD4+ cells recognize epitopes within three sequence regions of the TAChR a subunit (“dominant epitopes’). Immunization of mice with denatured or synthetic TAChR antigens sensitizes CD4+ cells to other TAChR sequence regions (‘cryptic epitopes’).We investigated here whether clustering of B and T epitopes within the same short sequence segments occurs during the anti‐TAChR response, as previously described for the response to hexogenous antigens unrelated to homologous self proteins.Twelve 19–20 residue synthetic sequences of the TAChRα, β and δ subunits, containing dominant or cryptic CD4+ epitopes for C57B1/6 mice, were tested for ability to induce anti‐peptide antibody production. C57B1/6 mice were immunized with the individual peptides. Ten peptides stimulated antibody production. Therefore >80% of these short TAChR sequences also contain B epitopes.Therefore also in the anti‐TAChR response leading to EAMG T and B cell epitopes frequently reside within the same short sequence segment.
Visceral Leishmaniasis in Ververt Monkeys: Immunological Responses During Asymptomatic Infections
Authors: GICHERU M. M. , OLOBO J. O. , KARIUKI T. M. , ADHIAMBO C. 
Published: July 2006

Nine vervet monkeys (Cercopithecus aethiops) were infected intradermally with 8 × 107 virulent L. donovani promastigotes. Four animals developed clinical visceral leishmaniasis and died over a period of 18 months. The remaining five animals have remained asymptomatic for a period of 3 years now. Attempts to isolate parasites from spleen and liver through biopsies were fruitless. Immunological respotises of these subclinically infected animals were examined. Enzyme‐linked itnmunosorbent assay (ELISA) and western blot analyses demonstrated Leishmania specific antibodies in these animals, but the antibody titres were low. When proliferation of peripheral blood monocytes (PBMC) to Con‐cunavalin A (Con A) of these animals was compared with control ‘disease free animals’ there were no significant differences iti response. However L. donovani antigen (fixed promastigotes) specific proliferation was demonstrated in the five subclinically infected animals. High and varying levels of interferon gamma (IFN‐γ) were secreted in PBMC cultures from the five vervet monkeys when stimulated with either Con A or L. donovani antigens. In control animals, IFN‐γ was only detected wheti PBMC were stimulated with Con A. Marked delayed‐type hypersensitivity (DTH) responses were demonstrated in the five subclinically infected animals 48 h after injection with formalin fixed promastgotes.It was concluded that the visceral Leishmania disease spectrum due to L. donovani observed in humans could be induced in vervet monkeys and that L. donovani asymptomatic/cryptic infected animals have competent humoral and cellular responses to homologous parasites.
Native Human Serum Amyloid P Component is a Single Pentamer
Authors: SØRENSEN I. J. , ANDERSEN O. , NIELSEN E. HOLM , SVEHAG S. E. 
Published: July 2006

Serum amyloid P component (SAP) and C‐reactive protein (CRP) are members of the pentraxin protein family. SAP is the precursor protein to amyloid P component present in all forms of amyloidosis. The prevailing notion is that SAP in circulation has the form of a double pentameric molecule (decamer) whereas CRP is a single pentameric molecule.We have investigated by gel permeation chromatography the Mr of SAP in freshly collected human serum and of SAP purified by carbohydrate affinity chromatography and anion exchange chromatography. SAP was monitored by quantitative immunoelectrophoresis and ELISA. and SAP peak fractions were analysed by use of SDS‐PAGE, Western blotting, and electron microscopy. The results indicate that native SAP circulates as a single pentamer, a part of which forms complexes with C4b‐binding protein. The properties of SAP changed during purification as indicated by rocket immuno‐electrophoresis and electron microscopy. Thus, electron micrographs of purified SAP showed a predominance of decamers. However, the decamer form of SAP reversed to single pentamers when purified SAP was incorporated into SAP‐depleted serum.
Characteristics of Immune Responses to Native and Protein Conjugated Pneumococcal Polysaccharide Type 14
Authors: VAN DEN DOBBELSTEEN G. P. J. M. , KROES H. , VAN REES E. P. 
Published: July 2006

The immune response to pneumococcal polysaccharide type 14 (PPS‐14), induced by native PPS‐14 was compared with the response induced by PPS‐14 conjugated with CRM197 (PPS‐14‐CRM197). In our animal model, immunization with PPS‐14‐CRM197 gave a significant enhancement of anti‐PPS‐14 serum titres for IgM and IgG. but not for IgA. Also an increase in total number of anti‐PPS‐14 antibody‐secreting ceils was found. Using immunohistochemical techniques, a different distribution pattern of specific antibody‐containing cells in spleen section after immunization with PPS‐I4‐CRM197 was observed. Furthermore, a higher number of IFN‐γ producing cells was found after immunization with PPS‐14‐CRM197, as compared with immunization with PPS‐14. This enhanced IFN‐γ production may be the cause for enhanced IgG response observed after immunization with PPS‐14‐CRM197.The specific immune response was less affected by splenectomy in animals immunized with PPS‐14‐CRM197 than with PPS‐14. However, an age‐related response to the native as well as the conjugated form of the PPS‐14 was observed, since no effect of conjugation with CRM197 was seen in the onset of the immune response to PPS‐14 in young animals.In conclusion, our results affirm the hypothesis that conjugation of polysaccharides changes the characteristics of the antigen towards a thymus‐dependent antigen.
Local T‐Cell Proliferation and Differentiation in Inflammatory Myopathies
Authors: LINDBERG C. , OLDFORS A. , TARKOWSKI A. 
Published: July 2006

Our objective was to investigate the patterns of proliferation and differentiation of infiltrating cells in inflammatory myopathies. Immunohistochemical staining was performed on muscle biopsy specimens from 18 patients with inclusion body myositis, polymyositis and dermatomyositis using monoclonal and polyclonal antibodies.An abundance of cells were TNF‐α+ (4–8%), ICAM‐1+ (7–65%). IFN‐γ+ (3–6%), and Ki‐67+ (4–8%). It was shown that 70% of the Ki‐67+ cells were Ki‐67+CD3+ cells. Very few mononuclear cells were IL‐2R+. MHC‐I expression was found on nearly all muscle fibres in all cases, while MHC‐II expression was found on occasional muscle fibres in 1/3 of cases. Analysis of repeated biopsies from four IBM patients after prednisolone treatment showed no change in the proportions of TNF‐α, ICAM‐1, IFN‐γ or Ki‐67 positive cells. In inflammatory myopathies there is an intense proliferation and differentiation of inflammatory cells in situ, indicating a local stimulation of the inflammatory process.
Impaired Antigen‐Specific B‐Cell Response and Altered Splenic Microstructure in Mice Following Continuous Administration of IL‐4 In Vivo
Authors: SCHILIZZI B. M. , SAVELKOUL H. F. J. , DE JONGE M. W. A. , THE T. H. , DE LEIJ L. 
Published: July 2006

The effect of long term in vivo administration of IL‐4 on the induction of antigen‐specific B cells, the splenic microenvironment and the yield of antigen‐specific antibody producing hybridomas was studied. Immunization with DNP‐KLH, followed by 12 weeks continuous IL‐4 treatment resulted in increased numbers of total splenic (non‐DNP) IgM and IgG AFC (antibody forming cells) on day 5 after booster, whereas the DNP‐specific IgG and IgG1 AFC were reduced compared to age‐matched control animals not treated with IL‐4. In addition, an almost 300‐fold increase in non‐DNP IgE was found while the IgE anti‐DNP response was minimal.When the splenic cells were used in a fusion protocol, a relative decrease in yield of antigen‐specific hybridomas was found in the long term IL‐4 treated mice. Immunohistological staining of spleen sections from mice treated with IL‐4 up until the time of booster revealed reduced B‐cell follicle area and germinal centre numbers. These results show that extensive IL‐4 treatment reduced antigen‐specific B‐cell formation and suggests a reduction in the number of B cells entering the memory B‐cell pathway in the spleen.
Engagement of MHC Class I Proteins on Natural Killer Cells Inhibits their Killing Capacity
Authors: PETERSSON M. G. E. , GRÖNBERG A. , KIESSLING R. , FERM M. T. 
Published: July 2006

We have studied whether engagement of MHC class I (MHC—I) molecules on natural killer (NK) cells can influence the NK killing activity. Human NK effector cells, enriched by nylon wool passage, were incubated with monoclonal antibodies (MoAb) to MHC—I followed by cross‐linking with secondary rabbit anti mouse Ig or streptavidin. Cross linking of MHC—I molecules on NK cells resulted in a clear inhibition of the NK activity against the target cells K562, Molt‐4 and U937. The inhibitory effect was selective for MHC—I and was not seen with MoAb to MHC—II or CD56 molecules. The inhibition was not mediated via Fc receptors since F(ab)2 fragments of the MHC—I MoAb W6/32 were as effective as the intact antibody. The best inhibition of NK activity was obtained using biotin‐labelled F(ab)2 fragments of W6/32 and streptavidin as a cross‐linker, where up to 70 % reduction in NK cell activity was observed. Antibody dependent cellular cytotoxicity (ADCC) was also inhibited by cross‐linking MHC—I molecules on the effector cells.The results show that antibody mediated cross‐linking of MHC—I proteins on NK cells can inhibit their killing capacity. This indicates that MHC—I molecules on NK cells can be involved in the regulation of NK cytotoxicity, perhaps by transmitting inhibitory signals into the NK cell.
The Somatic Hypermutation Activity of a Follicular Lymphoma Links to Large Insertions and Deletions of Immunoglobulin Genes
Authors: WU H. Y. , KAARTINEN M. 
Published: July 2006

A biopsy specimen from a patient with follicular lymphoma was divided into two fragments. DNA was extracted from one fragment and a 1.2 kb region of the functional heavy chain (IgH) gene was amplified, cloned and sequenced (eight clones). From the other fragment a cell line (HF‐1) was started. The IgH gene region was amplified from the cell line, and sequenced without cloning. The nine sequences obtained could be arranged into a genealogical tree where the individual sequences differed from the deduced ancestor by 16–29 single nucleotide changes, some also by an insertion and/or a deletion. It is apparent that the sequence alterations were caused by somatic mutations during the growth of the lymphoma.The comparison of the sequences with two published (allelic) germline sequences of the human JH region showed ∼20% non‐homology. The differences included five additional multinucleotide insertion/deletion changes, the longest of them a 101‐nucleotide insertion. Two long insertions were homologous to the adjacent germline sequences. We propose that most of the changes observed, including long deletions and insertions, represent or are linked to somatic hypermutation events of the Ig gene type. Although in a few cases large deletions and insertions (>2 bp) have been found in mutated immunoglobulin genes, our results, for the first time, firmly link these deletions/insertions to somatic hypermutations; their frequency was found to be 2.2% of the observed mutational events in the non‐translated gene regions. HF‐1 is the first follicular lymphoma line successfully established from a lymphoma known to have hypermutated its Ig genes during the malignant growth. It is a candidate cell line to be studied for its ability to generate mutations of B cell type in cell cultures.
Specific and Long‐Lasting Protection from Collagen‐Induced Arthritis and Oil‐Induced Arthritis in DA Rats by Administration of Immunogens
Authors: LORENTZEN J. C. , ERLANDSSON H. , MÜSSENER Å. , MATTSSON L. , KLEINAU S. , NYMAN U. , KLARESKOG L. 
Published: July 2006

DA rats develop transient arthritis after subcutaneous immunization with adjuvant‐oil, while chronic arthritis and collagen autoreactivity ensues when collagen is added to the oil. We show here that DA rats can be protected from oil‐induced arthritis (OIA) and rat collagen‐induced arthritis (rCIA) by addition of antigen to these arthritogenic inocula.We have investigated this remarkable phenomenon and demonstrate that both foreign and self antigens can be protective, apparently provided they are immunogenic; hence HSP‐65kDa, ovalbumin, rat myelin basic protein, rat IgG and bovine albumin are effective while rat albumin is not. This protection is long‐lasting and disease‐specific because rats protected from rCIA resist a later attempt to induce arthritis, but not experimental autoimmune encephalomyelitis (EAE). Protection from rCIA depends neither on the blocking of humoral autoreactivity to collagen nor on a change in the isotype profile of anti‐collagen antibodies. We demonstrate that immunogens can also be protective when injected intraperitoneally only a few days before onset of arthritis. Our results indicate that protection is mediated through bystander immune reactions towards the co‐immunized antigen and that the arthritogenicity of a given provocation, be it adjuvants, microbes or autoantigens, may be a complex net result of arthritogenic and contra‐arthritogenic immune reactions.
Monozygotic Rheumatoid Arthritis Twin Pairs Express Similar Levels of Conserved Immunoglobulin V Gene in Polyclonal Rheumatoid Factors Irrespective of Disease Status
Authors: VENCOVSKY J. , MAGEED R. A. , OLLIER W. E. , MAINI R. N. 
Published: July 2006

The degree of polyclonal RF heterogeneity was assessed in diseased and non‐diseased twins with rheumatoid arthritis (RA). The distribution of variable region determinants encoded by a set of immunoglobulin germline, or minimally mutated germline, genes within IgM RF, IgG RF and IgA RF isotypes was determined by ELISA using specific mouse monoclonal antibodies (MoAb) in fractionated plasma from 12 members of six monozygotic twin pairs with RA, The results reveal that at least 40% (range ∼ 18–87%) of IgM RF are encoded by a small set of ∼ 10 genes from the VH1, 3 and 4 families. Furthermore, a significant proportion of IgG RF and IgA RF (∼ 30%) are also encoded by these same genes. Comparison with RF‐negative fractions of immunoglobulins showed that the examined variable region determinants were overrepresented in the RF fractions.The level of expression of the variable region determinants in RF were generally similar within twins but different between unrelated twin pairs irrespective of disease status. The variability of VH gene usage between unrelated individuals suggests that the level of expression and regulation of the variable region determinants may be genetically regulated or influenced by common environmental factors.
The role of phloem sieve elements and laticifers in the biosynthesis and accumulation of alkaloids in opium poppy†
Authors: Samanani Nailish , Alcantara Joenel , Bourgault Richard , Zulak Katherine G. , Facchini Peter J. 
Published: July 2006

SummaryThe benzylisoquinoline alkaloids of opium poppy, including the narcotic analgesics morphine and codeine, accumulate in the multinucleate cytoplasm of specialized laticifers that accompany vascular tissues throughout the plant. In mature opium poppy plants, immunofluorescence labeling using specific antibodies showed that four alkaloid biosynthetic enzymes, (S)‐norcoclaurine 6‐O‐methyltransferase (6OMT), (S)‐coclaurine N‐methyltransferase (CNMT), (S)‐3′‐hydroxy‐N‐methylcoclaurine‐4′‐O‐methyltransferase (4′OMT) and salutaridinol‐7‐O‐acetyltransferase (SAT) were restricted to sieve elements of the phloem adjacent or proximal to laticifers. The identity of sieve elements was confirmed by (i) the specific immunogold labeling of the characteristic cytoplasm of this cell type, (ii) the co‐localization of a sieve element‐specific H+‐ATPase with all biosynthetic enzymes and (iii) the strict association of sieve plates with immunofluorescent cells. The localization of laticifers was demonstrated antibodies specific to major latex protein (MLP), which is characteristic of this cell type. In situ hybridization using antisense RNA probes for 6OMT, CNMT, 4′OMT and SAT showed that the corresponding gene transcripts were found in the companion cell paired with each sieve element. Seven benzylisoquinoline alkaloid biosynthetic enzymes, (S)‐N‐methylcoclaurine 3′‐hydroxylase (CYP80B1), berberine bridge enzyme, codeinone reductase, 6OMT, CNMT, 4′OMT and SAT were localized by immunofluorescence labeling to the sieve elements in the root and hypocotyl of opium poppy seedlings. The abundance of these enzymes increased rapidly between 1 and 3 days after seed germination. The localization of seven biosynthetic enzymes to the sieve elements provides strong support for the unique, cell type‐specific biosynthesis of benzylisoquinoline alkaloids in the opium poppy.
UPF1 is required for nonsense‐mediated mRNA decay (NMD) and RNAi in Arabidopsis
Authors: Arciga‐Reyes Luis , Wootton Lucie , Kieffer Martin , Davies Brendan 
Published: July 2006

SummaryAberrant mRNAs containing premature termination codons (PTCs) have the potential to be translated into truncated proteins, which could act to the detriment of the organism by interfering with normal cellular processes. Eukaryotes have mechanisms of mRNA quality control that identify PTC‐containing transcripts and target them for destruction, a process known as nonsense‐mediated mRNA decay (NMD). Surprising differences have been reported in the mechanisms of NMD between different organisms. UPF1 and UPF3 are structurally unrelated proteins, which function in the NMD pathway in yeast, mammals, Drosophila and Caenorhabditis elegans. Here we show that NMD in plants requires UPF1, as mRNAs containing PTCs become stabilized in upf1‐5 mutants. However, in contrast to NMD in mammals, UPF1‐dependent NMD is capable of targeting both spliced and unspliced PTC‐containing mRNAs. An allelic series of upf1 mutants exhibits a range of unexpected vegetative and floral abnormalities, including jagged leaves, late flowering, fused flowers and seedling lethality. We also show that mutants in UPF3 share these abnormalities. As both UPF1 and UPF3 are required for NMD, the similar phenotypes of the upf1 and upf3 mutants suggest that NMD regulates a common set of genes required for plant development and survival. Finally, gene silencing by an inverted repeat transgene is impaired in upf1‐5 mutants, indicating a connection between UPF1 and RNA interference in plants.