bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homologous C3 deposition and homotypic cell adhesion in a human myeloid cell line, P39
Authors: Matsumoto Misako , Seya Tsukasa 
Published: March 2007

AbstractIt has been accepted that decay‐accelerating factor (DAF) and membrane cofactor protein (MCP) on human cells block C3 deposition, thereby preventing homologous complement attack. In this study, we discovered that a human myeloid cell line, P39, was a target for human C3 even though it expressed normal DAF and MCP. This homologous C3 deposition was induced by serum containing Mg2+ and EGTA (Mg2+‐EGTA serum) selectively on a P39 subline [P39(+) cells] having the capacity to form cell aggregates. Another P39 subline [P39(‐)cells] growing as a separated form did not induce homologous C3 deposition. Multiple C3 fragments, C3b and C3bi, were fixed on P39(+) cells and a significant amount of C5a was released. Several distinct C3 fragment‐membrane acceptor molecule complexes were immunoprecipitated with anti‐C3c antibody from surface‐labeled P39 (+) cells treated with Mg2+‐EGTA serum and from unlabeled cells incubated with 125I‐labeled C3 and Mg2+‐EGTA serum. Two‐dimensional sodium dodecyl sulfate‐polyacrylamide gel electrophoresis revealed 90,60 and ≦ 40 kDa C3 acceptors on P39(+) cells. On these cells, some of the C3 bound to these acceptors remained in the form of C3b, which can form C3/C5 convertases. P39(+) cells differed phenotypically from P39(‐) cells in that P39(+) cells expressed intercellular adhesion molecule‐1 (ICAM‐1), whereas P39(‐) cells did not. Both cells were lymphocyte function‐associated antigen 1 (LFA‐1)+/CR3− counterreceptors for ICAM‐1. However, homotypic cell adhesion was not completely inhibited by antibodies against ICAM‐1 and LFA‐1, suggesting that the homotypic cell aggregation of P39(+) cells is due only in part to ICAM‐1 and LFA‐1. In addition, C3 deposition, the expression of ICAM‐1, and cell aggregation were enhanced by both tumor necrosis factor‐α and interferon‐γ. Although the principal causative mechanisms remain obscure, C3 deposition and cell adhesion appear in parallel in this cell line and may be involved in the modulation of cell‐mediated immune reactions.We are grateful to Dr. Iida for the generous gift of the mAb against human C3c and C3bi, to Dr. Yamada for anti‐ICAM‐1 mAb, and to Drs. Nakai, Kondo, Hamuro, Nihira, and Matsuda for cytokines. We also thank the JCRB for providing P39 cells, Drs. Akedo, Miyagawa, and Hatanaka (Center for Adult Diseases Osaka) for valuable discussions, Dr. S. Hori (Osaka Prefectural Institute of Public Health) for providing FACS can, Ms H. Fukuda for the photographs in phase‐contrast microscopy, Ms. F. Yamashita, A. Kojima and T. Hara for technical help, and Ms. A. Itoh for secretarial assistance.
Induction by anti‐CD40 antibody or soluble CD40 ligand and cytokines of IgG, IgA and IgE production by B cells from patients with X‐linked hyper IgM syndrome
Authors: Durandy Anne , Schiff Claudine , Bonnefoy Jean Yves , Forveille Monique , Rousset Françoise , Mazzei Gonzalo , Milili Michèle , Fischer Alain 
Published: March 2007

AbstractWe studied the ability of B lymphocytes from patients with X‐linked hyper IgM syndrome (HIGM1) to be activated via the CD40 membrane receptor. HIGM1 is caused by a CD40 ligand gene mutation, leading to defective expression on the membrane of activated T lymphocytes. We found that triggering of B cells by an anti‐CD40 monoclonal antibody or the soluble CD40 ligand plus interleukin (IL)‐4 or IL‐10 led to B cell proliferation and/or differentiation towards IgG, IgA and IgE secretion. This was reflected by transcription of Cγ, α and ε membrane isotype expression and IgG, IgA and IgE production. These results confirm the integrity of B cells in patients with the HIGM1 immunodeficiency and open up new therapeutic possibilities.
Epitope analysis of the T cell response to a complex antigen: Proliferative responses to human rhinovirus capsids
Authors: Hastings Gillian Z. , Francis Michael J. , Rowlands D. J. , Chain Benjamin M. 
Published: March 2007

AbstractUnderstanding the factors which regulate the repertoire of a T cell response is important when selecting T helper cell epitopes for inclusion in synthetic viral vaccines. In this study we have examined the T cell response to human rhinovirus (HRV) type 1A in a mouse model system, using a comprehensive set of synthetic peptides which span all four of the proteins which make up the HRV capsid. This constitutes the first study to use a set of peptides covering the entire sequence of all structural proteins of any virus. This study identifies the major proliferative (CD4) T cell epitopes within the minor receptor group HRV 1 A, and analyzes these epitopes with relation to their location within the three‐dimensional structure of the virus. The proliferative response to HRV is highly selective, with strong responses to only a very small number of epitopes, many of which are grouped together within restricted areas of the primary structure of the HRV proteins. The repertoire of the response is almost entirely specific to the major histocompatibility complex haplotype of the host. The major T cell epitopes are spatially distinct from the sites of the major antibody recognition sites, and are buried within the viral capsid. In striking contrast to the antibody responses, the T cell responses are highly cross‐reactive against a wide variety of viral serotypes.
Antigens targeted to the Leishmania phagolysosome are processed for CD4+ T cell recognition
Authors: Kaye Paul M. , Coburn Cara , McCrossan Maria , Beverley Stephen M. 
Published: March 2007

AbstractProcessing of antigen for recognition by class II‐restricted CD4+ T cells occurs within acidic compartments of the antigen‐presenting cell. The exact nature of this compartment has yet to be precisely defined, however, but may vary depending upon the cell type studied and the antigen used. The acidic compartments of macrophages are also responsible for the degradation of ingested micro‐organisms and play host to others which are adapted to an intracellular existance. To determine whether the phagolysosome (PL) formed in activated macrophages after ingestion of Leishmania parasites is also a site for entry of antigen into the class II presentation pathway, we have used the approach of genetic transformation. Hence, Leishmania were transfected with the genes for the protein antigens ovalbumin (OVA) and β‐galactosidase (β‐gal) and after infection were able to deliver these antigens specifically into the PL. Delivery of antigen to this site resulted in the ability of infected macrophages to present these antigens to antigen‐specific CD4+ T cells. After taking into account the absolute levels of antigen uptake by macrophages, a 4‐h processing period for OVA delivered by this or a soluble route led to equivalent levels of T cell activation. Unlike macrophages pulsed with soluble OVA, those with PL‐targeted OVA still retained the ability to stimulate T cells after a 24‐h processing period. This enhanced lifespan of antigen in macrophages corresponded to the kinetics of degradation of the parasite, suggesting slow release of antigen into the processing pathway. β‐gal presentation from the PL was tenfold less efficient under the same conditions. In addition to providing the first information on antigen processing in a protozoan PL, these studies highlight the usefulness of genetically transformed parasites for these types of studies.
A new macrophage differentiation antigen which is a member of the scavenger receptor superfamily
Authors: Law S. K. Alex , Micklem Kingsley J. , Shaw Jacqueline M. , Zhang Xi‐Ping , Dong Yin , Willis Antony C. , Mason David Y. 
Published: March 2007

AbstractThe antibodies Ki‐M8, Ber‐Mac3, GHI/61 and SM4 define a human macrophage‐associated antigen with a relative molecular mass of 130000 which we designate M130. The protein was purified by immunoaffinity chromatography and an N‐terminal and three internal amino acid sequences were obtained. A cDNA fragment was initially obtained by polymerase chain reaction (PCR) using reverse‐translated primers. Several variant cDNA clones, derived from alternative spliced messages, were obtained from a lipopolysaccharide‐stimulated human monocyte library and were sequenced. The relative abundance of these variants was evaluated by a series of overlapping PCR reactions. The size of the most representative cDNA is 3.7 kb and closely agrees with the mRNA size of 3.8 kb determined by Northern blot analysis. The membrane protein encoded contains a leader peptide of 40 residues, a putative extracellular domain of 1003 residues, followed by a hydrophobic segment of 24 residues and a cytoplasmic domain of 49 residues. The extracellular domain was found to contain nine repeating elements, of about 110 residues, which are similar to those of the scavenger receptor superfamily.
Construction, expression and functional analysis of a glycolipid‐linked form of CR1
Authors: Clissold Patricia M. , Ebling Hazel J. , Lachmann Peter J. 
Published: March 2007

AbstractBy genetic engineering of human CR1 cDNA and its stable transfection into cells we have produced a cell line which expresses CR1 anchored to the cell surface by a glycolipid anchor. The glycosyl‐phosphatidylinositol (GPI)‐CRl protects cells intrinsically from damage mediated by complement activated through the classical pathway. Cell surface GPI‐CR1 is more efficient on a molar basis than soluble CR1 in the assay, but extrinsic protection of other cells was not obtained. Soluble CRl‐protected cells extrinsically in the assay but was required at nearly ten fold higher amounts than the intrinsic protection conferred by GPI‐anchored CR1. Additionally, GPI‐CR1 was shown to act as a co‐factor to Factor I in the generation of C3c from iC3b. Since GPI‐anchored proteins can incorporate spontaneously into the membranes of living cells by virtue of their lipid tails, the isolated GPI‐CR1 will be used to introduce CR1 on to the surfaces of many different types of cell so that its role in immunity can be further investigated.
Cloning of a human immunoglobulin gene fragment containing both VH‐D and D‐JH rearrangements: Implication for VH‐D as an intermediate to VH‐D‐JH formation
Authors: Shin Euy Kyun , Matsuda Fumihiko , Fujikura Junji , Akamizu Takashi , Sugawa Hideo , Mori Toru , Honjo Tasuku 
Published: March 2007

AbstractIn an Epstein‐Barr virus‐transformed human B cell line we found an unusual immunoglobulin heavy chain gene rearrangement. Restriction mapping and sequencing analysis led us to conclude that VH‐D and D‐JH recombination took place in a single allele. Both VH‐D and D‐JH complexes still had their recombination signal sequences adjacent and the DNA sandwiched by these two complexes retained a germ line configuration, suggesting the potential for a secondary rearrangement resulting in a VH‐D(‐D)‐JH formation. With this finding, we propose a novel pathway, in which the VH‐D complex is an intermediate in the formation of a functional VH exon.
Suppression of apoptosis in normal and neoplastic human B lymphocytes by CD40 ligand is independent of Bcl‐2 induction
Authors: Holder Michelle J. , Wang Hong , Milner Anne E. , Casamayor Monserat , Armitage Richard , Spriggs Melanie K. , Fanslow William C. , Maclennan Ian C. M. , Gregory Christopher D. , Gordon John 
Published: March 2007

AbstractThe tendency of isolated germinal center (GC) B cells to undergo apoptosis was suppressed by recombinant cell‐bound CD40 ligand (CD40L): after 2 days at 37°C, > 80 % of cells remained viable in the presence of CD40L as compared to < 1 % in control cultures. CD40L sustained a high rate of DNA synthesis in GC cells and was more effective than monoclonal antibody to CD40 in this regard. Group I Burkitt lymphoma (BL) cell lines induced to undergo apoptosis with anti‐immunoglobulin or calcium ionophore were also protected by CD40L. In BL cells, this route of rescue was not accompanied by induction of Bcl‐2 protein, the expression of which has been linked to hemopoietic cell survival. Bcl‐2 was induced in GC cells responding to CD40L, but its appearance was a relatively late event not reaching significant levels over controls until day 2 of culture. Thus induction of Bcl‐2 appears to be secondary to the survival signal imparted by CD40L. These findings are discussed in relation to a potential role for CD40L in supporting B cell tumors in vivo and the discovery that the molecular defect in the X‐linked Hyper‐IgM syndrome is targeted to the CD40L gene.
Linomide, a novel immunomodulator that prevents death in four models of septic shock
Authors: Gonzalo José Angel , González‐García Ana , Kalland Terje , Hedlund Gunnar , Martínez‐A Carlos , Kroemer Guido 
Published: March 2007

AbstractIntravenous injections of 50 μ.g Staphylococcus aureus enterotoxin B (SEB) or bacterial lipopolysaccharide (LPS) are lethal, provided that mice are simultaneously sensitized with either N‐galactosamine (GalN) or the anti‐glucocorticoid RU‐38486. Similar to the synthetic glucocorticoid (GC) receptor agonist dexamethasone, pharmacological doses of the immunomodulator linomide (quinoline‐3‐carboxamide) prevent death in all four models of lethal septic shock (LPS + GalN, LPS + RU‐38486, SEB + GalN, and SEB + RU‐38486) and inhibit the secretion of tumor necrosis factor, one of the major intermediate effector molecules of SEB and LPS toxicity. In this system, cyclosporine A (CsA), although effective in suppressing SEB toxicity, fails to counteract the lethal effect of LPS. This observation, together with the fact that linomide acts in the presence of excess amounts of GC receptor antagonist, indicates that linomide functions in a different way to that of known immunosuppressive agents like CsA and GC.
Increased cytokine production in mononuclear cells of healthy elderly people
Authors: Fagiolo Umberto , Cossarizza Andrea , Scala Enrico , Fanales‐Belasio Emanuele , Ortolani Claudio , Cozzi Emanuele , Monti Daniela , Franceschi Claudio , Paganelli Roberto 
Published: March 2007

AbstractThe production of cytokines during aging, except interleukin (IL)‐2, has been neglected in humans. We measured the in vitro production of IL‐6, tumor necrosis factor (TNF)‐α, interferon (IFN)‐γ and IL‐1β by peripheral mononuclear cells from selected healthy young (mean age 26.8 years) and aged (mean age 80.2 years) subjects. Significant increases of IL‐6, TNF‐α and IL‐1bT levels were found in mitogen‐stimulated cultures from aged donors, occurring at 24 to 72 h after stimulation. No significant differences were observed for IFN‐γ production. Proliferative capability of cells stimulated with PHA was not impaired in aged subjects. Since the amounts of all cytokines studied were similar in unstimulated cultures from young and aged subjects, and also serum levels of TNF‐a did not differ, these data indicate that the cellular machinery for the production of these cytokines is well preserved in aging, and also that cells from old people are able to up‐regulate their production in response to appropriate stimuli. The increases in cytokine synthesis were not dependent on changes in the number of monocytes, nor were they related to the significant rise of CD45RO+, and the concomitant decrease of CD45RA+ occurring in both CD4+ and CD8+ lymphocytes from aged subjects. The increased production of pro‐inflammatory cytokines by stimulated mononuclear cells of healthy aged subjects may be relevant to several aspects of age‐associated pathological events, including atherosclerosis, osteoporosis, fibrosis and dementia.
Hyper‐reactivity of mouse CD45RA − T cells
Authors: Lightstone Elizabeth , Marvel Jacqueline , Mitchison Avrion 
Published: March 2007

AbstractMouse CD4 T cells have been partitioned into CD45RA and CD45RA− subpopulations by means ot the monoclonal antibody 14.8. The CD45RA− subpopulation proliferated more actively and generated more interleukin‐4 (IL‐4) in response to stimulation with anti‐CD3 antibody and phytohemaglutinin, and more IL‐2 in response to anti‐CD3. This subpopulation is therefore hyper‐reactive to these polyclonal stimulators, but does not show the bias towards T helper type 2 activity that has been found in studies with other related CD45 isoforms. No evidence of suppression was obtained by comparing proliferation of CD45RA− cells in the presence and absence of CD45RA cells. Thus mouse CD4 T cells behave in these respects similarly to those of man, as is evident in a brief review of the quiescence‐activation‐quiescence cycle in the two species.
Expressions of cytokine genes during development of autoimmune sialadenitis in MRL/Ipr mice
Authors: Hamano Hironori , Saito Ichiro , Haneji Norio , Mitsuhashi Yuriko , Miyasaka Nobuyuki , Hayashi Yoshio 
Published: March 2007

AbstractLocal cytokine gene expression in vivo was analyzed by direct analysis of RNA obtained from salivary gland tissues of MRL/lpr mice with autoimmune sialadenitis. The expression of cytokine genes were assessed by the reverse‐transcriptase polymerase chain reaction, and by immunohistochemical analysis. The expression of interleukin‐1(IL‐1)β and tumor necrosis factor was detected before the onset of inflammatory lesions in the salivary glands of mice of 1 or 2 months of age, and IL‐6 mRNA expression was clearly detected at the time of onset of typical autoimmune sialadenitis at 3 months of age in MRL/lpr mice, and was up‐regulated with advancing age. These results suggest that the overexpression of these inflammatory cytokine genes is involved in the development and progression of organ‐localized autoimmunity in the salivary glands of MRL/lpr mice.
Preferential distribution of Vβ 8.2‐positive T cells in the central nervous system of rats with myelin basic protein‐induced autoimmune encephalomyelitis
Authors: Tsuchida Masanori , Matsumoto Yoh , Hirahara Hiroyuki , Hanawa Haruo , Tomiyama Katsuhiro , Abo Toru 
Published: March 2007

AbstractTo determine the role of encephalitogenic T cells in the formation of lesions in the central nervous system (CNS), experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats by immunization with either myelin basic protein (MBP) or the synthetic peptide which corresponds to the 87–100 sequence of guinea pig MBP, and T cells expressing T cell receptor (TcR) Vβ8.2, Vβ8.5, Vβ10 and Vβ16 in the lymphoid organs and CNS were localized and quantified by flow cytometry (FCM) and immunohistochemistry. In normal rats, the percentage of T cells expressing these Vβ phenotypes to the total number of TcR αβ+ T cells, as determined by FCM, ranged from 5% to 10% in the lymph node. Vβi6+ T cells were the most predominant population among the four Vβ subsets tested. Essentially the same findings were obtained from the analysis of the lymphoid organs of rats with EAE which had been induced by immunization with the same two antigens. In sharp contrast, 15–20% of the T cells isolated from lesions of MBP‐induced EAE expressed Vβ8.2+. Thus, the percentage of Vβ8.2+ T cells in the EAE lesions was threefold higher than that in the lymph node, while the proportions of Vβ8.5+, Vβ10+ and Vβ16+ T cells were about the same in both organs. The predominance of Vβ58.2+ T cells in EAE lesions was confirmed by counts of immunohistochemically stained T cells in the spinal cord. Moreover, it was revealed that (i) the predominance of Vβ8.2+ T cells was greatest during the development of EAE and became less obvious at the recovery stage, and (ii) at the peak stage of EAE, approximately 85% of Vβ8.2+ T cells were distributed in the parenchyma while 15% were in the perivascular space of the CNS vessels. These findings indicate that encephalitogenic T cells which express Vβ8.2 infiltrate the CNS at a very early stage of EAE and become the predominant population in infiltrating T cells, and further suggest that encephalitogenic T cells, not only recruit inflammatory cells in the CNS, but also cause neural tissue damage, such as demyelination.
Murine CD8+ T suppressors against mycobacterial 65‐kDa antigen compete for IL‐2 and show lack of major histocompatibility complex‐imposed restriction specificity in antigen recognition
Authors: Khetan Smita , Sainis Krishna Balaji , Rath Satyajit , Kamat Ramesh 
Published: March 2007

AbstractThe mechanism of antigen‐specific suppression and reasons for aberrant major histocompatibility complex (MHC) class II restriction mediated by CD8+ T cells was investigated in a previously reported murine model of immunosuppression, generated by intraperitoneal priming with Mycobacterium vaccae. Both the CD4+ T helper cells (Th) and CD8+ T supressor cell (Ts) of M.vaccae‐primed mice recognized the 65‐kDa antigen of the bacillus, presented by I‐A and I‐E, respectively. The CD8+ Ts could inhibit non‐antigen‐specific proliferation of primed CD4+ T cells induced by the exogenously added interleukin (IL)‐2 (concanvalin A‐stimulated culture supernatant). For inhibition, the Ts had to be activated by the 65‐kDa antigen. The degree of inhibition was dependent upon the amount of added IL‐2 and the relative numbers of primed CD8+ and CD4+ T cells. On incubation with antigen‐presenting cells, and the 65‐kDa antigen, the primed CD8+ T cells absorbed IL‐2 as efficiently as primed CD4+ T cells. Based on this, it was concluded that the primed CD8+ T cells induced suppression by competition for IL‐2.Employing the same model, the MHC restriction of recognition of the suppressor epitope of the 65‐kDa antigen by the CD8+ Ts was investigated. The epitopes presented by diverse MHC class II molecules, such as self I‐A, I‐E and even allogeneic I‐E were similar, because they were recognized by the same population of primed CD8+ Ts. Further, immunization of C57BL/6 mice with Ltk‐cells expressing H‐2 DkKk alloantigens, stimulated CD8+ T cells capable of recognizing M.vaccae 65‐kDa antigen. Based on these data, it was proposed that recognition of the suppressor epitope of the 65‐kDa antigen by the primed CD8+ Ts exhibits lack of restriction specificity imposed by MHC diversity.
Polymorphism of the functional immunoglobulin variable region genes in the chicken by exchange of sequence with donor pseudogenes
Authors: Benatar Tania , Ratcliffe Michael J. H. 
Published: March 2007

AbstractWe have isolated a number of new allelic variants of the unique functional genes encoding chicken immunoglobulin heavy and light chain variable regions (VH1 and VL1, respectively). The distribution and nature of nucleotide variation among these and previously identified VH1 and VL1 alleles demonstrates that random point mutations are likely not the predominant cause of allelic variation at these loci. Comparison of the variant nucleotides with sequences from the pseudo‐VH and pseudo‐VL gene families, which lie 5′ to VH1 and VL1, respectively, suggests that the great majority of allelic variants can be accounted for by segmental transfer of sequence from donor pseudogenes into the germ‐line VH1 and VL1 genes. These results demonstrate that the chicken VH1 and VL1 genes are susceptible to sequence replacement at the germ‐line level as well as somatically during antibody diversification. The limited repertoire of Bcell specificities produced by gene rearrangement in the chicken has led to speculation that these specificities may play a critical role in the progression of chicken B cell development. The results presented here do not support this hypothesis since many of the allelic variant nucleotides described here encode non‐conservative amino acid substitutions within the antigen‐binding sites of the Ig molecule.