bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of high molecular weight isoforms of CD45 by mouse thymic progenitor cells
Authors: Goff Lindsey K. , Larsson Lena , Fisher Amanda G. 
Published: March 2007

AbstractWe have studied the expression of isoforms of CD45 (leukocyte common antigen, LCA) among T cell precursors using the organ culture system of Jenkinson et al. (Eur. J. Immunol. 1982. 12: 583). These experiments show that cells capable of recolonizing alymphoid embryonic thymic lobes in vitro can be detected in the thymus of fetal and adult mice and are enriched when thymocytes are depleted of cells bearing CD4 or CD8. These data are consistent with results from in vivo experiments of Fowlkes et al. (J. Exp. Med. 1985. 162: 802) indicating that T cell precursors lie within the double‐negative (CD4−CD8−) compartment. No precursors were detected among the reciprocal populations of cells bearing CD4 and/or CD8 (single and double positives). Double‐negative cell fractions were then divided on the basis of reactivity with monoclonal antibodies RA3‐2C2 and RA3‐3A1. These antibodies recognize the high molecular weight species of the LCA or, more accurately, a product defined by exon A of the CD45 gene. Recolonizing cells were found predominantly in the CD45RA+ (RA3‐2C2 and RA3‐3A1 reactive) fraction of double‐negative thymocytes; CD45RA− enriched populations had increased efficiency of recolonization and CD45RA− depleted populations had decreased ability to recolonize as compared with the whole CD4−CD8− fraction. To clarify whether progenitors enriched in the CD45RA+ fraction were capable of giving rise to mature CD4+, CD8+ and CD4+CD8+ cells, we analyzed the progeny of lobes seeded with CD4−CD8−CD45RA+ fractions. After 7–9 days in organ culture the proportion of CD4+, CD8+ or CD4+CD8+ cells had increased to 35.2%, 18.6% and 23.7%, respectively (mean of five experiments), indicating that progenitors among the CD45RA+ population were indeed multipotent. These results suggest that the majority of T stem cells in the thymus are among thymocytes that express the CD45RA molecule, an hypothesis supported by our finding that removal of CD45RA‐expressing cells (using complement and antibody) eliminated recolonizing capacity of thymic cell fractions.
Hypothermia and hypoglycemia induced by anti‐CD3 monoclonal antibody in mice: Role of tumor necrosis factor
Authors: Alegre Marisa , Vandenabeele Peter , Flamand Véronique , Moser Muriel , Leo Oberdan , Abramowicz Daniel , Urbain Jacques , Fiers Walter , Goldman Michel 
Published: March 2007

AbstractThe possible involvement of tumor necrosis factor‐α (TNF) in the metabolic disturbances induced by anti‐CD3 monoclonal antibodies (mAb) was analyzed in DBA/2 mice injected with 50 μg of the anti‐murine CD3 mAb 145‐2C11. First, we found that 145‐2C11 induces a profound hypothermia maximal between 3 h and 6 h after the injection (at 3 h: − 3.0 ± 0.1 °C) as well as hypoglycemia (blood glucose levels at 6 h and 24 h: 76 ± 13 mg/100 ml and 92 ± 22 mg/100 ml, respectively, p < 0.001 as compared with control values). These metabolic changes are preceded by the release of TNF into the circulation (peak serum TNF levels at 2 h: 50 ± 23 pg/ml, p < 0.01 as compared with controls). The release of TNF induced by 145‐2C11 depends on the effect of the mAb on T cells as it is not observed in athymic nude mice while lipopolysaccharide‐resistant C3H/HeJ mice also display a significant rise in serum TNF (peak levels at 2 h: 59 ± 44 pg/ml). Pretreatment of DBA/2 mice with 12 mg of rabbit anti‐murine TNF antibodies completely prevents the hypothermia while the hypoglycemia is significantly attenuated. Finally, F(ab')2 fragments of 145‐2C11 induce only a transient hypoglycemia (blood glucose levels at 6 h: 109 ± 14, p < 0.001 as compared with controls) but neither hypothermia nor significant TNF release. We conclude that TNF is a major mediator of the acute metabolic changes induced by the intact form of 145‐2C11.
Organization of the chimpanzee C4‐CYP21 region: Implications for the evolution of human genes
Authors: Kawaguchi Hiroshi , Golubic Mladen , Figueroa Felipe , Klein Jan 
Published: March 2007

AbstractWe prepared a cosmid library from chimpanzee DNA and screened it with a mouse probe specific for the complement component 4 (C4)‐encoding gene. We isolated 29 clones and constructed restriction maps for 20 of these. The clones could be arranged into two overlapping clusters covering the entire C4 region of both chromosomes in this particular heterozygous chimpanzee. The region is about 100 kilobases (kb) long and contains two C4 and two CYP21 genes, the latter coding for the enzyme 21‐hydroxylase. Using oligonucleotide probes we identified the genes as corresponding to human C4A, C4B, CYP21 and CYP21P genes. The last gene apparently contains an 8‐base pair (bp) deletion (as does the corresponding human gene), which renders it a pseudogene. The genes are arranged in the order C4A…︁ CYP21P…︁ C4B…︁ CYP21. Each of the two C4 genes is 16 kb long and thus corresponds to the short version of the human C4 genes. We suggest that the duplication of the basic C4‐CYP21 unit that generated the standard arrangement of the human C4‐CYP21 region occurred before the separation of the evolutionary lineages leading to humans and chimpanzees (i.e., more than five million years ago). We suggest further that the original form of the C4 gene was of the long variety and was generated by the insertion of a 6.8‐kb element into one of the C4 introns. The element was subsequently excised in the ancestors of the chimpanzees and in at least one lineage of the human C4B gene. We speculate that the presence of the 6.8‐kb insert in the human C4A and some C4B genes might largely be responsible for the great instability of this chromosomal region which leads to frequent duplications and deletions, some of which cause 21‐hydroxylase deficiency.
Inhibition of T cell developmemt in thymic organ culture: Implications for the mechanism of action of cyclosporin A
Authors: Siegel Richard M. , Yui Katsuyuki , Tenenholz Drew E. , Kubo Ralph , Greene Mark I. 
Published: March 2007

AbstractWe have examined the effects of the immunosuppressive drug cyclosporin A (CsA) on the phenotypic maturation of T cells in thymic organ cultures begun at day 16 of gestation. CsA specifically inhibited the generation of cells expressing high levels of α/β TcR/CD3 complexes and a mature phenotype defined by CD4 and CD8 surface markers. Adding interleukin (IL) 1β, IL 2 or IL 4 failed to reverse the effects of CsA, and major histocompatibility complex class II expression in the thymic medulla was preserved. Possible mechanisms of CsA‐mediated inhibition of T cell development are discussed.
Interleukin 2 receptor‐targeted cytotoxicity. Receptor binding requirements for entry of a diphtheria toxin‐related interleukin 2 fusion protein into cells
Authors: Waters Cory A. , Schimke Patricia A. , Snider Catherine E. , Itoh Kyogo , Smith Kendall A. , Nichols Jean C. , Strom Terry B. , Murphy John R. 
Published: March 2007

AbstractThe receptor binding requirements for entry of the NAD+ ADP‐ribosyltransferase component of DAB486‐IL 2 into target cells were examined. Experiments utilizing cell lines bearing either high‐affinity or individual subunits of the interleukin 2 receptor (IL 2R) as well as human peripheral blood mononuclear cells with natural killer activity demonstrate that the high‐affinity receptor facilitates delivery of fragment A from DAB486‐IL 2 to the cytosol approximately 1000 times more efficiently than either the intermediate‐(p75) or low‐affinity (p55) forms of the IL 2R. We show that elongation factor 2 (EF‐2) in these cells is not quantitatively or qualitatively altered indicating that the relative resistance to intoxication displayed by IL 2R variant cell lines cannot be attributed to an altered intracellular target of the hybrid toxin. We also demonstrate that an alteration in the binding of DAB486‐IL 2 to the p75 subunit of the IL 2R may account for the selective cytotoxicity of DAB486‐IL 2 for cells bearing the heterodimeric high‐affinity IL 2R.
Regulation of murine lymphokine production in vivo II. Dehydroepiandrosterone is a natural enhancer of interleukin 2 synthesis by helper T cells
Authors: Daynes Raymond A. , Dudley Donald J. , Araneo Barbara A. 
Published: March 2007

AbstractDehydroepiandrosterone (DHEA) is an adrenal steroid hormone produced in abundance by humans and most other warm‐blooded animals, is uniquely sulfated (DHEAS) prior to export into the plasma, and exhibits an age‐related decline in production with progressive age. No major physiological functions have been ascribed to the activity of this steroid, although DHEA is known to serve as an intermediary in sex steroid synthesis. Studies on the effects of glucocorticoids (GCS) on the immune system led us to question whether DHEA had effects on the ability of activated lymphocytes to produce interleukin 2 (IL 2). We determined that (a) lymphocytes from DHEA‐ or DHEAS‐treated mice consistently produced much greater levels of IL 2 than normals in response to stimulation, (b) direct lymphocyte exposure to DHEA at low doses (10−10 – 10−7 M) caused an enhanced capacity to secrete IL 2 following activation, (c) IL 2 production by activated cloned T cell lines could be augmented by DHEA treatment, and (d) GCS‐induced depressions in IL 2 synthesis by T cells or T cell clones could be overcome in vitro and in vivo by exposure to the effects of DHEA. These findings suggest that DHEA, presumably through receptor‐mediated mechanisms similar to other types of seroid hormones, may represent a natural and important regulator of IL 2 production in both normal and pathologic conditions.
Class I (H‐2Kb) gene transfection reduces susceptibility of YAC‐1 lymphoma targets to natural killer cells
Authors: Carlow Douglas A. , Payne Urula , Hozumi Nobumichi , Roder John C. , Czitrom Andrei A. 
Published: March 2007

AbstractA “hybrid gene” (MTKb) comprised of the human metallothionein IIA promoter ligated to the genomic sequence of the major histocompatibility complex class I (H‐2Kb) gene was subcloned into the expression vector pSV2neo and transfected into the natural killer (NK) cell‐sensitive YAC‐1 lymphoma. The Kb gene product was readily detectable on the cell surface of G418‐resistant transfectants using both Kb‐specific monoclonal antibodies and H‐2b‐specific cytolytic T cells. Unlike control pSV2neo transfectants, MTKb‐pSV2neo transfectants were relatively resistant to lysis by NK cells from H‐2a, H‐2b, H‐2k or H‐2 (a × b)F1 haplotype mice. These data strongly suggest that the effects of MHC expression on susceptibility to NK cells can be mediated by a single and well‐defined class I molecule, Kb.
Human monoclonal rheumatoid factors derived from the polyclonal repertoire of rheumatoid synovial tissue: Incidence of cross‐reactive idiotopes and expression of VH and Vϰ subgroups
Authors: Thompson Keith M. , Randen Ingrid , Natvig Jacob B. , Mageed Rizgar A. , Jefferis Roy , Carson Dennis A. , Tighe Helen , Forre Oystein 
Published: March 2007

AbstractA panel of 14 human monoclonal IgM rheumatoid factors (RF) derived from the synovial tissue of rheumatoid arthritis (RA) patients was studied for the expression of cross‐reactive idiotopes (CRI) and variable heavy (VH) and variable kappa (Vx) subgroups. Four of the twelve kappa RF expressed light chains of the Vx subgroup. Three of these were characterized as belonging to the VxIIIb sub‐subgroup, and expressed the VxIIIb associated CRI, 17.109. None of the RF expressed the VxIIIa‐associated CRI, 6B6.6. One of the fourteen RF expressed the VH‐associated CRI, G6, and five expressed either or both the VHIII‐associated CRI, B6 and D12. Seven RF bound to protein A (SpA), which indicates the expression of VHIII subgroup V regions. Together the data indicated that 9/11 RF express VHIII regions and 2/11 express VHI regions. There was no obvious correlation between V region usage or CRI expression and fine specificity of the RF for human IgG subclasses. These data indicate a difference in V gene usage by RF derived from RA patients compared with RF paraproteins derived from non‐RA patients. There is not a bias towards variable chains of the VxIII subgroup, but a marked preference for variable heavy chains of the VHIII subgroup is seen. Further studies may elucidate the pathological significance of these findings in RA.
Interferon‐γ‐activated human granulocytes kill ingested Mycobacterium fortuitum more efficiently than normal granulocytes
Authors: Geertsma Minke F. , Nibbering Peter H. , Pos Odette , Van Furth Ralph 
Published: March 2007

AbstractAlthough shortly after the onset of a mycobacterial infection granulocytes are present at the site of inflammation, the role of granulocytes in the elimination of mycobacteria is not well understood. In vitro studies with, for example Mycobacterium tuberculosis or M. bovis, are hampered by the slow proliferation and clumping of the bacteria. To avoid these disadvantages, we developed a model using the atypical mycobacterium M. fortuitum. The present study concerned two questions: whether human granulocytes are able to phagocytose and intracellularly kill opsonized M. fortuitum and whether intracellular killing of these bacteria can be enhanced by treatment of the granulocytes with recombinant human interferon‐γ (rIFN‐γ). The results showed that normal granulocytes phagocytosed opsonized M. fortuitum rapidly, but did not kill these bacteria effectively. The intracellular killing of M. fortuitum was significantly enhanced by incubation of the granulocytes with rIFN‐γ for 18 h before the start of the killing assay. Since these rIFN‐γ‐pretreated granulocytes did not release more O2− and H2O2 upon stimulation with phorbol 12‐myristate 13‐acetate or opsonized M. fortuitum than control granulocytes, non‐oxidative killing mechanisms are probably involved in the enhanced killing of M. fortuitum.
Identification of FcγRIIa, a product of the murine αFcγR gene
Authors: Daëron Marc , Bonnerot Christian , Latour Sylvain , Benhamou Marc , Fridman Wolf H. 
Published: March 2007

AbstractTwo genes, α and β, encode murine low‐affinity receptors for the Fc portion of IgG (FcγRII). The amino acid sequences deduced from the nucleotidic sequences of α and β cDNA are highly homologous in extracellular domains. As a consequence, the protein product of the αFcγR gene has not yet been distinguished from that of the βFcγR gene, α and β cDNA, however, show no homology in sequences coding for intracellular portions. We therefore raised antibodies against a synthetic peptide corresponding to the 26 intracytoplasmic amino acids of the expected product of the murine αFcγR gene. F(ab')2 fragments of α‐specific antibodies thus obtained stained specifically membrane proteins which were present in cells containing α transcripts but not in cells containing β transcripts only; they bound molecules carrying the 2.4G2 epitope, characteristic of the extracellular domains of murine FcγRII; they immunoprecipitated material which migrated as heterogeneous glycosylated proteins of 45–55 kDa when native and, when deglycosylated, as a single polypeptide with an apparent molecular mass of 29 kDa, which is compatible with the calculated molecular mass of the protein expected to be translated from αFcγR transcripts. These criteria identify a product of the murine αFcγR gene as a subtype of FcγRII which can be designated FcγRIIa.
Nurse cells of the bursa of Fabricius: Do they exist?
Authors: Wuorela Maarit , Jalkanen Sirpa , Pelliniemi Lauri J. , Toivanen Paavo 
Published: March 2007

AbstractCell‐cell interactions in B lymphocyte development have so far been incompletely characterized, mostly due to lack of a special organ for B cell maturation in the mammalian species. Certain well‐known lymphostromal interactions in the thymus have raised the question whether similar interactions with nurse cells would also operate in the development of B cells. We have tested this hypothesis in the chicken bursa of Fabricius, an organ specific for the B cell maturation. To identify possible nurse cells, with viable lymphocytes enclosed, the cells in the bursa of Fabricius were dispersed with collagenase and trypsin. Light and electron microscopic examination of bursa cell suspensions showed four types of aggregates, identified by low magnification light microscopy as potential nurse cell‐like complexes. Electron microscopy revealed that all aggregates consisted of epithelial cells, and complexes of epithelial cells with lymphocytes enclosed were not observed. These findings indicate that interactions similar to those seen in the avian and mammalian thymus between epithelial nurse cells and T lymphocytes are not a part of the avian B cell differentiation process.
Characterization of Vβ‐bearing cells in athymic (nu/nu) mice suggests an extrathymic pathway for T cell differentiation
Authors: Rocha Benedita 
Published: March 2007

AbstractIn the present article, the expression of the T cell receptor (TcR) β chain and other T cell molecules was evaluated in surface immunoglobulin‐negative spleen cell populations of young and old BALB/c and C57BL/6 nude mice, using a panel of monoclonal antibodies. The results obtained show that in young nude mice, most Thy‐1high cells do not express other T cell markers. These mice have, however, a sizable population of Thy‐1low cells with the same phenotype of α/β+, CD4−CD8− thymocytes or MRL/lpr peripheral T cells, expressing predominantly genes of the Vβ8 family. The evolution of α/β+ cells in aging nudes is strongly suggestive of an extrathymic pathway of differentiation of these cells since (a) the acquisition of high density TcR and CD3, as well as Thy‐1 or CD4CD8 antigens at the cell surface of nude Vβ+ T cells is not simultaneous; (b) α/β+ cells in nude mice co‐express other T cell markers at random and, even in old mice, they never completely resemble to the predominant high Thy‐1+ CD3+ TcR α/β+, CD4+CD8+ cells of euthymic controls; and (c) BALB/c nude T cells express Vβ11 genes, that are deleted in euthymic BALB/c mice. This latter finding may also indicate differences in the mechanisms of selection of T cell specificities in the thymus vs. the peripheral pools.
Retroviral interleukin 4 gene transfer into an interleukin 4‐dependent cell line results in autocrine growth but not in tumorigenicity
Authors: Blankenstein Thomas , Li Weiqun , Müller Werner , Diamantstein Tibor 
Published: March 2007

AbstractA retroviral vector has been constructed containing the mouse interleukin 4 (IL 4) gene under the transcriptional control of the thymidine kinase promoter. Infection of the IL 4‐dependent T cell line CT4S by the thymidine kinase IL 4 construct resulted in factor‐independent growth. The infected cells grow as a consequence of continous consumption of the endogenously produced IL 4. Clones were established secreting different amounts of IL 4 but none of them was capable of growing in vivo. The lack of correlation between factor‐independent growth and tumorigenicity distinguishes IL 4 from other growth factors and could reflect the recently reported activity of IL 4 to suppress tumor growth in vivo.
The phosphorylation of the CD3 γ chain of T lymphocytes is modulated by β‐endorphin
Authors: Kavelaars Annemieke , Eggen Bart J. L. , De Graan Pierre N. E. , Gispen Willem H. , Heijnen Cobi J. 
Published: March 2007

AbstractThe neuropeptide β‐endorphin can modulate the response of T and B cells to mitogenic or antigenic stimulation. In the present report we describe a novel mechanism by which β‐endorphin can interfere with T cell activation. It is shown here that β‐endorphin can modulate the phorbol ester‐induced phosphorylation of the γ chain of the CD3 complex. The effect of β‐endorphin is dose dependent and appears to be mediated via interaction of β‐endorphin with an opiate receptor on lymphocytes. Evidence is presented that the modulatory effect of β‐endorphin is specific for the phosphorylation of the CD3 γ chain. β‐Endorphin does not affect the phosphorylation of total cell protein, nor does it have any effect on the phosphorylation of the CD4 determinant on T cells. The possible consequence of a change in CD3 γ chain phosphorylation is discussed.
Identity of PB76 differentiation antigen and lymphocyte alkaline phosphatase
Authors: Márquez Carlos , De La Hera Antonio , Leonardo Esther , Pezzi Luis , Strasser Andreas , Martínez‐a Carlos 
Published: March 2007

AbstractAlkaline phosphatases (APases, EC 3.1.3.1) are ecto‐enzymes bound to cell membranes by a phosphatidyl‐inositol anchor. We have previously shown that APase is present on activated murine B cells and its expression correlates with the process of B cell differentiation into immunoglobulin secretion. Recently, a monoclonal antibody (mAb), G‐5‐2, that recognizes a 76‐kDa molecule preferentially expressed on the surface of pre‐B and plasma cells (PB76) was described. Some features shared by APase and PB76 differentiation antigen suggest that the G‐5‐2 mAb might be specific for lymphocyte APase.Here, we have analyzed this possibility and found an absolute correlation between PB76 expression in cells and their APase activity. Although PB76 has been described as a B cell‐restricted marker, PB76 is also expressed on some T cells, such as the YAC‐1 T cell lymphoma, that are known to bear APase. Treatment of YAC‐1 cells with phosphatidylinositol‐specific phospholipase C resulted in a quantitatively correlated removal of both APase and PB76 antigens. Moreover, we demonstrate that PB76 antigen has APase activity using an enzyme‐antigen immunoassay with the G‐5‐2 mAb. We conclude that PB76 and lymphocyte APase are one and the same antigen.
Transcription, translation and secretion of both IgA subclasses in polyclonally activated human lymphocytes
Authors: Islam Khalid Bin , Hassan Mohammed Sawkat , Engström Per‐erik , Hammarström Lennart , Edvard Smith C. I. 
Published: March 2007

AbstractTo analyze human IgA subclass‐specific mRNA we have developed RNA probes for quantitation of α1 and α2 heavy chain constant region genes by solution hybridization. Under our assay conditions, we can detect as little as 3 pg of specific mRNA andthere is less than 2% cross‐reactivity between the two IgA subclasses. Using this method, the relative proportions of IgA1 and IgA2 mRNA in pokeweed mitogen(PWM)‐stimulated cells were found to be 66% and 34%, respectively, while in the Epstein‐Barr virus (EBV)‐stimulated cells they were 77% and 23%, respectively. Cytoplasmic staining of the plasma cells and determination of IgA subclass distribution by flow cytometry revealed an almost even distribution of the two IgA subclasses as induced by both activators. The culture supernatant contained 72% IgA1 and 28% IgA2 after PWM stimulation, while EBV stimulation induced 85% IgA1 and 15% IgA2. This report thus describes a method for the quantitative analysis of IgA subclass‐specific mRNA. Furthermore, we present evidence that in response to in vitro stimulation of peripheral blood lymphocytes by polyclonal activators the IgA‐producing B cells not only synthesize both isotypes but also have the potential to secrete them.