bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non‐random expression of T cell receptor γ and δ variable gene segments in functional T lymphocyte clones from human peripheral blood
Authors: Borst Jannie , Wicherink Annemieke , Dongen Jacques J. M. Van , Vries Evert De , Comans‐Bitter W. Marieke , Wassenaar Fred , Elsen Peter Van Den 
Published: March 2007

AbstractHuman T cell receptor (TcR) γδ displays a variety of protein forms. Disulfide‐linked (type 1) or non disulfide‐linked (type 2) receptors occur, with γ chains encoded by the Cγ1 or the Cγ2 gene segment, respectively. Exon 2 of Cγ2 may either be duplicated or triplicated (type 2a or 2b receptors). TcR γ chains differ in molecular mass and charge between type 1 and type 2 receptors. The δ chains as well as the γ chains have different structural properties between receptor types. This cannot be due to the use of different Cδ gene segments, since the genome encodes only one. To understand the genetic basis of this dichotomy in γ/δ combinations, rearrangement and expression of Vγ, Jγ, Cγ and Vδ gene segments were determined in TcR γ/δ+ clones derived randomly from peripheral blood of normal donors. Most clones used Cγ1, a minority Cγ2. The different protein properties of receptor types could be explained by the nonrandom expression of Vγ(Jγ) and Vδ gene segments. Type 1 receptors preferentially used γ chains encoded by the Vγ9 and Jγ1.2 gene segments together with δ chains encoded by Vδ2. In type 2a receptors, Vγ9 was not predominant; often other Vγ gene segments were employed, but then in high frequency in coordination with Vδ1. Reactivity of the clones with monoclonal antibodies anti‐TiγA, BB3 and δ‐TCS‐1 correlated with the expression of the Vγ9, Vδ2 and Vδ1 gene segments, respectively. Therefore, Vγ and Vδ use in TcR γ/δ+ cells from peripheral blood of eight healthy individuals, including the two donors of the clones, could be determined tentatively by double immunofluorescence. Indeed, the Vγ9‐Vδ2 combination was predominant, while the Vγ9‐Vδ1 and particularly the Vγ9‐“Vδother” combination was rare. These data indicate that the TcR γδ repertoire in peripheral blood of normal individuals is largely dependent on junctional diversity and suggest that selection of receptors occurs.
Expression and function of HLA‐A2.1 in transgenic mice
Authors: Epstein Helen , Hardy Robert , May Janet S. , Johnson Martin H. , Holmes Nicholas 
Published: March 2007

AbstractWe have derived a number of transgenic mouse lines which express the human major histocompatibility complex class I gene HLA‐A2.1. Two lines carry the complete human HLA‐A2.1, the others bear a recombinant gene in which the HLA‐A2.1 coding regions are fused to the H‐2Kb promoter. Analysis of transgenic spleen cells by immunofluorescence demonstrates that these mouse cells express HLA‐A2.1 on their surface in association with mouse β2‐microglobulin (β2m), confirming that HLA‐A2 does not require human β2m to be expressed at the cell surface. The cells contain more HLA mRNA than endogenous H‐2 class I mRNA. There is also a large pool of non‐β2m‐associated HLA heavy chain inside the cell. In contrast the amount of HLA: β2m complex is low. Thus, in transgenic mice HLA‐A2 seems to compete poorly with H‐2 heavy chains for mouse β2m.The HLA‐A2.1 transgenic mice do not produce influenza‐virus‐specific cytotoxic T cells (CTL) restricted to the HLA transgene, at least in sufficient numbers to be measured in a direct bulk CTL assay. The dominance of H‐2‐restricted clones may be the result of quantitative rather than qualitative factors. However, HLA‐A2.1 transgenic spleen cells are effective in stimulating an allogeneic CTL response in normal mice. This response is not H‐2 restricted. Cold target inhibition studies show that there are at least two populations of CTL, one of which is specific for HLA‐A2.1 on mouse cells. This result suggests that at least some allo‐CTL are directed against major histocompatibility complex plus “self‐peptide”.
The effects of bacterial lipopolysaccharide, anti‐receptor antibodies and recombinant interferon on mouse B cell cycle progression using 5‐bromo‐2'‐deoxyuridine/hoechst 33258 dye flow cytometry
Authors: Seyschab Helga , Friedl Richard , Schindler Detlev , Hoehn Holger , Rabinovitch Peter S. , Chen Una 
Published: March 2007

AbstractPolyclonal stimulation of resting B cells with anti‐antigen receptor antibodies [anti‐IgM μ chain antibody (anti‐μ)] or with bacterial lipopolysaccharide (LPS) stimulates a proportion of B cells to proliferate. Exposure of resting B cells to both LPS and anti‐μ activates a larger population of resting B cells than either alone, suggesting a synergistic effect of these two stimuli. Although recombinant interferon (rIFN) either alone or in combination with anti‐μ has no apparent proliferative activity (as measured by [3H]thymidine incorporation), application of 5‐bromo‐2'‐deoxyuridine/Hoechst 33258 dye flow cytometry reveals a distinct effect of rIFN on B cell growth. In the presence of anti‐μ plus LPS, rIFN causes the majority of B cells to enter the cell cycle (CC), but a subset of B cells remains in the resting stage. Another subset of B cells has extremely rapid CC transit times, with a CC duration of less than 10 h. These studies show that both anti‐μ and LPS are competence factors (which move cells from the G0 phase to the G1 phase). LPS acts also as a CC progression factor, while rIFN is a CC potentiating factor.
The molecular basis of the low hemolytic activity of C4 molecules from low‐C4 mice with IgM‐coated erythrocytes
Authors: Dieli Francesco , Sireci Guido , Lio Domenico , Salerno Alfredo 
Published: March 2007

AbstractThis study investigated the origin of the different hemolytic activity of two allotypes of murine C4, C4H (C4‐high) and C4L (C4‐low) in the presence of IgM‐coated erythrocytes. C4H displayed a threefold higher hemolytic titer (expressed in hemolytic units/μg protein) than C4L. No difference was found between C4H and C4L either in stability at 37 °C at different pH values and in the rate of C4H and C4L hydrolysis by activated C1.The major functional difference was found in the covalent binding capacity to IgM‐coated erythrocytes, with the amount of C4H bound being about threefold higher than that of C4L. A marked difference in the reactivity of the C4b fragment of C4H and C4L toward amino and hydroxyl groups was detected. Using glycine and glucose to competitively inhibit the binding of C4H and C4L, it was observed that C4L selects preferentially for the amino groups of glycine, whereas C4H reacted preferentially with the hydroxyl groups of glucose. Furthermore, the chemical modification of the red cells amino groups by ethylacetimidate, had no appreciable effect on the binding of C4H, but reduced that of C4L. Southern blot hybridization experiments using Hind III‐digested liver DNA and a cDNA probe derived from the 5' end of the mRNA (clone pAT‐A) indicated that the C4H allele was associated with a 5‐kb Hind III fragment, whereas the C4L allele was associated with a 15‐kb Hind III fragment. The possibility that a structural difference between C4H and C4L is responsible for their different reactivities is discussed.
Visualizing interleukin 2 gene expression at the single cell level
Authors: Emilie Dominique , Peuchmaur Michel , Barad Marc , Jouin HéLèNe , Maillot Marie‐Christine , Couez Dominique , Nicolas Jean‐FrançCois , Malissen Bernard 
Published: March 2007

AbstractTo analyze the expression of the interleukin (IL)2 gene at the single cell level, we have constructed a chimeric gene in which the regulatory sequences from the mouse IL 2 gene were fused 5' proximal to the coding region of the Escherichia coli β‐galactosidase (lacZ) gene. Once stably introduced into a T cell hybridoma, the IL 2‐lacZ reporter gene was shown to display a pattern of induction similar to the one observed for the resident IL 2 gene. Two points emerged from monitoring IL 2 expression at the single cell level. First, upon activation the expression of the IL 2‐lacZ gene appears asynchronous. Second, at the peak of induction the percentage of β‐galactosidase+ cells never reached 100% and the level of β‐galactosidase reached among positive cells was highly heterogeneous within a cloned population of T cells. In combination with the possibility to sort viable lymphocytes according to lacZ expression, the IL 2‐lacZ reporter gene described herein should provide a way to isolate somatic cell mutants deficient in signal transduction by the T cell antigen receptor complex.
Allosuppression of B cells in vitro by graft‐vs.‐host reaction‐derived T cells is caused by cytotoxic T lymphocytes
Authors: Rozendaal Lawrence , Pals Steven T. , Schilham Marco , Melief Cornelis J. M. , Gleichmann Ernst 
Published: March 2007

AbstractAn acute graft‐vs.‐host reaction (GVHR) was induced by i.v. injection of 108 lymphoid cells from C57BL/10 (B10) donors (H‐2b/b) into adult non‐irradiated (B10 x DBA/2)F1 mice (H‐2b/d). Previous experiments have established that spleen cells obtained from such GVHF1 mice suppress the primary antibody response of normal F1 spleen cells to sheep red blood cells. This type of suppression was termed “allosuppression”, and it was shown to be mediated by Ly‐2+ T cells of donor origin that react against H‐2 antigens of the host. It was unclear, however, whether the actual mechanism of allosuppression was due to suppressive factors generated by donor T cells or whether the latter killed the F1 B cells. Here, we show that for their suppressive effect GVHF1 spleen cells need direct cell contact with F1 spleen cells; no suppressive effect was measured in a double‐chamber culture system in which the GVHF1 spleen cells were separated from the responding normal F1 spleen cells by a cell‐tight membrane filter. The suppressive effect only affected cells expressing the appropriate H‐2 class I alloantigen; in mixed cultures of irradiated F1 spleen cells and GVHF1 spleen cells with third‐party B cells the antibody response of the third‐party B cells was not suppressed. GVHF1 spleen cells showed cytotoxic T lymphocyte (CTL) activity specific for the allogeneic F1 H‐2 antigen. The suppressive effect of the GVHF1 spleen cells did not differ from that exerted by cloned CTL specific for MHC class I alloantigens; cloned CTL suppressed the primary antibody response of murine spleen cells without affecting the response of third‐party B cells added to the cultures. The combined findings show that “allosuppression” in vitro is not due to suppression of F1 B cells, but to a direct killing of these cells by alloreactive CTL.
Immunoglobulin‐specific T‐B cell interaction
Authors: Rudensky Alexander Y. , Yurin Vitalij L. 
Published: March 2007

AbstractImmunoglobulin (Ig)‐specific T‐B cell interactions have been studied in the model of T cell recognition of the χ chain Igχ‐1b allotype in Igχ‐1‐congeneic rat strains. An efficient presentation of endogenous Ig allotypic determinants by irradiated spleen cells from (WAG.1b x August)F1 (RT‐1u/c; Igχ‐1b/1a) rats to Igχ;‐1b‐specific lymph node T cells from Igχ;‐1‐congeneic (WAG x August)F1 (RT‐1u/c; Igχ‐1a) rats was demonstrated. This presentation was found to be sensitive to high irradiation doses (WAG x 1000 rad). By fractionation of Igχ‐1b+ F1 spleen cells on Percoll density gradient we have shown that a radioresistant, low‐density fraction, consisting mainly of macrophages (MΦ) and dendritic cells, triggers only weak Igχ;‐1b‐specific T cell response. The high level of response was observed against radiosensitive spleen cell fractions of intermediate and high density, suggesting that B cells were the main antigen‐presenting cells (APC) of Igχ;‐1b determinants of endogenous Ig. This conclusion was confirmed in the experiments using purified B cells from Igχ;‐1b‐bearing rats. Earlier we have shown that the responsiveness of August (RT‐1c; Igχ;‐1a) and WAG (RT‐1u; Igχ;‐1a) rats to Igχ;‐1b in vivo is controlled by the dominant allele of an RT‐1‐linked Ir gene. August and (August x WAG)F1 rats were found to be responders to Igχ;‐1b while WAG rats were nonresponders. The same pattern of Ir gene‐controlled reactivity was demonstrated using an Igχ;‐1b‐specific T cell proliferation assay. Igχ;‐1b‐specific F1 T cell response was only observed when Igχ;‐1b+ B cells or IgG (Igχ;‐1b)‐pulsed Mϕ‐bearing responder major histocompatibility complex (MHC) haplotype were used as the APC. Anti‐RT‐1 monoclonal antibody inhibition studies suggested that the RT‐1Bc molecule is the main restricting element of T cell recognition of Igχ;‐1b+ B cell as well as exogenous IgG (Igχ;‐1b). We have demonstrated allelic exclusion of Igχ;‐1b presenting function by negatively and positively selecting for Igχ;‐1b+ and Igχ;‐1a+ B cells from heterozygous F1(Igχ;‐1b/la) rats. This clearly indicate that the B cells presented exclusively Igx‐1b allotypic determinants of their own Ig. Furthermore, it was found that Igχ;‐1b‐specific T cell activation was not caused by the in vitro transfer of Ig(Igχ;‐1b) molecules from one B cell to another, or to some residual APC of another type. Thus, B cells presented with high efficiency Igχ;‐1b determinants of self‐synthesized Ig in association with MHC class II molecule to Igχ;‐1b‐specific T cells.
The heterogeneity of the reticulum of rat peripheral lymphoid organs identified by monoclonal antibodies
Authors: Berg Timo K. Van Den , Döpp Ed A. , Brevé John J. P. , Kraal Georg , Dijkstra Christine D. 
Published: March 2007

AbstractWe have developed a panel of six monoclonal antibodies, ED10–ED15, directed against reticular cells in peripheral lymphoid organs. Immunohistochemistry revealed prominent differences between these antibodies with regard to their tissue distribution in lymphoid and non‐lymphoid organs. Furthermore, the determinants recognized by ED10–ED13 were found to be differentially expressed by reticular cells occupying the various specialized compartments present in peripheral lymphoid organs. The reactivity patterns of these antibodies observed during the ontogenetic development of the spleen suggest that they recognize differentiation antigens expressed by reticular cells. In contrast, ED14 and ED15 were found to have a relatively ubiquitous tissue distribution recognizing reticular cells in each compartment, with a constitutive reactivity during splenic ontogeny. The present results indicate that reticular cells form a heterogeneous population within the lymphoid organs.
B cell repertoire in adult antigen‐free and conventional neonatal balb/c mice
Authors: Bos Nicolaas A. , Meeuwsen Cornelia G. 
Published: March 2007

AbstractEarly in ontogeny B cells preferentially use VH gene families which are most adjacent to the genes coding for the constant part of the immunoglobulin molecule. In conventional adult mice, however, a random usage of VH gene families has been found. We investigated the role of exogenous antigenic stimulation on this normalization of VH gene usage by B cells. Therefore, we made use of adult germ‐free BALB/c mice fed a chemically defined ultrafiltered antigen‐free diet (GF‐CD) and neonatal conventional BALB/c mice. Both the adult GF‐CD and the newborn conventional mice represent situations with minimal exogenous antigenic stimulation. The results obtained with RNA dot blot hybridization with probes specific for the different VH gene families showed in hybridomas from adult GF‐CD BALB/c mice a preferential usage of the CH‐proximal VH gene family PC7183. In hybridomas from 5‐day‐old conventional BALB/c mice a less frequent usage of the J558 VH gene family was found and an increased usage of the PC7183 VH gene family than what would be expected from random usage. Evidence is presented that the RNA giving a positive signal with the PC7183 probe represents functional messages for IgM production.
The restrictive role of sialic acid in antigen presentation to a subset of human peripheral cd4+ t lymphocytes that requires antigen‐presenting dendritic cells
Authors: Kapsenberg Martien L. , Stiekema Frank E. M. , Kallan Aram , Bos Jan D. , Roozemond Robert C. 
Published: March 2007

AbstractDendritic cells from human epidermis, i.e., Langerhans cells (LC), are more potent antigen‐presenting cells (APC) than APC from peripheral blood in proliferative in vitro responses of helper T lymphocytes to various soluble antigens. Analysis of antigen recognition by CD4+ T lymphocyte clones indicated that this increased potency of LC as APC results from a preferential requirement for LC of part of the T cell population. These T cells show a long‐lasting restoration of antigen responsiveness to peripheral blood APC after antigen‐specific restimulation in vitro, indicating that restrictive antigen recognition concerns T cells that are not fully differentiated. A similar restrictive antigen recognition was observed by treatment of the T cells or the APC with neuraminidase. This restoration of responsiveness is associated with the occurrence of nonspecific cell clustering between T cells and APC. These results suggest that the selective requirement for APC is regulated by the function of adhesion molecules that are functionally blocked by sialic acid groups on immature peripheral T cells but that are readily available on peripheral T cells at a later stage of differentiation.
Extracellular but not intracellular calcium mobilization is required for epstein‐barr virus‐containing supernatant‐induced b cell activation
Authors: Dugas Bernard , Mencia‐Huerta Jean‐Michel , Braquet Pierre , Galanaud Pierre , Delfraissy Jean‐FrançOis 
Published: March 2007

AbstractChanges in intracytosolic free calcium concentration ([Ca2+]i) are thought to be an important trigger for the initiation of the cellular events culminating in B cell activation. After exposure of human B lymphocytes loaded with the fluorescent indicator quin‐2 to the Epstein‐Barr virus (EBV)‐containing supernatant of B95‐8 cell line, a rise in [Ca2+]i is observed. To determine the respective contribution of the intra‐ and extracellular Ca2+ pools in EBV‐induced B cell activation, the pharmacologic modulation of these processes was investigated using an intracellular calcium chelator, 1,2‐bis(o‐aminophenoxy)ethane‐N,N,N',N'‐tetraacetic (BAPTA) or the calcium channel blocking drugs. When the extracellular Ca2+ contribution was minimized in the presence of calcium channel‐blocking drugs or incubation of the cells in Ca2+‐free medium, the EBV‐induced human B cell activation was fully inhibited. When the calcium channel‐blocking drugs, either verapamil or diltiazem, were withdrawn or when exogenous Ca2+ was added to the Ca2+‐free medium, EBV‐induced B cell activation was noted, demonstrating the reversibility of the inhibition. On the contrary, when the intracellular Ca2+ contribution was reduced after loading the cell with BAPTA, no alteration of the EBV‐induced B cell activation was observed. Thus, the EBV‐induced rise of [Ca2+]i required in the activation of human B cells appears to be essentially related to the entry of extracellular Ca2+ and not to the release of Ca2+ from internal stores.
Isolation and characterization of ige receptors from rat intestinal mucosal mast cells
Authors: Swieter Mark , Chan Bosco M. C. , Rimmer Carol , Mcneill Karol , Froese Arnold , Befus Dean 
Published: March 2007

AbstractHigh‐(FcϵRI) and low‐(FcϵRII) affinity IgE receptors were isolated from surface radioiodinated, Nonidet‐P40‐solubilized rat intestinal mucosal mast cells (IMMC) and compared with those on rat peritoneal mast cells (PMC) and rat basophilic leukemia (RBL) cells. FcϵRII were isolated by affinity chromatography using IgE‐Sepharose or by anti‐FcϵRII antisera and protein A‐Sepharose. The surface‐exposed, IgE‐binding α subunits of FcϵRI [FcϵRIα] were isolated by affinity chromatography using IgE and anti‐IgE‐Sepharose. FcϵRIα on IMMC had an apparent molecular mass of 59 kDa, somewhat larger than that of PMC (51 kDa), RBL‐2H3 cells (51 kDa) or RBL‐CA10.7 cells (46 kDa). Brief (45 s) incubation of IMMC or PMC in glycine‐HCl, pH 3, prior to iodination removed much of the surface‐bound IgE. This permitted more thorough labeling of the receptors, but had no affect on the estimate of receptor size. Surprisingly and in contrast to acid‐treated PMC, upon anti‐IgE‐Sepharose isolation acid‐treated IMMC yielded an intensely radioactive FcϵRIα band in the absence of added IgE. Such a finding suggests that IMMC, more so than PMC, may have an intracellular store of IgE, as has been suggested by many others. IMMC also differed from PMC in the number of forms of FcϵRII isolated; 50‐kDa and 58‐kDa forms of FcϵRII were obtained from IMMC, whereas PMC yielded most often a single 56‐kDa FcϵRII band. These results were mimicked by the two RBL cell sublines: RBL‐2H3 cells yielded two FcϵRII (46 kDa and 55 kDa), but only one form of FcϵRII (54‐kDa) was obtained from RBL‐CA10.7 cells. Thus, the two subtypes of rat mast cells, which have previously been shown to differ in mediator profile and responsiveness to secretagogues and antiallergic drugs, are also distinguished by differences in IgER profile.
The proliferation and life‐span of rat large granular lymphocytes: effects of cytokines
Authors: Vaage John Torgils , Reynolds Craig W. , Reynolds Della , Fossum Sigbjørn , Rolstad Bent 
Published: March 2007

AbstractPulse labeling of large granular lymphocytes (LGL) with [3H]thymidine for 1 h in vitro showed that 1%–7% of LGL were in S phase in the blood, spleen and liver of unstimulated euthymic and athymic rats as scored with autoradiography. Repetitive injections of [3H]thymidine over 2–7 days revealed that about half of the blood and spleen LGL had formed by division of precursors during this week. Stimulation of rats with the interferon inducer poly(I) · poly(C) increased the proportion of S phase LGL rapidly and simultaneously in the blood, spleen and liver, so that by 20 h after stimulation ca 30% of LGL were in the S phase in these organs. This LGL proliferation was accompanied by an increased number of LGL in all three compartments 48–96 h after poly(I) · poly(C) injection. Blood LGL cultured in cell impermeable diffusion chambers in the peritoneal cavity of poly(I) · poly(C)‐stimulated rats exhibited enhanced natural killer (NK) activity but no proliferative response, indicating that mature LGL were not induced to undergo blastogenesis by poly(I) · poly(C) in vivo. Pretreatment of NK cells with rat interferon (IFN‐α/β) and with human recombinant interleukin 2 (rIL2) in vitro, showed that these two cytokines, when combined, had opposing effects on NK activity and proliferation: whereas rIL2 inhibited the IFN‐induced augmentation in NK activity, IFN inhibited the rIL2‐induced LGL proliferation.