bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcription of protooncogenes during stimulation of normal human B lymphocytes
Authors: Smeland Erlend B. , Blomhoff Heidi Kiil , Ohlsson Rolf , Davies Catharina De Lane , Funderud Steinar , Boye Erik 
Published: March 2007

AbstractProtooncogenes play important roles in the regulation of growth and differentiation of normal cells. In this study we have examined the cell cycle‐dependent regulation of transcription of various protooncogenes after stimulation of human peripheral blood B lymphocytes. The transcriptional rate of various genes was determined by means of a nuclear run‐on assay. We found that several protooncogenes were transcriptionally activated after stimulation (myc, p53, K‐ras, H‐ras, sis and ets), but with different kinetics of induction. In contrast, some oncogenes, especially those encoding membrane‐associated or cytoplasmatic proteins like abl, rel or mil/raf, were transcribed at a relatively constant rate during the cell cycle.
Antigen presentation by liposomes as model system for T‐B cell interaction
Authors: Walden Peter 
Published: March 2007

AbstractUsing the earlier established liposome system for antigen presentation, in which liposomes bearing major histocompatibility complex (MHC)‐class II molecules inserted into and protein antigen covalently linked to the membrane were found to be sufficient for an antigen‐specific and MHC‐restricted activation of T cells, the minimal requirements for T‐B cell interaction were investigated. Liposomes carrying MHC class I1 molecules and antigen‐specific monoclonal antibodies were constructed and tested for their ability to present soluble antigen to T cells. With the antigens lactate dehydrogenase B and pigeon cytochrome c, a specific stimulation of T cell clones and hybridomas could be obtained. These results demonstrate the possibility of a direct involvement of the immunoglobulins on the B cell surface in their interaction with T cells.
Antigen recognition by H‐2‐restricted cytolytic T lymphocytes: inhibition of cytolysis by anti‐CDS monoclonal antibodies depends upon both concentration and primary sequence of peptide antigen
Authors: Maryanski Janet L. , Pala Pietro , Cerottini Jean‐Charles , Robson MacDonald H. 
Published: March 2007

AbstractWhile it is generally agreed that the specificity of the interaction between cytolytic T lymphocytes (CTL) and their target cells is controlled mainly by antigen‐specific T cell receptors (TcR), the molecular role of cell surface CD8 molecules in this interaction is less well understood. In the present study we have reinvestigated the apparent contribution of CD8 molecules to the overall avidity of interaction between CTL and their targets by using a recently developed system of major histocompatibility complex (MHC) class I‐restricted CTL clones that recognize defined peptide antigens. We demonstrate that under conditions where the density of MHC, TcR and accessory molecules remains constant, the susceptibility of CD8+ CTL to inhibition of cytolysis by anti‐CD8 antibodies is highly dependent upon the concentration and primary structure of the peptide antigen. Although the precise role of the CD8 molecule remains unknown, our results are compatible with models that suggest its contribution to the overall avidity of the CTL‐target cell interaction particularly in cases where the affinity between the TcR and antigen‐MHC is low.
Detection and characterization of functional T cells in mice with severe combined immune deficiency
Authors: Carroll Ann M. , Bosma Melvin J. 
Published: March 2007

AbstractCD3+ alloresponsive T cell clones were derived from mice with severe combined immune deficiency (scid mice). T cell receptor beta and gamma gene rearrangements were analyzed to obtain insight into the nature and origin of these clones. We hypothesized that developing scid lymphocytes with an active, impaired recombinase system might generate functional lymphocytes by rare productive rearrangements at two critical antigen receptor loci. One alloresponsive clone showed evidence of both normally rearranged T cell receptor genes and genes with abnormal J region‐associated deletions, supporting this hypothesis. Four additional alloresponsive clones, however, showed only conventional gene rearrangements. These data leave open the possibility that the recombinase activity, believed defective in scid mice, may be normalized in rare early B and T lymphoid cells or their precursors, to give rise to functional lymphocytes.
Comparative study of VH gene family usage by newborn xid and non‐xid mice, newborn NZB and adult NZB mice, and by splenic and peritoneal cavity B cell compartments
Authors: Dighiero Guillaume , Lim Annick , Lembezat Marie‐Pierre , Kaushik Azad , Andrade Luis , Freitas Antonio 
Published: March 2007

AbstractRNA from 170 different Ig‐secreting hybridomas was hybridized with VH gene probes 7183, QUPC52, S107, J558, J606, 36–60, V31, X‐24 and V‐GAM 3.8, with the aim of comparing xid to non‐xid mice, neonatal NZB to adult NZB, and the peritoneal cavity with the splenic compartments for VH gene family expression. Our results indicate that (a) defective F1 male xid mice express with high frequency 36–60 and J606 5′ proximal VH families, when compared to non‐xid F1 females of the same .matings. (b) Neonatal NZB mice express 3′ proximal 7183 and QUPC52 families with high frequency, when compared to adult mice and to the expected values derived from VH complexity. (c) Natural antibodies against cytoskeleton proteins, DNA, rabbit IgG and 2,4,6‐trinitrophenyl did not appear to prefer a particular VH family. The only difference found is related to age; neonatal clones preferentially employ 7183 and QUPC52 while J558 predominates among adult clones. (d) All the 15 antibodies directed against bromelin‐treated mouse red blood cells failed to hybridize with any of the nine VH probes employed. These results confirm previous findings indicating the highly homogeneous pattern of these latter antibodies, and suggest that they are encoded by a new VH family (VH11).
Structural and serological heterogeneity of γ/δ T cell antigen receptor expression in thymus and peripherar blood
Authors: Lanier Lewis L. , Ruitenberg Joyce , Bolhuls Reinder L. H. , Borst Jannie , Phillis Joseph H. , Testi Roberto 
Published: March 2007

AbstractMonoclonal antibodies (mAb) reactive against the γ/δ T cell antigen receptor (TcR) have been used to characterize the distribution and structural properties of γ/δ TcR‐bearing lymphocytes in blood and thymus. Consistent with prior reports the TcR γ/δ‐1 and δ‐1 mAb react with all γ/δ TcR+ T lymphocytes in blood and thymus. By contrast the TCS‐δ mAb was found only to react with a subset of the γ/δ TcR‐bearing T cell population. Several lines of evidence suggest that this reagent preferentially reacts with the Vδ1 gene product. Using these reagents, it was observed that γ/δ TcR+ T lymphocytes comprise 4.6 ± 3.5% (range 1.0–16.3%) of peripheral blood lymphocytes. However, analysis of peripheral blood from normal adult donors revealed that in 29 of 32 the TCS‐δ (possibly Vδ1)‐bearing cells comprised less than 30% of the total γ/δ‐TcR+ population. Biochemical analysis demonstrated that the predominant form of the γ/δ TcR in adult peripheral blood is a disulfide‐linked heterodimer, indicating preferential use of the C,1 gene. The δ TcR chain from these TcR‐γ/δ‐1+/TCS‐δ− T cells was remarkably basic in charge, as analyzed by nonequilibrium pH gradient electrophoresis. By contrast with peripheral blood the majority of freshly isolated and interleukin 2‐cultured γ/δ TcR+ thymocytes were predominantly TcR‐γ/δ‐l+/TCS‐δ+, and preferentially expressed Vδl. Moreover, both disulfide‐bonded and nondisulfide‐bonded γ/δ TcR heterodimers were expressed in all thymuses examined and both forms were contained within the TCS‐δ+ thymic subset. Similar to recent findings in the mouse, these studies suggest a possible bias in the structural form of γ/δ TcR based on tissue location.
Regulatory circuits in autoimmunity: recruitment of counter‐regulatory CD8+ T cells by encephalitogenic CD4+ T line cells
Authors: Sun Deming , Ben‐Nun Avraham , Wekerle Hartmut 
Published: March 2007

AbstractIn this study, pretreatment of Lewis rats with a syngeneic encephalitogenic T cell line (S1) was found to be able to constantly induce resistance to the subsequent induction of transferred experimental autoimmune encephalomyelitis (tEAE). This treatment was capable of protecting recipient animals for at least 2–4 months. Here we show an enhanced suppressor T(anti‐S1) cell activity, which can be readily detected in the lymphoid organs of animals which recovered from S1‐induced tEAE, or from rats pretreated with attenuated (irradiated, fixative treated or water‐lysed) S1 cells. Anti‐S1 cells, which uniformly express the CD8 phenotype, were selectively stimulated to grow and expand into lines by confronting primed lymphoid cells with irradiated S1 cells in culture. The proliferative response of anti‐S1 cells was independent of myelin basic protein and antigen‐presenting cells, and the responses against unrelated encephalitogenic T cell lines were minimal. It was also found that none of the monoclonal antibodies tested (including CD8 and MHC class I antigen‐specific antibodies) was able to block S1/anti‐S1 interactions. These cells are functionally suppressive to the proliferation of S1 cells in vitro, are specifically cytolytic directed against the EAE‐inducing S1 cells and are able to antagonize encephalitogenic capacity of S1 cells in vivo. In vivo elimination of the CD8+ T subset from Lewis rats, using a combined treatment of thymectomy and OX‐8 antibody injection before the initial cell transfer, totally blocked the induction of resistance. Our experiments document that induction of functionally active suppressor T cells is responsible for the induced resistance observed in tEAE.
A novel human Vδ gene expressed predominantly in the TiγA fraction of γ/δ+ peripheral lymphocytes
Authors: Triebel Frédéric , Faure Florence , Mami‐Chouaib Fathia , Jitsukawa Setsuko , Griscelli Annelise , Genevée Catherine , Roman‐Roman Sergio , Hercend Thierry 
Published: March 2007

AbstractWe have characterized a functional T cell receptor (TcR) δ transcript in a TiγA+ human cloned cell line derived from peripheral blood. This cDNA includes a novel V gene (V‐AB12), whose expression was initially studied in a series of TcR γ/δ′ clones. Nine TiγA+ clones derived independently from distinct donors have been tested: each of them was found to possess a unique V‐AB12/J‐IDP2 5.5‐kb Eco RI rearrangement, which was constantly transcribed. Surface expression of the protein encoded by this unique rearranged gene was demonstrated by immunoprecipitations performed on three TiγA′ polyclonal cell lines using a specific rabbit heteroantiserum. Further analysis strongly suggested that a monoclonal antibody (mAb), designated anti‐BB3, detects a V‐ABl2‐encoded antigenic determinant on the cell surface. Double‐color immunofluorescence analysis of peripheral blood lymphocytes from ten donors indicated that most BB3+ cells are recognized by anti‐TiγA mAb. In previous studies, we have shown that a majority of TcR γ/δ+′ peripheral T cells expresses a γ chain including V9 (TiγA) and most frequently JP‐encoded peptides. Given the present results on the δ chain, it can be concluded that, in many individuals, a predominant fraction (Vγ9+/V‐AB12+) of circulating CD3+ TcRa/β− T lymphocytes expresses a receptor with little, if any, combinatorial diversity.
Identification of a novel monocyte cell surface molecule involved in the generation of antigen‐induced proliferative responses
Authors: Dougherty Graeme J. , Dransfield Ian , Hogg Nancy 
Published: March 2007

AbstractA monocyte molecule, identified by a monoclonal antibody (mAb) named 24, is involved in the antigen‐specific proliferation of T cells. Several types of antigen‐induced responses are blocked by mAb 24, but mitogen responses, even at low doses, are not. The 24 molecule is found on circulating monocytes and no other cell type. Normally only a proportion of monocytes express the 24 molecule but it can be induced rapidly on monocytes in culture, possibly from intracellular sources. The epitope is present on a heterodimer of 175 and 95 kDa which is similar to the leukocyte cell adhesion molecule (Leu‐CAM) family. These findings suggest that although the 24 molecule shows some functional and biochemical similarities with the Leu‐CAM family of molecules, it represents a novel structure primarily associated with mononuclear phagocytes.
Higher level expression of lymphocyte function‐associated antigen‐1 (LFA‐1) on in vivo natural killer cells
Authors: Nishimura Takashi , Itoh Tsunetoshi 
Published: March 2007

AbstractNormal mouse spleen cells express low levels of lymphocyte function‐associated anti‐gen‐1 (LFA‐1) as well as other lymphoid cells. However, fractionation of spleen cells with Percoll discontinuous gradients resulted in the appearance of lymphocytes expressing high levels of LFA‐1 molecule (LFA‐1 high lymphocytes) in parallel with the enrichment of natural killer (NK) activity. Lower density spleen cells (fractions 1 and 2) expressed higher level of LFA‐1 antigen than unfractionated spleen cells and showed a higher NK activity. In contrast, higher density spleen cells (fractions 3 and 4) expressed lower levels of LFA‐1 antigen and revealed lower NK activity. LFA‐1 high lymphocytes possessed a high level of asialo GM1, which was the cell surface marker for NK cells. Moreover, sorting of LFA‐1 high lymphocytes from spleen cells caused a great enrichment of NK cells. These results demonstrated that in vivo NK cells expressed higher levels of LFA‐1 molecule, which was an important adhesion molecule for NK cell‐mediated cytotoxicity.
CD4+lymphocytes are extracted from blood by peripheral lymph nodes at different rates from other T cell subsets and B cells
Authors: Washington Elizabeth A. , Kimpton Wayne G. , Cahill Ross N. P. 
Published: March 2007

AbstractThe circulation of lymphocyte subsets through prescapular lymph nodes in sheep has been quantified using a panel of monoclonal antibodies against sheep lymphocyte surface antigens. Differences in the extraction of lymphocyte subsets from blood by the lymph node were found with CD4+ lymphocytes being extracted at a faster rate (1/2) than CD8+, SBU‐T19+, major histocompatibility complex class II+ and B cells (1/4 to 1/5). In order to accommodate existing data on organ‐specific cell migration, the possibility is raised that two distinct families of lymphocyte adhesion molecules, one subset specific and one tissue specific, expressed on vascular endothelium could act jointly to regulate the migration of recirculating lymphocytes.
Processing requirements for T cell activation by Mycoplasma arthritidis‐derived mitogen
Authors: Bauer Andrea , Rutenfranz Inge , Kirchner Holger 
Published: March 2007

AbstractMycoplasma arthritidis produces in culture a polyclonal mitogen which is active for murine and human T lymphocytes in the presence of accessory cells (AC). We studied the requirements for processing and presentation by AC of Mycoplasma arthritidis supernatant (MAS) mitogen to human T cells. As inhibitors of AC processing, several agents were used which inhibit lysosomal function: the weak bases chloroquine and NH4Cl, the cationic ionophore monensin and the competitive protease inhibitor leupeptin. When these agents were used to inhibit processing by presenting cells and washed out before T cells were added to culture, they inhibited lymphocyte activation and, therefore, we assume that they interfered with the presentation of the mitogen. Thus, if MAS requires a processing step, it appears to involve lysosomal proteolysis which can be blocked in vitro.
Functional responsiveness in vitro and in vivo of α/β T cell receptors expressed by the B2A2 (J11d)– subset of CD4–8– thymocytes
Authors: Howe Rawleigh C. , Pedrazzini Thierry , Robson MacDonald H. 
Published: March 2007

AbstractB2A2‐CD4‐8‐ cells represent a rare subpopulation of thymocytes normally comprising 0.5% of the total adult thymus. These cells are known to express CD3‐associated T cell receptor (TcR) α/ß molecules. In the present study we have examined the functional capacity of α/ß heterodimers on B2A2‐CD4‐8‐ cells. In the presence of monoclonal antibody (mAb) specific for either murine CD3 or TcR expressing the Vβ8‐encoded ß chain (F23.1), B2A2‐CD4‐8‐ cells proliferated. Such proliferation was blocked by mAb to interleukin 2 receptor (IL 2R), suggesting an autocrine mechanism involving IL 2 production and subsequent utilization. IL 2 and also IL 3 production by mAb‐stimulated B2A2‐CD4‐8‐ cells was directly confirmed. Furthermore, a panel of B2A2‐CD4‐8‐ clones were derived to assess the role of the TcR in cytolysis. Many clones were isolated which killed Fc receptor‐bearing P815 target cells only in the presence of F23.1 mAb. Finally, in vivo treatment of neonatal mice with F23.1 mAb resulted in a marked reduction of Vβ8 B2A2‐CD4‐8‐ thymocytes. Collectively, these results indicate that the TcR α/ß complex on CD4‐CD8‐B2A2‐ cells is fully capable of transducing signals that lead to proliferation, lymphokine production and cytolysis in vitro, as well as to disappearance of this subset from the thymus in vivo.
Studies on the mechanism of polyclonal B cell stimulation by TH2 cells
Authors: Lohoff Michael , Dirks Meike , Rohwer Peter , Röllinghoff Martin 
Published: March 2007

AbstractRecently, it has been shown that cloned L1/1 T helper cells of type 2 (TH2 ‐cells), when stimulated with antigen, are able to induce polyclonal B cell proliferation. Here we present evidence that this process is dependent on direct cell‐cell interaction between T and B cells, which in the effector phase, i.e., during stimulation of the B cells by activated T cells, can be mediated by a mechanism other than cognate interaction. This conclusion is derived from experiments in which highly purified, small B cells of high density were polyclonally stimulated by L1/1 T cells triggered by an anti‐T3 monoclonal antibody in the absence of antigen. The triggering process was independent of the presence of the Fc part of the antibody and occurred in cultures devoid of macrophages. Thus, the well‐established cognate recognition does not appear to be the only mechanism of B cell induction by T helper cells.
Inhibition of the responses of a cloned CD4 T cell line to different class II major histocompatibility complex ligands by anti‐CD4 and by anti‐receptor Fab fragments are directly related
Authors: Portoles Pilar , Janeway Charles A. 
Published: March 2007

AbstractThe responses of a single cloned T cell line to three different class II major histocompatibility complex (MHC) ligands have been compared for avidity, determined by inhibition with anti‐T cell receptor Fab fragments directed at two different receptor epitopes, and for ease of inhibition with anti‐CD4 antibody. It has, thus, been directly demonstrated that ease of inhibition of the response of a T cell to a class II MHC ligand by anti‐CD4 is inversely related to the avidity of the T cell receptor for that ligand. The difficulties in inferring from this finding that CD4 acts primarily by increasing receptor avidity for its class II MHC ligand are discussed in the light of evidence suggesting that CD4 is an active signaling component of the T cell receptor for class II MHC ligands.
Immunogenic capacity of macrophage hybridomas
Authors: Tzehoval Esther , Dagan Shlomo , Eisenbach Lea , Atsmon Jacob , Feldman Michael 
Published: March 2007

AbstractTwo clones, E2‐7.7 and E2‐10.50, derived from two macrophage(MΨ)hybridomas, E2‐7 and E2‐10, have been studied. The first clone, E2‐7.7, is Ia and Fc receptor (FcR) negative and manifests a strong antigen‐presenting capacity. When we pulsed its cells in vitro with keyhole limpet hemocyanin (KLH) antigen and injected them into syngeneic animals, we found that as small a dose as 103 cells initiated an immune response in vivo. On the other hand, antigen‐pulsed cells of the E2‐10.50 clone, which are Ia‐ and FcR, were almost incapable of triggering immunity, even when injected at a dose of 105 cells. Thus, the two clones differ in their immunogenic capacity (both cellular and humoral immunity). In experiments aimed at testing the stimulation in vitro of primed lymph node (LN) cells by antigen‐pulsed cells of these two hybridoma clones, we observed that E2‐7.7 stimulated the unfractionated population of LN cells and the LN‐derived population of T cells. The E2‐10.50 cells stimulated only the unfractionated population of LN cells, but not the T cell population. Subsequent tests indicated that the E2‐10.50 cells require an intermediate Ia accessory cell to present the antigen to the T lymphocytes.Analyzing the molecular structure of the MΨ hybridomas, we discovered that major histocompatibility complex (MHC) genes of the myeloma haplotype (H‐2d), and of the splenic MΨ used for fusion (H‐2k), which were not expressed in the parental myeloma or in the E2‐10.50, were expressed in the E2‐7.7. Thus, somatic cell fusion of MΨ resulted in the activation of suppressed genes of the myeloma partner. It appears that these antigens participate in controlling the immunogenic properties of the E2‐7.7 clone. Testing the effects of interferons on the MΨ hybridomas, we observed that interferon‐γ activated, at both the mRNA and the cell surface‐antigen levels, the expression of H‐2Dk, H‐2Kd and H‐2Dd in the E2‐10.50 cells, but not in the E2‐7.7. Consequently, interferon‐γ augmented significantly antigen presentation by E2‐10.50 but not by E2‐7.7 cells. These two hybridoma clones might represent two distinct subsets of normal MΨ, manifesting two different sets of functional properties. Having described earlier the E2‐10.20 clone that takes up, but does not present antigen, we may in fact be facing three types of MΨ hybridomas, representing three functional subpopulations of MΨ.
B cell precursors are present in the thymus during early development
Authors: Kimoto Hiroshi , Shirasawa Takuji , Taniguchi Masaru , Takemori Toshitada 
Published: March 2007

AbstractAn in vitro system for transforming immature lymphoid cells present in the thymus at early development has been established. By phenotype analysis of the transformants obtained, we observed that B cell precursors, susceptible to Abelson murine leukemia virus (A‐MuLV)‐ or Harvey murine sarcoma virus (H‐MuSV)‐induced lymphogenesis, were present at high frequency in the fetal thymus of BALB/c mice. These precursors recolonized alymphoid thymus lobes in vitro, as do T cell precursors. It was further observed that B precursors in the fetal liver were also capable of recolonizing alymphoid thymus lobes and were stored in a thymic environment. These results suggest that stroma cells of the fetal thymus may possess the capacity to support the growth of B precursors. On the other hand, B cell precursors sensitive to the viral transformation were undetectable in the fetal thymus of C57BL/6, although immunohistochemical analysis suggested their presence. However, in the fetal liver of the same strain, B precursors recolonizing alymphoid thymus in vitro were sensitive to the viral transformation. Based on these results, we will discuss both the role and fate of thymic B precursors. In addition, we also obtained T cell lymphomas at different stages of differentiation from the fetal thymus of C57BL/6 infected with A‐MuLV or H‐MuSV. These data indicate the usefulness of our system in establishing cell lines derived from intrathymic lymphogenesis at early development.