bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of uterine intraepithelial γδ T cell receptor‐positive lymphocytes during pregnancy
Authors: Meeusen Els , Fox Annette , Brandon Malcolm , Lee Chee‐Seong 
Published: March 2007

AbstractIntraepithelial lymphocytes (IEL) of the uterus of non‐pregnant sheep were analyzed by single‐ and two‐color flow cytometry. Very few lymphocytes carrying classical B and T cell markers (CD5, surface immunoglobulin) were detected in the uterine epithelial cell suspensions and all IEL expressed the CD8 surface marker although with varying intensities. Three distinct subpopulations were identified including a major (46‐56%) population of CD8+CD45R−γδ T cell receptor (TcR)‐negative cells and approximately equal numbers of CD8+CD45R+γδTcR− and CD8+CD45R+γδTcR+ lymphocytes. The same three subpopulations were also present in the interplacentomal areas of the uterus of ewes at a late stage of pregnancy but there was a dramatic increase (60‐70%) in the γδ TcR+ subpopulation. In addition, a pronounced increase in both size and granularity was observed in the IEL population of pregnant uteri and this was attributed to the γδ TcR+ cells. Light and electron microscopic examination of these γδ TcR+ IEL revealed an increase in metabolic activity and the formation of exceptionally large cytoplasmic granules and confirmed their restricted localization within the uterine epithelium close to the trophoblast. These results represent for the first time, a clear example of the activation of γδ TcR+ cells which is not associated with an ongoing disease process or infection, γδ TcR+ cells have recently been observed in the epithelium of the murine reproductive tract and were characterized by their unique homogeneous receptor structure. The present results indicate that these cells may play an important physiological role during pregnancy.
Interleukin‐9 stimulates in vitro growth of mouse thymic lymphomas
Authors: Vink Anne , Renauld Jean‐Christophe , Warnier Guy , Van Snick Jacques 
Published: March 2007

AbstractThe ability of interleukin (IL)‐9 to stimulate the in vitro proliferation of freshly collected mouse thymic lymphoma cells was tested on a panel of 45 tumors, induced by N‐methyl‐N‐nitrosourea (MNU) or by X‐ray irradiation. IL‐9 significantly stimulated the proliferation of 26 of these tumors. Out of 11 other factors tested, only IL‐2, IL‐4 and IL‐7 showed similar activities. In addition to the responses to IL‐9 alone, a potent synergy was often observed between IL‐9 and IL‐2 for MNU‐induced tumors. Synergies between IL‐9 and IL‐7 or IL‐9 and IL‐4 were also observed but less frequently. The growth‐promoting activity of IL‐9 and the synergistic activities of IL‐2 and IL‐9 for thymic lymphoma cells were confirmed with cell lines established from the fresh tumors.
Chicken major histocompatibility complex class II B genes: analysis of interallelic and inter‐locus sequence variance
Authors: Zoorob Rima , Bernot Alain , Renoir Dominique Martel , Choukri Fatima , Auffray Charles 
Published: March 2007

AbstractFive different chicken B‐LB genes were cloned and sequenced. The comparison of these sequences shows that they can be classified as members of two different families, the B‐LBII family (containing the B‐LBI and B‐LBII genes) and the B‐LBIII family (containing the B‐LBIII, B‐LBIV, and B‐LBV genes). The extent of polymorphism within each of these families was assessed by in vitro amplification of DNA fragments encompassing exon 2 in several haplotypes. The nucleotide sequences were determined, and pairwise relationships were evaluated. In the course of this work, a sixth gene termed B‐LBVI was identified, defining a third family (B‐LBVI family). Polymorphism of the B‐LBIII or B‐LBVI families is far less extensive than that of the B‐LBII family. In this latter, the distribution of conserved and polymorphic residues is similar to what has been described in mammals. These families seem to have been generated by gene duplication events giving rise to several isotypes, as observed in mammals. However, phylogenetic analyses indicate that these families are not homologous to their mammalian counterparts. Evaluation of the level of transcription of these different genes showed that genes from the B‐LBII family are predominantly transcribed over those of the other families.
Autoantibodies from patients with systemic lupus erythematosus bind a shared sequence of SmD and Epstein‐Barr virus‐encoded nuclear antigen EBNA I
Authors: Sabbatini Alessandra , Bombardieri Stefano , Migliorini Paola 
Published: March 2007

AbstractSmD is one of the small nuclear ribonucleoproteins frequently targeted by autoantibodies in systemic lupus erythematosus. We isolated and characterized the antibodies present in lupus sera that are specific for the C‐terminal region of SmD (sequence 95–119). This region is highly homologous to sequence 35‐58 of the EBNA I antigen, one of the nuclear antigens induced by infection with Epstein‐Barr virus. Antibodies affinity purified over a peptide 95–119 column were able to recognize this sequence in the context of the whole SmD molecule, as they reacted with blotted recombinant SmD. Anti‐SmD 95‐119 antibodies bound also the EBNA I 35–58 peptide and detected the EBNA I molecule in a total cell extract from Epstein‐Barr virus‐infected lines. A population of anti‐SmD antibodies is, therefore, able to bind an epitope shared by the autoantigen and the viral antigen EBNA I. To investigate the involvement of this shared epitope in the generation of anti‐SmD antibodies, we immunized mice with the EBNA I 35‐58 peptide. Sera from immunized animals displayed the same pattern of reactivity of spontaneously produced anti‐SmD antibodies. They reacted in fact with the EBNA peptide as well as with SmD 95‐119 and recombinant SmD. These data suggest that molecular mimicry may play a role in the induction of anti‐SmD autoantibodies.
Characterization of the human T cell receptor α‐chain repertoire and demonstration of a genetic influence on Vα usage
Authors: Moss Paul A. H. , Rosenberg William M. C. , Zintzaras Elias , Bell John I. 
Published: March 2007

AbstractDespite considerable knowledge of the determinants and profile of the Tcell receptor (TCR) β‐chain repertoire, very little is known about the repertoire of the Vα and Jα segments of the TCR in man or mouse. We have used the anchored polymerase chain reaction (PCR) to analyze the human TCR α‐chain repertoire at the mRNA level in peripheral blood lymphocytes. We find marked differences in the usage of individual Vα segments. The Vα repertoire is determined both by differences in the use of individual Vα gene segments at the time of gene rearrangement and by genetic influences on the selection of the expressed Vα repertoire, presumably during thymic maturation. Analysis of the Jα repertoire shows non‐random usage of individual Jα segments but no obvious relationship to chromosomal position. We also report three new Vα segments, three new Jα segments and possible allelic variation in Vα gene segments. Two unusual TCRα transcripts are described which add new information on the nature of TCRα transcript assembly.
Essential role of tumor necrosis factor‐α in the differentiation of human tonsil in vivo induced B cells capable of spontaneous and high‐rate immunoglobulin secretion
Authors: Rodríguez Carmen , Roldán Ernesto , Navas Gloria , Brieva José A. 
Published: March 2007

AbstractHuman tonsils contain B cells capable of spontaneous and high‐rate immunoglobulin (Ig) secretion in vitro. These cells are in vivo induced mature B cells, and, as such, they provide an adequate model for studying tonsil B cell differentiation. The present report analyzes the effect of a variety of factors on purified tonsil B cells capable of spontaneous IgG secretion in fetal calf serum (FCS)‐containing and serum‐free supplemented cultures. Tumor necrosis factor‐(TNF)α was found to be important for these B cells to reach the high‐rate IgG‐secreting stage, as is indicated by the following findings: (a) none of the factors used modified tonsil B cell IgG secretion in FCS‐containing cultures; (b) TNF‐α (5‐20 ng/ml), but not other cytokines or factors including interleukin (IL)‐6, was capable of restoring missing IgG production in serum‐free supplemented cultures of tonsil B cells; and (c) IgG secretion in FCS‐containing cultures was inhibited by the addition of blocking anti‐TNF‐α antibodies, but not anti‐IL‐6 antibodies, and this inhibition could be specifically reversed by exogenous TNF‐α. TNF‐α was actively produced by tonsil B cells (range 120‐750 pg/ml) in the presence, but not in the absence, of FCS. The TNF‐α inductive effect occurred during the first 12 h of culture and did not require DNA synthesis. These results indicate that the early and endogenous generation of TNF‐α seems to be essential for tonsil in vivo induced B cells to differentiate into the high‐rate Ig‐secreting stage.
Engagement of CD40 lowers the threshold for activation of resting B cells via antigen receptor
Authors: Wheeler Kay , Pound John D. , Gordon John , Jefferis Roy 
Published: March 2007

AbstractCross‐linking of surface Ig (sIg) on resting B cells can generate intracellular signals; however, for T‐dependent antigens to promote growth and differentiation additional surface receptors must be engaged. Ligation of CD40 can stimulate B cell proliferation in the presence of interleukin‐4. A recently identified counterstructure for CD40 is found on T helper cells and is believed to represent the cognate ligand for B cell activation. This study investigates the role of CD40 as an accessory molecule in sIg‐dependent B cell activation. Simultaneous ligation of sIg and CD40 by monoclonal antibodies (mAb) in the presence of mouse L cells which express human Fey receptor type II (FcγRII‐L cells) results in potent stimulation of small resting B cells. When CD40 is co‐ligated, picomolar concentrations of mouse IgG1 anti‐μ, and anti‐δ mAb can stimulate B cell proliferation. This requires interaction of the anti‐Ig mAb with the FcγRII‐L cells: a mouse IgG2a anti‐μ, mAb which is not recognized by FcγRII, was ≥ 1000‐fold less effective. These findings suggest a mechanism for B cell activation whereby engagement of T cells via CD40 and its cognate ligand provides potent enhancement of signals delivered through sIg. Based on these observations, models for the activation of B cells by T‐dependent antigens are presented.
T cell response in murine Leishmanial mexicana amazonensis infection: production of interferon‐γby CD8+ cells
Authors: Chan Marion Man‐Ying 
Published: March 2007

AbstractThe immune response to Leishmania major has been the subject of many investigations. However, Leishmania includes many species with different clinical manifestations. In this report, we studied the Tcell response to L. mexicana amazonensis, a New World species, in a murine model. We found that, similar to L. major, an Old World species, resistant C57BL/6 mice produced a high level of IFN‐γ and a low level of IL‐4. Conversely, susceptible BALB/c mice produced a much lower level of IFN‐γ and higher level of IL‐4.Although IFN‐γ is one of the important lymphokines that mediate macrophage activation and thus the destruction of the intracellular parasites, which lymphocyte subsets are producing the IFN‐γ is still a controversy. Much evidence including the isolation of protective, IFN‐γ‐producing, CD4+ cell lines have confirmed the participation of CD4+ Thl cells unequivocally. However, both CD4+ and CD8+ cells produced IFN‐γ. Recently, an increasing body of evidence has appeared suggesting that CD8+ cells also play a role in the resolution of murine L. major infection. We found that in the L. m. amazonensis model, when CD8+ lymphocytes from resistant C57BL/6 mice were eliminated by anti‐CD8 antibody and complement‐mediated lysis, the IFN‐γ production was reduced by 77%. This indicated that CD8+ cells produced a significant amount of the IFN‐γ. However, our results also indicate that IFN‐γ production by CD8+ cells was dependent on CD4+ cells.
Expression of the CD28 costimulatory molecule on subsets of murine intestinal intraepithelial lymphocytes correlates with lineage and responsiveness
Authors: Ohteki Toshiaki , MacDonald H. Robson 
Published: March 2007

AbstractThe CD28 antigen has been recently demonstrated to be a costimulatory molecule and is expressed by almost all thymic and peripheral T cell receptor (TcR) αδ+ and γλ+ cells in the mouse system. We show here that expression of CD28 is heterogeneous among murine intestinal intraepithelial lymphocytes (IEL). Whereas some TcR αβ‐expressing IEL subsets such as CD4+8− and CD4−8α+β+ cells express CD28 at the same levels as their phenotypic counterparts in lymph node, other subsets of TcR αβ cells (including CD4−8α+β− and CD4+8αβ+β cells) as well as TcR γλ+ IEL fail to express CD28. Parallel experiments using aged BALB/c‐nu/nu mice indicated that CD28 expression patterns among IEL are quite similar to those of normal BALB/c mice. Furthermore, forward light scatter analysis showed that CD28− cells are considerably larger than CD28+ cells in the gut, although cycling cells were rare in both subsets. Finally CD28− cells in the gut did not proliferate or produce IL‐2 upon stimulation by anti‐CD3 monoclonal antibodies (mAb) and phorbol 12‐myristate 13‐acetate, whereas CD28+ cells in the gut and lymph nodes responded to these stimuli. The response of the CD28+ cells was enhanced by anti‐CD28 mAb. These results suggest that CD28− IEL (CD4‐8α+β− cells, and some CD4+8α+β−cells) may follow a different developmental pathway from that of CD28+ IEL in a thymus‐independent environment, and that expression of CD28 correlates with responsiveness of the cells to triggering via the TcR‐CD3 complex.
Restricted T cell receptor expression by human T cell clones specific for mycobacterial 65‐kDa heat‐shock protein: Selective in vivo expansion of T cells bearing defined receptors
Authors: Henwood Judy , Loveridge Jason , Bell John I. , Gaston John S. Hill 
Published: March 2007

AbstractWe have examined the T cell receptor (TcR) expression of clones specific for epitopes of mycobacterial 65‐kDa heat‐shock protein (hsp65) in the context of two different HLA molecules, and used this system as a model to assess the selection of T cells responsive to this antigen in vivo.DR3‐restricted clones were raised from both the synovial fluid (SF) and peripheral blood (PB) of a patient with reactive arthritis in three separate cloning events. Five of five SF‐derived clones tested expressed either Vβ5.2 or a closely related β chain, Vβ5.6.The α chains expressed by Vβ5.2+ and Vβ5.6+ clones were from different families, Vα2.4 and Vα23.2, respectively. Nine of ten clones derived from two cloning procedures on PB taken 3 years later also expressed either Vβ5.2 or Vβ5.6. This suggests that the TcR repertoire for recognizing this major histocompatibility complex/peptide complex is relatively restricted and favors the use of Vβ5. Conservation of the β chain third complementarity‐determining region (CDR3) sequence was not evident, however. Sequencing α and β chains of representative Vβ5.2+ and Vβ5.6+ PB‐derived clones revealed TcR which were identical to those utilized by the SF‐derived clones, showing that the repertoire for recognition of this antigen is stable over time.Similar studies of TcR expression were carried out on hsp65‐specific, DP4‐restricted clones derived from the SF of a patient with rheumatoid arthritis by two independent cloning procedures. There was conservation of a chain usage, since all clones expressed a member of the Vαl family, but again CDR3 sequence conservation was not apparent, β chain usage was not restricted since different clones expressed Vβ6.7, Vβ22.3 and Vβ12. Subtle differences in epitope specificity were detected for two clones with differing TcR. Once more, T cell clones with identical α and β TcR chains were obtained from the separate cloning procedures, suggesting oligoclonalty of T cells with this defined specificity in the patient's SF.
B cell development in mice with a defective λ5 gene
Authors: Rolink Antonius , Karasuyama Hajime , Grawunder Ulf , Haasner Dirk , Kudo Akira , MeLchers Fritz 
Published: March 2007

AbstractThe surrogate light chain encoded by the two pre‐B cell‐specific genes VpreB and λ5 plays a critical role in B cell development of the mouse. It has been shown that targeted disruption of the λ 5gene results in a depletion of B220+ CD43− IgM− pre‐B cells in bone marrow, and in a delayed appearance both of CD5+ as well as CD5− surface immunoglobulin (slg)+ B cells in the periphery. In this report we show that DHJH‐rearranged B220− and B220+, CD43+, c‐kit+, sIgM− pro‐ and pre‐B‐I cells with long‐term capacity to proliferate in vitro on stromal cells in the presence of interleukin‐7 are present in normal numbers in the bone marrow of λ 5T/λ.5T mice at various ages. They express normal levels of VpreB mRNA but, in contrast to normal pre‐B‐I cells, do not express surrogate light chain on their surface. Pre‐B‐I cells from fetal liver and bone marrow of λ 5T/λ 5T mice differentiate with normal kinetics and in normal numbers to sIg+, mitogen‐reactive B cells. These results suggest that the delayed generation of sIg+ B cells in the peripheral, mature compartments of CD5+ and CD5− cells could be accounted for by the daily production of approximately 5 × 105 sIg+ B cells from the pre‐B‐I cell pool in the absence of a normal pool of pre‐B‐II cells.
Functional characterization of the promoter for the human germ‐line T cell receptor J α (TEA) transcript
Authors: De Chasseval Régina , De Villartay Jean‐Pierre 
Published: March 2007

AbstractTheT cell receptor (TCR)‐α and ‐δ loci are contained on the same chromosomal region, and yet are developmentally and genetically independent. The first element of the Jα cluster (ΨJα) is the site of an active rearrangement in the human thymus (δRec‐ΨJα rearrangement) and is localized downstream of a region expressed as a germ‐line sterile transcript (TEA) in the human developing thymus.We hypothesized that the transcription of TEA could be indicative of (or responsible for) the opening of the Jα to the V(D)J recombinase and undertook to analyze cis‐acting sequences controlling the TEA transcription. The promoter of TEA was characterized. It was part of a region that is highly conserved between human and mouse and contained many sites for the putative binding of T cell‐specific transcription factors. The in vitro activity of this promoter was dependent on the association with an enhancer. A strong DNase I hypersensitive site was found in the vicinity of this promoter again suggesting the possible presence of protein‐DNA interactions in this region. The implications of these results in the general perspective of TCR‐α/δ gene regulation is discussed.
Agents that activate protein kinase C rescue sheep ileal Peyer's patch B cells from apoptosis
Authors: Motyka Bruce , Griebel Philip J. , Reynolds John D. 
Published: March 2007

AbstractThe ileal Peyer's patch (PP) is the major site of B cell production and is a site of immunoglobulin gene diversification in the sheep. Within the ileal PP follicles there is both intense proliferation and death of B cells. We have previously demonstrated that most, if not all of this death can be attributed to apoptosis. Likewise, ileal PP B cells die rapidly by apoptosis in culture ‐ after 6 h many cells appear pyknotic and about 50% of cellular DNA is fragmented. We now show that the DNA fragmentation and cell death of ileal PP B cells can be almost completely abrogated during the first 12 h of culture by the addition of the phorbol esters, phorbol dibutyrate (PBu2) or phorbol myristate acetate. This inhibition of apoptosis could be sustained for greater than 24 h by the concomitant addition of both PBu and the Ca2+ ionophore A23187. However, the rescue of B cells from apoptosis by PBu, with or without Ca2+ ionophore, was prevented by macromolecular synthesis inhibitors or inhibitors of protein kinase C activation. Furthermore, treatment of cultures with PBu, with or without Ca2+ ionophore, resulted in an activated B cell phenotype and a three‐ to fourfold increase in cell proliferation. We conclude that protein kinase C activation in conjunction with an increase in intracellular [Ca2+] can provide the signals necessary to rescue ileal PP B cells from apoptosis, and speculate that these ileal PP B cells are destined to die unless they receive a signal that rescues them from the death pathway.
HLA‐DRβ chain residue 86 controls DRαβ dimer stability
Authors: Verreck Frank A. W. , And Annemarie Termijtelen , Koning Frits 
Published: March 2007

AbstractMajor histocompatibility complex class II molecules exist in two forms, which can be distinguished on the basis of their stability in sodium dodecyl sulfate (SDS) as SDS‐stable and SDS‐unstable αβ dimers. The ratio of stable vs. unstable αβ dimers varies between murine H‐2 alleles and isotypes, but the molecular basis for this observation is unknown. Here we show that for the human HLA‐DRB1 and HLA‐DRB3 gene products this ratio is controlled by the valine/glycine dimorphism at position 86. Haplotypes coding for DRβ chains with a valine at position 86 express higher numbers of stable dimers compared to similar haplotypes expressing DRβ chains with a glycine at that position. Reverse‐phase high‐performance liquid chromatography analysis of iodinated peptides, which were eluted from DR dimers with either a DRB1*1101 or a DRB1*1104 β chain which differ only at position 86, indicated that these DR dimers contain (partially) distinct sets of peptides.The valine/glycine dimorphism is highly conserved, present in most HLA‐DR alleles and influences peptide‐binding. Analysis of the occurrence of theVal86 and the Gly86 gene products revealed that these are not equally present in the population. Depending on the DR specificity either the Val86 of Gly86 allelic variant is favored.Thus, the natural, highly conserved dimorphism at HLA‐DR β chain position 86 influences peptide selection. The dimorphism is therefore likely to influence antigen presentation and forms the molecular basis for the observed differences in stability of Val86‐ and Gly86‐containing DR dimers in the presence of SDS.
Induction of CD3δεω) by phorbol 12‐myristate 13‐acetate
Authors: Vangsted Annette , Neisig Anne , Wallin Håkan , Zeuthen Jesper , Geisler Carsten 
Published: March 2007

AbstractThe effect of phorbol 12‐myristate 13‐acetate (PMA) on the synthesis, assembly and processing of the components of the T cell receptor (TcR) was studied with special focus on the CD3ω chain. Treatment of the human leukemic T cell line Jurkat with PMA increased the synthesis of the Tiα, CD3γ and CD3ζ chains two‐to threefold and the synthesis of Tiβ and CD35δεω complexes five‐ to sevenfold as assessed by metabolic labeling, immunoprecipitation and sodium dodecyl sulfate‐polyacrylamide gel electrophoresis followed by scanning densitometry. The amount of total assembled TcR complexes increased approximately threefold and the maturation of the TcR was not affected as determined by analysis of oligosaccharide side chain processing in the Golgi apparatus. Activation of Jurkat cells with anti‐CD3 monoclonal antibody, calcium ionophore, or mitogenic lectins did not affect the synthesis of the TcR components. In other cells studied (the human leukemic T cell line CEM, a panel of variants of the Jurkat T cell line and peripheral blood mononuclear cells) PMA also increased the synthesis of the TcR components. However, for all cell lines studied the amount of TcR complexes expressed on the cell surface was decreased after 16 h of PMA treatment. Based on these results we propose a role of CD3ω in retention of TcR complexes. From PMA‐treated CEM cells more than 50‐fold the amount of CD3δεω complexes was immunoprecipitated as compared to the amount obtained from untreated Jurkat cells, and these observations indicate that the CEM cell line may be a qualified candidate for purification of CD3ω.