bluuebunny/crossref_metadata_2025_split huggingface dataset:
Restoration of H‐2b expression and processing of endogenous antigens in the MHC class I pathway by fusion of a lymphoma mutant to L cells of the H‐2k haplotype
Authors: Öhlén Claes , Bastin Judy , Ljunggren Hans‐Gustaf , Imreh Stephan , Klein George , Townsend Main R. M. , Kärre Has 
Published: March 2007

AbstractThe RMA‐S lymphoma mutant cannot process and present antigens to H‐2‐restricted cytotoxic T lymphocytes. It synthesizes major histocompatibility complex class I heavy (H‐2KbDb) and light β2‐microglobulin (β2mb) chains of normal size and charge, but only a fraction of these assemble and reach the cell surface. As a first step investigating the genetic defect of this line, we have fused it to a L cell fibroblast line (H‐2KkDk/β2ma). The fusion restored H‐2Kb, Db and β2mb expression as well as the ability to process and present internally derived (minor histocompatibility and influenza virus nucleoprotein) antigens in RMA‐S. This shows that the mutation(s) responsible for the phenotype of RMA‐S is (are) not located within the MHC class I heavy and light chain genes. Other cellular factors, derived from the L cell fusion partner, can control antigen processing and transport of MHC class I molecules. These findings are discussed in relation to the observation that assembly and transport of MHC class I molecules can be induced in the mutant by H‐2b‐restricted peptides. The recessive nature of the defect and its independence of MHC class I genes in the mutant has important implications for future transfection studies, of this and similar mutants, aiming at establishing cells containing non‐assembled MHC class I molecules of different alleles and identifying the gene(s) controlling processing of endogenous antigens.
The G protein coupling T cell antigen receptor/CD3‐complex and phospholipase C in the human T cell lymphoma Jurkat is not a target for cholera toxin
Authors: Sommermeyer Henning , Schwinzer Reinhard , Kaever Volkhard , Behl Berthold , Resch Klaus 
Published: March 2007

AbstractIntact Jurkat cells could be stimulated by monoclonal antibodies against the T cell antigen receptor complex (OKT3 directed against the CD3 complex, BMA031 directed against constant framework epitopes in the α/β heterodimer). The accumulation of inositol phosphates was inhibited by prior incubation of the cells with cholera holotoxin. The inhibitory effect of cholera toxin (CT) was not cAMP mediated because forskolin (a direct activator of adenylate cyclase) did not mimic the inhibitory effect. When measuring phospholipase C (PLC) in a cell‐free assay system by using [3H]inositol‐labeled membranes, the enzyme could be stimulated by the poorly hydrolyzable GTP analogue guanosine 5′‐O‐thiotriphosphate (GTPγS). Both anti‐receptor antibodies augmented the GTPγS stimulatory effect, while the antibodies alone had no stimulatory capacity. In membranes from CT‐pretreated Jurkat cells GTPγS had the same stimulatory effect on PLC as in untreated cells, whereas the antibodies lost their stimulatory capacity in the presence of GTPγS. These data imply that CT exerts its inhibitory effect on signaling by acting at the receptor level while the PLC regulating G protein is not a target for CT‐mediated alterations. This assumption is supported by the finding that in intact Jurkat cells CT, which ADP ribosylated only the α‐subunit of the stimulatory G protein of the adenylate cyclase, led to a loss of the T cell antigen receptor complex from the cell surface as demonstrated by a decrease of receptor density using flow cytometry analysis. Receptor loss could not be achieved by forskolin treatment or incubation of the cells with the binding subunit of the toxin alone.
Dual effects of interleukin 4 on antigen‐activated human B cells: induction of proliferation and inhibition of interleukin 2‐dependent differentiation
Authors: Llorente Luis , Mitjavila Francesca , Crevon Marie‐Claude , Galanaud Pierre 
Published: March 2007

AbstractWe analyzed the effects of interleukin 2 (IL 2) and IL 4 isolated and in association on the specific response of human B cells triggered by trinitrophenylated polyacrylamide beads (TNP‐PAA). IL 2 induced an increase (more than 10 times) in the number of hapten‐binding cells [detected by a rosette‐forming cell (RFC) assay] as well as the generation of antibody‐producing cells [detected by a plaque‐forming cell (PFC) assay]. IL 4 induced an isolated RFC response without PFC response. We verified that the IL 4 (as well as I2)‐induced RFC were hapten specific and mediated through membrane IgM. Density fractionation experiments showed that IL 4‐induced RFC were equally distributed between highdensity and intermediate‐density B cells. IL 2 appeared to drive more B cells into the intermediate density fraction. IL 2‐induced PFC belonged to the RFC population and were intermediate‐size B cells. IL 2 drove more RFC into an activated stage and it induced the differentiation of a number of them into antibody‐producing cells. The evaluation of the proportion of RFC able to incorporate thymidine showed that both IL induced a substantial proliferation of antigen‐activated B cells. However, IL 4 inhibited the IL 2‐dependent PFC without affecting the number of RFC nor the proportion of proliferating RFC induced by this IL. These results directly demonstrate that human IL 4 triggers the expansion of antigen‐activated B cells and selectively inhibits the IL 2‐induced differentiation.
Mast cell heterogeneity: two‐dimensional gel electrophoretic analyses of rat peritoneal and intestinal mucosal mast cell
Authors: Abe Tatsuya , Swieter Mark , Imai Toru , Hollander Neal Den , Befus A. Dean 
Published: March 2007

AbstractPeritoneal mast cells (PMC) and intestinal mucosal mast cells (IMMC) were purified from rats infected with the nematode Nippostrongylus brasiliensis. Overall protein constituents of both mast cell subtypes were analyzed by two‐dimensional gel electrophoresis using either nonequilibrium pH gradient electrophoresis (NEPHGE) or isoelectric focusing (IEF) in the first dimension and SDS‐PAGE (10%) in the second dimension followed by silver staining. PMC had seven dominant basic proteins (PB2–8; PI 9–9.5) with estimated molecular masses of 26 to 37 kDa, as well as 80 to 90 neutral or acidic proteins, most of which had pI 6 to 7.5 and estimated molecular masses of 20 to 100 kDa. All the basic proteins were granule‐associated. Three basic proteins, PB6 (29 kDa), PB7 (28 kDa) and PB8 (RMCP I, 26 kDa), bound [3H]diisopropyl fluorophosphate (DFP), suggesting that they are serine proteases. However, only PB8 was reactive with antibodies to RMCP I. Another basic component (< 14 kDa), perhaps a degradation product of PB6, PB7 or PB8, also bound [3H]DFP. By comparison, IMMC possessed nine basic proteins (IB1‐9) and, in general, they were more acidic (pI about 8.5–9) than those of PMC. Four major basic proteins (IB6–9) were all 24 kDa but were slightly different in isoelectric points. These and another 46‐kDa basic component (IB2) were reactive with antibodies to RMCP II and bound [3H]DFP. There were no other DFP‐binding proteins in IMMC. In spite of remarkable differences between basic granule‐associated proteins in PMC and basic proteins in IMMC, spots in the neutral‐acidic range were for the most part similar in the two mast cell subsets, although quantitative differences were evident for some spots. Thus, rat mast cell populations from the peritoneal cavity and intestinal mucosa exhibit marked heterogeneity in their protein constituents with basic pI, including in their granule‐associated proteins with serine protease activity.
The biological effects of IgM hexamer formation
Authors: Randall Troy D. , King Leslie B. , Corley Ronald B. 
Published: March 2007

AbstractThe inducible B cell lymphoma, CH12, and its in vitro adapted subclone, CH12‐LBK, produce immunoglobulins of identical sequence, specificity and isotype, with equivalent affinities for the hapten trimethyl ammonium. However, the hemolytic efficiencies of the antibody secreted by the two cell lines are quite different. Antibody preparations from lipopolysaccharide‐stimulated CH12 cells lyse erythrocytes six‐ to ten times more effectively than antibody preparations of the same concentration from CH12‐LBK cells. Both cell lines secrete polymeric IgM, but while CH12‐LBK cells secrete predominantly the canonical pentameric IgM, CH12 cells secrete a mixture of pentamers and hexamers. High‐efficiency complement‐dependent cytolysis is associated with hexameric IgM, which has a specific activity that is approximately twenty times higher than that of the pentameric form. J chain protein is found in the secreted IgM of both cell lines, but is associated only with the pentameric IgM and not with the hexameric form, nor with any intermediate polymers smaller than a pentamer. A deficit in, or the inaccessibility of, J chain protein appears to facilitate hexamer formation. These experiments confirm previously published data showing that J chain is not necessary either for assembly or secretion of polymeric IgM, and suggest instead that J chain may be important in regulating the lytic efficiency of polymeric IgM by controlling the IgM pentamer/hexamer ratio. The experiments further suggest a mechanism, in addition to isotype switching and somatic mutation, by which the biological efficiency of antibodies from a single clone of B cells can be regulated.
Requirements for the growth of TH1 lymphocyte clones
Authors: Germann Tieno , Partenheimer Andrea , Rüde Erwin 
Published: March 2007

AbstractBesides the signal generated in a T lymphocyte after triggering the T cell receptor (TcR), most lymphocytes need a “second signal” to become fully activated. The necessity and nature of the “second signal” differs between different types of T cells. At the level of CD4‐positive T helper lymphocytes interleukin 1 (IL 1) serves as “second signal” for those of the TH2 subtype (IL 4, 5, 6 producer) but not for those of the TH1 subtype (IL 2, IFN‐γ producer). This correlates with the absence of the IL 1 receptor at the surface of TH1 clones. We report herein the further purification of T cell stimulating factor (TSF), a soluble mediator involved in the proliferation of TH1 lymphocytes. A preparation free of detectable IL 1, 2, 4 and IL 6 activity could act as “second signal” required for the growth of TH1 lymphocytes in a TcR‐mediated, as well as a TcR‐independent activation system. In addition, we suggest that IL 1 can influence the proliferation of TH1 clones in an indirect way, probably via the induction of TSF in accessory cells.
Rat bone marrow cells undergo thymopoiesis in mouse fetal thymic organ culture
Authors: Deugnier Marie‐Ange , Dargemont Catherine , Denoyelle Monique , Blanche Martine , Imhof Beat A. , Thiery Jean Paul 
Published: March 2007

AbstractWe have developed an in vitro differentiation assay allowing the study of thymopoiesis from rat bone marow cells. In this assay, Wistar rat bone marrow cells repopulated fetal Swiss mouse thymic lobes depleted in endogeneous lymphoid cells by deoxyguanosine treatment. Due to the xenogeneic situation, repopulating rat cells from any hemopoietic lineage could be easily recognized by anti‐rat monoclonal antibodies such as anti‐Thy‐1.1 that did not react with Swiss mouse thymocytes. After 15 days in vitro, 80% of the developing rat cells were Thy‐1.1+ lymphoid cells and about 70% of the Thy‐1.1+ cells expressed CD5, CD2 and leukosialin. The percentages of cells expressing pre‐B cell, B cell and myeloid determinants were < 20%. The developing thymocytes comprised CD4−CD8− T cell receptor (TcR) α/β−, CD4−CD8+TcR α/βlow and CD4+CD8+TcR α/βlow cells, indicating that the early stages of rat thymopoiesis occurred within mouse thymic lobes. Limiting dilution assays showed that 50% of positive assays were obtained with 3000 nucleated bone marrow cells, which is in good agreement with recent estimates derived from in vivo reconstitution after intrathymical transfer. Moreover the limiting dilution assays proved to be sensitive enough to evidence a tenfold enrichment of pre‐T cell activity in the low‐density fraction of rat bone marrow. This xenogeneic system might greatly facilitate studies on prethymic and intrathymic stages of rat T cell development and permit new in vitro approaches of the colonizing bone marrow T cell precursor properties.
Expression of T cell receptor genes in the thymus: localization of transcripts in situ and comparison of mature and immature subsets
Authors: Held Werner , Mueller Christoph , MacDonald H. Robson 
Published: March 2007

AbstractWe have analyzed the expression of T cell receptor (TcR) genes in the thymus using in situ RNA hybridizations with probes to the constant regions of the TcR α, β, γ and δ chains. Localization of transcripts revealed low TcR α mRNA levels in the thymus cortex and very low levels in the subcapsular region. In contrast, TcR β message was very abundant in the cortex. TcR γ or δ mRNA+ thymocytes showed a scattered, predominantly cortical localization. In contrast to γ, TcR δ transcripts were abundant in the subcapsular region. Control experiments with sorted TcR α/β or γ/δ cells revealed a detection efficiency of 75%–85% for the respective TcR mRNA and data on TcR gene expression in mature, CD3+ thymocytes were consistent with previous reports. The analysis of immature, CD3− thymocyte subsets, however, revealed a virtual absence of TcR α transcripts and an unexpectedly high proportion of cells (14%–29%) expressing the gene for the TcR δ chain. The data are discussed in view of current models of lineage relationships in the thymus.
Detection of interleukin 8 biological activity in synovial fluids from patients with rheumatoid arthritis and production of interleukin 8 mRNA by isolated synovial cells
Authors: Brennan Fionula M. , Zachariae Claus O. C. , Chantry David , Larsen Christian G. , Turner Martin , Maini Ravinder N. , Matsushima Kouji , Feldmann Marc 
Published: March 2007

AbstractThe presence of neutrophils in the synovial joint of patients with rheumatoid arthritis (RA) is thought to be due to the activity of chemotactic factors released by activated cells in the joint. We have shown in this report, for the first time, the abundance of one such factor, interleukin 8 (IL 8), in the synovial fluid of patients both with RA and other non‐RA joint diseases, and the spontaneous production of IL8 mRNA by RA synovial cells in culture. There was no correlation between the levels of chemotactic activity and IL8 protein, suggesting that other factors with similar neutrophil chemotactic activity are also present in the synovial fluid exudate. In support of this concept neither the level of chemotactic activity nor IL8 protein levels correlated with neutrophil or leukocyte infiltration, indicating that the mechanism of migration into the inflammatory environment of the joint is complex. Such migration is likely to be due to a number of chemotactic signals in addition to IL8, which may either synergize with, or inhibit, the action of IL8.
Analysis of the immune‐encodrine feedback loop in the avian system and its alteration in chickens with spontaneous autoimmune thyroiditis
Authors: Brezinschek Hans P. , Faessler Reinhard , Klocker Helmut , Kroemer Guido , Sgonc Roswitha , Dietrich Hermann , Jakober Rosanna , Wick Georg 
Published: March 2007

AbstractIn both mammals and chickens, immunization with exogenous antigens results in a surge of serum glucocorticoid hormone levels concomitant with the antibody response. This effect is mediated by glucocorticoid‐increasing factors (GIF) produced by cells of the immune system. In the avian system, GIF appear to act via the hypothalamo‐pituitary axis and not directly on the adrenal gland. Interleukin 1 is the main active substance responsible for GIF activity, as shown by molecular sieve and immunoaffinity chromatography studies. In contrast to data from mammals, we found no evidence that interleukin 2 elevates chicken corticosterone.Obese strain chickens with spontaneous Hashimoto‐like autoimmune thyroiditis are deficient in their in vivo GIF response. Because no differences were found between autoimmune and healthy chickens in the corticosterone response of the adrenal gland after ACTH administration, and since autoimmune animals are able to react normally to immobilization stress, it is assumed that this deficiency is due to a specific defect rather than a general disturbance in the endocrine system.
The activation of resting lymphocytes is accompanied by the biogenesis of lysosomal organelles
Authors: Olsen Irwin , Bou‐Gharios George , Abraham David 
Published: March 2007

AbstractThe degradative activity of lymphocytes plays by important role in a number of essential immune functions. In the present study we have examined how the activation of resting lymphocytes, by the mitogen concanavalin A (Con A), affects three major components of the lysosomal compartment: the lysosomal enzyme β‐glucuronidase (Gus); an integral lysosomal membrane protein (LAMP‐1); and the mannose 6‐phosphate receptor (MPR) which directs lymphocyte enzyme transport. Resting T cells were found to contain only very low levels of these proteins, but they were actively synthesized by, and far more abundant in, stimulated lymphoblasts. Although the lysosomal antigens did not have a distinct cytoplasmic localization in the resting lymphocytes, in the activated T lymphoblasts they were present in several highly developed intracellular structures, including the rough endoplasmic reticulum and the Golgi complex. Furthermore, in these latter cells Gus was also found to be accumulated within the lumen of large vesicles which we characterized as lysosomes by the presence of LAMP‐1 at the periphery and by the absence of MPR. Subcellular fractionation confirmed that these organelles were present in the activated lymphocytes only, and not in the resting T cells. Our results demonstrate that lymphocyte activation is accompanied by the synthesis of the enzymic and structural components of the lysosomal compartment which are sorted and assembled into distinct organelles in the activated cell.
Human IgE mRNA expression by peripheral blood lymphocytes stimulated with interleukin 4 and pokeweed mitogen
Authors: Qiu Gang , Gauchat Jean‐Francois , Vogel Monique , Mandallaz Michele , de Weck Alain L. , Stadler Beda M. 
Published: March 2007

AbstractExpression of human IgE mRNA by peripheral blood lymphocytes (PBL) and an IgE‐producing myeloma cell line, U‐266, was examined by Northern blot hybridization and compared with IgE levels in culture supernatants. A 2.35‐kb IgE mRNA was detected in unstimulated atopic PBL and U‐266 cells but not in normal PBL, and its levels correlated with IgE protein levels in the supernatant. Upon stimulation with interleukin 4, a new 1.75‐kb transcript was revealed in both atopic and normal PBL but not in U‐266 cells. Its expression did not correlate with IgE levels in the supernatant. Pokeweed mitogen also induced the expression of the 1.75‐kb transcript without concomitant induction of IgE synthesis by normal PBL and even suppressed the spontaneous expression of the 2.35‐kb transcript and IgE protein synthesis by atopic PBL. Interferon‐γ, which suppressed both the 2.35‐kb transcript and IgE protein production, had no inhibitory effect on the 1.75‐kb transcript. Expression of the 1.75‐kb transcript was already high after 2 days of stimulation and peaked around day 4. The length of the transcript is smaller than that of mRNA coding for secreted human IgG and IgA and contains all four Cε exon sequences, suggesting it might be a truncated transcript without v region and might be a human counterpart of the murine germ‐line Cε transcript.
T‐T cell interactions are mediated by adhesion molecules
Authors: Brod Staley A. , Purvee Meghan , Benjamin Deborah , Hafler David A. 
Published: March 2007

AbstractThe mechanism by which T cells signal other T cells is not well defined. This was investigated by studying the ability of circulating T cells to induce the proliferation of autologous T cell clones. Peripheral blood T cells activated by cross‐linking of the CD3/T cell receptor complex, which increased the expression of cell adhesion molecules LFA‐1, LFA‐3 and ICAM‐1, induced the proliferation of autologous T cell clones. Irradiated antigen‐activated peripheral blood T cells could also induce the proliferation of T cell clones which could not recognize that antigen. T‐T cell activation required cell contact, was not major histocompatibility complex (MHC) restricted and was blocked by monoclonal antibodies directed against adhesion molecules CD2 and LFA‐3 but was not blocked by antibody to class II MHC determinants. As CD2 is the natural ligand for LFA‐3, increased expression of T cell surface adhesion molecules LFA‐1, ICAM‐1 and particularly LFA‐3 during an inflammatory response may rapidly recruit T cells that are activated through the CD2 pathway. These results allow a simplified model to explain how relatively few antigen/MHC‐specific T cells can recruit large numbers of non‐antigen‐specific T cells in the generation of an inflammatory response and postulates a novel role of the CD2 molecule in T cell immune function.
Mutations in the major histocompatibility complex class I antigen‐presenting groove affect both negative and positive selection of T cells
Authors: Jacobs Heinz , Von Boehmer Harald , Melief Cornelis J. M. , Berns Anton 
Published: March 2007

AbstractIn several transgenic mouse models T cell development was shown to be controlled by the binding of the α/β T cell receptor (TcR) to ligands in the thymus. In transgenic mice expressing a male‐specific TcR α/β, the presence of the restricting Db major histocompatibility complex (MHC) molecule plus the male specific peptide deleted thymocytes at an early stage of development. On the other hand, maturation of T cells required an interaction of the TcR with the thymic Db MHC molecules in the absence of specific peptides. This could imply that negative and positive selection of this receptor are affected differently by mutations in the HY peptide‐binding groove of the Db MHC molecule. Such mutants have been isolated and were shown to affect the response to HY antigen in that both the bm14 (residue Glu70 → Asp) and the bm13 (residue Leu114 → Glu, Phe116 → Tyr and Glu119 → Asp) strains do not normally mount cytotoxic responses to male cells. Here we show that these mutations affect antigenicity of male cells, as well as negative and positive selection of T cells in TcR α/β transgenic mice.
Differential responsiveness to CD3‐Ti vs. CD2‐dependent activation of human intestinal T lymphocytes
Authors: Pirzer Ursula C. , Schürmann Guido , Post Stefan , Betzler Michael , Meuer Stefan C. 
Published: March 2007

AbstractHuman lamina propria lymphocytes were recovered from surgical specimens of unaffected large bowel and compared with peripheral blood lymphocytes (PBL) from the same individual. We investigated their capacities to respond to triggering stimuli delivered by mitogenic monoclonal antibodies directed at the T cell receptor/CD3 complex or, alternatively, the CD2 glycoprotein. In marked contrast to PBL, expression of the interleukin 2/interleukin 2 receptor system was markedly reduced in LPL following activation through the CD3/T cell receptor. Perhaps, more important, responses to CD2 triggering were similar or even stronger in LPL as opposed to PBL. This indicates that the CD2‐dependent alternative pathway of T cell activation might serve a functional role in local immunity in the gut.