bluuebunny/crossref_metadata_2025_split huggingface dataset:
T cell activation: distinct pathways involve phosphorylation of different cellular proteins
Authors: Peyron Jean‐François , Pont Suzanne , Pierres Michel , Fehlmann Max 
Published: March 2007

AbstractThe murine T cell clone D10.G4.1 can be induced to proliferate by monoclonal antibodies (mAb) to the T cell receptor (TcR) or to Thy‐1 molecules. When cells were stimulated by anti‐TcR mAb, a group of 4 proteins (19–25 kDa) was specifically phosphorylated. This effect was completely mimicked by the Ca2+ ionophore A23187, whereas only two of these proteins (19 kDa and 25 kDa) were phosphorylated after cell exposure to the phorbol ester 12‐O‐tetradecanoylphorbol 13‐acetate. By contrast, anti‐Thy‐1 mAb had no effect on the phosphorylation of these proteins, but induced specifically the phosphorylation of a protein of 32 kDa. These results therefore demonstrate that distinct activating pathways in T cells involve the phosphorylation of different proteins, suggesting that the stimulation of protein kinases in T lymphocytes is an early event in cell activation.
The regulation of IgG subclass production in man: low serum IgG4 in inherited deficiencies of the classical pathway of C3 activation
Authors: Bird Prudence , Lachmann Peter J. 
Published: March 2007

AbstractHuman serum IgG subclasses have been measured by a sensitive enzyme‐linked immunoassay in 52 subjects with severe genetic deficiency of a complement component. The mean serum IgG4 in 4 subjects with C3 deficiency was 8.2 γg/ml and in 14 subjects with (C1‐4 deficiency was 27.9 γg/ml. These means are severely depressed compared with the mean normal IgG4 of 292 γg/ml. IgG4 levels in C5‐9 deficiency (175 γg/ml) and ClINH deficiency (179 γg/ml) did not differ significantly from normal. Serum IgG2 was reduced significantly, but far less severely than IgG4, in C3 and in some cases of C1‐4 deficiency. IgGl and IgG3 levels were within the normal range in all complement‐deficient groups. Age differences between the groups do not explain the very low levels of IgG4 in C1‐4 and C3 deficiency. These data suggest that serum IgG4 synthesis is dependent on an intact classical, but not alternative, pathway for activation of C3 and that IgGCcommitted B cells require a complement‐dependent maturation pathway not required by B cells committed to other IgG isotypes. IgG4 antibody responses are associated with secondary responses to T‐dependent antigens. The possibility that IgG4 may be the product of a memory B cell which has been through a stage of differentiation in a germinal centre is discussed.
Expression of CR2/EBV receptors on human thymocytes detected by monoclonal antibodies
Authors: Tsoukas Constantine D. , Lambris John D. 
Published: March 2007

AbstractThe biologic effects of the third component of complement, C3, are mediated via receptors which specifically bind the enzymatic degradation products resulting from the cleavage of C3. One of the products, C3d, has been associated with binding to the second complement receptor CR2 (CD21). This receptor, which is identical to the receptor for Epstein‐Barr virus (EBV), has been primarily found on cells of the B lineage, but not on mature T cells or other cells of erythroid or myeloid lineages. In the present investigation, we report the presence of CR2 on human thymocytes. Indirect immunofluorescence analysis employing monoclonal anti‐CR2 antibodies revealed a range of thymocyte reactivity from 15% to 63% in thirteen experiments using cells of different donors. Reactivity was always greater with the monoclonal anti‐CR2 (CD21) antibody HB‐5 than with two other antibodies which recognize distinct epitopes on the CR2 molecule. Two‐color immunofluorescence analysis indicated that the brightest of the HB‐5‐stained thymocytes also reacted with the monoclonal anti‐CD1 antibody T6 (immature thymocyte marker) while some of the duller HB‐5‐staining cells reacted with the monoclonal anti‐CD3 antibody Leu‐4 (mature thymocyte marker). Immunoprecipitation of CR2 on thymocytes with antibody HB‐5 and polyacrylamide gel electrophoretic analysis revealed a protein of 145 kDa molecular mass which is consistent with the size of CR2 found on B lymphocytes. These findings raise several questions regarding the biologic role of CR2‐EBV receptor on cells of the T lineage.
Low doses of interleukin 2 induce bystander cell lysis by antigen‐specific CD4 inflammatory T cell clones in short‐term assay
Authors: Gromkowski Stanislaw H. , Hepler Kristin M. , Janeway Charles A. 
Published: March 2007

AbstractThe effect of recombinant interleukin 2 (rIL2) and interferon‐γ (IFN‐γ) on the cytolytic activity of a CD4 class I1 major histocompatibility complex‐ovalbumin (OVA)‐specific murine clone called 5.8.6 was examined. Low doses of IL2 (0.1–1.0 U/ml) induce clone 5.8.6 to kill in an antigen‐independent fashion in short‐term 51Cr‐release and 3H‐release assays (6–12 h). Targets killed by 5.8.6 cells include P815, YAC‐1 and B lymphoma cells. IFN‐γ, alone or in combination with IL2, has no effect. 5.8.6 and similar inflammatory CD4 T cell clones have been shown to lyse bystander target cells in the presence of a specific stimulator target. We propose that killing of bystander targets by clone 5.6.8 is due to nonspecific cytolytic activity induced by the clone's own IL2 secreted in response to recognition of the specific target.
Inhibition of interleukin 2‐induced proliferation of cloned murine T cells by glucocorticoids. Possible involvement of an inhibitory protein
Authors: Redondo Juan Miguel , Fresno Manuel , López‐Rivas Abelardo 
Published: March 2007

AbstractThe ability of glucocorticoids to inhibit interleukin 2 (IL2)‐induced T cell proliferation in two cytotoxic T cell (CTL) clones has been studied. A complete inhibition of DNA synthesis by dexamethasone (Dx) could be observed when IL2‐depleted cultures of CTL were either incubated for 6 h with the hormone prior to the addition of IL2 or treated simultaneously with Dx and a low concentration of IL2. No significant reduction in the number and affinity of IL2 receptors was seen after 6 h incubation with Dx. The order of potency observed with the different steroids indicated that this inhibitory effect was mediated through binding to a specific glucocorticoid receptor. The action of these hormones possibly involves the synthesis of an inhibitory protein(s), since the presence of cycloheximide during the incubation with Dx prevented the inhibition of DNA synthesis. Furthermore, supernatant from Dx‐treated CTL contained a nondialyzable factor which inhibited DNA synthesis and cell growth of CTL clones induced by IL2. Blocking of IL2 synthesis and IL2 receptor formation have been proposed as one of the major mechanisms of glucocorticoid‐induced immunosuppression. Our results indicate that these hormones may also affect T cell proliferation by inhibiting IL2 activity.
A predominant idiotype independent of specificity, or Ig and H‐2 allotypes, is found in the primary but not the secondary murine antibody response to lysozyme
Authors: Kaplan Mark A. , Keller Margaret A. , Hsu Di‐Hwei , Ch'Ng Lean‐Kuan , Miller Alexander , Sercarz Eli E. 
Published: March 2007

AbstractRemoval of just the three N‐terminal residues Lys‐Val‐Phe (TIP) on hen egg white lysozyme (HEL), by aminopeptidase cleavage, eliminates an antigenic determinant which is a recurrent and dominant focus of primary but not secondary antibody responses to HEL in a variety of mouse strains. We have generated an anti‐idiotypic rabbit antiserum against such a TIP‐dependent monoclonal antibody (mAb). This antiserum reacts with many different primary anti‐HEL mAb, but fails to react with all of a variety of secondary anti‐HEL mAb. The idiotype defined by this antiserum, termed IdXE, is a common feature of early anti‐HEL antibody responses but does not appear in secondary responses. Although the presence of IdXE and TIP dependence is correlated in primary responses, studies of idiotype expression on mAb and on plaque‐forming cells (PFC) using mixed erythrocyte monolayers clearly show that at the single‐cell level the properties are separable, ie., not all TIP‐recognizing PFC display IdXE and a sizable proportion of cells producing non‐TIP‐dependent antibodies are IdXE+. The restricted idiotypy and specificity of early antibody responses to HEL occur in each of eight diverse mouse strains tested: it is not associated with a particular MHC haplotype, heavy chain allotype or light chain allotype. The finding of such strain‐independent restriction in the early response pattern to a typical protein antigen is novel and suggests the involvement of highly conserved, potent regulatory mechanisms which are manifested as a limitation in the initial expression of the available repertoire.
Interferon‐γ and tumor necrosis factor induce the L‐arginine‐dependent cytotoxic effector mechanism in murine macrophages*
Authors: Drapier Jean‐Claude , Wietzerbin Juana , Hibbs John B. 
Published: March 2007

AbstractWe tested several monokines and muramyl dipeptide (MDP) to determine whether they induce the L‐arginine‐dependent effector mechanism in cultured murine macrophages. Recombinant interferon‐γ (rIFN‐γ) and recombinant tumor necrosis factor (rTNF) synergize to induce nitrite (NO2−) and nitrate (NO3−) synthesis from L‐arginine as well as to cause inhibition of the iron‐dependent enzyme aconitase in macrophages. Unlike rTNF, recombinant interleukin 1 (rIL1) and rIL6/B cell stimulatory factor 2 (rIL 6/BSF‐2) did not act as cofactors when added to macrophages in the presence of rIFN‐γ. rIFN‐γ plus MDP induced the L‐arginine‐dependent effector mechanism in murine macrophages. However, induction by rIFN‐γ plus MDP was inhibited by anti‐rTNF antibodies which suppressed both NO2−/NO3− synthesis and aconitase inhibition. This result indicates that endogenously produced TNF is involved in the induction of the L‐arginine‐dependent effector mechanism when MDP is the co‐stimulant with rIFN‐γ. In contrast, anti‐rTNF antibodies did not fully suppress the effect of combining rIFN‐γ and lipopolysaccharide, suggesting that, in this case, activation of the L‐arginine‐dependent effector pathway may involve more than induction of TNF synthesis by the macrophages. These results provide information, at a biochemical level, on a mechanism through which combination of IFN‐γ and TNF can modulate macrophage functions involved in the control of cell proliferation.
Studies on the release of cell‐associated interleukin 1 by paraformaldehyde‐treated murine macrophages
Authors: Streck Helmut , Günther Christian , Ulrich Beuscher Horst , Röllinghoff Martin 
Published: March 2007

AbstractExperiments are presented demonstrating the release of interleukin 1 (IL1) by lipopolysaccharide‐stimulated murine macrophages (Mϕ) after treatment of the cells with paraformaldehyde (PFA). The IL 1 activity set free was completely blocked by a rabbit anti‐mouse IL 1α antiserum. Immunoprecipitation studies revealed that the IL 1 released was of Mr 33 kDa, 23 kDa and 17 kDa. Incubation of PFA‐treated Mϕ in the presence of leupeptin reduced the amount of detectable low molecular mass (i.e. 23 kDa and 17 kDa) IL lα. Addition of leupeptin to PFA‐treated Mϕ also reduced the amount of released IL 1 activity, suggesting that proteolytic modification of the IL lα precursor is involved in the generation of biological active IL lα. It is proposed that the cell‐associated 33‐kDa IL 1 is released from the Mϕ by vesiculation of parts of the Mϕ cell membrane, followed by a proteolytic cleavage step.
Clonal analysis of CD4 CD8‐ human thymocytes expressing a T cell receptor γ/δ chain. Direct evidence for the de novo expression of CD8 surface antigen and of cytolytic activity against tumor targets*
Authors: Mingari Maria Cristina , Varese Paola , Bottino Cristina , Melioli Giovanni , Moretta Alessandro , Moretta Lorenzo 
Published: March 2007

AbstractCD4−CD8− human thymocytes were obtained by treating total thymocyte suspensions with antiCD4 and anti‐CD8 monoclonal antibodies (mAb) and complement. The resulting cell populations contained virtually no CD4+, CD8+ or WT31+ cells and 17–65% CD3+ cells. In addition, analysis of cell reactivity with delta‐TCS‐1 mAb (specific for the Cγ2‐encoded, nondisulfide‐linked form of TcR γ/δ), revealed the presence of a variable proportion of δ‐TCS‐1+ cells (the % of δ‐TCS‐1+ cells were lower than the percentage of CD3+ cells). Upon culture in recombinant interleukin 2 (IL2, in the presence of irradiated mononuclear cells), CD4−CD8− thymocytes underwent extensive proliferation. In addition, a progressive increase of CD8+ cells (but not of CD4+ or WT31+ cells) could be detected. Cells also progressively acquired cytolytic activity against K‐562 or fresh melanoma cells. Fresh CD4−CD8− thymocytes were cloned under limiting dilution conditions. The cloning efficiencies were relatively high (1/3 cells); in addition, virtually all the clonal progenies obtained displayed cytolytic activity and expressed the CD3+WT31−δ‐TCS‐1+ surface phenotype. About half of the clones analyzed were CD8+, whereas none expressed CD4 antigens. We conclude that (a) only δ‐TCS‐l‐reactive, TcRγ/δ+ cells can be isolated from CD4−CD8− thymocytes cultured in IL2, and (b) the expression of CD8 antigen and of cytolytic activity reflects a true in vitro phenotypic change of CDK, noncytolytic precursors (and not the preferential growth of few contaminating cells).
Interferon‐gamma protects human endothelial cells from lymphokine‐activated killer cell‐mediated lysis
Authors: Renkonen Risto , Ristimäki Ari , Häyry Pekka 
Published: March 2007

AbstractIn adoptive immunotherapy the lymphokine‐activated killer (LAK) cells, known to be cytotoxic to many tumor cell lines, are injected i.v. into tumor‐bearing animals or cancer patients. However, in addition to a significant reduction in tumor masses, complications occur in many cases, most severe of which are the vascular leak syndrome and hypotension. In this report we show that LAK cells are also cytotoxic to normal vascular endothelial cells, which may partly contribute to these complications. Incubation of the endothelial cells with interferon‐gamma (IFN‐Γ), but not with inter‐leukin 1 (IL1) or tumor necrosis factor, protects the endothelial cells from LAK‐mediated lysis in a dose‐ and time‐dependent manner. The protective effect is abolished by monoclonal antibody against IFN‐γ. However, the IFN‐γ treatment does not protect LAK‐sensitive tumor cell lines from LAK‐mediated lysis. Concomitantly IFN‐γ also induces both class I and class II antigens on endothelial cells. The induction of these major histocompatibility complex (MHC) antigens does not explain the protective effect: timewise, the protection is complete already within 24 h after addition of IFN‐γ to endothelial cell culture, whereas the induction of MHC antigens peaks at 72 h, and antibodies against these antigens are not able to abolish the protective effect.
Specificity of proliferative response of human CD8 clones to mycobacterial antigens
Authors: Rees Ann , Scoging Anne , Mehlert Angela , Young Douglas B. , Ivanyi Juraj 
Published: March 2007

AbstractHuman CD8 T lymphocyte clones (TLC) were generated from the pleural effusion of patients with tuberculosis using a protocol that required, in addition to antigen, co‐culture of purifed CD8+ T cells, accessory cells, interleukin 2 (IL2) and anti‐CD3‐Sepharose. The TLC obtained were stimulated by mycobacterial soluble extracts in an IL2‐dependent and MHC class I‐restricted manner. When antigen‐responsive TLC were screened with extracts from the recombinant mycobacterial library they were found to respond to either the Y3125 (100‐kDa) or the Y3111 (71‐kDa) λgt11 clones. Polyacrylamide gel immunoblot analysis demonstrated that the CD8 TLC responded to fractions with the molecular mass range 27–45 kDa in the Y3125 lysogen and 60–90 kDa in the mycobacterial soluble extract. The specificity of TLC reactive with the Y3111 clone was confirmed using the 71‐kDa antigen purified from the same lysogen. These TLC recognized sequences common to the 71‐kDa protein derived from mycobacteria, E. coli or a human cell line. Studies of three TLC using antigen‐presenting cells of known genetic haplotype indicated that stimulation with both the Y3125 and the 71‐kDa antigens were restricted by determinants encoded by HLA‐B8.
Class I alloantigen is sufficient for cytolytic T lymphocyte binding and transmembrane signaling
Authors: Kane Kevin P. , Goldstein Steven A. N. , Mescher Matthew F. 
Published: March 2007

AbstractBased largely on antibody blocking studies, a number of surface “accessory” molecules on effector cytolytic T lymphocytes (CTL) have been implicated as having a role in mediating CTL binding and lysis of target cells, possibly via binding to ligands on the target cell surface. Despite this, cloned allogeneic CTL were able to specifically bind cell‐size, artificial membranes (pseudocytes) bearing only class I alloantigen. This binding triggered CTL degranulation, as measured by serine esterase release. Thus, class I alloantigen alone is both a necessary and sufficient ligand for specific binding and effective transmembrane signaling to occur.
Postnatal B cell development: influence of trinitrobenzenesulfonic acid treatment during pregnancy
Authors: Zöller Margot 
Published: March 2007

AbstractPrenatal treatment with a reactive hapten may be well suited for analyzing the establishment of self tolerance because the hapten binds ubiquitously to proteins and cells and persists for a long period in the developing organism. Based on this consideration, pregnant BALB/c mice were treated with 2,4,6‐trinitrobenzenesulfonic acid (TNBS), searching for differences in 2,4,6‐trinitrophenyl (TNP) responsiveness in their offspring as compared to litters of untreated mice.The frequency of TNP‐specific T‐independent B cells of litters from TNBS‐treated mothers was very low at birth and remained below 10% of controls until the age of 42 days. On the contrary, in 8‐day‐old prenatally TNBS‐treated litters, the frequency of TNP‐specific T‐dependent B cells was higher than in controls. Expansion of TNP‐specific B cells after antigenic stimulation of control mice started at the age of 3–4 weeks and expansion rates increased with age, while in prenatally TNBS‐treated mice, significant expansion rates were seen at the age of 2 weeks only. Yet, after restimulation with TNP‐lipopolysaccharide or with a TNP‐anti‐TNP conjugate, but not after restimulation with TNP‐ovalbumin, similar numbers of plaque‐forming cells (PFC) were observed with spleen cells of prenatally untreated and TNBS‐treated mice, the latter revealing an exceptional predominance of IgG PFC.Thus, TNP‐specific B cells were not deleted, but prenatal TNBS treatment resulted in an altered compositon of TNP‐specific B cell subpopulations, their regulation differing qualitatively from the one observed in prenatally untreated mice.
Concomitant production of different lymphokines in activated T cells
Authors: Andersson Ulf , Sander Birgitta , Andersson Jan , Möller Goran 
Published: March 2007

AbstractThe intracellular accumulation of five different lymphokines in individual cells could be identified by lymphokine‐specific antibodies and an indirect immunofluorescence technique with UV microscopy. When peripheral blood mononuclear cells from one healthy donor were activated in vitro by the T cell mitogen anti‐CD3 monoclonal antibody, the maximal number of cells producing interleukin (IL)2, IL6 or tumor necrosis factor (TNF)−α occurred 6 h after initiation of the cultures, while peak numbers of interferon‐γ, TNF‐β and a second wave of TNF‐α‐synthesizing cells were noted approximately 20 h later. By performing two‐color immunofluorescence studies we observed a variegated production pattern with cells making no, one or several lymphokines simultaneously. All five cytokines accumulated in the Golgi organelle resulting in a very characteristic morphology of the staining with or without additional cytoplasmic immunofluorescence.
Expression and functional role of CD23 on T cells
Authors: Armitage Richard J. , Goff Lindsey K. , Beverley Peter C. L. 
Published: March 2007

AbstractWe have found that approximately 10%–15% of tonsil, but not peripheral blood, T cells express the CD23 antigen following activation with 12‐O‐tetradecanoylphorbol 13‐acetate (TPA), phytohemagglutinin (PHA) or recombinant interleukin 4. The proliferative response of tonsil T cells is significantly increased when CD23 monoclonal antibodies (mAb) are present in the cultures. In contrast, no such proliferative augmentation is seen when peripheral blood T cells are cultured in this way. Supernatant (SN) of Epstein‐Barr Virus‐transformed B lymphoblastoid cell lines (EBVLCL), is found to have a similar co‐stimulatory effect on the proliferation of tonsil T cells to that seen with CD23 mAb. This effect is greatly diminished by preclearing SN with CD23 mAb. Similarly, SN from a CD23 L cell transfectant augments the proliferative response of tonsil T cells to both TPA and PHA. The CD23 molecule expressed by TPA‐driven T cell blasts appears identical in size to the 45‐kDa glycoprotein present on EBVLCL and activated B cells. In constrast, a 42‐kDa molecule is observed when CD23 is precipitated from T cells activated with PHA. The results presented here demonstrate that CD23 is expressed on activated tonsil, but not peripheral blood T cells and plays a role, via the binding of CD23 mAb and CD23 material, present in EBVLCL and CD23 transfectant SN, in the regulation of T cell proliferation in response to mitogens such as PHA and TPA.
Human lamina propria lymphocytes bear homing receptors and bind selectively to mucosal lymphoid high endothelium
Authors: Jalkanen Sirpa , Nash Geoffrey S. , Toyos Juan De Los , Macdermott Richard P. , Butcher Eugene C. 
Published: March 2007

AbstractIt has been hypothesized that the selective recognition of tissue‐specific endothelial cell molecules helps determine the in vivo distribution of lymphoid effector cells by controlling the extravasation of their circulating precursors. Here we report (a) immunofluorescence studies of the cell surface phenotype of human lamina propria lymphocytes (LPL), including staining with monoclonal antibody Hermes‐1, which defines a 90‐kDa lymphocyte surface glycoprotein involved in recognition of high endothelial venules (HEV); and (b) functional analyses of the ability of LPL to bind to HEV in frozen sections of mucosal lymphoid tissues (appendix or Peyer's patch) vs. peripheral lymph nodes. Essentially all LPL bear the Hermes‐1 antigen, over 90% at levels comparable to those of circulating PBL. As a population, LPL display a quantitative preference for adherence to mucosal HEV, binding 0.8–1.5 times as well as PBBL to mucosal HEV, but only 0.1–0.5 times as well to HEV in peripheral lymph nodes. Of particular interest was the behavior of the lymphoblast fraction, which typically constituted 3–7% of LPL. These cells, defined by size, consisted of a mixture of T cells and surface IgA blasts. One hundred percent were Hermes‐1bright, and they bound 4–8 times more efficiently to mucosal HEV than PBL while failing to bind detectably to lymph node HEV. LPL binding to mucosal HEV involves the gp90Hermes, since the monoclonal anti‐gp90 antibody, Hermes‐3, and a polyclonal anti‐gp90 antiserum inhibit the binding of small LPL and of LP blasts. The remarkable efficiency and specificity of binding by LP blasts may reflect retention of homing properties of the blood‐borne precursors of these blasts and is discussed in relation to the capacity of immunoblasts in mesenteric nodes and in thoracic duct lymph to traffic selectively to mucosal lymphoid and extralymphoid sites. The demonstration of organ‐specific endothelial cell recognition by LP lymphoblasts provides considerable support for the concept that selective interactions with endothelium play an important role in directing the distribution of activated lymphocyte subsets in vivo.