bluuebunny/crossref_metadata_2025_split huggingface dataset:
The commitment of secretory cells to the selective expression of immunoglobulin CH genes is determined by the available concentrations of the triggering ligand
Authors: Primi Daniele , Viale Giovanna , Cazenave Pierre‐André 
Published: February 2007

AbstractThe property of lipopolysaccharide to induce B cells to both proliferate and differentiate to IgM, IgG3 and IgG2b expression can be ascribed either to a precommitted sequence of molecular events in the activated B cells or, alternatively, to separate activities which independently modulate the two events. To discriminate between these two possibilities we have investigated the relationship between the doses of the polyclonal stimulus and the commitment of the activated cells to proliferate and to produce various isotypes.Low doses of ligand supported proliferation as well as IgM but not IgG2b secretion. On the contrary, high doses of the same ligand were less efficient in supporting proliferation but strongly induced heavy chain class switch. The effect of lipopolysaccharide concentrations on CH genes expression decayed with the distance from μ to the respective Cγ gene.Although we could define different B cell subsets on the basis of their proliferative response to various doses of the ligand, all these B subpopulations were found to be multipotential in terms of their switching capacity.Taken together our data show that in lipopolysaccharide cultures B cell proliferation and heavy chain switch are two events completely dissociable on the basis of their inducing requirements.
Selective elimination through a cytolytic mechanism of bovine serum albumin‐specific T helper lymphocytes by T suppressor cells with the same antigen specificity
Authors: Heuer Joachim , Kölsch Eckehart 
Published: February 2007

AbstractAn antigen‐specific T suppressor cell clone isolated from a CBA/J mouse tolerized to low doses of bovine serum albumin (BSA) has previously been analyzed with regard to its effector functions. The T suppressor cell clone HF1 specifically inhibits T helper cell responses to the antigen. It also has characteristic cytolytic activity which can neither be classified as cytotoxic T cell nor as natural killer cell activity. Since this lytic capacity might be of relevance in immunoregulation, it has now been studied in more detail. For that purpose BSA‐specific T cell lines have been isolated from immune CBA/J mice in order to test them in 51Cr‐release assays as possible targets for HF1 T suppressor cells. Two T cell lines, both BSA specific and restricted to recognition of I‐Ek major histocompatibility complex determinants, have been selected for the studies because one is a helper cell (83/1), the other a suppressor cell type (83/2). HF1 T cells are able to lyse cells of line 83/1 but not those of line 83/2. Control experiments show that 83/1 cells are not a natural killer cell target and that on the other hand 83/2 cells are susceptible to lysis in an alloreactive BALB/c anti‐CBA/J cytotoxic T cell response. The extent of lysis of 83/1 T cells by HF1 T cells changes with time after antigenic stimulation. The lysis is based on direct effector: target cell interaction and not caused by soluble mediators. The data are discussed with regard to the effector function of a type of T suppressor cells which expresses I‐A and I‐E molecules and whose proliferation is restricted to the recognition of I‐A or I‐E determinants.
Effects of pyocyanine, a blue pigment from Pseudomonas aeruginosa, on separate steps of T cell activation: Interleukin 2 (IL 2) production, IL 2 receptor formation, proliferation and induction of cytolytic activity
Authors: Mühlradt Peter F. , Tsai Hsin , Conradt Peter 
Published: February 2007

AbstractPyocyanine was isolated by chloroform extraction of cultures of Pseudomonas aeruginosa, and purified by thin layer chromatography. The effects of pyocyanine on the various stages of T cell activation were studied with concanavalin A‐stimulated CBA/J mouse splenocyres. At 12.5 μM concentration pyocyanine totally inhibited Con A‐dependent prolifzration and development of cytotoxic effector cells. Protein and RNA synthesis was only 50% inhibited at this concentration. Inhibitory doses of pyocyanine were nontoxic, in that cell viability was maintained, and the inhibitory effects were reversible after removal of the drug. Pyocyanine did not interfere with interleukin 2 synthesis, nor did it affect the lytic stage of cytotoxic effector T cells. However, T blasts generated by Con A in the presence of pyocyanine did not grow in response to IL2 even in the absence of pyocyanine, and IL2 receptors, detected by indirect immunofluorescence with the receptor‐specific monoclonal antibody AMT‐13, were diminished in pyocyanine‐treated cells. Pyocyanine also inhibited IL2‐dependent proliferation of T blasts with fully developed IL2 receptors. The substance thus interferes with several discrete stages of T cell activation.
Influence of carriers on the development and localization of anti‐2,4,6‐trinitrophenyl (TNP) antibody‐forming cells in the murine spleen: II. Suppressed antibody response to TNP‐Ficoll after elimination of marginal zone cells
Authors: Claassen Eric , Kors Nel , Van Rooijen Nico 
Published: February 2007

AbstractThe macrophages in the marginal zones in mice spleens were eliminated by i.v. injection of dichloromethylene diphosphonate encapsulated in liposomes. After immunization with a thymus‐dependent (trinitrophenylated keyhole limpet hemocyanin; TNP‐KLH) or thymus‐independent type 1 (TNP‐lipopolysaccharide) antigen, no differences in antibody responses in treated and untreated mice were observed. However, immunization with a thymus‐independent type 2 (TI‐2) antigen (TNP‐Ficoll) resulted in a strong decrease of the antibody response in macrophage‐depleted animals. Anti‐TNP serum levels dropped 10‐fold and the number of antibody‐forming cells in the spleen 30‐60‐fold. These results confirm the special role of the marginal zone macrophages in the processing of TI‐2 antigens, as earlier suggested in splenectomy studies.
Presentation of alloantigens by host cells
Authors: Sherwood Rosemary A. , Brent Leslie , Rayfield Lee S. 
Published: February 2007

AbstractPresentation of alloantigens by host cells has been examined in vivo by means of a murine cell transfer system. Primary (1°) hosts were activated by the i.p. administration of allogeneic spleen cells and their spleen or peritoneal cells were transferred into syngeneic secondary (2°) hosts 3 days later. Sensitization of 2° hosts was assessed by their ability to reject donor strain skin grafts prematurely. The transferred cells were routinely depleted of T lymphocytes. We show that (a) 5 × 107 spleen and 3 × 106 peritoneal cells consistently caused marked accelerated graft rejection; (b) this effect was antigen specific and observable in all strain combinations studied; (c) it was caused by the active sensitization of 2° hosts, but not by contaminating donor strain cells; (d) the cells involved were plastic adherent and viability was not a requirement; and (e) both class I and II, but not minor, histocompatibility antigens played a role in this model. We conclude that presentation of alloantigens by host antigen‐presenting cells can be a potent route of allosensitization.
IgE antibody and resistance to infection II. Effect of IgE suppression on the early and late skin reaction and resistance of rats to Schistosoma mansoni infection
Authors: Kigoni Emmanuel P. , Elsas Pedro P. X. , Lenzi Henrique L. , Dessein Alain J. 
Published: February 2007

AbstractMost helminth parasites induce a strong IgE antibody and elevated eosinophil response in their mammalian hosts and a number of in vitro studies have suggested that IgE, possibly in association with eosinophils, may be an essential element of the host protective immunity against helminth infections. To assess the role of IgE in protective immunity, we examined the effect of suppressing the IgE antibody response on rat immunity to Schistosoma mansoni. Suppression was achieved in neonates by injections of rabbit anti‐ϵ chain γ‐globulins, control rats received injections of unspecific γ‐globulins. IgE suppression caused a marked reduction of the inflammatory reaction that developed in the skin of immune rats at the site of a cercarial challenge: the early (30 to 60 min) wheal and flare reaction was abolished, and the late cutaneous reaction (6 to 18 h) associated with intense pruritus, edema and local eosinophilia was greatly reduced. This shows that IgE was critical to the recruitment of effector cells and molecules in the skin during the first 24 h following parasite invasion.Worms were recovered 18 to 30 days after a primary infection and 18 days after a challenge infection from IgE‐suppressed and control rats. IgE‐suppressed rats cured a first infection as rapidly as the control rats; however, they were two to three times less efficient than the controls at eliminating a second or a third challenge. These observations demonstrate that IgE antibodies are essential for the full development of rat acquired protective immunity against Schistosoma mansoni.
T lymphocytes activated by interleukin 2 alone acquire permissiveness for replication of herpes simplex virus
Authors: Braun Rudiger W. , Kirchner Holger 
Published: February 2007

AbstractNot only mitogen stimulation or mitogen stimulation in combination with interleukin 2 (IL 2) was capable of causing susceptibility of human T lymphocytes to herpes simples virus (HSV) infection, but also selective stimulation with recombinant IL 2‐induced permissiveness of T lymphocytes to HSV infection. Replication of HSV in such IL 2‐stimulated T cell cultures was shown to be restricted to a T cell subset not exceeding 5% of the total population. Furthermore, IL2 stimulation was sufficient to obtain virus replication in T cells previously infected by HSV and cultivated for several days. This could not be achieved by stimulation with mitogens such as phytohemagglutinin. The level at which virus replication was restricted in nonpermissive T cells was determined to be before immediate early gene expression as assessed by indirect immunofluorescence with monoclonal antibodies against viral proteins expressed at different stages of the viral replicative cycle.
Differentiation antigens on rhesus monkey lymphocytes II. Characterization of RhT3, a CD3‐like antigen on T cells
Authors: Nooij Frans J. M. , Jonker Margreet , Balner Hans 
Published: February 2007

AbstractA monoclonal antibody FN18 is described, which is specific for mature rhesus monkey T lymphocytes. It defines a cell surface antigen, composed of two polypeptide chains with a molecular mass of 22 and 27 kDa. In view of these and other similarities with the human T3 or CD3 antigen, it was designated as RhT3. Expression, distribution and certain functions of RhT3 were compared with those of its human counterpart. Analogous to anti‐CD3 antibodies in man, FN18 is able to modulate its target antigen, has mitogenic properties and is able to block the pokeweed mitogen and concanavalin A‐driven cell proliferation, but not that caused by phytohemagglutinin. In spite of such minor dissimilarities the available data strongly suggest that the RhT3 antigen is the rhesus monkey's homologue of the human CD3 antigen.
Characterization of human T cell‐derived IgE‐potentiating factor
Authors: Young Michael , Geha Raif S. , Maksad Kurt N. , Leung Donald Y. M. 
Published: February 2007

AbstractWe have previously shown that Fcε receptor‐positive (FcεR+) T cell lines from patients with the hyper IgE syndrome secrete IgE‐binding factors which selectively enhance IgE but not IgG synthesis in cultures of B cells obtained from patients with allergic rhinitis but not from nonatopic subject. In the present study we have tested the effect of supernatants from FcεR+ T cell lines on a large panel of B cells from atopic patients (n = 20). We found that IgE synthesis was selectively enhanced only in B cell cultures in which there was ongoing spontaneous synthesis of IgE. The target of IgE‐potentiating factor(s) was a large low‐density B cell present in the circulation of responding atopic donors. In addition, we further characterized IgE‐potentiating factors derived from FcεR+ T cell lines. The factor(s) fractionated into 2 peaks on Sephadex G‐75 with approximate molecular masses of 15000 and 60000 kDa, and had affinity for lentil lectin but not for peanut agglutinin. Release of IgE‐potentiating factor(s) was enhanced by the addition of exogenous human IgE to FcεR+ T cell cultures and was inhibited by tunicamycin, an inhibitor of N‐glycosylation. These studies suggest a close homology between the physicochemical characteristics of human and rodent IgE‐potentiating factors and the immune signals which modulate production of these IgE regulatory factors.
Idiotope‐specific T cell clones that recognize syngeneic immunoglobulin fragments in the context of class II molecules
Authors: Bogen Bjarne , Malissen Bernhard , Haas Werner 
Published: February 2007

AbstractWe have established idiotope (Id)‐specific T cell lines and clones derived from at least 4 different BALB/c mice immunized with the light chain (λ2315) of the BALB/c myeloma protein M315 (α,λ2). Independently derived clones were indistinguishable in that they reacted to Vλ2315, one or more of the amino acids corresponding to somatically mutated codons 94, 95 and 96 of the third hypervariable region being essential for expression of the Id. While the Id was efficiently expressed on Vλ2315, Fv315 and λ2315 fragments, about a 100–1000‐fold higher molar concentration of Fab315and M315 was needed to induce equivalent responses. Thus, Ig quaternary structure heavily influenced the availability of the Id for T cells. The Vλ2315‐specific T cells were Thy‐1.2+, L3T4+, Ly‐2.2− and I‐Ed restricted. Some of the T cell clones produced interleukin 2 (IL2), IL3 and B cell growth and differentiation factors upon activation. In addition, T cells were cytotoxic in long‐term assays for EE, but not EE‐transfected L cells in the presence of Id. The cytotoxic effect was the basis for an L cell growth inhibition assay for T cell activation that was at least 10‐fold more sensitive than ordinary proliferation assays.
Stable expression of Lyt‐2 homodimers on L3T4+T cell clones
Authors: Gallagher Pauline F. , de St. Groth Barbara Fazekas , Miller Jacques F. A. P. 
Published: February 2007

AbstractThe murine T lymphocyte antigen Lyt‐2 is considered to act as an accessory molecule to the class I‐restricted T cell receptor during antigen recognition. We have previously described two unusual Lyt‐2+L3T4+ class II‐restricted T cell clones whose activation by antigen is inhibited by antibodies to L3T4 but not to Lyt‐2 (B. Fazekas de St. Groth et al., Proc. Natl. Acad. Sci. USA 1986. 83: 2594). The Lyt‐2 immuno‐precipitated from one of these clones was indistinguishable from the molecule found on splenic T cells, as analyzed under reducing conditions on polyacrylamide gels, in two‐dimensional charge/size separations and in peptide mapping. The molecule from the second clone showed slightly more extensive glycosylation but was within the range described for functional Lyt‐2 on cytotoxic T cell lines. Lyt‐2 mRNA from both clones showed no abnormalities on Northern analysis. Lyt‐2 is normally expressed on thymocytes and peripheral T cells as a heterodimer disulfide bonded to the Lyt‐3 glycopeptide, yet Lyt‐3 could not be detected on the cell membranes of our clones; Lyt‐2 existed as stable homodimers without Lyt‐3. Thus Lyt‐3 is not required structurally for the spontaneous expression of Lyt‐2 on lymphoid cells.
A 93‐kDa glycoprotein expressed on human cultured monocytes and dendritic reticulum cells defined by an anti‐K562 monoclonal antibody
Authors: Farace Franjoise , Kieffer Nelly , Caillou Bernard , Vainchenker William , Tursz Thomas , Dokhelar Marie Christine 
Published: February 2007

AbstractAn IgG2a monoclonal antibody, referred to as 12B1 and raised against the K562 cell line, reacted with adherent monocytes maintained in culture for several days but not with bone marrow or peripheral blood cells including freshly isolated monocytes. Among human leukemic cell lines, 12B1 reacted essentially with the promyelocytic HL60 cell line. 12‐O‐Tetradecanoylphorbol 13‐acetate treatment, but no other differentiation inducer, strongly enhanced its reactivity on K562, HL60 and the histiocytic U937 cell line. Immunoperoxidase staining of sections of normal human tissues showed that 12B1 specifically recognized dendritic reticulum cells in germinal centers of lymph nodes, spleen and tonsils. The 12Bl‐detected antigen is a highly glycosylated polypeptide of an apparent molecular mass of 93–86 kDa. The 12B1 antigen appears to be a new glycoprotein marker shared by adherent monocytes and dendritic reticulum cells. The association of the 12B1 epitope with cells which present antigen and/or exert accessory function suggests that this molecule could play a role in these activities.
Antigen presentation in the peripheral nervous system: Schwann cells present endogenous myelin autoantigens to lymphocytes
Authors: Wekerle Hartmut , Schwab Martin , Linington Christopher , Meyermann Richard 
Published: February 2007

AbstractSchwann cells (SC) isolated from neonatal rat sciatic nerves are shown to immunogenically present foreign and exogenous autoantigen to antigen‐specific syngeneic T line cells in vitro. The antigen‐presenting SC express Ia antigens on their membranes upon treatment with interferon gamma and contact with syngeneic T line cells. Monoclonal antibodies against Ia block specific antigen presentation, but not polyclonal mitogenic T cell activation. The antigen‐presenting SC bind antibodies specific for astrocytic glial fibrillary acidic protein and may thus be related to the nonmyelinating glia cells of the peripheral nerve.Furthermore, SC isolated from 6‐day‐old rats activate rat myelin basic protein (MBP)‐specific syngeneic T line cells in the absence of exogenous MBP. In contrast, they activate purified protein derivative of tuberculin (PPD)‐specific T cells only in the presence of PPD. Since the MBP‐specific T line cells are not activated by syngeneic professional antigen‐presenting cells in the absence of MBP, endogenous MBP produced in the 6‐day‐old sciatic nerves appears to be presented by autochthonous SC to the autoreactive T cells.The Clinical Research Unit for MS is supported by funds of the Hermann‐and‐Lilly‐Schilling Foundation.
Early events in human B cell activation: metabolic pathways vary according to the first signal used
Authors: Dugas Bernard , Vazquez Aimé , Klein Bernard , Delfraissy Jean‐Francois , Rammou Marietherese , Gerard Jean‐Philippe , Galanaud Pierre 
Published: February 2007

AbstractThe effects of the calcium channel blocking drug Verapamil and of palmitoyl‐carnitin (PTC), an inhibitor of protein‐kinase C activity, on human B cell activation were measured. Both Verapamil and PTC inhibited the B cell proliferation induced by costimulation with anti‐μ antibody and with 3 different growth factors: interleukin 2, 20‐kDa B cell growth factor and 50‐kDa B cell growth factor. Both uridine and thymidine incorporation induced by costimulation with ionomycin and phorbol 12‐myristate 13‐acetate (PMA) were inhibited by Verapamil and PTC. In contrast, B cell proliferation was resistant to Verapamil (while being still inhibited by PTC) in two situations: (a) when B cells were costimulated with PMA and growth factors and (b) when B cells previously activated in vitro (by anti‐μ antibody or PMA) were stimulated with growth factors. These results confirm that the late stage (Gl → S transition) of B cell activation is independent of Ca2+ entry. More importantly, they show that the initial events induced by anti‐μ antibody and by PMA are based on different biochemical pathways: PMA would act on a subpopulation of B cells which has already received an early signal of activation in vivo. This emphasizes the functional and biochemical heterogeneity of the G0 stage among circulating B cells.
Interleukin 1 and poly(rI) · poly(rC) induce production of a hybridoma growth factor by human fibroblasts
Authors: Van Damme Jo , Cayphas Sylvie , Opdenakker Ghislain , Billiau Alfons , Van Snick Jacques 
Published: February 2007

AbstractCultures of normal diploid fibroblasts and of a human osteosarcoma cell line (MG‐63) are shown to be able to produce a factor which promotes the growth of B cell hybridomas (hybridoma growth factor, HGF). The induction is stimulated by treatment of the cells with interleukin 1 (IL 1) (α or β) or polyriboinosinic‐polyribocytidylic acid [poly(rI) · poly(rC)]. Combined treatment with cycloheximide and actinomycin D also stimulates production and enhances production induced by IL 1 or poly(rI) · poly(rC). Extremely small doses of IL 1 (0.1 units/ml) are active as inducer of HGF. Also, under optimal conditions the yield of HGF can attain as much as 104 units/ml. Tumor necrosis factor (TNF‐α), which otherwise shares various properties with IL 1, is a weak inducer of HGF.Although there is a superficial resemblance between induction of HGF and that of interferon‐β, the two activities are serologically distinct and conditions for their induction are quite different. In fact, conditions for induction of HGF are indistinguishable from those described for the induction of the mRNA of the so‐called 26‐kDa protein (also known as interferon‐β2). Finally, the HGF derived from IL 1‐ or poly(rI) ‐ poly(rC)‐treated fibroblasts is serologically not distinguishable from that produced by mitogen‐stimulated peripheral blood leukocytes.
Glycoprotein profiles of macrophages at different stages of activation as revealed by lectin binding after electrophoretic separation
Authors: Irimura Tatsuro , North Susan M. , Nicolson Garth L. 
Published: February 2007

AbstractGlycoprotein profiles of rat macrophages (MΦ) at different stages of activation were studied by examining the reactivity of varous lectins to the glycoproteins separated by polyacrylamide gel electrophoresis. Ricinus communis agglutinin 1 (RCA1) revealed several components including glycoproteins of Mr 160 kDa and 65 kDa prominent in resident MΦ. A pokeweed mitogen (PWM) isolectin, Pa‐4, recognizes branched poly(N‐acetyllactosamine)‐type carbohydrate chains, and revealed a significant increase in glycoproteins of Mr ranging from 70 kDa to 150 kDa on thioglycolateelicited MΦ. Increased reactivity of PWM tothioglycolate‐elicited MΦ was observed by direct binding of 125I‐labeled Pa‐4 to intact or glutaraldehyde‐fixed MΦ. Histochemical staining of formaldehyde‐fixed MΦ in vitro with biotinylated Pa‐4 wasa consistent with the gel analysis, that is, resident MΦ had no reactivity while thioglycolate‐elicited MΦ showed slight reactivity. Alveolar and intratumoral MΦ bound more Pa‐4 than resident or thioglycolate‐elicited MΦ. The PWM isolectin may therefore serve as a marker for an early stage of MΦ activation.