bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of B cell surface Ia antigen recognition by T cells in B cell triggering. Analysis of the interaction of cloned helper T cells with normal B cells in differing states of activation and with B cells expressing the xid defect
Authors: Tite John P. , Kaye Jonathan , Jones Barry 
Published: February 2007

AbstractTwo discrete mechanisms of T‐B cell collaboration appear to exist. In cognate recognition, B cell triggering results from a direct recognition of antigen and MHC determinants at the B cell surface. Alternatively, B cells can be triggered by transstimulation, in which the Th cell is activated by an antigen‐presenting cell to produce soluble factors which in turn trigger the B cell. This report addresses the question of whether antigen recognition at the B cell surface in association with Ia determinants delivers a signal to the B cell, which is qualitatively different from the signals delivered by the soluble mediators released by the activated Th cell. Previous reports from a number of laboratories suggest that cognate recognition is obligatory for the triggering of small resting B cells and B cells of the Lyb‐5− phenotype, whereas enlarged B cell blasts and the Lyb‐5+ subset can be triggered solely by soluble mediators. Contrary to these findings, the experiments described here indicate that B cells isolated in different states of activation from normal spleens on the basis of their bouyant density in Percoll density gradients, or unfractionated B cells from mice differing genetically due to the xid defect [Lyb‐5− B cells from (CBA/N × BALB/c)F1 male mice], do not discriminate between the two modes of Th cell function. In both stimulation modes, the high density B cells, and the B cells from xid mice made very poor immunoglobulin secretory responses measured in terms of reverse plaque formation on protein A‐coupled erythrocytes. When the responses of different density fractions of B cells were compared under conditions where stimulation occurred either directly or indirectly via transstimulation, the following hierarchy of responsiveness in both the proliferative and plaque‐forming cell (PFC) responses was observed in the density fractions 60% > 65% > 70% > 75%. The hierarchy was the same in both modes of interaction and the deficiency of the high density, small B cells was far more marked in the PFC assay than in the proliferative assay. We conclude that the initial proliferative response of the resting B cell can be triggered comparably in vitro under conditions of direct or transstimulation. Thus, recognition of B cell surface Ia by Th cells is not obligatory for B cell activation and does not transfer an essential transmembrane signal to the B cell.
Human T cell antigens involved in cytotoxicity against allogeneic or autologous chemically modified targets. Association of the Leu 2a/T8 antigen with effector‐target cell binding and of the T3/Leu 4 antigen with triggering
Authors: Platsoucas Chris D. 
Published: February 2007

AbstractMonoclonal antibodies (mAb) recognizing human T cell differentiation antigens were employed to analyze the role of these antigens on T cell‐mediated cytotoxicity against autologous 2,4,6‐trinitrophenyl (TNP)‐modified targets. The OKT3/anti‐Leu 4 and anti‐Leu 2a/OKT8* mAb inhibited T cell‐mediated cytotoxicity against autologous or unrelated TNP‐modified targets, in the absence of complement and at the effector cell level. These cytotoxic effector cells were T3+, T8+, T11+, T4−. To analyze the role of the T3/Leu 4 and Leu 2a/T8 T cell differentiation antigens in the cytolytic process, we investigated the stages of this process that were inhibited by the OKT3/anti‐Leu 4 and anti‐Leu 2a/OKT8* mAb. Using: (a) visual adhesions, and (b) a single cell cytotoxicity assay in agarose, we observed that the OKT3 and anti‐Leu 4 mAb did not inhibit binding of effector cells to allogeneic targets or to autologous E rosette‐negative TNP‐modified targets, although they significantly inhibited both the proportions of target cells in conjugates that were lysed, and the 51Cr release. In contrast, the anti‐Leu 2a and OKT8* mAb blocked cytotoxicity by inhibiting binding of effector cells to the allogeneic or to autologous chemically modified targets. To further analyze the stages of the cytolytic process (adhesion; programming for lysis or lethal hit; and cytotoxic cell‐independent lysis) that were inhibited by these mAb, we employed the detachment and dispersion method. This method is based on the differential temperature requirements of adhesion (which occurred both at 37 °C or 20 °C) and of programming for lysis (which occurred at 37 °C but not at 20 °C). Operational adhesions were determined by the 51Cr‐release assay after dispersion of effector and target cells in a 10% solution of dextran (mol. wt. 500000). Programming for lysis was determined by the 51Cr‐release assay after detachment of effector‐target cell conjugates with 10 mM EDTA and dispersion in 10% dextran solution. Using this method we determined that mAb recognizing the Leu 2a/T8 antigen blocked cytotoxicity by inhibiting adhesion and binding of effector cells to target cells. These antibodies do not affect post‐adhesion stages of the cytolytic process. In contrast, the OKT3 and anti‐Leu 4 mAb inhibit a post‐adhesion step of the cytolytic process, that occurs before irreversible events of the programming for lysis stage have taken place.These results and other properties (lymphokine production, mitogenic properties) of the OKT3/anti‐Leu 4 mAb suggest that the T3/Leu 4 antigen may be associated with triggering of lethal hit (and triggering of T cell functions in general) and signal transfer or transduction. In contrast, the Leu 2a/T8 antigen appears to be involved in binding of effector to target cells and may contribute to the affinity of the effector cells for the target.
Purification and characterization of an antigen involved in neutrophil chemotaxis and degranulation using a monoclonal antibody
Authors: Cotter Thomas G. , Henson Peter M. 
Published: February 2007

AbstractIn a previous study we described an anti‐neutrophil monoclonal antibody, which inhibited human neutrophil chemotaxis and degranulation without any detectable effect on phagocytosis or oxidative metabolism (Cotter, T. G., Spears, P. and Henson, P. M., J. Immunol. 1981. 127: 1355). This antibody was termed NCD 1. In this study we determined the number of NCD 1‐binding sites per neutrophil. Approximately 25000 NCD 1 IgG‐binding sites per cell were found with an equilibrium dissociation constant (Kd) of 6.5 μM for antibody binding. NCD 1 Fab bound to approximately 39000 sites per cell with a Kd of 16.5 μM. Affinity chromatography columns prepared by coupling NCD 1 to Sepharose 4B beads were used to purify the antigen which bound this antibody. The antigen was a 110‐kDa glycoprotein which was not susceptible to reduction by 2‐mercaptoethanol. The antigen was not internalized following phagocytosis of opsonized sheep erythrocytes by neutrophils.
Schistosoma mansoni: escape from complement‐mediated parasiticidal mechanisms following percutaneous primary infection
Authors: Ruppel Andreas , McLaren Diane J. , Diesfeld Hans Jochen , Rother Ursula 
Published: February 2007

AbstractSchistosomula were recovered from the skin of mice following primary infections. On the surface of such “infecting schistosomula”, mouse C3 could not be detected by immunofluorescence. Subsequent incubation in vitro with fresh mouse serum led to the effective deposition of mouse C3 on schistosomula only when they were recovered within a few hours but not after one or two days following infection. In vitro deposited murine C3c was lost from i.v. injected schistosomula in the mouse circulation within one day as was human C3c. Infecting schistosomula exhibited a close to complete resistance to the lytic in vitro activity of human complement. This resistance was complete in older parasites. It existed in spite of the presence of parasite‐bound human C9, which was detectable on all developmental stages of schistosomes following incubation in fresh, but not inactivated human serum. Lung schistosomula, 3‐week and 6‐week‐old schistosomes were resistant to cellular cytotoxicity upon incubation with fresh human serum and rat peritoneal exudate cells although cell adherence mediated by human C3b was demonstrated with lung worms. The data suggest that schistosomula may evade in vivo the lytic activity of complement and also complement‐mediated cellular cytotoxicity. Depending on the species of serum, this can be demonstrated in vitro by lack of opsonization or by resistance to lytic and cellular attack mechanisms.
Preservation of the helper and suppressor/cytotoxic T‐lymphocyte phenotype in continuous culture
Authors: Gramatzki Martin , Baum Wolfgang , Burmester Gerd R. , Kalden Joachim R. 
Published: February 2007

AbstractThe objective of the present investigation was to culture helper or suppressor/cytotoxic T cell subsets after extensive purification in interleukin 2‐containing medium to determine whether phenotype changes for OKT4/91d6‐ or OKT8/Leu‐2a‐defined antigens do occur with prolonged culture. Repeated and sequential analysis of such polyclonally activated cultured T cells documented stability of the OKT4/91d6+ and OKT8/Leu‐2a+ phenotype. Both populations could be considerably expanded in culture. However, mixing experiments revealed a growth advantage of the OKT8/Leu‐2a+ subset. A significant number of cells expressing both phenotypic markers was not detectable. While cultured T cells promoted on interleukin 2 were stable for expression of these functionally important differentiation markers, additional studies on activation antigens revealed high numbers of Tac+ cells at an early time of culture and decreasing numbers during further incubation. The expression of Tac antigen preceded the exponential expansion of the culture. In contrast, the number of cells bearing Ia determinants steadily increased with prolonged culture.
Self‐ and allo‐specific suppressor T cells evoked by intravenous injection of F protein
Authors: Lukic Miodrag L. , Avrion Mitchison N. 
Published: February 2007

AbstractThe liver/serum protein F appears to inactivate clones reactive towards itself in the T helper cell but not the B cell compartment. To examine the extent of self‐reactivity in the T suppressor cell compartment, the well‐established procedure of i.v. injecting milligram doses of the protein was used. To detect suppression, an entirely in vitro proliferation assay was devised, based on use of immunopurified F antigen. In this way T suppressor cells could be detected after activation either by allogeneic F, or (though to a lesser extent) by self‐F protein. Thus the T suppressor cell compartment contains potentially self‐reactive clones, and to that extent the receptor repertoire of T suppressor cells overlaps with B rather than T helper cells.
Production of IgE‐potentiating factor in man by T cell lines bearing Fc receptors for IgE
Authors: Young Michael C. , Leung Donald Y. M. , Geha Raif S. 
Published: February 2007

AbstractThe regulation of human IgE production in vitro by soluble T cell factors was examined. T cells were isolated from the peripheral blood of 2 patients with the hyper‐IgE syndrome on the basis of their expression of Fc receptors for human IgE (FcϵR). The T cells were incubated with human myeloma IgE (10 μg/ml), washed, reacted with immunosorbent‐purified goat anti‐human IgE conjugated with fluorescein isothiocyanate, and then separated into FcϵR and FcϵR− T cells on the fluorescence‐activated cell sorter. FcϵR T cells and FcϵR− T cells were propagated in culture using supernatants of phytohemagglutinin‐stimulated peripheral blood mononuclear cells (PBMC) and irradiated autologous PBMC. Supernatants of FcϵR T cell lines but not of FcϵR− T cell lines selectively enhanced IgE synthesis in cultures of B cells obtained from patients with allergic rhinitis but not from normal nonallergic subjects. The surface phenotype of the FcϵR T cell line was predominantly T3−, T4, Ia with few (15%) T8 cells. Two T cell clones were grown from the FcϵR− T cell line by limiting dilution (0.3 cells/well). These clones possessed the T4− helper/inducer phenotype and secreted IgE‐enhancing factor(s). The IgE‐enhancing factor(s) which had affinity for insolubilized human IgE was sensitive to treatment with trypsin and neuraminidase, and had as its target an IgE‐bearing B cell. These results suggest that a subset of human T cells bearing an FcϵR secretes an IgE‐binding glycoprotein which selectively enhances IgE synthesis by IgE‐bearing B cells.
T cell clones interacting with accessory and T helper cells for a proliferative response
Authors: di Pauli Raimund , Brückner Thomas 
Published: February 2007

AbstractThe requirement for cell interactions in T cell activation has been studied with two continuously in vitro growing T cell clones. These clones are specific for minor histocompatibility antigens, are H‐2K restricted, and one clone is functionally a cytolytic T lymphocyte. Both can proliferate when interleukin 2 is added to the cultures, but for continuous growth they require irradiated spleen cells carrying the specific minor histocompatibility antigen and the restricting H‐2.In this study we show that for proliferation the clones require at least two cell populations in the stimulator spleen, one is a splenic‐adherent cell (SAC), the other a T cell. The SAC are plastic adherent, Thy‐1−, Ia. The T cells are nylon wool nonadherent, Thy‐1, Lyt‐12− and Ia−. Cell mixing experiments of stimulator cells (all were done with H‐2‐syngeneic cells), depleted of either SAC or T cells confirm the requirement for a specific interaction between these two cell types and the T clone. Neither SAC, syngeneic with the T clone when mixed with T cells of the stimulator type, nor T cells syngeneic with the clone added to stimulator SAC, can induce an optimal proliferative response. Such a response is obtained only if both cell types, SAC and T cells, are of the stimulating genotype. This suggests that, in addition to an interaction of clonal T cells with SAC, a specific recognition at the T cell level between T stimulator and T clone is necessary.The interaction of the T clones with stimulator SAC and T cells leads to an activation, mediated by antigen recognition, of all three cell populations. Since we also show that each of the stimulator cell types are impaired by ultraviolet light irradiation, we conclude that factor production by SAC and T helpers is the final prerequisite for clonal expansion.
The immunoglobulin heavy chain variable region (Igh‐V) locus in the mouse. I. One hundred Igh‐V genes comprise seven families of homologous genes
Authors: Brodeur Peter H. , Riblet Roy 
Published: February 2007

AbstractSeven families of Igh‐V genes have been defined by Southern blot analysis of genomic DNA from eighteen inbred strains of mice. Each of twenty‐four cloned Vh genes hybridized to one of seven nonoverlapping sets of Eco RI restriction fragments. These families contain from 2 to ∼40 hybridizing fragments. From these data we estimate that the mouse Igh‐V locus consists of one hundred Vh genes. Genes within a Vh family share >80% sequence homology while the sequence homology between families is generally <70%. There is extensive restriction fragment length polymorphism among the strains analyzed allowing the assignment of complete (Igh‐V + Igh‐C) Igh haplotypes for eighteen inbred mouse strains.
Protection of mice against the intracellular bacterium Listeria monocytogenes by recombinant immune interferon
Authors: Kiderlen Albrecht F. , Kaufmann Stefan H. E. , Lohmann‐Matthes Marie‐Luise 
Published: February 2007

AbstractImmune interferon, available at high specific activity through recombinant DNA technology, is known to activate macrophages to intra‐ and extracellular cytotoxicity. We now report that murine recombinant IFN‐γ activates macrophages to cytotoxicity also when applied in vivo. Furthermore, recombinant IFN‐γ can protect mice in vivo against the intracellular bacterial pathogen Listeria monocytogenes in a local as well as in a systemic infection model. The role of T lymphocyte‐produced lymphokines in acquired resistance to facultative intracellular pathogens and their possible involvement in novel immunotherapy are discussed.
Thymocytes appear to ignore class I major histocompatibility complex antigens expressed on thymus epithelial cells
Authors: von Boehmer Harald , Schubiger Katrin 
Published: February 2007

AbstractBALB/c nu/nu mice were grafted with embryonic 14‐day‐old C57BL/6 thymi which were transplanted either nontreated or after elimination of hemopoietic cells with 2‐deoxyguanosine. In both types of grafts host cells developed normally into functional thymocytes. Thymocytes from 2‐deoxyguanosine‐treated but not from untreated grafts contained as many cytolytic T lymphocyte precursors specific for class I MHC antigens on thymus epithelium as normal BALB/c thymocytes. As cytolytic T lymphocyte precursors were neither suppressed nor activated in these grafts it is concluded that thymocytes ignore class I MHC antigens expressed on thymus epithelium.
Frequent coexpression of cytolytic activity and lymphokine production among human T lymphocytes. Production of B cell growth factor and interleukin 2 by T8+ and T4+ cytolytic clones
Authors: Mingari Maria Cristina , Moretta Alessandro , Maggi Enrico , Pantaleo Giuseppe , Gerosa Franca , Romagnani Sergio , Moretta Lorenzo 
Published: February 2007

AbstractThese studies were designed to determine the degree of overlapping between cytolytic function and lymphokine production among peripheral blood human T lymphocytes. T8+ and T4+ cells were obtained by sorting purified T cells using the fluorescence‐activated cell sorter (FACS) and cloned at 0.25 cells/well in a microculture system that allows clonal growth of every T cell. 49/49 T8+ clones but only 5/102 T4+ clones displayed cytolytic activity, as assessed by a lectin‐dependent assay. Cytolytic clones were further analyzed for their ability to release interleukin 2 (IL 2) and B cell growth factor(s) (BCGF) upon 24 h stimulation with phytohemagglutinin. Fifteen percent and 18% of T8+ cytolytic clones were producing IL2 and BCGF, respectively; in addition 3 out of 5 T4+ cytolytic clones released both lymphokines. Although the majority of cytolytic clones producing IL2 were also producing BCGF, 5 clones released either BCGF or IL2. The present studies indicate that the coexpression of cytolytic and helper/inducer functions is relatively common among peripheral blood T lymphocytes, irrespective of their T8+ or T4+ phenotype.
B cell activation potential of insulin‐reactive T cells in H‐2b mice
Authors: Huber Brigitte T. , Hochman Paula S. 
Published: February 2007

AbstractThe murine T cell response to heterologous insulins provides a good model system for studying the mechanism of immune response (Ir)‐gene function, since insulin is a small, chemically well‐defined molecule. H‐2b mice respond predominantly to A chain loop determinants of beef insulin, presented by the I‐A epitope Ia.W39. However, using a library of insulin‐specific T cell hybridomas (THy), we previously found that immunization of H‐2b mice with beef insulin activates a much wider population of T cells than are detected in T cell proliferation assays. Using such cloned THy we were able to study Ir‐gene control at the level of antigen presentation. We compared the ability of the various THy to induce differentiation in I‐A‐matched B cells in response to antigen. Although both A and B chain‐reactive clones respond with interleukin 2 production, they differ markedly in their potential to activate B cells in that only the former are able to induce B cell differentiation in the presence of the intact beef insulin molecule. The latter, however, can serve as helper cells in the presence of isolated B chain, and can synergize with a suboptimal concentration of A chain‐reactive THy to induce an optimal B cell response. These results suggest that the insulin molecule is presented by I‐Ab antigen‐presenting cells in a very specific configuration that allows more effective T cell recognition of the A chain loop than the B chain determinants.To explain the discrepancy between the interleukin 2 assay and the induction of polyclonal activation, it can be assumed that in the former assay antigen is presented by macrophages, while presentation by B cells is necessary for induction of polyclonal activation. Macrophages are able to process the intact beef insulin molecule and, therefore, present B chain determinants, while nonimmune B cells may be unable to process antigen and could present B chain determinants only when the isolated B chain is given as antigen.
Mouse monoclonal antibodies against the idiotype of human B cell non‐Hodgkin lymphomas: production, characterization and use to monitor the progress of disease
Authors: Rankin Elaine M. , Hekman Annemarie 
Published: February 2007

AbstractFour monoclonal anti‐idiotype (Id) antibodies against B cell non‐Hodgkin lymphomas have been made by a simple and rapid procedure for hybridoma production that does not use isolated Id‐carrying immunoglobulin. Mice were immunized with plasma membranes from the tumor cells. Screening of hybridoma colonies using an autologous T cell line and a cell line bearing the same immunoglobulins as the malignant lymphocytes as well as the capping phenomenon on the patient's own tumor cells, allowed selection of hybridomas producing anti‐Id antibodies. These anti‐Id antibodies were used to demonstrate variations in the circulating malignant cell population and fluctuations in the level of circulating free Id.
Detection and localization by the monoclonal antiinterleukin 2 receptor antibody AMT‐13 of IL 2 receptor‐bearing cells in the developing thymus of the mouse embryo and in the thymus of cortisone‐treated mice
Authors: Takacs Laszlo , Osawa Hisao , Diamantstein Tibor 
Published: February 2007

AbstractDuring embryonic development of the mouse, before expressing classical T cell markers, the blast cells colonizing the thymus react with the monoclonal antibody AMT‐13 shown previously to detect interleukin 2 receptors. The proportion of AMT‐13+ cells decreases as gestation time increases. On the other hand, the proportion of Thy‐1+, Lyt‐1+ and Lyt‐2+ cells increases during ontogenesis. On the 19th day of gestation when the thymus architecture is comparable to the adult thymus, the AMT‐13+ cells become localized in the subcapsular area of the cortex. In the adult thymus after cortison treatment the regenerating cells express the AMT‐13 antigen. The AMT‐13 antigen presumably the interleukin 2 receptor is the first marker of the early embryonic thymocytes reported until now that may be related to cellular function.
Human monocyte heterogeneity: Interleukin 1 and prostaglandin E2 production by separate subsets
Authors: Khansari Nemat , Chou Yvan K. , Fudenberg H. Hugh 
Published: February 2007

AbstractHuman peripheral blood monocytes were separated into four different subpopula‐tions by means of a discontinuous bovine serum albumin gradient. Of the least dense population, 7% were present in fraction A, 11% in fraction B, 28% in fraction C and of the most dense, 34% were in fraction D. The rest (17%) of the recovered cells sedimented as a pellet, of which 95% were dead. The monocytes of fraction D (ϱ = ⩾ 1.075 kg/l) were major interleukin 1 (IL1) producers and their presence enhanced immunoglobulin synthesis in vitro. Fraction C (ϱ = ⩾ 1.070 kg/l) were the major prostaglandin E2 (PGE2) producers and demonstrated suppressor activity on in vitro IgG and IgM synthesis. Fractions A and B had minimal production of either IL1 or PGE2 and lesser effects on the IgG and IgM synthesis. These data demonstrate functional heterogeneity of peripheral blood monocytes with respect to production of both IL1 and PGE2 as well as accessory cells for immunoglobulin synthesis.